Carrida Camera Program User Documentation

Revision: 4.5.0
Date: 2020-08-31
Contact: support@carrida-technologies.com
Copyright: 2017-2020 Carrida Technologies GmbH, Ettlingen, German
Author: Carrida Technologies

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Table of Contents

1   Introduction

Carrida is a software library for Automated License Plate Recognition (ALPR) in images. The Carrida Camera combines an imaging and processing device with the Carrida 4 software engine, resulting in a smart and compact license plate reading sensor.

The camera offers a set of flexible IO protocols for communication with the outside world so that almost all requirements of applications can be covered with the built in features already available.


Typical applications of the Carrida Camera include:

  • Parking lot management
  • Vehicle ticketing and vehicle management
  • Automatic barrier opening
  • Vehicle counting
  • Law enforcement applications
  • Traffic planning (count vehicles, map traffic to geographic regions)
  • Traffic flow monitoring

Carrida offers the following features and benefits:

  • Easy to configure
  • Support for State/Country recognition
  • Supports license plates with two rows
  • Supports license plates with stacked characters
  • Robust against illumination, contrast, noise, and rotation

Note

Note Sign

For details on the Carrida camera, see Carrida Cam Basic+ Information.

1.1   Secure communication with the Carrida Camera

From Carrida Version 4.5.0 on, secure encrypted communication with the camera is possible using the https protocol and a specialized version of Carrida. This feature enables encryption of all communication for log in, data transfers with the user interface (including login) and all REST API calls.


A list of abbreviations used throughout this document

ALPR
Automatic License Plate Reader.
ARM64
Stands for processors with the v8 AARCH 64-bit instruction set.
ARM
Stands for processors with the v7 ARM 32-bit instruction set.
dB
Decibel, used to describe a relative sensitivity (gain) value in cameras.
fps
Frames per second.
FOV
Field of view.
HW
Hardware.
LP
License Plate.
mA
Milli-Ampere, one 1/1000 th of an ampere.
ms
Millisecond, one 1/1000 th of a second.
PC
Personal Computer.
PK
Product Key (for software licensing).
px
Pixel. The smallest unit of resolution in an image. For example, VGA images are made up of 640x480 pixels.
ROI
Region of Interest, typically a marked area in an image.
SDK
Software Development Kit.
SW
Software.
x86
Stands for Processor Architectures with the Intel instruction set. 32-bit hardware.
x86_64
Stands for Processor Architectures with the Intel instruction set. 64-bit hardware.
VC
Vision Components GmbH.
OSD
On-screen display

Image symbols used in this document

Symbol Meaning
Note Sign Points to especially important aspects of the manual or the software.
Hint Sign The lightbulb highlights the hints and the ideas that may be helpful.
Warning Sign This warning sign alerts of possible pitfalls to avoid. Please pay careful attention to sections marked with this sign.

The Carrida Camera user interface uses the following symbols and icons

Symbol Description
1q

Add button

add single entries, new actions or new servers to the already existing ones.
2q

Add user button

add new User profiles.
3q

Apply changes button

apply changes.
4q

Export as csv:

export the text result table as csv.
5q

Export as excel

export the text result table as an excel table.
6q

Export images

export images for filtered results of the text result table.
7q

Upload button

upload (import) certain files (ex.: result images, classifiers, single list entries or entire lists as .txt files).
8q

Download button

download (export) certain files (ex.: entire lists as .txt files).
9q

Cancel button

cancel editing and to stash the changes.
10q

Edit button

edit some settings in the configuration menu.
11q

Delete button

delete all entries in a list.
12q

Filter button

filter the results from the Text results menu by date, time, plate and/or state confidence.
13q

Full-screen button

stream the video from Live view in full-screen mode.
14q

Info button

display additional information
15q

Left button

move left
16q

Right button

move right
17q

Remove button

remove a single entry (ex.: when manually adding list entries, a single defined period of time can be removed this way).
18q

Reload/ Sync button

it is used in:

  • Text results to reload the page and show the newest results.
  • To synchronize the Brightness ROI with the ALPR ROI.

2   Quick start with the Carrida Camera

2.1   Connect and Login

The Section provides a quick overview of basic features of the Carrida camera and how it is setup and used.

The first step involves the connection of the power and the LAN cable to the camera. About a minute after connecting the camera to a power supply it is ready to be used.

Note

Note Sign The default IP-address of the camera is 192.168.3.15. It is necessary that you configure your PC to use a local network address 192.168.3.xx temporarily so that it can see and access the camera.

Once the camera is connected to your local network, it can be accessed by using a web browser. Enter the IP address of the camera in the address bar of your browser (i.e. Chrome, Firefox, Opera, Safari) to get to the login page.

Alternatively, by using the Carrida discovery tool (see Carrida Camera Discovery) you can find all cameras which are active in your local network. The software allows you to open any discovered device with the click of a button.


For the next step, a username and a password are required to sign in. The Carrida User Interface offers five different user profiles respective privilege levels: super user, administrative, basic user, setup and viewer.

The main difference between these profiles is the level of access to configuration and system settings of the camera. The factory Login credentials for those users levels are as follows:

Administrator Basic User Setup Viewer SuperUser

username: admin

password: secret

username: user

password: simple

username: setup

password: setup

username: viewer

password: pass

username: su

password: car0000rida

Access to all settings. Has the authority to add, delete and edit other users. Access to the most commonly used settings. Access to view live image streaming and reading results. Has the authority to change the ROI and classifier settings. Access to view live image streaming and reading results. No authority to change any parameters. Access to all settings, deleting admin users and access to UI Design setting.

To switch between User modes, click on the User button in the upper right corner of the interface.

tt

Note

Note Sign Administrators have access to all camera, system and configuration settings. We recommend not to change configuration settings which are only visible in the administrator mode unless absolutely necessary.

Note

Note Sign

All graphical images in the remaining parts of the manual will display the interface in admin mode.

2.2   Camera User Interface Language

To switch between different languages, click on the languages button in the upper right corner of the interface. Five different languages (English, French, German, Russian and Dutch) are offered at the moment.

lc

2.3   Essential Camera Configuration

Although the Carrida camera can work well with default parameters, a few settings have to be adjusted before proper operation can begin. Most important, the region(s) of interest for reading and brightness control need to be setup.

ROI, short for Region of Interest, refers to the area in which some processing is done. There are two different types of ROIs used by the Carrida Camera:

  • The ALPR detection ROI to define where license plates are to be detected. The ALPR detection ROI is drawn as a yellow polygon.
  • The ALPR brightness control ROI defines which area is used to to adjust the brightness of the video stream. The ALPR brightness control ROI is drawn as a green polygon. Typically the ALPR ROI and the brightness control are more or less identical.

Both ROI for brightness control and ROI for ALPR detection can be defined in the Settings page, see Sections ALPR Region of Interest and Brightness Control Region of this manual for further details.

The OSD on the Live result page continuously displays a live image stream, the yellow polygon represents the currently defined ALPR ROI.

t1


The definition of the brightness control area is done in the Settings page of the camera. The green polygon represents the Brightness control ROI in the live screen of the settings page. The Brightness control settings are only applied to the area inside this polygon.

It is recommended to limit the brightness control ROI to the area where the vehicles might move through the image. Typically this corresponds to the ALPR ROI.

t2

Hint

Hint Sign

Resize the polygons by clicking on any of the highlighted corners and drag it to the desired position. When finished resizing, click on the Apply button.

The ALPR detection ROI should be larger than and enclose the brightness control ROI, in order to achieve best performance.

2.4   Display results

Two pages in the camera interface are dedicated to display reading results:

  • The Live result page displays live images with reading results and updates the latest results in a compact table view.
  • The Text result page displays the results in a tabular form. Clicking on a list entry opens the associated image which can also be downloaded. It is also possible to export the entire list as a CSV or an XLS document. The result list can be limited to a certain amount of entries and/or have a time limitation. When one of those criteria is met, the oldest entries will be removed from the list.

The camera can optionally display the following information over a live image, configurable for each element:

  • state of vehicle registration,
  • state recognition confidence,
  • vehicle number plate,
  • number plate recognition confidence,
  • character recognition confidence.
./images/Image08.png

Processed image with an overlaid reading result.

In the example image above, AT stands for the state in which the vehicle is registered, and it is recognized with 68% confidence. W _ _ 4 3 3 is the vehicle number plate, recognized with 100% confidence. The recognition confidence for each character of the license plate is also displayed in the example above, it is 100% for each character.

2.5   The Carrida Camera User Interface

The Carrida 4 camera user interface gives you access to all features which the Carrida camera supports. The camera software is based on modern web technologies so that you can use a standard web browser on a PC, tablet, or phone to access the camera. The following Sections describe all features of the Carrida camera and how to properly configure them.

By using the Carrida discovery tool (see Carrida Camera Discovery) you can find all cameras which are active in your local network. The software allows you to open any discovered device with the click of a button.

3   The Carrida Home Screen

3.1   Logging into the camera

Before the camera can be accessed and configured in a web browser, you have to provide your credentials by logging into the device. The Carrida user interface offers several levels of access control with different sets of permissions. Only the super user and administrator is allowed to modify all settings and parameters of the camera, basic users are only allowed to modify certain or even no configuration settings in the camera.


./images/1_login.png

The username and password you for logging into the camera are typically provided by the administrator of the camera(s), but a set of default users is stored in the camera. The factory login credentials for the default users are as follows:

Administrator Basic User Setup Viewer SuperUser

username: admin

password: secret

username: user

password: simple

username: setup

password: setup

username: viewer

password: pass

username: su

password: car0000rida

Access to all settings. Has the authority to add, delete and edit other users. Access to the most commonly used settings. Access to view live image streaming and reading results. Has the authority to change the ROI and classifier settings. Access to view live image streaming and reading results. No authority to change any parameters. Access to all settings, deleting admin users and access to UI Design setting.

Note

Note Sign We strongly recommend to change the default passwords for the user accounts before or during the installation of a new camera.

Submitting a valid username and password opens the homepage of the camera. From here you can choose the menu pages to monitor the camera operation or change its configuration and manage access lists.

The Camera Information Section of the home page upper half displays a compact overview of the current software versions and classifier currently used by the camera. Classifiers contain pre-trained data sets, which are used to enable the recognition of characters and symbols for a specific country. They contain information about plate specific details like font styles, plate dimensions and valid text patterns. For details see Section Classifier.

By clicking on the icons in the dialog area Navigation in the lower half of the home page, you can quickly access connected configuration pages. Hovering the mouse pointer over an icon displays short description of the associated functionality.

./images/1_home.png

Note

Note Sign When TCP is enabled, the camera will have a dynamic IP address. The Camera ClientTool can be used to detect and configure the cameras in the network. More information on how to use the ClientTool can be found in Carrida CameraTool .

3.2   The User Menu

Located in the upper right corner of the homepage is the User menu which allows you to easily switch between user profiles. For example, you can switch between a regular user and an administrator here.

./images/0_logoutbutton.png

3.3   Language Settings

With the languages button, Located in the upper right corner, you can select one of five languages currently supported by the camera web interface. The default language of the interface is English. In addition, the camera offers:

  • Dutch
  • French
  • German
  • Russian

as translations. Future releases will add more languages to the interface.

./images/0_language_change.png

4   Live Result Page

The main purpose of the Live Result page is to verify the camera operation and configuration settings in real-time once the camera is setup and running.

4.1   Live Image

To provide all essential information, a live image stream from the camera is displayed together with current reading results. The live image shows you the selected ALPR ROI as well as detection results with confidences. If the display of additional information has been selected in the Settings menu (like date and time), it will also be displayed as OSD in the live image.

The details of how to configure the OSD can be found in Section Display Information.

It is possible to display the video stream in full-screen mode by clicking on the green button in the lower, right corner of the live image. You can leave the full-screen mode by pressing the ESC (escape) key.

The yellow polygon overlaying the image represents the region of interest (ROI) within which the camera reads the license plates. The camera will only process license plates that are detected inside of this area. You can add and define the positions of up to 5 regions of arbitrary shape in the image. The polygons can be added and/or adjusted on the Settings page, under the Engine tab (see Engine).

./images/2_liveresult.png

4.2   Overview Text Results

In addition to the video stream of the camera, the latest reading results are listed in the table on the right side of the Live result Page. If a new reading has been made by the camera, the result table is updated. A new reading is signaled with an animated green bar underneath the new entry. Note that This animation can be turned on/off in the Settings page.

./images/live_result_table.png

5   Text Result Page

The Text Result page allows you to view all reading results of the camera in a table view. Note that the configuration at the bottom of the table must be set so that the storage of table results is allowed respective possible (see below).

The number of entries in the result and log tables is unlimited for all practical purposes. They can contain thousands of entries, if necessary.

./images/3_textresult_tabs.png

There are three different events that the results are listed for: Accepted Results, Wrong Direction Results and the NoRead Events Log:

Accepted Results
Lists all the plates that were detected in an LPR ROI and which were moving in the right direction.
Wrong Direction Results
Lists all the plates that were detected, but were moving in the wrong direction.
NoRead Events Log
Logs all the NoRead events since the server started.

The number of results that are stored on the camera is configurable through the History List Length (max 10000 entries), and the History Hour (max 10000 hours) input fields at the bottom of the page. When either the defined time limit or the maximum number of stored results has been reached, the oldest results are discarded and overwritten.

Note

Note Sign History List Length and History hour are, by default, set to 0.

5.1   Reading Results

The result tables for the Accepted Results and the Wrong Direction Results are identical and consist of:

  • A Timestamp with the date and the time when the plate was detected.
  • The License plate text.
  • The Confidence for the given license plate recognition.
  • The detected Country of the vehicle license plate.
  • The Confidence for country recognition.

r1

5.2   NoRead Events Log

The table of results for the NoRead Events Log consists of:

  • A Timestamp with the date and the time when the plate was detected.
  • An Action that was performed.
  • The Status of the action aka whether the action was performed successfully or not.

r2

5.3   Refreshing the Text Results

The result table is generated when the Text Result page is opened, it is not automatically updated. Since the camera reads in the background new entries may be created while you watch the text results.

To update the table with the latest results, click on the blue Reload button on the right side below the table.

./images/text_result_pages_logos.png

5.4   How to browse the text result table

The result tables potentially contains thousands of entries which cannot be displayed at once. If necessary the results are therefore separated into pages which can be individually loaded from the camera. You can navigate through the pages using the buttons below the result table:

  • Click on the Previous or Next button to switch page page.
  • Directly jump to a page of the text results table by clicking the page number box.
  • Type a page number into the GoTo Page field and click the right arrow.

trnb

5.5   Searching a table

To get the most out of the result tables,they are fully searchable and can be queried for any given piece of information like plate number, date or time.

The simplest method is to type the text you are looking for (e.g. the license plate string, or only a part of it, or a number) into the search field in the right upper corner of the page. You can search for multiple strings by separating them with a blank character in the search field. In this case, all of the strings must be contained in a reading result.

./images/3_textresult_search.png

For example, if you type are looking for text results which contain the text element BR and the number 80, type 'BR 80' into the search field like shown below. The '80' would be searched for in license plate strings as well as confidence values since it is interpreted as text element.

./images/BR_80_search.png

Note

Note Sign

All numbers in the result table are considered to be text for the purpose of the search function.


The search results from above can be further refined by restricting them to a

  • Date range
  • Time range
  • Plate confidence
  • State confidence

The filter option dialog opens by clicking on the Filter button above the Search field. If you provide only one of the parameters in the parameter field, e.g. only the starting date or the lower confidence value, the opposite parameter is set to a value that maximizes the search range.

./images/3_textresult_filter.png

The following example below shows how you combine the the text search field and the parameter filter options to look for license plates

  • which contain the string 'BAC3',
  • which have been detected between the 26th and the 27th of November 2019,
  • between 8 am and 8 pm,
  • with a minimum confidence of 80
./images/3_textresults_filteredsearch.png

5.6   Deleting Individual Entries

Individual entries of the text result table, filtered or unfiltered, may be deleted by selecting the row and then pressing the red trashcan icon beneath the table.

./images/text_result_pages_logos.png

5.7   Exporting a result table

The content of (a potentially filtered) text result from the table Accepted Results or Wrong Detection Results can be exported from the camera in several different formats. By clicking on one of the three blue/white buttons on the top left side above the text result list, you can choose to export as:

  • CSV (comma separated value) file.
  • XLS file readable by Excel.
  • ZIP archive which contains all images. The naming format of the images is fixed as <timestamp_platestring_confidence_state_confidence.jpg>

The export buttons are shown below, from left to right the buttons are used for export to CSV, XLS or ZIP file.

./images/3_textresult_export.png

The exported files are stored locally on your PC in the location which your browser has defined as download location.

Do not forget to update the table with the refresh button prior to export.

5.8   Images linked to text results

The right side of the Text Result page is reserved for images related to text result entries. To display an image related to a reading result, click on the desired entry in the table.

Individual images can be downloaded by clicking on the Download button above the image.

Right below the image actions and their result states which are connected to this image are listed. This provides useful information about which concrete action was defined for this reading result, in which ROI area it occurred, and also if the action has been successfully performed.

./images/3_textresult_download.png

6   ACCESS Configuration Page

The ACCESS configuration page of the Carrida camera provides the tools to define what the camera has to do when a license plate has been detected. For example, an action could send the image and license plate string to an ftp server when its string has been matched with an entry from the Blacklist.

It is useful to understand the following terms used by Carrida:

Events

are triggered when some pre-configured state change within the camera happens. This can be a reading of a new license plate (LP), not detecting a LP within an externally triggered and timed reading operation, a LP moving in the wrong direction, or a LP with low confidence.

Events can trigger actions - this is the basic mechanism used by the camera to do something when a LP has been (or has NOT been) detected.*

Events may also be tied to a LP string, which is matched in one of the three lists maintained by the camera. E.g. a new LP may be matched in the Whitelist and subsequently trigger some action.

Lists

provide the means to define which license plates can trigger actions. The three list categories Whitelist, Blacklist and Ignorelist can each have their own associated actions triggered.

The three lists maintained be the camera may be used for arbitrary purposes, they have assigned names for convenience only.

Actions

tell the camera what to do when a specific event happens. Actions can either be triggered by general events, e.g. the detection of a new license plate, by specific events related to lists, or they can be related to external trigger lines.

Actions allow the user to make full use of the I/O capabilities of the camera, including the network interface, I/O lines and the internal flash storage.

In the general case, any actions may be performed whenever a license plate is being read (Read Action) or NOT being read (NoRead) within a timeout defined by a triggered read. These actions are not related to lists.

In order to trigger actions only for specific license plates, Whitelist match/mismatch, Blacklist match/mismatch and Ignorelist match/ mismatch events may be used to trigger actions. In this case, the action will only be executed when a LP text from the list is detected (match) or when a plate is detected but is not found in the list (mismatch).


The ACCESS configuration page provides two tabs Actions and Lists, which are used in conjunction to set up the camera as needed:

./images/5_actions.png

Access control configuration page.


Carrida supports four types of events, which may trigger actions:

Read Events
Events are considered to be Read events when the camera reads any license plate.
NoRead events

occur when NO plates are detected when the camera is configured to be externally triggered. For example, if Start and Trigger timeout is defined and no valid plates are detected within the timeout period, the camera will perform a NoRead action if one is defined. Triggers are explained in detail in Section Trigger.

NoRead events can be produced periodically in the Free_run Trigger Mode. For any time interval defined by NoRead Event Interval (s) without any plate readings, any defined Noread action will be executed.

Wrong Direction read events
occur when a license plate is detected, but not moving in a valid direction. The areas and associated direction ranges can be defined in the ALPR ROI editing page, see Section ALPR Region Of Interest.
Low confidence read (LCR) events
a Low confidence read event is created when the plate is read, but the confidence level of the reading is lower than set in the parameter Limit of Low Confidence. This type of event can be used to collect low-quality readings for further analysis.

6.1   ACCESS lists

The three access lists available on the camera allow you to sort license plates in three different categories. The lists may be used for arbitrary purposes, they have assigned names for convenience only.

The three types of Access Lists on the Carrida camera are:

  • Whitelist
  • Blacklist
  • Ignorelist
./images/4_listcat.png

The Access List page.

The lists may contain an arbitrary number of license plate texts. They may be edited manually through the camera's user interface, they may be imported from your PC, or they may be updated through the REST API of the camera.

Every time the camera reads a new license plate, it compares its string with all of the entries stored in each of the lists. If an entry matches, a previously defined action, if specified, is performed. Likewise, if the newly found license plate does not match and an action is defined for that case, that action will be performed.

Assume for example, that a license plate 'B 12345' is read by the camera. Next this text is compared with all list entries. If it matches with one of the entries of any of the three lists, the camera checks to see if any action has been defined for this list. If, for example, an ftp action has been defined, it will be performed with the actual LP data as obtained from the reading.

The figure below shows the list Sub-menu. You can switch between the three lists by clicking on the '<', '>' icons left and right,

./images/access_cursor.png

or by directly clicking one of the three dots at the bottom, which represent the three lists:

./images/access_dots.png

An arbitrary number of actions may be defined and performed by the camera, but consider that network transfers and store operations may consume a significant amount of CPU time on the camera and may slow down its operation.

6.2   Additional lists properties

License plate entries may either be defined as full strings, or as patterns which are called regular expressions. In the latter case, you can define in a simple and very flexible way a text pattern, which describes a whole set of strings. For example, you can easily write a regular expression to match all license plates which start with the character 'B'.

Regular expressions are explained in detail in Section Regular Expressions below.

A list entry contains at least the plate number, but it can optionally contain a date- and time range as well. Only text matches within the defined date and/or time range will then be accepted as valid. Several date- and time ranges per license plate are allowed.

The camera checks once per hours if any of the lists contains an expired license plate text, and deletes any outdated entries. This is to make sure that lists cannot grow indefinitely. For example, if the license plate entry 'B1234A' is in the Whitelist and it has a date of validity 12-May-2020 8:00 am-14:00 pm attached, it is considered only on this day. It will automatically be deleted from the Whitelist ca. at 15:00 pm on this day.

As mentioned above, there are several ways to create or update the lists with new entries:

A new list entry can either be created directly in the dialog window in the camera interface or one or more list entries can be imported as text files from the PC. The latter method is more efficient if a large number of license plate entries has to be created, or if an external database of license plate entries (e.g. employees of a company) already exists and needs to be moved over to the camera. Both methods for access list update are described in the following sections.

6.3   Manual creation of a list entry

A new list entry can be directly created using a dialog in the camera's interface. Click on the green '+' button in the lower right corner of the Lists page to open the Add List Entry dialog, which is shown below.

ls

The first entry in the dialog box is the license plate text. Turn the Regex switch to the right of the plate entry to ON, if it shall be interpreted as regular expression.

When Always enabled is turned ON, a match will not be restricted to a specific time or date range. When Always enabled is turned OFF, time and date limits apply. These can be defined through the date and time fields below. The time window can be defined through the start and end date, start and end time, and on individual days of the week, which are marked as So, Mo, Tu, We, Th, Fr, Sa.

A new list entry is pre-set with a time range from 00:00 to 23:59 (the whole day), and Monday to Friday, for a month from the current date.

In the example on the dialog shown above, Monday-Friday is checked, meaning that if an LP is detected on any working day between the set dates, any defined action will be triggered.

After finishing the list entry details, click on Add (the green plus button) to add the time/date details to this plate text.

Another date/time range may be added, or by clicking the Save button (the green/white right arrow), the new plate entry is added to the list, and the dialog is being closed.


White Spaces and List Entries
Depending on whether Carrida is configured to evaluate and use white spaces (see Section Whitespace Matching), the text field used to manually enter the license plate accepts a blank character ' ',or not.

Note

Note Sign Each plate can have multiple date/time windows attached (e.g. Monday 8-12 am and Wednesday 2-5 pm). Use the Add button to attach a new time/date definition to the plate. After all the definitions have been made, press the Save button to store the entry for this license plate in the access list.

6.4   Import of list files into the camera

If a larger number of license plates needs to be imported into one of the access lists of the camera, the import of a text file with license plate data and associated date/time range definitions may be more efficient.

For this purpose Carrida provides an import dialog which allows you to upload and check a properly formatted text file. The following image shows this import dialog:

2s

The imported text file must to be formatted according to the rules described in the next Section below. To import it to the camera, the following steps are required:

  1. Create the text file according to the Formatting rules for external files described in the next paragraph
  2. On the ACCESS page under the List tab, click on Import and select the newly created document from your PC.
  3. During the import of the text file, all entries are checked for validity.
  4. All valid entries will be displayed on the screen after the text file has been loaded.
  5. If necessary, entries can be edited directly in the table.
  6. When the list is finished, click on Upload to save the list on the camera.

6.4.1   Formatting rules for external files

External text files with license plate definitions have to be formatted properly so that the camera can parse their content. The following rules apply:

  • Every list entry must be placed in a single, separate line without blank spaces.

  • Each line is formatted inthe order license plate; date window(s); or license plate; date window(s); time window(s)

  • Time window definitions are optional, but if given, they must be defined for every date window.

  • Plate number, date and time must be separated with semicolons (;).

  • When listing multiple dates/times, separate them with a comma (,).

  • Date format: YYYYMMDD-YYYYMMDD, with no space between the numbers.

  • Time format: HH:MM-HH:MM. Time is always defined in combination with the date and a symbol (0/1) for the preferred day of the week.

  • Days of the week are represented with zeros and ones (0-not active, 1-active) written inside the parenthesis starting with Sunday, ending with Saturday. For example, "0111110" non-active days are Sunday and Saturday.

  • If days of week are used, they must be specified together with a time range. If the whole day shall be valid, use 00:00:23:00(0..1) as pattern.

    E.g. 00:00-23:59(0111110) to specify weekdays, 24 hrs.

  • The number of dates set must be equal to the number of time ranges. If there are more dates than time restrictions (and vice versa), the definition of this entry will be regarded as invalid.


Example:

W223344;20170101-20170125;08:00-12:00(0111110):

an action will be taken if the vehicle with plate number W223344 is detected

from 01.01.2017 until 25.01.2017

between 08:00 and 12:00 on

any day of the week, except Saturday and Sunday.


More practical examples and descriptions for the rules:

  Entry Description
Plate number W223344 Actions will be taken when a vehicle with this number plate is detected.
Plate number and date   Date format: YYYYMMDD-YYYYMMDD, no blanks.
W223344;20170925-20170926 Actions will be taken if the plate is detected on a date inside set limitations ( 20170926<=[current date]<=20170925).
W223344;20170925-20170926,...,20170529-20170629 Multiple dates can be set, separated by a comma defined in one line, without blanks.
Plate number, date and time   Time format: HH:MM-HH:MM(0111110); 1 and 0 represent days of the week, starting from Sunday(0) till the last day Saturday(0), 0 meaning not active, 1 meaning active.
W223344;20170925-20170925;03:00-04:00(0111110) Time must be set in combination with the date.
W23344;20170925-20170925,201701012-20171112,...;03:00-04:00(0111110),05:00-06:00(0111110 ),...
When there are multiple dates, if time is set for one date it must be defined for all the dates or the limitation will be found invalid.
In this example, two dates with their respective times are set where date(1) 20170925-20170925 is combined with time(1) 03:00-04:00, and date(2) 20170112-20171112 is combined with time(2) 05:00-06:00 and so on.

6.4.2   Regular Expressions

Regular expressions are used to conveniently define patterns for license plates or groups of license plate strings. You can use regular expression when you enter list entries manually, or in text files which are imported.

Carrida uses a powerful set of regular expressions, of which the most important details are described in the following paragraphs.

Note

Note Sign Regular expressions can be used in the dialog for list entry of the camera or in the list text files which are imported.

If you use the camera dialog for a list entry, turn the regular expression switch on. See also Section Manual creation of a list entry.

In the import text file a license plate regular expression must be preceded with a "!" character, e.g. !B*.

Hint

Hint Sign Details to all features of the Carrida regular expression syntax can be found here: https://www.boost.org/doc/libs/1_61_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html

In Carrida regular expressions, all characters match themselves (example: A is always A, B matches B, etc.) except for some special characters:

.
[]
{}
*
+
?

The '.' character matches every single character. E.g. the regular expression

G.23456

will match

G123456, or
GU23456, etc.

(In the above expression, the "." is matched by 1 or U respectively)


A character range is defined by a list of characters enclosed in []. For example [A-D] will match any single character in the range 'A' to 'D'. This character range may also be defined as [ABCD].


An atom is defined as a character or character range.

A single atom can be repeated with the * , +, ?, and {} operators.


The * operator will match the preceding atom zero or more times. For example, the expression

A*B

will match any of the following:

B
AB
AAAAAAAAAB

or the expression

A[BC]*D

will match

AD
ABCD
ACCCBBD

(between A and D, the characters B and C as defined by the atom [BC] may be repeated any number of times.

Note

Note Sign A regular expression beginning with a * is invalid because the * operator does not precede any other atom. Use the combination .* instead!

The + operator will match the preceding atom one or more times. For example, the expression

A+B

will match any of the following:

AB
AAAAAAAAB

But will not match:

B

The ? operator will match the preceding atom zero or one time. For example, the expression CA?B will match any of the following:

CB
CAB

But will not match:

CAAB


An atom can also be repeated with a bounded repeat, where the number of allowed repeats is defined as part of the regular expression:

A{n} Matches 'A' repeated exactly n times.

A{n,} Matches 'A' repeated n or more times.

A{n, m} Matches 'A' repeated between n and m times inclusive.



For example:

A{2,3}

Will match either of:

AA
AAA

But neither of:

A
AAAA

Some useful examples for regular expressions are given below:


To match any license plate string of at least length 1:

.+

Match license plate strings which consist of digits only:

[0-9]+

Match all taxis, under the assumption that taxis have a license plate string that ends with TX:

.+TX

Match all license plates that start with a letter and end with a digit:

[A-Z]+.*[0-9]+

Match all license plates from the Carrida company, assuming that their license plates consist of a CAR string and a following 3 number digit (like CAR001):

CAR[0-9]{3}

6.5   Actions

Once the camera detects a license plate, it checks whether some action has to be taken based on this reading (e.g. a list match is found).

The camera checks also regularly the IO lines and other comm ports in order to detect other state changes which could possibly create an internal event. As mentioned earlier, there are several types of events which can trigger actions:


Sources which may trigger actions are

Read events
occur when the camera detects and reads any license plate.
NoRead events
occur when NO plates are detected in a triggered reading mode. The use of external triggers is explained in detail in Section Trigger.
Wrong Direction read events
occur when a new license plate is detected, but it's moving in a direction that is not within the allowed direction range, i.e. it moves the wrong way.
LCR events
a Low Confidence Read event is created when the plate is read, but the confidence level is lower than set in the parameter Settings-Access control-Limit of Low Conf. This type of event is mostly used for debugging and testing.
Whitelist match, Blacklist match, and Ignorelist match
the license plate is found in one of those lists.
Whitelist mismatch, Blacklist mismatch, and Ignorelist mismatch
the license plate is NOT found in one of those lists.

6.6   How to setup Actions

The definition of actions is done from the Actions menu of the Access page. Here you can choose which action should be performed based on the event type.

./images/5_actions.png

Access actions categories.


The following possible actions can be created (details follow below):

Ftp Upload
Create a new file from the reading result and transfer it over ftp.
Ftp Database
Update a database file on an ftp server with the new reading.
Store
Save the current image in a specified location on the camera.
Digital out
Set a digital output line of the camera for a specified time.
Serial
Format and send a message over the serial port of the camera.
TCP
Format and send a TCP message.
HTTP
Format and perform a request on a specified HTTP server.
LEDBlink
Activate the LEDs on the camera for a specified time interval.

6.7   Adding Actions

To add an action, first choose the event category for which the action is to be added, then press the ADD button to open a dialog window for configuration. A specific action can then be selected and configured in the dialog window as shown below.

./images/5_actions_add.png

The Add/Edit Action Dialog changes dynamically based on the type of action you want to define. The description of each action below describes each of the action types and how it is to be configured.


6.7.1   The use of Placeholders

All actions which create messages or files can use placeholders for actual values of an event. For example, an action may create a filename which uses the actual license plate text and/or the current date and time. This feature allows you to create dynamic actions, which are much more useful and give you more flexibility for the integration of the camera into your environment.

The concept of Placeholders is used to specify the text elements which are needed in order to generate your dynamic text. Placeholders have the form %placeholder-name% - this text will be substituted by the actual dynamic element information when the action is performed.


Example:

A placeholder for the license plate is %LP%, for the date is %DAY% %MONTH% %YEAR%, level of confidence for plate recognition is %CONF%.

The camera detected a vehicle with number plate W223344 on the 03.08.2017, with confidence 98%.

An action definition of

Detected %LP%(%CONF%) on %DAY%/%MONTH%/%YEAR%.

could result in the actual created message

Detected W223344(98) on 03/08/2017.


A complete list of placeholders can be found in Placeholders for naming patterns.

6.8   Actions and their definition

This section describe in detail all possible actions that can be triggered by an event.

Each of the actions must be enabled by sliding the Enable button to the right.

Actions may be valid on one of the defined ROIs (see Section ALPR Region Of Interest ) or on all ROIs. Use the pull down selector roi_selector to specify which of the areas shall trigger the action.


6.8.1   Ftp Upload

f

Ftp upload is the most commonly used action. It is used to transfer image files of detected plates to a remote ftp server.

Enter the Host ftp server IP address in the form of (s)ftp://xxx.xxx.x.xxx/[...].

Username and Password of the ftp server must be written in the form of [username]:[password]. Example: for the username "user123" with the password "pass123" the correct form is: user123:pass123.

Use placeholders to include specific dynamic information (date, time, plate...) in the file name which is created on the server.

fnp

Use the green Test FTP button to check the ftp connection after you have specified all access data to the server.

Images can be cropped and uploaded dynamically in size according to the following options:

  • Empty file: create and empty file
  • Full image: transfer the whole image
  • LP Image: transfer only the LP image
  • Cropped Image Size Relative Image: an image cropped around the LP with a size in % relative to the original size and scaled to 'final Image Width/Height' dimensions.
  • Cropped LP Size Relative Image: an image cropped around the LP with a size in % relative to the original LP size and scaled to 'Final Image Width/Height' dimensions.

Image quality refers to the JPEG compression of the transferred image, it can be set from 1 to 100%, 1 being the maximal compression level which will produce images with the lowest quality, and 100 being the minimal compression level with the highest image quality. We recommend setting this parameter to 65-70%.

If your Carrida cam supports a second camera (e.g. on a Jetson Nano board), this additional option is visible in the dialog. It allows you to also transfer the full image of the 2nd camera (the overview camera).


6.8.2   Ftp Database

4

This action creates and automatically updates a text file on the specified ftp server.

Enter the Host ftp servers IP address in the form of (s)ftp://192.168.3.127/[...].

Username and Password of the ftp server should be written in the form of [username]:[password]. Example: for the username "user123" with the password "pass123" the correct form is user123:pass123.

Use the green Test FTP button to check the ftp connection after you have specified all access data to the server.

Filename stands for the name of the database to be updated (created) with a new result string.

Use placeholders to include specific dynamic information (date, time, plate...) in the result string.


6.8.3   Store

Warning

Warning Sign

This action is recommended for expert users only!

s

This action stores image data on the camera. Use this action type to collect images for later use.

The filename is constructed of a path name, and a dynamic filename, which may contain placeholders. Note that we recommend using the file path /root/data as a storage location on the camera.

fnp

Images can be cropped and uploaded dynamically in size according to the following options:

  • Empty file: create and empty file
  • Full image: transfer the whole image
  • LP Image: transfer only the LP image
  • Cropped Image Size Relative Image: an image cropped around the LP with a size in % relative to the original size and scaled to 'final Image Width/Height' dimensions.
  • Cropped LP Size Relative Image: an image cropped around the LP with a size in % relative to the original LP size and scaled to 'Final Image Width/Height' dimensions.

The Free space parameter defines the minimal free disc space required to be available on the camera in order to allow the action to perform. If there is less space available on the camera than defined here, the files will not be saved.


6.8.4   Digital Out

6

This activates a specified digital output line on the camera for a specific time period (Output duration).

Select which Output pin will be activated by the action.

Output duration defines the duration of the output signal in ms.

The Invert signal option can be disabled/enabled in order to invert the polarity of the IO line.


6.8.5   Serial

8 Construct a message using strings and placeholders and send it through the serial port of the camera with the specified Baud rate.

6.8.6   TCP

9

Write a message for the action using TCP with text and placeholders.

Enter the IP address and port of the receiver of the TCP address to send the TCP message.


6.8.7   HTTP

ö

Run an HTTP action with the specified Request Type.

Define the URL and enter the credentials, username and password for the URL.

The message field may contain placeholders.


7   Settings

The Carrida camera provides the necessary configuration parameters to optimize its operation for different application scenarios. The adjustment of the settings for image acquisition, detection sensitivity, etc. ensures that the camera is configured properly to the needs of your application.

7.1   Overview

The Settings page groups the available camera parameters into several logical menus, which can be opened and closed by clicking on the triangle next to the menu name.

./images/settings_overview.png

All Settings sub-menus.


There are three types of control parameters used to modify settings:

Drop-down menus
Use drop-down menus to choose from a predefined list of options.
Input fields
Used to enter values like numbers, texts, or filenames.
Enable/disable options
Changed by clicking on either the green checkmark (enabled) or a red cross mark (disabled).
Confirm a value
apply

The following sections describe each of the menus in detail.

7.2   Camera

The Camera settings page is used to optimize the imaging performance of the camera. It allows you to modify brightness control parameters, and define gain settings and exposure times. How to adjust these parameters properly, and what they mean is described in the following paragraphs.

Gain and Shutter options directly impact image acquisition. Gain, expressed in decibels, represents the camera's sensitivity to light, and Shutter speed measures the exposure time in microseconds.


What does the green polygon in the live image represent?

The area inside the green polygon is called the brightness control region. It defines the area within which the camera measures and corrects the image brightness by controlling exposure time and gain.

It is recommended to limit this brightness control area to the actual image region where license plates are expected to be visible. This maximizes the effect of the control parameters and allows the camera to achieve the best image quality in all possible scenarios.

How to adjust the brightness control polygon and for more information about it, see the Brightness Control Region section.


What is gain?

Gain controls the amplification of the image signal from the camera's sensor, and thus affects its overall light sensitivity.

A higher gain setting boosts the image brightness at the cost of introducing noise. A lower gain setting results therefore in general better image quality, but may require you to use a longer exposure time.


What is the shutter resp. exposure time?

A camera shutter is a mechanism that lets the light in through the lens onto the sensor of the camera. It has two states: open and closed, and the time it stays open is measured in microseconds (μs) in the Carrida camera.

A 'fast' shutter speed means that the shutter will open and close quickly, limiting the amount of light that can hit the sensor. A 'slow' shutter speed, or long exposure time, means that more light can pass through to the sensor, producing brighter images.

The maximum allowed shutter time gives you control over motion blur, should vehicles move too fast. A shorter shutter time reduces the chance for motion blur on moving vehicles.


The following four parameters define the limits for gain and exposure time as used by the camera's automated brightness control algorithm. When these limits are set to extreme values, the camera may be able to capture optimally exposed images, but possibly at the cost of reduced image quality.

For example, if the gain is allowed to become too high, images may become too noisy for detection, or if the exposure time is becoming too high, motion blur may be visible.


7.2.1   Minimum Gain (dB)

The Minimum Gain parameter defines how low the camera can go with the gain control when it tries to adjust the image brightness. For best image quality it is recommended to set this parameter to 0.


7.2.2   Maximum Gain (dB)

The Maximum Gain value defines how high the camera can go with the gain control when it tries to adjust the image brightness. The higher the camera can turn up the gain, the more noise can be introduced into images, thus making them harder to read.

We recommend a maximum gain value of 10 for the Carrida Camera.


7.2.3   Minimum Shutter

The Minimum Shutter value defines how short the shutter time can become when the camera tries to adjust the image brightness. The Minimum Shutter time must always be lower or equal the Maximum allowed shutter time.

The lowest possible value for Minimum shutter time is 10 μs, but we recommend to set a value of 50 μs, especially when the camera is located indoors.

Note

Note Sign If the Minimum Shutter time is set too high, the camera may not be able to adjust the image in very bright illumination conditions. If the Sun is directly behind the camera and its is being reflected from license plates a low minimum shutter time is crucial.

7.2.4   Maximum Shutter

The Maximum Shutter time defines how long the shutter can stay open when the camera tries to adjust the image brightness.

The Maximum Shutter time must always be higher or equal to the minimum allowed shutter time.

If the Maximum Shutter time is allowed to become too high (e.g. allowing up to 10000 microseconds in an urban environment), vehicles that move too fast are likely to become blurred.

If the Maximum Shutter time needs to be reduced to avoid motion blur, and the resulting image brightness becomes too low, try the following measures to increase obtain a brighter image:

  • Set a longer LED flash time (see LED Flash for a description).
  • Try to increase the power of the built-in LED flash by configuring more LED current.
  • Increase the maximum allowed gain.

Hint

Hint Sign
As a general recommendation, the following shutter times are advised:
  • shutter time of 50-3000 μs on highways, for high-speed vehicles
  • shutter time of 50-5000 μs in urban areas, for medium-speed vehicles
  • shutter time of 100-10000 μs in parking situations, for slow vehicles
How to estimate the maximum allowed shutter time:

The maximum possible shutter time can be calculated from the viewing geometry and image resolution. The basic principle is that a vehicle at maximum possible speed should not move more than 1 px in the image during the exposure time period.

It is possible to either compute this value exactly using measurements of the visible street section, viewing angles, etc. or it can be approximated.

By measuring the time (T in seconds) it takes a vehicle from top to bottom or left to right of an image - whatever time is shorter - and the image resolution in this direction is known, the maximum allowed exposure time in ms can be computed as follows:

exposureTime(ms) = 1000*(T/resolution)


7.2.5   Low Resolution

The Carrida camera sensor can operate in two resolution settings

  1. A high-resolution of typically 1280x1024 px. This is the resolution of the built in image sensor.
  2. A low-resolution mode which halves the original sensor resolution by 2. Use this mode if you need the highest processing rate on the camera.

The low-resolution mode allows the camera to achieve a higher processing rate so that the faster moving vehicles are captured with higher capture rate. The disadvantage of the low-resolution mode is that the camera can read license plates only up to a maximum distance of about 5 meters.

The high-resolution mode enables the camera to read license plates up to a distance of about 9 meters, but at the cost of a 30% slower processing rate.


7.2.6   Image Rotation (deg)

In situations where the camera has an oblique view onto the street, it might be preferable to rotate the camera image after capture so that the license plates appear horizontally. This is not a strict requirement for good readings, but it can improve recognition quality. Enter a rotation angle here in order to optimize the image alignment. The effect of the rotation parameter is directly visible after you set a new value.


7.2.7   Initial IO Activation

By enabling this option, all available output IO pins are set to low state when the camera boots, restarts or server software in the camera re-starts. Our recommendation is to leave this option enabled at all times.


7.2.8   Brightness control Region

The Brightness control region is the area enclosed in the green polygon shown in the live image when the Camera menu is selected in the Settings page:

./images/7_settings_camera.png

The Brightness control area defines the region used by the camera to continuously analyze and adjust the brightness of the next image. To achieve this, the camera tries to adjust shutter time and gain setting in a way that gives the image the best possible average brightness even in difficult situations.


Adjusting the Brightness control polygon

The shape of the region which is used for the adjustment of image brightness can be easily adjusted using the real-time camera display and the overlaid green brightness ROI.

Click, drag and release a corner of the polygon to move it. Additional points can be inserted into the polygon by double-clicking close to an existing corner point. The newly created point can then be dragged to its new location.

To delete an existing corner point move the mouse over it and right click.

After the polygon has been drawn, click on Apply at the bottom to save your changes.


In the example below the camera is mounted in front of a gate. The ROI covers only the path that the vehicles might take to make it as small as possible.

brightness_roi


A good image should have neither too many overexposed pixels nor too many dark pixels. Overexposed pixels are particularly bad because all information is lost, pixels that are too dark are less problematic because they still contain useful information.

All pixels with brightness levels below 100 will be considered too dark, all pixels with levels over 220 are considered to be overexposed.

For many application scenarios, especially in entrance ways of parking garages or during night-time, the just mentioned goal of a perfectly exposed image is very hard to achieve, if not impossible. The differences in illumination encountered in those situations are just too high to be faithfully captured by a sensor. The Carrida camera brightness control algorithm therefore puts the emphasis on not overexposing images. It allows you to tolerate a certain number of overexposed pixels and also a minimum number of good pixels that is to be reached.

In any case, lowering the image brightness to avoid overexposure has priority in the brightness adjustment algorithm.

Hint

Hint Sign We recommend setting the brightness control area to the smallest possible size and shape so that the camera can optimize the image brightness for the relevant image region. A good idea is to synchronize the BC area with the ALPR ROI, this can be easily done by pressing the blue Sync button in the right lower corner of the live image.

./images/Image15_sync.png

7.2.9   Use Brightness control

This setting turns the automatic brightness control on or off. Our recommendation is to leave this parameter enabled at all times, as it will enhance image quality and produce better ALPR results.

If the this setting is disabled, the camera uses the Maximum Shutter, and Maximum Gain (dB) values as fixed settings. They can thus be used to manually control camera exposure.

Note

Note Sign

Pixel counts respective percentage measures are indicated relative to the Brightness ROI polygon area.

7.2.10   BC max bright pixels (%)

During automatic exposure control, the camera counts all the 'good' pixels within the brightness control area. Good pixels are neither too dark nor overexposed as explained above.

In cases where there are too many overexposed pixels, as indicated by this parameter in percent relative to the polygon size, the camera will change its exposure settings to make the image darker.

Hint

Hint Sign What to do if the license plates are constantly overexposed?

If the license plates are constantly too bright, the percentage value of maximum saturated pixels needs to be reduced, so that the camera tries to decrease the count of those pixels on its own.

Example: reduce the value from 5% to 3% and observe the effect on the live image stream.

Another possible cause for constantly overexposed images could be that the Minimum Shutter time is set too high, so that the camera is not allowed to decrease the brightness of the image any more. See Minimum Shutter for more information on how to reduce the Minimum Shutter time.

7.2.11   BC min correct pixels (%)

In order to assure good image quality, the camera checks not only for overexposed images, but also for a minimum number of well exposed pixels.

This parameter defines the minimum number of good pixels as defined above, and tries to make corrections if necessary. In this situation the camera will only try to enhance the image brightness if the limits of gain and shutter value allow for. BC min correct pixels is of secondary importance for brightness control and should only be used if absolutely necessary. It may be deprecated in future versions of the Carrida software.

Hint

Hint Sign What to do if the license plates are constantly too dark?

If the plates are constantly too dark, the value of minimum correct pixels needs to be increased, so that the camera is forced to increase the image brightness.

Example: modify the value from 3 to 5% and observe the effect in the live image.

Another possible cause for constantly underexposed images would be setting either the Maximum Shutter time or the Maximum Gain too low, so that the camera is not allowed to brighten up the image more. See Maximum Shutter time on how to increase the Maximum Shutter time or Maximum Gain (dB) on how to increase the Maximum Gain.

As a third option, try to increase the LED flash power, see LED Flash or more information.

7.3   LED Flash

Some Carrida cameras have a built-in IR flashlight which can be controlled through the LED flash settings.

It is recommended to have the flash turned on at all times to optimize the contrast of license plates. In addition to the LED, the Carrida camera is also equipped with a daylight blocking filter which is tuned to the LED wavelength. This feature reduces the influence of sunlight as well as reflections from the headlights of vehicles.


The relative strength of the LED light is controlled via two parameters. Those two parameters are only visible if the camera supports a controllable flash power and duration.

LED flash duration
in µs defines how long the LED flashes when it is triggered by the camera. The flash duration may be as short as 10 microseconds and at most as long as the camera shutter time, but never longer than that.
LED current

defines the total power or strength of the flash by controlling the current through the LED. The flash current is set in mA and may range from 150-1500 mA.

Note that on the Carrida Cam Basic+ a Flash current setting of less than 150 mA will turn the flash off.


./images/8_ledflash.png

LED Flash settings on the Configuration screen.


7.3.1   Enable Flash

Use this control to enable/disable LED flash.

We recommend leaving the flash enabled at all times.


7.3.2   Flash Duration (µs)

The Flash Duration parameter defines the duration for which the flash is actually emitting light when triggered by the camera. The flash is synchronized with the beginning of image acquisition by the camera. Its duration may be shorter than the current exposure time, but it will never be longer. E.g. if the current exposure time by the camera is 500 µs and the flash time is set to 800 µs, it will nevertheless be cut off after 500 µs.

When the flash duration is set to a short duration, motion blur on fast vehicles can be avoided. For example in a typical city environment with up to 70 km/h (45 mph), a flash duration of 1000 µs would be a good choice.


7.3.3   Flash Current (mA)

Independent of the flash duration, the current which flows through the LEDs is another means to control LED power. The more current is sourced through the LEDs, the brighter they become.

Note that on the Carrida Cam Basic+, the LED controller circuit covers a current range from 150-1500 mA, a value of less than 150 mA turns the LEDs off.


It is recommended to set the LED current in a range from 500 mA to 1000 mA, so that

  1. it is bright enough even for LP at larger distances
  2. the flash is strong enough to illuminate license plates even in the presence of vehicle lights. This becomes especially important when the Carrida camera is used indoors.

7.4   Trigger

The Carrida camera may not only operate free running, it can also be triggered by external signals. These trigger signals can enable and disable the reading of the camera in a flexible way.

Within a trigger period, when the camera is active, it behaves like in free running mode. This means that reading and sending of LP texts, list matching etc. is performed.

In addition the camera can also create an event and perform an action, if no LP has been detected at the end of the active trigger period. See Actions for further explanation of actions and events.

The trigger type parameter is used to select the trigger source, it is chosen from a pull down menu. The trigger type None deactivates all trigger sources and puts the camera back into free running mode.

./images/trigger_type.png

Selection of the trigger type.


Four different trigger types are available, more details are given in the following sections below.

None
When selected, the trigger mode is turned off and the camera operates in free running mode. This should be the default mode when an external trigger is not available or not required.
Digital I/O Lines
The trigger signals are provided using the available I/O lines on he camera. It is possible to use one I/O line to Start and Stop, or you can send the Start and Stop signal using separate I/O lines.
TCP

This trigger type allows SW triggering. Send a TCP message from your server to Start and S*top* the camera.

The messages all have exactly length 1:

  • A message with value 1 (0x01) is interpreted as Start signal
  • A message with value 0 (0x00) is interpreted as Stop signal (in start-stop mode)
  • all other messages will be ignored
HTTP

This trigger type allows SW triggering using a simple REST API.

Send a HTTP GET request to


Each of the above mentioned trigger types supports five different trigger modes, which define how a trigger signal is interpreted.

The selection of the trigger mode will change the available parameters in the user interface below it so that this specific trigger mode can be parameterized accordingly (see detailed description below):

Single_Line
This trigger mode is available only for the IO trigger type. Read as long as the trigger is active.
Start_Stop
Start reading when the defined start signal is received, stop reading when the defined Stop signal is received.
Start_Time
start reading for a defined time upon receiving a trigger.
Start_Sequence
Start reading for a defined number of images after the trigger signal. Note that aapproximately 8 images per second are processed.
Single_shot
Grab an image after activating, do a reading and deactivate. Stream mode has to be set to Single to use this trigger mode.

Note

Note Sign In the following section, the term session will be used to describe the time between the start signal by a trigger and the end of a triggered period, which can either be signaled through another I/O line or by a timer.

A session is the only time period in which the camera reads license plates.

Hint

Hint Sign The electrical requirements for digital IO and triggering are defined in the Carrida Cam Basic+ Information Manual.

The following paragraphs explain the possible trigger modes, their setup and operation in detail.


7.4.1   Trigger mode

This secion lists all different trigger types and their associated trigger modes. Each trigger mode is first setup and configured, in addition the start and stop signal activation are explained:

  • The Setup section lists the parameters which are related to the mode and are used for its configuration.
  • The Start section describes the signals which will start a session.
  • The Stop section describes the condition which will end a session.

We recommend to choose and configure a trigger as follows:

  1. Choose the trigger type (IO, TCP, HTTP), Apply
  2. Choose the trigger mode (Start-Stop, Start-Time, etc.). Apply
  3. Configure each required parameter, Apply

After choosing the mode from the drop-down menu, press the Apply button to activate the trigger mode and set the parameters as needed.

Freerunning mode, no trigger:

  None
none Setup: no need for setups The optional NoRead interval allows you to trigger NoRead events in regular intervals. These intervals also reset the parking mode. See Noread Event Interval (s) below.
Start: when a HTTP GET Request gets to the endpoint http://camera_ip/trigger/start


Trigger using IO lines:

  IO Lines
sl Setup: Define Start trigger line, Start trigger polarity. If Start trigger polarity high is enabled, the session will start when the input signal is transitioning from low to high. If Start trigger polarity high is disabled, the session will start when the input signal is transitioning from high to low.
Start: The session will start when the signal from Start trigger line is received.
Stop: The session is ended when the signal on the input line changes its state again.
ss Setup: Define Start trigger line, Start trigger polarity. In addition, define Stop trigger line and Stop trigger polarity. If Start trigger polarity high is enabled, the session will start when the input signal is transitioning from low to high. If Start trigger polarity high is disabled, the session will start when the input signal is transitioning from high to low.
Start: The session will start when the signal from Start trigger line is received.
Stop: The session stops when the signal from Stop trigger line is received. In case a new trigger signal is received while the old session is still open, the camera closes the old session and opens a new session immediately.
st Setup: Define Start trigger line, Start trigger polarity. and Trigger timeout (ms). If Start trigger polarity high is enabled, the session will start when the input signal is transitioning from low to high. If Start trigger polarity high is disabled, the session will start when the input signal is transitioning from high to low.
Start: The session will start when the signal is received.
Stop: The session lasts for a defined time period as set in Trigger timeout. After the time passes the session is closed. In case a new trigger signal is received while the old session is still open, the old session will be extended to a new timeout period. In this case, the camera does NOT generate NoRead events for the interrupted session.
sseq Setup: Define Start trigger line, Start trigger polarity. and Sequence length in frames. If Start trigger polarity high is enabled, the session will start when the input signal is transitioning from low to high. If Start trigger polarity high is disabled, the session will start when the input signal is transitioning from high to low.
Start: The session will start when the signal from Start trigger line is received.
Stop: The session lasts for the defined sequence length.
sshot Setup: Define Start trigger line, Start trigger polarity. and Sequence length in frames. If Start trigger polarity high is enabled, the session will start when the input signal is transitioning from low to high. If Start trigger polarity high is disabled, the session will start when the input signal is transitioning from high to low.
Start: The session will start when the signal from Start trigger line is received.
Stop: The session ends after grabbing one shot.


TCP trigger type:

  TCP
tss

Setup: TCP Trigger Port

TCP Trigger Port - set a port used for the TCP Trigger.

Start: when a messages with value 1 (0x01) Byte is received.
Stop: when a messages with value 0 (0x00) Byte is received.
tst

Setup: TCP Trigger Port, Trigger Timeout (ms)

TCP Trigger Port - set a port used for the TCP Trigger. Trigger timeout (ms) - maximal waiting time in milliseconds for an ALPR reading after a trigger signal.

Start: when a messages with value 1 (0x01) Byte is received.
Stop: when the time defined in Trigger timeout (ms) ends.
tsseq

Setup: TCP Trigger Port, Sequence Length (frames)

TCP Trigger Port - set a port used for the TCP Trigger. Sequence Length (frames) - the number of frames that will be read after a trigger signal is received.

Start: when a messages with value 1 (0x01) Byte is received.
Stop: when the number of frames defined in Seqence Length (frames) have been read.
tsshot

Setup: TCP Trigger Port

TCP Trigger Port - set a port used for the TCP Trigger.

Start: when a message with value 1 (0x01) Byte is received.
Stop: The session ends after grabbing one shot.

HTTP trigger type:

  HTTP
hss Setup: no need for setups
Start: when an HTTP GET Request gets to the endpoint: http://camera_ip/trigger/start
Stop: when an HTTP GET Request gets to the endpoint: http://camera_ip/trigger/stop
hst

Setup: Trigger Timeout (ms)

Trigger timeout (ms) - maximal waiting time in milliseconds for an ALPR reading after a trigger signal.

Start: when an HTTP GET Request gets to the endpoint: http://camera_ip/trigger/start
Stop: when the time defined in Trigger timeout (ms) ends.
hsseq

Setup: Sequence Length (frames)

Sequence Length (frames) - the number of frames that will be read after a trigger signal is received.

Start: when a HTTP GET Request gets to the endpoint: http://camera_ip/trigger/start
Stop: when the number of frames defined in Sequence Length (frames) have been read.
hsshot Setup: no need for setups
Start: when a HTTP GET Request gets to the endpoint http://camera_ip/trigger/start
Stop: The session ends after grabbing one shot.

7.4.2   Noread Event Interval (s)

This parameter specifies the interval of images without any plate readings before a NoRead event is triggered. This parameter is only used in freerun mode.

By using this parameter you can set up the camera to trigger an action if no license plate has been detected within this time duration.

The NoRead event mechanism can be used in all modes of operation (parking, single, etc.). For example, if parking mode is used, the camera will send the first reading of LP to a server. As long as the same car is detected, no further readings will be sent, nor will a NoRead be triggered. When the car leaves the gate, after NoRead event seconds, an action will be triggered if no other car enters the field of view of the camera.

If you do not define a NoRead action, or the time interval is set to 0, this parameter will be ignored by the camera.


7.4.3   Start Trigger Line

This parameter defines a start trigger line that begins the session.

When the input line on the camera is activated/triggered, it will send a signal to the camera to start the session.

An overview of active input and output pins can be found in System settings.


7.4.4   Start Trigger Polarity High

This parameter defines the active polarity of the input line in order to start a session.

If Start trigger polarity high is enabled, the session will start when the input signal is transitioning from low to high.

If Start trigger polarity high is disabled, the session will start when the input signal is transitioning from high to low.


7.4.5   Stop Trigger Line

This parameter defines a stop trigger line which ends a session.

When this pin is activated/triggered it will send a signal to the camera to end the current session.

An overview of active input and output pins can be found in System settings.


7.4.6   Stop Trigger Polarity High

This parameter defines the active polarity of the input line in order to stop a session.

If Stop trigger polarity high is enabled, the session will stop when the input signal is transitioning from low to high.

If Stop trigger polarity high is disabled, the session will stop when the input signal is transitioning from high to low.


7.4.7   Trigger Timeout (ms)

This parameter defines time duration (in milliseconds) of one session. The session starts when Start trigger line signal is received and ends after the defined time passes.


7.4.8   Sequence length (frames)

This parameter defines the number of frames which will be processed in one session. The session starts when Start trigger line signal is received and it ends after a defined number of frames has been acquired and processed.

Note that the effect of this parameter depends on the reading frame rate of the camera, which vary depending on the actual camera HW, the ROI settings, Engine settings etc.

7.5   Engine

The Engine page controls all parameters necessary to set up the actual reading of license plates. The preset default values will usually result in good general reading results, but they can be modified to tune the camera operation to specific situations.

./images/10_settings_engine.png

7.5.1   ALPR Region Of Interest

The ALPR Region of Interest (ROI) is the area enclosed in the yellow rectangle shown on the camera image, it defines the image region were the actual reading takes place.

A ROI polygon can have an arbitrary number of contour points, but it must contain at least 3 points. The shape of the ROI polygon can be modified using the following methods:

Adjusting the ALPR ROI polygon

Click, drag and release a corner of the polygon to move it.

Additional points can be inserted into the polygon by double-clicking close to an existing corner point. The newly created point can then be dragged to its new location with the mouse.

To delete an existing corner point, move the mouse over it and right click.

After the polygon has been adjusted, click on Apply at the bottom to save your changes.


More than one region of interest can be defined by setting the number of desired regions in the Number of Areas box. You can also provide a custom name for this area. This name, as well as optionally the area number, can be used in actions as reference.

./images/area_definition.png

7.5.2   ALPR Region Of Interest with Direction

The direction and range parameters define which motion direction of a detected license plate is accepted within the polygon area. A sector of allowed motion direction has a center and a range in degrees around it.

In the example below, a direction from top to bottom of the image with a range of 120 degrees is defined. This means that only license plates which move from top to bottom +-60 degrees are being accepted.

./images/area_definition_range.png

Note

Note Sign

It is only possible to compute a motion direction if at least two detections of a license plate have been made. When the minimum number of detections is set to 1, the situation may occur that only one instance of a license plate has been detected as valid. In this situation, the license plate is accepted regardless of the direction and range specification of the ROI.

If the direction evaluation of a license plate is mandatory in your application, the minimum number of detections must be set to a value >=2.

7.5.3   Reading mode

The Carrida engine can operate in several performance modes, which balance processing speed and reading accuracy differently. The faster modes offer a higher reading speed on the camera at the cost of lower reading accuracy and vice versa. The Carrida camera offers the following reading modes, ordered from fastest to slowest:


  Mode Description
mo Fastest Fastest possible processing speed with lower recognition quality than in other modes. Recommended for open traffic where recognition speed has priority.
Fast Fast processing speed with slightly better recognition quality than in the fastest mode. Also intended for open traffic situations.
Standard A good compromise between speed and reading performance, recommended to be used in most situations.
High High mode is about half the speed compared to fast mode. The reading accuracy of the high mode is typically 2-3% better than the fast mode.
Best The best possible reading quality. It can be up to three times slower than in the fast mode. At the same time, reading confidence will be about 3-4% better.

7.5.4   Min letter height (px)

Defines the minimal height of characters, in pixels, that are to be recognized. The camera will only accept characters larger in height than set with this parameter.

Use this parameter if license plates above a minimum size should be read- e.g. by enforcing a value of 16 px, license plates that are too far away from the camera will be ignored.

We recommend that this value should not be less than 8 pixels.


7.5.5   Max letter height (px)

Defines the maximum height of characters, in pixels, that are to be recognized. The camera will only accept characters smaller in height than set with this parameter.


7.5.6   Max plate angle (deg)

Should be used if there is a chance that the vehicles can appear rotated relative to the camera. This parameter allows to adjust the maximum rotation under which LP are still accepted.

The best results are achieved when Max plate angle is between 5° and 20°, we recommend a maximum value of 40°.

Try to avoid rotated LPs by installing the camera so that license plates appear level.


7.5.7   Min plate confidence (%)

Minimum plate confidence refers to the minimum confidence level at which the camera will accept the plates as valid. All readings with confidence smaller than this value will be ignored.

A typical value for Min Plate Confidence is 65 %. A higher value can assure that only good readings will be made, but there is also a chance that good and correct readings with a lower confidence value may be discarded.


7.5.8   Maximum Plates

Refers to the maximum number of plates that can be detected in a single image. Setting it to 0 means that an unlimited number of plates can be detected.


7.5.9   Minimum contrast

This parameter defines the minimal contrast to differentiate foreground (characters) from the background (the license plate itself).

Modifying the minimum detected contrast may help read LPs in difficult lighting situations, at the cost of slower reading time.

It is recommended not to modify this parameter and use the default value provided by the camera unless absolutely necessary.


7.5.10   Scale Height/Width

Scaling means to resize an image in % relative to its original size, with separate scaling for width and height.

Scaling may help in situations where the camera views license plates from the top or the side at a steep angle >30 deg. The LP will be distorted in this case, and to adjust for that, it is possible to re-scale the opposite image dimension to a scale value <100. This would compensate the perspective effect of the oblique view to a great degree.

The values are provided in percent of the original image size (100 = original size).


7.5.11   Search inverted

Search inverted is an option that controls the way the Carrida engine will search for the LP in terms of contrast of the characters (black-on-white or white-on-black contrast) as follows:

Search inverted Description
Disabled The camera will only search for plates with a bright background and dark characters This is the fastest mode and it is recommended if only this type of LP can occur.
Search The camera will only look for white-on-dark license plates when no dark-on-white license plates have been detected. This option is a reasonable compromise between speed and detection rate. It is still recommended to turn it on only when necessary.
Always The camera will always look for white-on-black plates. This option is slow and should only be used if absolutely necessary.

./images/Image27.png

Example of inverted and regular plates.


7.6   Mode of Operation

Depending on the application of the Carrida camera, different methods for image acquisition and internal data processing might be needed. These configuration settings affect the way the camera handles image sequences, duplicate readings, or reading errors.

Given an access control application for example, the camera should only read and transmit unique license plates so that a server in the background is not inundated with duplicate reading results.

./images/11_modeofoperation.png

The Mode of Operation parameter lets you configure the camera so that it behaves differently in terms of delay until a result is available, internal buffering and reading performance.

The dialog in this menu offers you good starting points for parameter sets which are useful for the intended application scenarios, but they can be adjusted to your needs.

The following table describes the default setups and their typical use case, the following sections describe each individual parameter in more detail.

  Mode Usage Output
m4 Single The camera reads every single image as quickly as possible. Each input image is considered on its own and unrelated to images before and after it. Every single license plate reading.
m3 Parking

This mode is designed for access and parking control uses. Each vehicle number plate is required to be detected at least the number of times defined in the Minimum Detections parameter.

If Minimum Detections value has been reached, the LP will be available as a detection, and it will be ignored until it is no longer visible.

Unique license plates, redundant readings are ignored.
m2 Offline In this mode the results are available with a delay of about 25 frames. The reading quality is the best in this mode, as the engine has more frames to analyze before producing results. The main purpose of this mode is to detect LP with the best possible quality without the need for real-time operation. Unique license plates, best possible reading quality.
m1 Freeflow

This mode is designed for freeflow operation. Considering the Minimum Detections parameter, the camera tries to read as quickly as possible. Results may become available with a delay of up to 15 frames.

The difference to Parking Mode is a larger internal Buffer Size, which increases reading quality at the cost of a higher delay of results.

Unique license plates. Longer delay until LP are read, but close to real-time.

7.6.1   Minimum Detections

The Minimum Detections parameter controls how many readings of the same license plate have to be made until a definite result is accepted by the camera.

A new reading is accepted as valid if:

  • The number of character differences to previously read strings is not greater than Maximum character Mismatch, see Maximum characters mismatch.
  • If it is detected inside the ALPR region of interest

Note

Hint Sign Minimum Detections delays the transmission of images and readings because the camera is set up to wait until this number of correct readings has been made.

7.6.2   Maximum characters mismatch

Maximum characters mismatch refers to the maximum number of characters by which two consecutive readings are allowed to differ and still be considered identical.

The useful range for this parameter is 1-3.

Example: If Maximum plate mismatch is set to 1, then two readings B12345 and B1245 are still considered to be identical, but not B12345 and B12456.


7.6.3   Reset After (s)

This option is used to reset the reading history of the camera. For example if the camera is in*Parking* mode and a car is in the image for longer than this parameter, its license plate will be re-transmitted.

This parameter is useful in Parking, Freeflow, and Offline mode.

If this option is set to zero, the plates will not be cleared.


7.7   Access control

Access control is always enabled by default, which means that the consideration of the Blacklist, Whitelist and Ignorelist and their related user-defined actions is always on.

This menu allows you to configure some details of the Carrida camera operation.

./images/12_accesscontrol.png

7.7.1   Low Confidence Threshold (%)

This parameter is used to set a limit below which a LP reading confidence is to be considered low, but still valid. The lower confidence limit must be equal to/greater than the Min Plate Confidence.

The typical use of this parameter in conjunction with the Low Confidence Read action is to detect and store low quality (= low confidence) readings for further analysis or retraining.


7.7.2   Whitespace Matching

This parameter defines whether whitespaces (' ') should be considered during reading. Camera readings will not contain whitespaces if this option is turned off.

This may be relevant in the following situations:

  • Matching of strings in the Whitelist
  • Matching of strings in the Ignorelist
  • Matching of strings in the Blacklist

The setting of this parameter affects the manual entry of list entries. If whitespace matching is allowed, you may enter a space character in the manual list entry dialog.

Warning

Warning Sign Special care has to be taken when lists with whitespaces are created or imported, and whitespace matching is disabled. In this scenario whitespaces are not read by the camera and LP entries with a whitespace will never be matched.


7.7.3   JPEG Compression Level - Actions

This option refers only to images that are sent using actions.

JPEG compression significantly reduces the size of the images - this results in faster data transfers (e.g. ftp uploads) and reduces the bandwidth consumption of the camera when it has to send live images to the web browser on your PC.

The level of compression can be set on the scale from 1 to 100, where a lower number means a higher compression rate with a resulting lower image quality.

Our recommendation is to set the JPEG compression level to 65, as this is a good compromise between image quality and required network bandwidth. If the camera is connected to a slow network, the JPEG compression should be reduced to a value of 50 or less.

Note

Note Sign It is a typical sign of a slow network connection if live images from the camera are not fully displayed in your browser. In this situation, the lower part of images is either sporadically or constantly missing during the live stream because the camera does not have enough time to transmit the whole image with the available bandwidth.

7.8   Display Information

The set of parameters in the Display Information menu allows you to configure the display of information in Live View with the On-Screen-Display (OSD).

Enabling/disabling any of these options will take immediate effect on the live image display.


./images/13_displayinformation.png

7.8.1   OSD Size

This parameter affects the size of the Display characters. Select between small, medium or large.


7.8.2   OSD Position

The HUD can be positioned on the top/bottom left side, or top/bottom right side of the image.


7.8.3   Text Info

Text information is an optional arbitrary string that can be displayed as a part of the OSD. Typically this field describes the location or use of the camera ('exit North').

The display of this text field is enabled with the Display info flag, see Display Info below.


7.8.4   Display Info

Display Info, when enabled (checked), displays the Text information defined in the text parameter above.


7.8.5   Display Time

When enabled, the current time will be overlaid on the result images and over the live stream images.


7.8.6   Display Date

When enabled, date information will be overlaid on the result images and over the live stream images.


7.8.7   Display Shutter

By enabling this parameter, the current exposure time (in microseconds) will be displayed.


7.8.8   Display Gain

If enabled, information about the camera analog gain (in dB) will be displayed.


7.8.9   Display Camera Framerate

Framerate refers to the number of individual frames (images) per second, which are currently retrieved from the camera sensor. Not all of those images are being processed. Depending on the processing load of the camera, some images may be skipped, resulting in the actual Reading Framerate - see next Section below.


7.8.10   Display Reading Framerate

Enabling this parameter allows information about the average processing framerate to be displayed in the OSD.

This number depends on the image size (low- or high-resolution), the ALPR ROI size (smaller is better) and other settings.


7.8.11   Draw Plate

When enabled, the camera will display LP reading results and confidences in the live image.


7.8.12   Draw State

If Draw State is enabled, the name of the detected state, as well as the reading confidence, will be shown.

This parameter will only be considered in combination with the Display Plate flag. If Display Plate is not enabled, the state information will also not be displayed.


7.8.13   Draw character confidence

By enabling Draw character confidence, the confidence of recognition for each character will be overlaid above the vehicle number plates.


Shown in the table below are examples of overlaying plate, state and character confidence.


Example:

Image (A) displays an LP image with the state and plate visualization enabled.

In image (B) plate, state and character confidence visualization is enabled.

Image (C) is generated with only plate visualization enabled.

vz

7.8.14   JPEG Compression Level - User Interface

This option refers only to the transmission of live images in the camera GUI.

JPEG compression significantly reduces the size of the images - this results in faster data transfers (e.g. ftp uploads) and reduces the bandwidth consumption of the camera when it has to send live images to the web browser on your PC.

The level of compression can be set on the scale from 1 to 100, where a lower number means a higher compression rate with a resulting lower image quality.

Our recommendation is to set the JPEG compression level to 65, as this is a good compromise between image quality and required network bandwidth. If the camera is connected to a slow network, the JPEG compression should be reduced to a value of 50 or less.

Note

Note Sign It is a typical sign of a slow network connection if live images from the camera are not fully displayed in your browser. In this situation, the lower part of images is either sporadically or constantly missing during the live stream because the camera does not have enough time to transmit the whole image with the available bandwidth.

8   System Configuration

The System Configuration page allows you to maintain the camera, adjust network settings and upgrade its components.

The following configuration settings can be modified:

  • Network - set the IP address of the camera, network mask, gateway IP and DNS IPs.
  • Time - turn the network time protocol on or set the local timezone.
  • Users - create, delete or change user profiles.
  • Classifier - upload and manage classifiers.
  • System - view trigger input/output activity and the camera SW version.
./images/14_sysconf.png

8.1   System Actions

The System Actions menu in the left upper area of the System Configuration page allows you to perform a number of basic maintenance function on he camera. Each of the functions is described in the following Sections below.

./images/system_actions.png

8.1.1   Restart ALPR

This option restarts the camera firmware including the web server.


8.1.2   Reboot system

This option completely reboots the camera. This is equivalent to a cold start of the camera.


8.1.3   Shutdown System

In case that you need to power down the camera, we recommend to shut it down using this action and then disconnect it from the power supply.


8.1.4   Download Logs

All camera logs can be downloaded by clicking on the Download logs button. The log files will be collected and compressed into a file name logs.zip. This file will be downloaded to the default download location of your browser.

After unzipping the log files on your PC, you can view them with a regular text editor.


8.1.5   Save Configuration

The complete set of camera configuration parameters can be exported and stored on your PC with this button. This feature may be useful in order to make a backup of the configuration, or even to transfer the settings to another camera.


The following parameters will be saved:
  • classifiers
  • date and time settings
  • network settings
  • parameter settings and region of interest definitions
  • users and their permissions
  • access lists
  • action definitions
  • information about Carrida software versions on this camera
  • the serial number of the camera

Saving the configuration is a three-step process, consisting of i) collecting the files on the camera, ii) creating an archive and iii) storing it on your PC. A popup window informs you about the progress while the export is being performed.

./images/20_configuration_save.png

8.1.6   Import Configuration

The state of a camera can be restored by importing a previously saved configuration file using this button.

An import effectively resets the camera to the state of the configuration file.

It is possible to import configuration settings from another camera - this may be useful when you want to quickly copy and distribute camera setups. If you import the configuration from a camera with a different serial number, you will be notified with a warning dialog.

For best compatibility, we recommend that you exchange only configuration files of the same firmware versions.

Note

Note Sign

Import has some limitations regarding the camera firmware versions:

  • version 4.3.1 cannot import configurations other than 4.3.1.
  • version 4.3.2 can import the configuration of version 4.3.2 and 4.3.1.
  • version 4.4.x can import the configuration of versions 4.4.x, and 4.3.x.
  • version 4.5.0 can import the configuration of all versions down to 4.3.1.

Warning

Warning Sign

A warning dialog will appear if the serial number of the imported configuration and the actual camera are different. You will be asked to choose whether to proceed with the import or cancel it.

You can choose which system settings to import by enabling or disabling features from the import dialog. This may be useful if you need to import only specific features like network settings.

After the camera is done importing the settings, a confirmation window appears to inform you about the settings that have been restored and to notify about a reboot which is necessary at this point.

./images/22_configuration_import.png

Importing server and network configuration


8.1.7   Change Camera Password

The root password of the camera can be changed with this setting.


8.1.8   Update Software

Carrida may provide a software update for your camera as update package, which may be installed using this menu. Select an update package and press the Apply button to start the update process. sw_update_apply

Usually a SW update will not change the camera settings, but this may be the case for certain types of updates.

./images/update_software.png

Status display during software update of the camera.


8.1.9   Factory Reset

This option is used to reverse the camera configuration back to factory settings.

All custom configuration data will be lost.


8.2   Network

With this configuration page you can setup the network connection of the camera:

  • DHCP - use DHCP on/off
  • Hostname - set the hostname of the camera
  • IP Address - set the IP address of the camera
  • Network mask - set the network netmask
  • Gateway IP - set the gateway IP address
  • DNS IP - set the DNS IP address of the camera
  • DNS IP 2 - set an optional second DNS IP address

Hint

Hint Sign

The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on TCP/IP networks where the DHCP server dynamically assigns an IP address and other network configuration parameters to each device on the network. A DHCP server enables computers to request IP addresses and networking parameters automatically from the Internet service provider, reducing the need for a network administrator or a user to manually assign IP addresses to all network devices. In the absence of a DHCP server, a computer or any other device on the network needs to be manually assigned an IP address.

Any of the above parameters can be changed by clicking on the Edit button, as shown in the image below:

./images/15_sysconf_network.png

System configuration for network settings.


Note

Note Sign When DHCP is enabled, the camera will have a dynamic IP address. Camera ClientTool can be used to detect and configure the cameras in the network. More information on how to use the ClientTool can be found under Carrida CameraTool .

If DHCP is turned OFF, manual network settings for all fields have to be provided in order to set up networking on the camera.

8.3   Time

The Time menu allows you to set the current time on the cameras as well as the local timezone. You may either set the date and time manually,or use a time server in the network to automatically sync the camera clock with an external source.

./images/16_sysconf_time.png

8.3.1   Manual setup of date and time

A click on the Edit button brings you to the time setting edit dialog.

In order to manually set the camera's time, NTP has to be turned OFF by sliding the NTP knob to the left. NTP_off

First select a timezone using the pull down dialog Chose Timezone, then manually enter date and time in the Set Time field.

By pressing the apply button the date/time settings will be saved and the dialog is closed.

./images/time_settings.png

8.3.2   NTP Protocol

You may configure the camera to automatically synchronize its internal clock with a time server in the network using the NTP protocol. The camera is provided with a list of standard NTP time servers, but you can customize the server list if necessary.

A click on the Edit button brings you to the time setting edit dialog.When you enable the NTP protocol by sliding the selector button at the top, NTP_on, the list of active NTP servers is displayed and may be edited:

./images/ntp_servers.png

Press the '+',or '-' buttons to add or delete servers. You still may choose a timezone, but not modify the date and time display.

By pressing the apply button the date/time settings will be saved and the dialog is closed.

8.4   Users (User Management)

The Carrida camera allows you to manage a number of user profiles, which are differentiated by the level of access to configuration and system settings. The addition of new users, deletion of old ones, or password changes can be performed in the user menu.

By default, each user has the following sign-in credentials. Note that the camera hides elements which are not accessible by the currently set user level:

  Username Password Description
Administrator admin secret Immediate access to all settings.
Basic User user simple Access to the most commonly used settings.
Setup setup setup The same access level as "viewer", plus change the ROI and the classifiers.
Viewer viewer pass Permission to view reading results and live image streaming.
SuperUser su car0000rida
This is a default password and it should be changed on the first start of the server.
Access to all settings, delete admin users and access to UI Design setting.

Note

Note Sign

The Users dialog is only accessible in advanced modes (Administrator and SuperUser).

After clicking on the Create new button, a dialog box will appear, as shown in the image below, allowing you to create a new user profile on the camera.

The user name and the password both have to have a minimum of 5 characters.

./images/17_sysconf_users.png

Note

Note Sign

The camera password is used for the internal system software, and it is not to be confused with the user passwords mentioned in this section.

8.4.1   The Carrida Super User

In Carrida 4.3.2 release the user type SuperUser has been introduced. This user has the username su and has the highest priority. The super user can delete and create admin users, it can also effect design changes in the user interface of the camera, e.g. change colors and icons.

The default password for the super user is constructed using the serial number of the camera as follows:

car<SN of the camera>rida.

The serial number of the camera is only available on the Carrida Cam Pro, Carrida Cam Basic+ models. All other supported devices use the code '0000' as default serial number. As per factory default, the SuperUser password is set to car0000rida on those devices.

It is highly recommended to change the default password for this user immediately during setup of the camera.


When you log in to a camera as super user for the first time, you will be prompted with a dialog window and asked to change the super user password.

For later password changes the standard method should be used as described in the Section Users (User Management).

./images/2_su_password_dialog.png

8.5   Classifier

Classifiers are files which store the trained country specific details about license plates. This information can, for example, be the size and the font of letters and numbers, the alphabet used, etc.

Classifiers are created for different countries, or regions of the world (Europe, USA, Thailand...) by Carrida.

The Carrida camera stores classifiers as a part of its firmware, and this list of classifier files may be updated and expanded by the user. As an overview, the the currently available classifier files are listed in the Available Classifiers section of the Classifier page.

The Classifier menu of the Configuration page allows you to upload new classifiers, delete old ones, or activate any classifier which is stored on the camera.

The dialog to modify classifier parameters can be called by clicking on the blue pencil icon on the right side of the Classifier menu:

./images/18_sysconf_currentclassifier.png

Note

Note Sign

Only one classifier may be active on the camera at a time, but a classifier can contain information about an arbitrary number of countries (e.g. all countries of the EU).

8.5.1   Switching Classifiers

As mentioned above, the camera can store a large number of classifiers as a part of its firmware and those classifiers can be selected and activated anytime. To do so, click on the edit icon, this opens a dialog with a drop down list of classifiers.

By selecting a new entry from the list and pressing the green apply button, the selected classifier will be activated.

./images/19_sysconf_switchclassifier.png

Switching classifiers


For the new classifier to become activated, the camera software will be initialized and restarted. This may take up to a minute.


8.5.2   Uploading Classifiers

The list of available classifiers can be extended by uploading new classifier files to the camera. In this way you can setup the camera for new regions of the world, or update and improve its existing reading capabilities.

New classifiers can be uploaded by clicking on the green upload button under the the drop down list. This brings up a dialog window into which a new classifier can be dropped ('Drop classifier file here...').

Alternatively, a click into the rectangular drop box opens a new dialog that prompts you for a classifier file to load from your PC.

./images/20_sysconf_uploadclassifier.png

Upload classifiers


A pop-up dialog which appears after the upload operation will ask whether you want to set this new classifier as the new default.

When uploading a new classifier, you can opt for deleting all other stored classifiers by turning on the option Delete other classifiers. Use this option with care!

8.6   System

The system menu page displays general information about the camera software versions, disk usage, as well as the status of the available digital input and output lines.


./images/21_sysconf_system.png

8.6.1   Libraries

This table lists all versions and build dates of the Carrida software libraries on the camera.


8.6.2   Inputs/Outputs

Outputs and Inputs section shows information about the status of the digital IO lines of the Carrida camera.

The status of the available digital input lines is displayed in the Inputs section.

The outputs can be electrically switched through the user interface by clicking on the respective output box Out#1, Out #2, ....


./images/io_control.png

The I/O line status is updated approximately every 200 ms.


8.6.3   Disk Usage

This graph displays the amount of free space left on the camera internal flash storage.


9   Placeholders for naming patterns

This section describes all the special keywords that can be used as placeholders in messages used within actions. See Actions for a description of actions and their use.

During the creation of a message as a part of an action, placeholders will be replaced with their respective dynamic values.

Note that some special characters like ',' are used internally by Carrida. Those characters need to be replaced by special placeholders within an action message. You can enter those characters directly in the user interface though, they will be converted to the placeholder representation automatically.

Only within message definitions in the REST API of the camera it is necessary to use the placeholder strings.


Placeholder Description
   
"%LP%" This keyword will be replaced by the license plate value string.
"%LP_WS%" This keyword will be replaced by the license plate value string containing found white spaces.
"%STATE%" This keyword will be replaced by the state string.
"%CONF%" This keyword will be replaced by the confidence value string.
"%CONF_STATE%" This keyword will be replaced by the state confidence value string.
"%NUM_ROWS%" This keyword will be replaced by the count of rows of the license plate as a string.
"%REGION%" This keyword will be replaced by the region string (if available). Example: "Bayern"
"%REGION_CITY%" This keyword will be replaced by the city string (if available). Example: "Munich"
"%REGION_SHORT%" This keyword will be replaced by the region abbreviation. Example: "M"
"%ENDING%" This keyword will be replaced by the LP suffix (if available). Example: "Taxi"
"%ENDING_SHORT%" This keyword will be replaced by the LP suffix abbreviation (if available). Example: "TX"
"%COL_PLATE%" This keyword will be replaced by the color of the plate as a string.
"%COL_CHARS%" This keyword will be replaced by the color of characters as a string.
"%POS_X%" This keyword will be replaced by x position in the image of the left upper corner of the license plate as a string.
"%POS_Y%" This keyword will be replaced by y position in the image of the left upper corner of the license plate as a string.
"%POS_W%" This keyword will be replaced by the width of the license plate in the image as a string.
"%POS_H%" This keyword will be replaced by the height of the license plate in the image as a string.
"%ANGLE%" This keyword will be replaced by the direction angle in degrees (0..360) of the found plate.
"%YEAR%" This keyword will be replaced with the year string. (When a license plate was detected)
"%MONTH%" This keyword will be replaced by the month string. (When a license plate was detected)
"%DAY%" This keyword will be replaced by the day string. (When a license plate was detected)
"%HOUR%" This keyword will be replaced by the hour string. (When a license plate was detected).
"%MINUTE%" This keyword will be replaced by the minute string. (When a license plate was detected).
"%SECOND%" This keyword will be replaced by the seconds string. (When a license plate was detected).
"%FRACSEC%" This keyword will be replaced by a fraction of seconds string. (When license plate was detected).
"%CR%" This keyword will be replaced by the carriage return sign.
"%LF%" This keyword will be replaced by the line feed sign.
"%FULL_IMG%" This keyword will be replaced by base64 encoded full image string.
"%LP_IMG%" This keyword will be replaced by base64 encoded cropped LP image string.
"%REL_IMG_<w>_<h>_<p>%" This keyword will be replaced by base64 encoded image cropped relative to the full image size and resized to defined output size. <w> should be replaced with the output image width (in pixels), <h> with the output image height and <p> should be replaced with the with the cropping percentage (0 < <p> <= 100).
"%REL_LP_<w>_<h>_<p>%" This keyword will be replaced by base64 encoded image cropped relative to the LP image size and resized to defined output size. <w> should be replaced with the output image width (in pixels), <h> with the output image height and <p> should be replaced with the with the cropping percentage (100 < <p>).
"%FULL_OV%" This keyword will be replaced by base64 encoded full overview image string.
"%REL_OV_<w>_<h>_<p>%" This keyword will be replaced by base64 encoded overview image cropped relative to the overview image size and resized to define output size. <w> should be replaced with the output image width (in pixels), <h> with the output image height and <p> should be replaced with the with the cropping percentage (100 < <p>).
"%AREA_INDEXES%" This keyword will be replaced by a string constructed with the indexes of areas where the plate is detected, separated by a comma.
"%AREA_NAMES%" This keyword will be replaced by a string constructed with the names of areas where the plate is detected, separated by a comma.
   
Placeholder for REST API Description
"%COMMA%" This keyword will be replaced by a ','.
"%BR_ON%" This keyword will be replaced by a '('.
"%BR_OFF%" This keyword will be replaced by a ')'.
"%SQ_BR_ON%" This keyword will be replaced by a '['.
"%SQ_BR_OFF%" This keyword will be replaced by a ']'.
"%EQUALS%" This keyword will be replaced by a '='.
"%AND%" This keyword will be replaced by a '&'.

Example:

The camera has detected a German plate "TEST123" on 01.01.2017 at 10:15:20. You can form a naming pattern as follows:

" License plate value: %LP% from %STATE% " the form will be displayed as : " License plate value: TEST123 from DE "
" Filename_%HOUR%_%MINUTE%_%SECOND%.jpg " the form will be displayed as : " Filename_10_15_20.jpg"

10   Modifications of the User Interface

From version 4.3.2 on, the Carrida web interface allows you to modify some aspects of the user interface design. You can change the colors of user interface elements, or replace the icons with custom icon sets.

These changes are only allowed for the *SuperUser*.

Once you login as super user, you get access to the UI Design menu of the camera,

./images/ui_design_menu.png

from which you can choose the design editing page with the two sub-menus Style, and Icons.

./images/22_design_style.png

10.1   Style Change

In order to provide the possibility to personalize the Carrida UI, the website color design is split into multiple groups. The color for each group can be edited independently by clicking on the Edit button in the lower right corner:

  • Primary and secondary colors The color of the page details such as buttons, table headers, and navigation.
  • Error color The color of error status visualizations.
  • Font color The color of the text elements.
  • Body color The color of the body background.
  • Sidebar color The color of the navigation sidebar.
  • Card color The color of the background of UI cards.
  • Panel color Color of the panels contained in the access and settings pages.
  • Border Radius The radius of corners drawn for various elements.
./images/general_changes_ui.png

The Style menu contains a table with the current values for all properties. These values can be edited by clicking into the numeric field of each element. A pop-up editor contains a color picker for color values respectively a number input for the border radius.

Changes you make are immediately visible in the live user interface.

./images/design_style.png
./images/color_picker.png

Click on the Apply button to permanently save changes. The camera will store the chosen values and show a message dialog with the following info: "You have to perform a hard reload of the page or clear the cache in order to see changes in the current browser".

The Reset to default values button (white circular arrow) can be used to revert the UI back to factory settings.

Use the Cancel button to exit the UI design page without saving.

Do not forget to clear the browser cache after reset of the style elements!

10.2   Icon change

Each icon which is used in the Carrida Web UI can be replaced with a custom version. This allows you to adjust the Carrida UI to your corporate design more closely than just with color changes.

All currently used icons are displayed in the Icons tab. By clicking on any of the icons, a dialog window pops up with the options for icon replacement. You can choose to upload a new icon image or to reset it to the default version.

./images/icon_change.png

After changing the icon, a message dialog window with the notification about the status of the changes will pop up.

Note

Note Sign

In cases where the change was successful, a hard reload of the camera UI webpage or a cache clear should be performed in your browser.