Carrida Camera Program User Documentation

Revision: 1.3
Date: 2018-12-10
Contact: support@carrida-technologies.com
Copyright: 2017-2018 Carrida Technologies GmbH, Ettlingen, Germany
Author: Carrida Support

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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 integrates an imaging and processing device, together with the Carrida 4 engine into a compactly embedded license plate reading sensor.

Typical applications of the Carrida Camera include:

  • Parking lot management
  • Vehicle ticketing/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

For further details and information see also the related documents:

A list of abbreviations used throughout this document:

ARM64
Stands for processors with the v8 AARCH 64-bit instruction set.
ARM
Stands for processors with the v7 ARM 32-bit instruction set.
ALPR
Automatic License Plate Reader.
dB
Decibel, in the Carrida documents 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.

2   Quick start with Carrida Camera

Enter the provided IP address in the address bar of any Internet browser (i.e. Chrome, Firefox, Opera etc.) and the Carrida Sign in page will open. A username and a password are required to sign in.

The Carrida User Interface offers three different user profiles: administrative, user and viewer. The main difference between the three is the level of access to configuration and system settings. Factory Sign in credentials are as follows:

Administrator: Basic user: Viewer:

username: admin

password: secret

username: user

password: simple

username: viewer

password: pass

Access to all settings. Has the authority to add, delete and edit other users. Access to most commonly used settings. Access to view live image streaming and reading results. No authority to change any parameters.
tt

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

Modes differentiate depending on the level of access to parameter settings. Viewers can only view reading results, Users are granted access to most commonly used settings.

Administrators have access to all camera, system and configuration settings. Configuration settings visible in administrator mode are not recommended being changed unless necessary. When changing these settings follow the instructions written for each parameter in the manual.

Note

Note Sign

All graphical images will display the interface under admin mode.

2.1   Configure the ROI

ROI, short for Region of interest, refers to the area on which ALPR software will focus while processing the image. There are two different types of ROIs: ALPR brightness control ROI and ALPR detection ROI.

The notable difference between the two is in color. Brightness control ROI is shown as a green polygon and the ALPR detection ROI as a yellow polygon.

How these regions differentiate and how to resize them is explained in the table below.

Live view Camera settings Server settings
t1 t2 t3

The OSD on the Live result page will continuously display a live image stream.

The yellow polygon overlaying the image represents the ALPR ROI. Only plates detected inside this area are going to be processed by the SW. The polygon can be adjusted in the Settings, in the Interface tab.

Both ROI for brightness control and ROI for ALPR detection can be defined on the Settings page.

The green rectangular area overlaying the OSD in Camera settings is called the Brightness control ROI. Brightness control features will be applied to the area inside the ROI.

The size of Brightness control ROI should depend on the size and movement of vehicle plates. It is recommended to limit this area to the surface where the vehicles might move through the screen. This directs the SW to focus on fewer pixels thus reducing the time needed to process the images. Brightness control parameter can be turned on/off in Camera settings. It is recommended to have it switched on at all times to ensure better image acquisition quality.

The ROI found in Interface settings is different in color and functionality from the previously described brightness control ROI.

The yellow rectangular area overlaying the OSD represents the ALPR detection

Plates positioned outside this frame will not be processed.

When the vehicles are not expected to appear in the entire frame it is recommended to resize the ROI. This will decrease processing time as the program will not search the entire frame for plates.

View on Live results tab. ROI changes in Settings -> Camera ROI changes in Settings -> Interface
  Resize the rectangle by clicking on any of the highlighted corners and drag/drop it to the wanted position. When finished resizing, click on the Apply button.

Note

Note Sign The ALPR detection ROI should be bigger and enclose the brightness control ROI.

2.2   Result images

Two pages display reading results:

  • Live result - displays processed images with overlaid reading results and lists the latest results in table view.
  • Text result - results are listed in table view. Clicking on a list entry will open the processed image with overlaid reading information.

The result list can be limited to a certain amount of entries and have a time limitation. In the image above the list is limited to 100 entries or the last 24 hours. When one of those conditions is met the entry will be removed from the list. In cases where multiple recordings have been made and the list is too long, the user can move through the entries by using the Go to page button.

Images can be downloaded from the Text result page by clicking on Download button in the top right corner above the image. It is also possible to export an entire list as a csv or an excel document.

Overlaid on processed images are the ALPR reading results. Reading results can consist of:

  • state of vehicle registration,
  • state recognition certainty,
  • vehicle number plate,
  • number plate recognition certainty,
  • character recognition certainty.
./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% certainty. W _ _ 4 3 3 are the vehicle number plates, recognized with 100% certainty. The certainty of recognition is displayed above each character; in this case it is 100%.

3   Carrida Home

Entering the IP address in any web browser Carrida will open the login page. Submitting a valid username and password will open the homepage as illustrated in the image below.

./images/1_home.png

Homepage of Carrida Camera Configuration


In the upper right corner of the page is the User menu. Easily log out and switch between user profiles by clicking on this link.


Classifiers are files which are used to support ALPR. They are sorted by regions and provide additional information about plate specifics, i.e. size of characters, font style, plate dimensions etc. Usage of classifiers significantly improves ALPR. Information of which classifier is being used is listed under camera information section.


The bottom of the page contains navigation links to different sections of the interface. Hover the mouse pointer over the icons and read a short description of the section functionality.

4   Live Result

The main part of the Live result tab is the live image streaming. The latest nine reading results will be displayed on the list on the right side of the GUI. The OSD on the Live result page will continuously display a live image stream. The yellow polygon overlaying the image represents the ALPR ROI. SW will only process the plates that detected inside of this area. The polygon can be adjusted on the Settings page, under the Interface tab.

The main advantage the Live Result tab has, lies in the fact that it can be used to check if the reading results are correct, in real-time.

./images/2_liveresult.png

5   Text Result

On the Text Result page, processed image results are displayed in table view. The table consists of:

  • Timestamp with the date and time when the plate was detected.
  • License plate information.
  • Confidence meaning the percentage of confidence for the given license plate recognition.
  • Country of vehicle registration.
  • Country confidence meaning the percentage of confidence for country recognition.

The maximal capacity of results is 10000 and the longest time period for images to stay on the list is 10000 hours. When the limitations are reached, the oldest images will be replaced by new images.

./images/3_textresult.png

ALPR Text results.

Complete lists can be exported as csv and excel files by clicking on the buttons on the top left side above the list (see image).

The list can be searched through by any given information (plate number, date, time, etc.) or by typing a page number in the GoTo Page field, clicking on the arrow next to it and going through all the entries on that page.

When results are generated quickly to display recent results it needs to be reloaded, the Reload button is on the right bottom side of the tab.


The right side of the interface is reserved for result images. To see the images just click on the desired entry on the list and an image will be displayed. Individual images can be downloaded by clicking on the Download button above the image.

Under the result image actions, related actions and their states are listed. This provides information on which concrete action was defined for the detected plate, and if the action was successful or not.

6   ACCESS Configuration

ACCESS configuration provides the tools for controlled vehicle access. Actions and lists are a crucial part of Access control. Actions are a way to tell the SW what to do with the images that have been collected and are prompted by a certain event (detection of any LP, ALPR detection of a specific LP or no ALPR detection). Lists are a way to read the results from Actions. They can be formatted into three categories: Whitelist, Blacklist and Ignorelist. Each category supports Importing and Exporting of lists as well as adding single entries. Formatted lists will then be used to prompt actions previously defined in the Actions tab. Detection of a specific plate defined in the list will trigger an action.

./images/5_actions.png

Access control configuration page.


There are three types of events associated with the actions:
  • Events are considered to be "Read events" when ALPR detects any license plate. The SW will then trigger actions defined under this category.
  • NoRead events occur when NO plates are detected between limitations set in Settings-Trigger. For example, Start and Trigger timeout are defined and no valid plates are detected, ALPR will then perform an action defined in this section. Triggers are explained in detail in Section 7.4.
  • LCR events - a Low confidence read event is created when the plate is read but the confidence level is lower than set in parameter Settings-Access control-Limit of Low Conf.

Furthermore, Whitelist match/mismatch, Blacklist match/mismatch and Ingorelist match/mismatch may be used for triggering actions. In this case, the action will be prompted when a plate from the list is detected (match), or when a plate is detected but not on the list (mismatch).


Hint

Hint Sign

Use the "!" sign to indicate all plates. Use ".*" sign as a wild character.



Example:If the user wants to have an action performed on all plates that start with AZ, the list entry should be: !AZ.* . If the user wants to have a certain action performed on all plates that start with AZ and end with TX, the list entry should be: !AZ.*TX

Concrete actions that can be defined for events will be explained in detail in the continuation of the manual.


6.1   Actions

Actions are prompted by a certain event. This event can be ALPR detection of any plate, ALPR detection of a specific plate or no ALPR detection.


List of actions:
  • Ftp Upload
  • Ftp Database
  • Store
  • Digital out
  • Serial
  • TCP
  • HTTPPUT

After clicking on the ADD button, the user is prompted to choose a specific action.

./images/6_addaction.png

When clicking on the selected action (i.e. ftp upload) the list of related parameters becomes visible. Different actions offer a different set of parameters individually explained in the flowing sections.


Some actions offer a naming pattern field.

Naming patterns are used to specify which name ALPR should generate with the reading result. They can be constructed using placeholders for specific information.

Placeholders are characters written between two percentage (%) symbols (look at the example below). They are later substituted with specific information about a reading.



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 ALPR detected a vehicle with number plate W223344 on the 03.08.2017, with a level of confidence 98%. The following naming patterns can be formed

  • Naming pattern: Detected %LP% on %DAY% / %MONTH% / %YEAR% .
  • Output: Detected W223344 on 03 / 08 / 2017 .
  • Naming pattern: %LP%(%CONF%) on %DAY%/%MONTH%/%YEAR%.
  • Output: W223344(98) on 03/08/2017.

A complete list of placeholders can be found in Chapter 9.


6.1.1   Ftp Upload

f

To create the action, enable it as shown in the image on the left.

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

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

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 .

Naming patterns are used to include specific reading information (date, time, plate...) in the file name. How to use and format names using patterns read in Chapter 9.

Images can be uploaded as following:

  • Empty file
  • Full image
  • License plate image only

Empty file sends files with no images. This saves memory and increases the upload speed.

Image quality refers to the compression rate, it can be set from 1 to 100%, 1 being the maximal compression level which will produce images with the lowest quality, and 99 being the minimal compression level with the highest image quality. We recommend setting this to 65-70%.

Enable the setting by sliding the Enable button to the right side, until a blue ON button is revealed


6.1.2   Ftp Database

4

To create the action, enable it as shown in the image on the left.

This action will create and automatically update a text file on the ftp server, containing information about vehicle number plates recorded by the ALPR.

Set Enable to true for the action to be executed (as shown in the image).

Enter the Host ftp servers IP address in form of sftp://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 .

Filename stands for the name of the database to be updated (created) with newly recorded information.

Naming patterns define the database entry string. How to form naming patterns read in Chapter 9.

Enable the setting by sliding the Enable button to the right side, until a blue ON button is revealed


6.1.3   Store

5

To create the action, enable it as shown in the image on the left.

This action will store data on the cameras internal memory.

Define the name of the Folder and the Postfix.

The Postfix field must not be left empty. It is the part of the name which will be appended after the name and the extension.

Minimal free disc space required to save the file is defined by Free space parameter. If there is less space than defined here the files will not be saved.

Enable the setting by sliding the Enable button to the right side, until a blue ON button is revealed


6.1.4   Digital Out

6

To create the action, enable it as shown in the image on the left.

This action will produce digital output 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.

The Non-blocking and Invert signal can be disabled/enabled.

Enable the setting by sliding the Enable button to the right side, until a blue ON button is revealed


6.1.5   Serial

8

To create the action, enable it as shown in the image on the left.

Construct a message using Naming patterns and this

message will be sent through the serial port.

Enable the setting by sliding the Enable button to the right side, until a blue ON button is revealed


6.1.6   TCP

9

To create the action, enable it as shown in the image on the left.

TCP (Transmission control protocol) requests re-transmission of lost data, rearranges out-of-order data, and reduces other problems that may occur due to network congestion, traffic load balancing or other unpredictable network behavior. It is optimized for accurate, rather than timely delivery.

Write a message for the action using name patterns (Chapter 9). Enter the IP address of the receiver of the TCP address and the Port used to send the TCP message.

Enable the setting by sliding the Enable button to the right side, until a blue ON button is revealed


6.1.7   HTTPPUT

ö

The PUT method puts a file or resource at a specific URL. If there is already a file or resource at that URL, PUT will replace that file or resource. If there is no file or resource there, PUT creates one.

Set Enable to true for the action to be executed (as shown in the image).

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

In patterns define the name of the file using the guidelines in Chapter 9

Enable the setting by sliding the Enable button to the right side, until a blue ON button is revealed

6.2   ACCESS lists

Access Lists are text documents that contain LP numbers. They are used to trigger previously defined actions when a plate from the list is detected. An example of an action can be sending plate information with an image file to the defined ftp server, a signal can be sent for gate control, csv file can be updated, etc.

There are three types of events that can be set to trigger actions:
  • Read event - when ALPR recognizes a plate
  • No-read event - when there are no plates recognized between given limitations set in ALPR Configuration-Trigger (i.e. Start and Stop trigger, or Start trigger and Trigger timeout). More information about Triggers find in Section 7.4.
  • Low confidence read (LCR) events - Low confidence read event is created when the plate is read but the confidence level is lower than set in parameter Limit of Low Confidence

LCR events are connected with access control. The configuration page can be found under Settings (Section 7).


Form a list combining up to 3 parameters:

  • plate number
  • start/stop date
  • start/stop time.

There are two ways to form access lists: importing or creating it directly on the ACCESS configuration page.


The first entry in the dialog box is the plate number. Actions can be set to Always enabled when the plate is detected or they can be triggered between defined times This time window can be defined through the start and end date, start and end time, and on individual days of the week (marked with So, Mo, Tu, We, Th, Fr, Sa). By default, the time span is set to 24/7, Monday to Friday, for a month up from the current date.

In the example image, Monday-Friday are checked, meaning that if a vehicle is detected on any working day between the set dates, an action will be triggered.

After finishing the list click on add and save.

ls
How to import a list?

Open any text editor to create a file and save it any_name.txt. Only textual documents can be imported.

Enter the information according to the formatting rules and save the file. On the ACCESS page under the List tab, click on Import and select the newly created document from your device.

If importing was successful the content from the document will display on the screen. If needed, the imported list can easily be edited directly on the page.

When the list is finished click on Upload to submit. After uploading the ALPR will register the information and implement the list.


Formatting rules:
  • Do not use blank spaces, everything should be written in a single line.
  • Plate number, date and time must be separated with semicolons (;).
  • When listing multiple dates/times separate them with a comma (,).
  • Date format is: YYYYMMDD-YYYYMMDD, with no space between the numbers.
  • Time format is: 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 brackets starting with Sunday, ending with Saturday (0111110). In this example "0111110" non-active days are Sunday and Saturday, represented with zeros (0).
  • The amount of dates set must be equal to the amount of time restrictions ( W223344;20170101-20170101,20170102-20170102,20170103-20170103;03:00-04:00(0111110),03:00-04:00(0111110),03:00-04:00(0111110) ). If there are more dates than time restrictions (and vice versa) the command will be perceived as invalid.


Practical examples and descriptions of the rules are shown in the table below.

  Example Description
Only plate number W223344 Actions will be taken when a vehicle with this plate number 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.

     
Example: W223344;20170101-20170125;03:00-04:00(0111110) an action will be taken if the vehicle with plate number W223344 is detected from 01.01.2017 (00:00) until 25.01.2017 (23:59) between 03:00 and 04:00 on any day of the week, except Saturday and Sunday (0111110).

To trigger actions when any plate is detected upload a combination of symbols !* to a list class (i.e. permanent list).

Example:
If " !* " is on the permanent.txt list, and for this list, a positive matching action Store is enabled, the program will store all detected plates. pc

6.2.1   Regular Expressions

Regular expressions are used to conveniently define patterns for license plates or groups of license plate strings.

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

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 single character '.' when used outside of a character set (see below) will match any single character. E.g. the regular expression

G.23456

will match


G123456, or
GU23456

(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 being 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 preced any other atom! Use .* 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

The following paragraphs give some examples for regular expressions and use cases:


To match any license plate strings 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}

Note

Note Sign When making a list using regular expressions, the string should always start with "!" sign.

7   Settings

The essential segment of ALPR is image acquisition (gathering) which can be controlled by different parameters.


Difficulties that may occur during image gathering:
  • poor image resolution, if the plate is too far away,
  • blurry images as a result of motion blur,
  • poor lighting and low contrast due to overexposure, reflection or shadows,
  • object obscuring (part of) the plate.

To eliminate these irregularities it is important to understand how changing the settings would influence image acquisition and reflect on image quality.

Camera settings allow the user to modify brightness control parameters and define gain and shutter speed. How to set these parameters properly and what they mean can be read in Section 7.1.

The camera has an internal IR LED light which can be turned on/off through the LED flash tab, as explained in Section 7.2..

7.1   Camera

OSD properties are modified with the first 9 parameters of the Camera menu:

Changing these settings will reflect on the overlaid information on the OSD.

./images/8_settingscamera.png

Gain and shutter options directly impact image acquisition. In short, gain represents the camera's sensitivity to light, in decibel, and shutter speed measures the exposure time in microseconds. Read more on how Minimum gain (7.1.11.) and Maximum gain (7.1.12.), Minimum shutter (7.1.12.) and Maximum shutter (7.1.13.) affect image gathering in following sections.


What does the green polygon represent?

The area inside the borders is called the brightness control region of interest. It defines the field within which the camera measures and corrects the image brightness.

It is important to minimize this field. Limit it to the area only where plates are expected to appear. This maximizes the impacted of brightness control parameters on the selected area during image acquisition.

How to change this polygon and more information about the ROI find in Section 7.1.18..


When the ROI is defined enable Use Brightness control ( Section 7.1.18. ) to allow brightness control over the ROI.


7.1.1   Text Info

Text information is an optional identification name of the camera appointed by the user, i.e. "Carrida ALPR" on sample images in the manual.

Enable Draw info, Section 7.1.2. and text information will be displayed on the OSD and Result images.



7.1.2   Draw Info

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



7.1.3   Draw Time

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



7.1.4   Draw Date

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



7.1.5   Display Shutter

By enabling this parameter, the average shutter speed (in milliseconds) will be overlaid on the OSD.



7.1.6   Display Gain

If enabled, the information of average gain (in decibel) will be overlaid on the OSD.



7.1.7   Display Camera Framerate

Frame rate refers to the number of individual frames (images) that are displayed in a video per second (fps).

Enabling this parameter allows the information about camera's processing frame rate speed to be displayed on the OSD.



7.1.8   HUD Size

This parameter affects the size of previously defined information overlaying images on the OSD and result images.

Select between small, medium or large format and click Apply for the changes to take place.



7.1.9   HUD Position

HUD can be positioned on the top/bottom left side, or top/bottom right side of the OSD. Select a position and click Apply for the changes to take effect.



7.1.10   JPEG Compression Level

JPEG compression reduces the size of images. That results in faster ftp uploads and reduces bandwidth consumption.

The level of compression can be set on the scale from 1 to 100%. A higher rate of compression results in lower image quality.

Our recommendation is to set the level on 65%, as the best compromise between the quality and size.



7.1.11   Minimum Gain (dB)

Gain controls the amplification of the signal from the camera's sensor. It boosts the signal by some amount, thereby making already captured images look brighter.

As a result of signal enhancement, negative image blur may occur. The reason is that the overall signal is boosted, making also the noise more visible.

Our recommendation is to set this parameter to 0.



7.1.12   Maximum Gain (dB)

Gain controls the amplification of the signal from the camera's sensor. It boosts the signal by some amount, thereby making already captured images look brighter.

As a result of signal enhancement, negative image blur may occur. The reason is that the overall signal is boosted, making also the noise more visible.

Reasonable upper limits are typically 6-10 dB. We recommend a maximum gain value of 10 for the Carrida Camera.



What is a shutter?

Camera's shutter is a mechanism that lets the light in through the lens onto the camera's sensor. It has two states- open and closed, and the time it stays open is measured in fractions of a second.

Fast shutter speed means the shutter will open and close quickly, therefore only a small fraction of light passes through. Slow shutter speed means that it stays longer open, which allows more light to pass through, producing brighter images.

Closing the shutter in fractions of a second gives control over motion blur. What that means is, if the shutter closes faster in the relation to the object, the resulting image will be sharper. Vice versa, if the shutter speed is slower than the object in the image, images may be blurred.

In further text read how to set minimal exposure(shutter) speed (7.1.13.) and maximal exposure(shutter) speed (7.1.14.) accordingly to vehicle speed. Setting these parameters will give the ALPR SW a range (in microseconds) in which the exposure time can vary.



7.1.13   Minimum Shutter

Minimum shutter refers to minimal exposure time in microseconds that the shutter will stay open.

Shutter speed should be changed according to the vehicle speed. If the vehicle is approaching at high speed, the exposure time should be reduced.

When Minimum shutter is set too high (in relation to the vehicle speed) it may cause lower reading performance because images can turn out blurry.

As a general recommendation, the following exposure (shutter) times are advised:

  • shutter time of 0.1-3 ms on highways, for high-speed vehicles
  • shutter time of 0.1-3 ms in urban areas, for medium speed vehicles
  • shutter time of 1-20 ms in parking situations, for slow vehicles
What to do if vehicles are blurry?
  • In that case, the shutter speed might be set too high. Try reducing it according to recommended exposure times on the list above.


7.1.14   Maximum Shutter

Maximum shutter refers to maximal exposure time (in microseconds) that the shutter will stay open for.

It is recommended to set this parameter higher during lower light exposure. It will raise the visibility of the plates, as more light will come through the lens. This does not mean the higher the shutter is set, the better. In the same scenario when a car is in higher speed it will cause distorted images.

How to estimate the maximum allowed exposure time:

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

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) 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 (i.e. number of pixels), the maximum allowed exposure time in ms can be computed as follows: exposureTime(ms) = 1000*(T/resolution)

A general recommendation on how to set exposure time can be found in Section 7.1.13. .



7.1.15   Low Resolution

Carrida camera sensor can operate in two resolutions, low resolution 640x480 pixels and high resolution, 1280x960 pixels.

If Low resolution is enabled images will be captured in 640x480 pixel resolution. If it is disabled, the high resolution will be activated.

Hint

Hint Sign Enabling low resolution has the advantage that the achievable reading framerate becomes higher because less data has to be transferred to memory, thus less processing is necessary.



7.1.16   Image Rotation

Rotate the angle of input images in one degree steps so cars appear in images horizontally. This is not a requirement, but it can slightly improve the recognition quality.



7.1.17   Brightness control Region

Brightness control region is the area enclosed in the green polygon. This field will be affected by brightness control parameters.

It is important to define the region within the polygon only to the area where the plates will move through the screen. Making the ROI as small as possible, but big enough to cover the movement of the plates through the screen will maximize the effects of brightness control parameters on the image.

Resizing the Brightness control polygon
Click, drag and release the corner of the polygon. Click on Apply next to the Brightness control region option under the image to save the changes.
example

In this case, the camera is mounted in front of the gate. The polygon captures the path which the vehicle will take. This will direct parameters for brightness control to affect a more specific area, therefore producing clearer images with less processing time.

Note

Hint Sign In order to produce clear and sharp images, the SW will try to keep the conditions (lighting, brightness, exposure) inside the ROI optimal.



7.1.18   Use Brightness control

Use Brightness control allows brightness control over the defined region of interest (ROI). Detailed information on brightness control ROI can be found in the Section 7.1.17. .

Our recommendation is to leave this parameter enabled at all times, as it will enhance image quality and produce better ALPR results through the following settings:

These parameters are by default set to suit most indoor/outdoor situations and are recommended not to be changed if not necessary.



7.1.19   Brightness control maximum saturated pixels

Exposure control of the camera counts all the good pixels within the brightness control area. Good pixels are neither too dark nor overexposed. A pixel is saturated when it takes on its maximal value. When pixels are oversaturated they lose information about the scene. In cases where there are too many overexposed pixels, the camera will change its exposure settings to make the image darker. The correct pixel counts are indicated as a percentage (0-100) relative to the image size.

Hint

Hint Sign What to do if the license plates are continuously 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 reduce 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.



7.1.20   Brightness control minimum correct pixels

All pixels with brightness below the grey value threshold 90 will be considered as pixels that are not illuminated enough. All pixels with the grey value of over 200 will be considered as overexposed. Pixels that are between low and high brightness levels are considered well lit/correct pixels.

Correct pixel count is indicated as a percentage (0-100) relative to the image size. If there are too many overexposed and/or underexposed pixels the camera will adjust exposure settings to get the correct pixel amount to reach at least the minimal level set here.

Hint

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

If the plates are constantly too dark, the value of minimum correct pixels needs to be increased, so that the camera tries to increase the number of those pixels. Example: modify the value from 3 to 5% and observe the effect in the live image.



7.2   LED Flash

Carrida camera is equipped with infrared (IR) LED flash. It produces artificial light to illuminate vehicles.

./images/9_settingsledflash.png

LED Flash settings on the Configuration screen.



7.2.1   Enable Flash

Carrida camera IR LED lights produce artificial light to illuminate the approaching vehicles. Enabling flash will turn the IR LED lights on.

We recommend leaving flash enabled at all time.



7.2.2   Flash Duration (µs)

Flash duration defines the duration for which the flash is actually on and emitting light. As the duration gets shorter, its ability to obtain control over motion blur gets better. For example, shorter flash durations are desirable when dealing with vehicles that are moving faster. In a typical city environment with up to 70 km/h (45 mph), a flash duration of 1ms would be a good choice.



7.2.3   Flash Current (mA)

Carrida camera IR LED lights produce artificial light to illuminate vehicles. The controller covers a current range from 150 to 1500 mA. It is recommended to leave the current set in a range from 500 mA to 1000 mA, so that it is bright enough and the LP could be illuminated even in the presence of vehicle headlights.

Note

Note Sign

If the duration is set to 150 mA or lower, the flash will be turned off.



7.3   Interface

The set of parameters under the Interface tab allow configuring how the result image plates will be visualized.

Visual properties of ALPR result images can be modified through the following parameters:



Enabling/disabling any of these options will reflect on the design of result license plate images, as shown in the Example, Section 7.3.5.

./images/10_settingsinterface.png


Here is where the term ALPR region of interest (ROI) is introduced. This is the area within the yellow rectangle whose purpose is to limit the ALPR detection and the processing only to the vehicles within the borders.

The rectangle can be re-sized with "click and drag" method by selecting and moving one of the marked corners. When done with resizing, click Apply beneath the OSD, next to the ALPR region of interest field for the changes to be saved.

Resizing will not improve the readout rate from the sensor, but nevertheless, it will achieve a higher processing rate because the ALPR software needs to process fewer pixels.



7.3.1   Display Plate

When enabled, ALPR will generate an image of the read plate and overlay it on the processed images (see Example).



7.3.2   Display State

If display state is enabled, the name of the detected state, as well as the percentage of reading confidence, will be overlaid onto processed images.

This parameter will be activated only in combination with Display Plate. If display plate is not enabled state information will also not be displayed.

Example:

Enable display plate and display state.

A vehicle with number plates W554433 was detected.

As a reading result, the SW will overlay "AT 68 W554433 100" onto the result image. "AT 68%" AT stands for Austria, the state, and 68% is the percentage of recognition confidence for the state. "100" stands for 100% certainty that the plate read is "W554433"(see Example).



State/country recognition is possible when appropriate classifiers are in use. Classifiers will be included when initializing ALPR. In case there is a need for additional classifier packages they can be uploaded through `System Configuration-Upload classifier`.



7.3.3   Display character confidence

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



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

Example:

Image (A) displays a result plate image with visualization of state and plates enabled.

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

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

vz


7.3.4   Display reading framerate

Frame rate refers to the number of individual frames (images) that are displayed in a video per second (fps).

If Display reading frame rate is turned on (enabled), the reading frame rate will be displayed on the upper right side of the image stream.



7.4   Trigger

Trigger modes are used to start/stop image gathering and processing under the influence of specific impulses or external trigger signals.


There are five different trigger modes available:

  • Free_Run
  • Single_Line
  • Start_Stop
  • Start_Time
  • Start_Sequence

By default, the mode is set to Free run. When ALPR is in free run, all triggers are turned off allowing the SW to freely grab images any time vehicle plates are detected.

For other trigger modes, operations will be influenced by impulses received through start and stop trigger lines. In the following text, a term session will be used to describe the process between the start and stop triggers where images are collected, processed and results for each frame are generated.

./images/11_settingstrigger.png

Trigger configuration page.



How to define Start/Stop trigger polarity high?

When Trigger polarity high is enabled (checked) the input signal will be sent when the minimum voltage of 12V is put on the trigger line.

If Trigger polarity high is disabled ALPR will start when the trigger line is inactive.

Concerning activation and deactivation, the focus is on the rising or falling edge of the input. Meaning, if Start trigger polarity high is enabled, the requirement is that the input becomes active after it was inactive. Vice versa, if the Start trigger polarity is disabled, the requirement for the impulse to be sent is that the input is initially active and when inactive it triggers ALPR.



Hint

Hint Sign The electrical requirements for digital IO and triggering are defined in * VC pro Z Series Operating Manual



7.4.1   Trigger mode

Trigger modes differentiate by impulses which prompt ALPR to start a new session or to stop an ongoing session.

If there is no need for trigger usage leave the mode in free_run and ALPR will always be operating in image collection mode.


The table below describes each mode in a few different steps.

  • The Setup row lists significant parameters which are related to the specific mode and need to be defined.
  • The Start row describes in which circumstances sessions will begin.
  • The Stop row describes which actions will close a session.

fr Setup: No other parameters need to be defined for this mode.
Start: The session starts simultaneously with the camera. No signal is needed to start the image gathering. The vehicles are detected automatically.
Free run should be the default mode when an external trigger is unavailable or not required.
sl

Setup: Define Start trigger line, Start trigger polarity high (enable/disable).

If Start trigger polarity high is enabled the session will start when the input signal is activated. If Start trigger polarity high is disabled the session will start when the input signal is deactivated.

Start: The session will start when the signal from Start trigger line is received.
Stop: THe end of the session depends on the signal. When ALPR no longer receives the defined signal, the session is finished.
ss

Setup: Define Start trigger line, Start trigger polarity high (enable/disable), Stop trigger line and Stop trigger polarity high.

If Start/stop trigger polarity high is enabled, the session will start when the input signal is activated. If Start/stop trigger polarity high is disabled the session will start when the input signal is deactivated.

Start: The session will start when the signal from Start trigger line is received.

Stop: The session stops and result images are generated when the signal from Stop trigger line is received.

In case the new signal is received while the old session is still open, ALPR will produce reading results, close the old session and open a new one immediately.

st

Setup: Define Start trigger line, Start trigger polarity high (enable/disable) and Trigger timeout (ms).

If Start trigger polarity high is enabled (checked) the session will start when the input signal is activated. If Start trigger polarity high is disabled the session will start when the input signal is deactivated.

Start: The session will start when the signal is received.

Stop: The session lasts for a defined time period (set in Trigger timeout). After the time passes the session is closed and output results generated.

In case the new signal is received while the old session is still open, ALPR will produce reading results, close the old session and open a new one immediately.

sseq

Setup: Define Start trigger line, Start trigger polarity high (enable/disable), and Sequence length (in frames).

If Start trigger polarity high is enabled the session will start when the input signal is activated. If Start trigger polarity high is disabled the session will start when the input signal is deactivated.

Start: The session will start when the signal from Start trigger line is received.
Stop: The session stops and result images are generated after the defined number of frames set in Sequence length.


7.4.2   Start Trigger Line

Define a starting trigger through input pins.

When the pin is activated/triggered it will send a signal to the camera to start the reading cycle.

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

The start trigger line parameter is directly influenced by the Start trigger polarity high parameter.

Used in START_TIME, START_STOP, START_SEQUENCE and SINGLE_LINE modes.



7.4.3   Start Trigger Polarity High

Turn on (enable) start trigger polarity high, meaning that the high state will be the active state.

When Start Trigger polarity high is enabled the input signal will be sent when the trigger line is activated. When Start Trigger polarity high is disabled the input signal will be sent when the trigger line is inactive.

Used in START_TIME, START_STOP, START_SEQUENCE and SINGLE_LINE modes.



7.4.4   Stop Trigger Line

Define a stop trigger through input pins. There are 4 pins available.

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

An overview of active input and output pins can be found in the `Configuration-System` tab.

Used in START_STOP mode.



7.4.5   Stop Trigger Polarity High

Allows the user to turn on stop trigger polarity high. That means that the high state will be the active state.

By default, this parameter is set to true (enabled).

Used in START_STOP mode.



7.4.6   Trigger Timeout (ms)

Trigger Timeout 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.

If a new start trigger signal occurs before the Trigger timeout passes, the old session will be closed, a new one opened and the time period will be reset.

If this parameter is set to 0 there will be no time delay between sessions.

Used in START_TIME mode.



7.4.7   Sequence length (frames)

Define the number of frames which will be processed in one session. The session starts when Start trigger line signal is received, and ends after the defined number of frames are processed.

Used in START_SEQUENCE mode.



7.5   Mode of Operation

./images/12_settingsmodeofoperation.png


7.5.1   Stream Mode

In order to make some basic setups easier to handle, the demo program provides several presets, which can be used depending on the operation type (parking mode, images, offline video or free flow movement).

The stream presets provide processing settings for various application scenarios which are detailed in the table below.

Mode Usage Output
Single Streaming parameters are configured in such a way that the video handling function is switched off. Each input image is considered not to be related to adjacent images. Every single detected license plate. Recommended for folders with images.
Parking mode This mode is designed for access and parking control systems. 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. Recommended for live streams and USB cameras.
Offline video 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-team operation (for example, to collect LP images). Unique license plates. Recommended for video files.
Freeflow This mode is designed for freeflow real-time systems. It is configured in such a way that it tries to catch all passing vehicles. The result may become available with a delay of up to 15 frames. Unique license plates. Recommended for live streams and USB cameras.
./images/12_settingsmodeofoperation_modes.png


The following table describes the default values of parameters that are used for different streaming modes of the camera.

Parameter/Preset single parking offline freeflow Description
MinReadings 1 3 3 2 A minimal number of required readings per vehicle before its license plate will be produced to the output. This parameter can be used to suppress occasional wrong readings.
StreamBufferLength 1 1 20 1 If set > 1, results will be available with a delay - the number of delayed frames is equal to the StreamBufferLength - 1. The advantage in this case is that the engine has more frames to analyse before producing the output results - this allows correcting possible reading errors by merging multiple readings results. A good strategy is to set this parameter to a lower value for real-time applications where any delay is critical, and to increase this parameter for offline applications.
DropAfterFrames 0 15 25 15 Ideally, a license plate should be detected in each frame during which a vehicle moves across the video scene. In practice, however, there can be some time (frame) gaps in readings. DropAfterFrames parameter specifies the max allowed gap in frames to keep the license plate strings in the processing history. After reaching this gap, the vehicle with the relevant LP string is removed from the memory; new readings would trigger new detections. In contrast to the StreamBufferLength, this parameter does not produce a delay in results and can safely be set to higher values.

7.5.2   Minimum Detections

Minimum Detections parameter controls how many readings of the same license plate will be made until a definite result is produced. The result transmission takes place only after this number of readings.

A new reading is accepted as valid if:

  • The number of character differences to previously read strings is not greater than Maximum character Mismatch, Section 7.5.2..
  • If it is detected inside the ALPR region of interest

Note

Hint Sign Minimum Detections will delay the transmission of images and readings.



7.5.3   Maximum characters mismatch

Maximum plate mismatch refers to the maximum amount of characters allowed to be different between two plate strings for them to merge.

It is recommended to set it to 1.


7.6   Engine

The engine settings control the actual reading of license plates.

Under Engine settings, the search can be refined by setting the character size, style (number of characters, inverted color plates), plate confidence or any other parameter explained in the following sections, as illustrated in the image below.

./images/13_settingsengine.png

7.6.1   Reading mode

The Carrida engine can operate in several performance modes, which are differentiated by recognition/processing speed and reading accuracy.

  • Fastest
  • Fast
  • Standard
  • High
  • Best

The modes are explained in detail in the table below.

  Mode Description
mo Fastest Fastest possible processing speed with lower recognition quality than in other modes. Recommended for open traffic when 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. This mode will give the best results for open traffic situations with processing speed slightly lower than in previous modes.
High The high mode is about twice as slow compared to the fast mode (e.g. from 50 ms to 100 ms), the reading accuracy of the high mode is typically 3-4% better than in fast mode.
Best The best possible reading quality. Can be up to two times slower than in the fast mode. At the same time, reading confidence will be about 3-4% better.

7.6.2   Min letter height (px)

Defines the minimal height of characters, in pixels. The ALPR will only accept characters larger in size than set in this parameter. This value should not be set to less than 8 pixels. Characters that are smaller defined in minimal letter height will not be recognized by the ANPR.



7.6.3   Max letter height (px)

Defines the maximal height of characters, in pixels, that ALPR will acknowledge. All characters larger than the given size will not be processed and will be dismissed by the engine. We recommend setting this value to 40 pixels.



7.6.4   Max plate angle (deg)

If there is a chance that the vehicles will appear under a certain angle to the camera, ANPR can be instructed to search for plates in a wider angle relative to x-Axis. The angle can be set between 0 and 90°, but best results are recognized between 5° and 30°.



7.6.5   Minimal plate confidence (%)

Minimum plate confidence refers to the minimum confidence level at which the ANPR will recognize a license plate as valid. Range varies between 0 and 100 percent.

If minimal plate confidence is set to 70% the program will produce only results with the level of recognition certainty 70% or above. All lower readings will be ignored.



7.6.6   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 processed.



7.6.7   Minimum contrast

Minimal contrast to differentiate foreground (characters) from background (license plate itself). Reducing this parameter increases both the reading performance and the processing time. It is recommended to leave this setting on 50, as this is the best compromise between the accuracy and the speed.



7.6.8   Scale Height/Width

When these parameters are adjusted, the input image will be modified by the given ratios before the processing starts. The re-sizing values have to be provided in percent of the original size (100 = original size).



7.6.9   Search inverted

Search inverted is an option that controls the way the ALPR engine will search for the LP in terms of color contrast for the characters (black-on-white or white-on-black contrast).

Search inverted Description
Disabled ALPR will only search for plates with a light background and dark characters (i.e. black symbols on white background). This is the fastest mode and it is recommended if only this type of LP can occur.
Search ALPR 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 only turn it on when necessary.
Always ALPR will, in addition to black-on-white LP, 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.

7.7   Access control

./images/14_settingsaccesscontrol.png

When Access control is enabled, the ALPR will turn on the consideration of the blacklist, whitelist and ignorelist and their related user-defined actions.



7.7.1   Limit of Low Conf(%)

This parameter is used to set a limit under which the reading confidence will be considered low, but still valid. The lower confidence limit has to be equal to/greater than the Min Plate Confidence. Used in action type Low Confidence Read.



7.7.2   Noread Event Interval

This parameter specifies the interval of images without any plate readings before defined no-read actions are executed.



7.7.3   Download Lists from Ftp

If this parameter is enabled, the server will try to download lists from a previously specified FTP server by using the credentials defined in the next two parameters. This feature can be used to update the ignore-, black- or white lists from an external server.



7.7.4   List FTP Server

FTP Server address to download list files from will be specified in this parameter. The address has to be written in the following format: sftp://xxx.xxx.xxx.xxx



7.7.5   List FTP Server Credentials

FTP Server credentials have to be given in the following format: username:password

Example:For the username "user123" with the password "pass123" the correct form is user123:pass123 .

8   System Configuration

As shown in the image below, the following Configuration settings can be modified:

  • Network - set the IP address of the ALPR device, network mask, gateway IP and DNS IPs.
  • Time - turn the network time protocol on, or set the timezone.
  • Users - create, delete or change user profiles.
  • Classifier - upload a classifier and view the supported state list.
  • System - view trigger input/output activity and the camera SW version.

After changing these settings the system needs to be rebooted. Depending on the camera model it might be necessary to power-off and then power-on the camera to complete the reboot process. For older camera models rebooting is done by turning the camera off and on again.

./images/16_configuration_network.png

8.1   System Actions

./images/20_configuration_systemsettings.png

The System actions button is located on the upper right side of the screen. As illustrated in the image above, clicking on it reveals a drop-down menu. System Actions is a group of settings and parameters used to control the system.



8.1.1   Restart ANPR and Reboot system

Restarting and rebooting the system is possible by clicking on the Restart ANPR or Reboot system buttons. On the newer camera models, it is possible to restart or reboot the system by clicking on these options instead of manually turning the camera off and on again.



8.1.2   Download Logs

All stored camera logs may be downloaded by clicking on Download logs



8.1.3   Save Configuration

Configurations can be stored locally by clicking on Save configuration. Saving the configuration is a three-step process, consisting of collecting the files, creating an archive and storing it locally, as illustrated in the image below.

./images/20_configuration_save.png


8.1.4   Import Configuration

Previously saved configuration settings can be imported by clicking on Import configuration. Importing may take some time. The user can choose which system settings will be imported by sliding the red OFF button to reveal the blue ON button, thus enabling the changes.

./images/20_configuration_import.png

Importing server and network configuration



After the server is done importing the settings, a confirmation window will appear listing the restored settings and notifying the user of a reboot.

./images/20_configuration_import_window.png

Note

Note Sign

Import Server Configuration imports ALPR Parameters and List settings.



8.1.5   Change Camera Password

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



8.1.6   Factory Reset

The last option on the System tab is the Factory reset. This option is used to reverse all changes and switch the camera to factory settings.



8.2   Network

On this page the following Network settings can be modified:

  • DHCP
  • IP Address - set the IP address of the ANPR device.
  • Network mask - set the network net mask.
  • Gateway IP - set the gateway IP address.
  • DNS IP - set the IP address.
  • DNS IP 2 - second IP address, if needed.

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 these parameters can be changed by clicking on the Edit button, as shown in the image below.

./images/16_configuration_networkedit.png

System configuration for network settings.

Sliding the DHCP slider from OFF to ON allows for the changes to be made.

After changing any one these settings, the system needs to be rebooted. Depending on the camera model it might be necessary to power-off and then power-on the camera to complete the reboot process.


8.3   Time

In Time settings, the time or the timezone can be set and the NTP server list can be customized.

./images/17_configuration_time.png

Clicking on the Edit button brings the user to the following window with the list of active NTP servers:

./images/17_configuration_timeedit.png

The camera can use any of these servers to synchronize its internal clock.

It is important to note that the time can only be set if the NTP is turned OFF. NTP can be enabled/disabled by clicking on the red OFF button that switches into a blue ON button after clicking on it. NTP is, by default, turned on.


8.4   Users

There are three default profiles to choose from: administrative, user and viewer. Profiles are differentiated by the level of access to configuration and system settings.


Factory Sign in credentials for these profiles are:
  Username Password Description
Administrator admin secret Immediate access to all settings.
Basic User user simple Access to the most commonly used settings.
Viewer viewer pass Permission to view reading results and live image streaming.

Adding new users, deleting the old ones, or changing the password(s) can be done on the Configuration-Users tab. This is only possible in advanced mode. After clicking on the Create new button, a dialog box will appear as shown in the image. Fill in the data and save the profile.

./images/18_configuration_users.png

Note

Note Sign

Camera password is not the same as user passwords.


8.5   Classifier

Classifiers are files which contain state/country- specific information. This information can, for example, be the size a font of letters and numbers, the number of rows the plate is made of, the alphabet used etc.

Classifiers are created specifically for different regions of the world (Europe, USA, Thailand...). Upload the provided classifier by selecting the file on your computer and clicking on the Upload button.



8.5.1   Switching Classifiers

./images/15_configuration_classifiers.png

Edit classifiers

There is an unlimited number of classifiers that the camera can store and they can be switched anytime. Clicking on the information icon (illustrated in the image) will display a complete list of supported states.



8.5.2   Uploading Classifiers

New classifiers can be uploaded by clicking on the drop down menu, which brings the user to a list of already available classifiers and an Upload New option, as illustrated in the image below.

./images/15_configuration_classifiers_upload.png

Upload classifiers

While uploading a new classifier, the user can opt for deleting all previous classifiers by moving the OFF slider to ON.

After uploading a classifier, the ALPR will automatically restart in order for the changes to take place.


8.6   System

./images/19_configuration_system.png

8.6.1   Software version

The System page provides information about libraries that the SW uses with the version number and the built date.



8.6.2   Inputs/Outputs

Outputs and Inputs parameters show which lines are active and which are inactive. I/O Status is important for the usage of triggers.


9   Placeholders for naming patterns

Placeholders can be used to customize the result file name.

Placeholders are built out of keywords placed between two percentage signs (%). This form will be replaced with specific information about the reading when ALPR produces a result (i.e. date, time, etc).

Listed in the table below are all keywords and their meaning.

Placeholder Description
   
"%LP%" This keyword will be replaced by the license plate value string.
"%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 license plate as string.
"%REGION%" This keyword will be replaced by the region string.
"%REGION_CITY%" This keyword will be replaced by the city string.
"%REGION_SHORT%" This keyword will be replaced by the region short value string.
"%ENDING%" This keyword will be replaced by the state value string.
"%ENDING_SHORT%" This keyword will be replaced by the state value string.
"%COL_PLATE%" This keyword will be replaced by the color of plate as string.
"%COL_CHARS%" This keyword will be replaced by the color of characters as string.
"%POS_X%" This keyword will be replaced by x position in image of left upper corner of license plate as string.
"%POS_Y%" This keyword will be replaced by y position in image of left upper corner of license plate as string.
"%POS_W%" This keyword will be replaced by width of license plate in image as string.
"%POS_H%" This keyword will be replaced by height of license plate in image as string.
"%YEAR%" This keyword will be replaced by year string. (When license plate was detected)
"%MONTH%" This keyword will be replaced by month string. (When license plate was detected)
"%DAY%" This keyword will be replaced by day string. (When license plate was detected)
"%HOUR%" This keyword will be replaced by hour string. (When license plate was detected).
"%MINUTE%" This keyword will be replaced by minute string. (When license plate was detected).
"%SECOND%" This keyword will be replaced by seconds string. (When license plate was detected).
"%FRACSEC%" This keyword will be replaced by fraction of seconds string. (When license plate was detected).
Example:
ALPR has detected a German plate "TEST123" on 01.01.2017 at 10:15:20. You can form the naming pattern i.e. like following:
" 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"
ALPR has detected an Austrian plate "W112233BC" on 15.06.2017 with 89% state recognition certainty, and 100% plate recognition certainty.
" LP_%LP%-%CONF% State_%STATE%-%CONF_STATE% " the form will be displayed as : " LP_W112233BC-100 State_Austria-89 "

Placeholders are replaced with actual data, and plain text stays unchanged.