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Welcome to Metrici LPR! This comprehensive guide will help you understand and configure your License Plate Recognition system. Whether you're setting up a new installation or fine-tuning an existing one, this manual provides clear, step-by-step instructions for every feature.

Table of Contents

1. Introduction

What is Metrici LPR?

Metrici LPR v7.1 is an advanced AI based License Plate Recognition system designed to automatically detect, recognize, and record vehicle license plates from video streams. The system can identify plates from over 57 countries worldwide and provides extensive integration capabilities with external systems like barriers, gates, traffic lights, weight scales and speed radars.

Key Features

Typical Applications

First Settings - Add Cameras

Metrici Control Panel starts automatically when the server is on. You will add here the cameras and do settings for your location. You can have active as many cameras/applications as licenses acquired.

Metrici Control Panel main window showing the camera list and management buttons
Fig.A Metrici Control Panel

To add a camera click on Add (1) button. A popup window will show as in the next image with the following fields

Add Camera dialog with fields for ID, Name, Application Type, CPU Cores, Execution Type, GPU and Log Level
Fig.B Add Camera Settings

2. Main Application Interface Overview

When all above settings were done, a window like next one appears and it is designed to give you immediate visibility into the recognition process for each detection engine/ camera while providing easy access to all configuration options. Understanding the layout will help you monitor the system effectively and quickly identify any issues.

Metrici LPR main application interface showing the settings panels and live video preview
Fig.1 Main Interface of Application Settings

Video Display Area

The main window displays your video streams in a tabbed interface. You can switch between the LPR input stream view (your main camera — see Fig.1 Main Interface (1) ) and the Companion stream view (optional secondary camera — see Fig.1 Main Interface (2)).

Each video display shows:

Plates Panel

The right side of the interface shows detected plates information:

Recognized plates list panel on the right side of the LPR interface
Fig.2 Plates view

Also Info about what type of vehicle, color, brand, plate size, last seen and probability.

Control Buttons

3. Camera and Stream Configuration

Proper camera configuration is essential for accurate plate recognition. The system supports two video streams: a main LPR input stream and an optional companion stream. The companion stream can provide additional context, such as a wider view of the detection area.

Stream Type Options

Metrici LPR supports multiple camera protocols and formats. Choose the option that matches your camera type:

Protocol Description Best For
MJPEG over HTTP Motion JPEG stream via standard web protocol Most IP cameras, easy setup
RTSP H264/H265 Real-time streaming protocol with compressed video High-resolution cameras, low bandwidth
Video File Process pre-recorded video files Testing and batch processing

Supported Camera Brands

The system includes optimized drivers for many popular camera brands:

Configuring Camera Connection- LPR Input Stream

LPR input stream configuration panel with camera URL, protocol and credentials fields
Fig.3 LPR input stream

Step-by-Step Setup:

  1. Click the Settings button on the main interface — see Fig.1 Main Interface (8).
  2. Select "LPR input stream" from the settings categories — see Fig.3 LPR input stream (1).
  3. Stream Type: Select your camera's protocol from the dropdown list — see Fig.3 LPR input stream (2).
  4. IP Address: Enter the camera's IP address or hostname (without http://) — see Fig.3 LPR input stream (3).
  5. Port: Enter the HTTP port (default HTTP is usually 80)-other protocols have different ports — see Fig.3 LPR input stream (4).
  6. Use SSL: Enable if your camera requires secure connection — see Fig.3 LPR input stream (5)
  7. Username/Password: Enter credentials if your camera is password protected — see Fig.3 LPR input stream (6).
  8. Limit FPS: Set to 0 for unlimited, or specify a maximum frame rate — see Fig.3 LPR input stream (7).

Use Companion Stream tab and fill in data only if one camera (different from LPR one) is available for this purpose. Otherwise leave it blank.

Tip:Higher frame rates provide more opportunities to capture clear images of passing vehicles. In parking lots, 2-3 FPS is usually enough. More are required on highways.

Camera Positioning Guidelines

Proper camera placement significantly impacts recognition accuracy. Consider these factors:

Testing Your Camera Setup

After configuring the camera, the connection status indicator on the main interface will show:

4. Detection Window Configuration

The detection window allows you to define a specific area within the camera view where the system will look for license plates. This is crucial for improving accuracy and reducing false detections from areas where plates cannot be found.

Detection window configuration showing the area-of-interest overlay drawn on the camera feed
Fig.4 Detection window

Why Use a Detection Window?

Configuring the Detection Window

Manual Configuration:

  1. Open Settings and navigate to "Detection window" — see Fig.1 Main Interface (8).
  2. Check "Detection window active" to enable the feature — see Fig.4 Detection Window (1).
  3. Set the origin coordinates (X, Y) for the top-left corner of the detection area — see Fig.4 Detection Window (2, 3).
  4. Set the width and height for the detection area dimensions — see Fig.4 Detection Window (4, 5).
  5. Or just drag the corners of the polygon in the main window

Companion Window

If you're using a companion camera stream, you can also configure a detection window for it. The companion window works similarly to the main detection window and can be used for additional validation or wider area coverage. As this camera is not usually used for detection, a window will not affect overall recognition performance but displaying it and streaming can overload bandwith and power. However it is useful in Red Light runner detection applications, when a window is to be placed for the traffic light.

Interactive Configuration:

For easier setup, you can position the detection window directly on the video feed:

Important! If you want to position the detection window directly on the video feed you need to have the Settings menu open!

  1. In Settings, navigate to the Detection window section
  2. Click on the video display in the main window
  3. Drag the corners of the detection box to resize
  4. Drag the center to reposition the window

Note: Width and height values must be divisible by 4. This is a technical requirement for the recognition engine to function correctly.

5. Plate Recognition and Detection Settings

Fine-tuning recognition settings helps balance between detection accuracy, processing speed, and the types of vehicles you want to capture. To access the plates menu go to settings, Plates — see Fig.5 Plates.

Plate recognition and detection settings panel with minimum plate width and recognition options
Fig.5 Plates

Same Plate Delay (seconds)

This setting defines the minimum time (in seconds) before the same license plate can be detected and reported again. During this delay, repeated detections of the same plate are ignored. — see Fig.5 Plates (1). This is useful if the view is briefly obstructed by an object.

Minimum Plate Width

This setting defines the smallest plate size (in pixels) that will trigger a detection. Plates smaller than this threshold will be ignored — see Fig.5 Plates (2). Recommended value=200.

Setting Value Effect Use Case
100-150 pixels More sensitive, captures distant plates. Prone to errors. Wide-angle views, longer detection ranges
200-250 pixels Balanced detection Typical parking or access control. High speed also.
300+ pixels Only close plates detected Tight spaces, high accuracy requirement

Recommendation: For optimal recognition quality, set the minimum plate width to at least 200 pixels. Smaller plates often result in poor recognition accuracy.

Maximum Plate Width

Sets the largest plate size that will trigger a detection. This prevents very large objects from being mistakenly identified as plates and reduces processing of oversized images — see Fig.5 Plates (3).

Single Plate Mode

When enabled, this mode assumes there is only one license plate in the camera view at any time — see Fig.5 Plates (4). This is particularly useful for:

Caution: Single plate mode may miss vehicles when multiple cars are present in the frame. Only enable this when your specific use case requires it.

6. Countries and Plate Selection

Metrici LPR can recognize license plates from 57 countries worldwide. Selecting the correct countries improves recognition accuracy by telling the system which plate formats to expect.

Country and plate selection panel listing supported countries for license plate recognition
Fig.6 Countries

Selecting Countries

In the Settings Window:

  1. Open Settings and select "Countries" — see Fig.6 Countries.
  2. You will see two lists: "Available countries" and "Selected countries".
  3. Select a country from the available list and click Push (→) to add it to selected — see Fig.6 Countries (1).
  4. To remove a country, select it and click Pop (←) — see Fig.6 Countries (2).
  5. Use Up/Down arrows to change the priority order (first in list = higher priority) — see Fig.6 Countries (3, 4).The country where the installation is in should always be first on the list. No matter how many countries are on the detection list, when first syntax match is done, Metrici will stop looking further. This is why it is important to place countries acoording to the probability top.

Country List

The system supports plates from these regions:

Catch-All Mode

When "Catch all" is enabled, the system will attempt to recognize and report ANY license plate, even from countries not in your selected list. — see Fig.6 Countries (5).

Warning: Catch-all mode may increase false positives because the system attempts to read plates using all available country formats. Use this only when you need to detect plates from many different countries.

7. Trigger Modes and Detection Timing

This tab allows settings the way the engine acts. The trigger mode determines when the system processes video frames to look for license plates. Choosing the right trigger mode affects both recognition accuracy and system resources.

LPR engine working mode panel showing trigger modes and detection timing settings
Fig.7 LPR engine

LPR Engine Working Modes

From "LPR engine working mode:" — see Fig.7 LPR engine (1), you can choose between three options:

1. Continuous Mode

2. Triggered - End After Time Period

3. Triggered - End After Level Change

Trigger Device Types

This setting can be changed from "Trigger device and type: " — see Fig.7 LPR engine (2).

Trigger Type Description Use Case
None No external trigger, use continuous or internal detection Standalone operation
Barionet 50 Industrial I/O controller with digital inputs (I1-I4) Physical sensors, loops
Metrici Virtual Trigger Software trigger controlled by the other application Testing, virtual loops
Multicontroller Multi-function controller with RFID support Access control systems
Vehicle Detection Internal detection of vehicles in video- Metrici Virtual Loop No external hardware needed

Trigger Duration Settings

When using time-based trigger modes, set "How many seconds to analyze after trigger" to define how long the system continues processing after receiving a trigger signal. — see Fig.7 LPR engine (3).

Tip: Set this value based on typical traffic flow.

Virtual Loop Configuration

The virtual loop is a Metrici proprietary specific point within the detection window that triggers plate recognition when a vehicle passes over it. This mimics the functionality of physical induction loops used in some access control systems.

Setting Up Virtual Loop:

  1. In Settings, under "LPR engine working mode and Trigger IN", you need to select "Vehicle detection" — see Fig.7 LPR engine (2).
  2. Set Virtual loop X and Virtual loop Y coordinates— see Fig.7 LPR engine (4,5).
  3. These coordinates define where in the image the "trigger point" is located.
  4. You can also use the mouse to move the Virtual Loop icon on the live stream in the main interface, if the settings window is open.

8. Vehicle Analysis Features

Beyond license plate recognition, the system can analyze vehicle characteristics using deep learning. These features require additional processing power and work best with GPU acceleration.

Vehicle classification panel showing detected vehicle type, color and manufacturer information
Fig.8 Vehicle classification

Vehicle Classification

When enabled, the system identifies the type of vehicle detected:

Vehicle Maker Recognition

Identifies the manufacturer (brand) of the detected vehicle (Over 60 brands recognized). This is useful for:

Color Recognition

Determines the vehicle's primary color. Common colors detected include:

Red Light Infringement

When combined with traffic light monitoring, this feature can identify vehicles that pass through intersections when the light is red. This requires:

Requirements: Vehicle analysis features require significant processing power. They are recommended only when:

Enhanced Recognition Mode

This mode increases recognition accuracy at the cost of:

When to use: Enable enhanced mode when accuracy is critical and vehicles move slowly (under 30 km/h). Disable for high-speed traffic monitoring. Metrici recommeds to keep it OFF.

9. External System Integration - Reporting, Check Action and Trigger Out

Metrici LPR can integrate with various external systems to create automated workflows. This section covers the communication protocols and configuration for external connections.

External system integration panel with reporting URL, check action URL and trigger out fields
Fig.9 Reporting and check action URL

Reporting URL

The reporting URL specifies where the system sends detection events. Each time a plate is recognized, the system sends data to this address: http://IP_ADDRESS/path/reporting_event.php. In case the reporting and administration interface is installed on the same computer as the analysis application, IP_ADDRESS will be 127.0.0.1 or localhost and path will be /io/lpr/ — see Fig.9 Reporting... (1). This address is usually where the Metrici Interface License is installed, to see all events in Interface and build database, reports, etc.

Data Format:

POST http://your-server.com/path/reporting_event.php
Content-Type: application/x-www-form-urlencoded

plate_number=ABC123&country=RO×tamp=20240101120000&confidence=0.95

Check Action URL

This address specifies where the system sends a request to check which actions should be executed when a license plate is recognized. Actions are configured in the Metrici LPR Web Interface and may include opening a barrier, sending an e-mail, showing a pop-up message on the screen, or changing a traffic light.

The URL has the following format: http://IP_ADDRESS/path/check_action_event.php. If the reporting and administration interface is installed on the same computer as the analysis application, set IP_ADDRESS to 127.0.0.1 or localhost and path to io/lpr. — see Fig.9 Reporting... (2).

The Reporting URL and Check Action URL may be different. The system typically calls the Check Action URL first, when a vehicle is detected, and sends the Reporting event later, when the vehicle exits the camera’s field of view. In parking or barrier-control scenarios, you can define rules in the Metrici Interface for the camera connected to the barrier, for example: open the barrier when a specific plate number is recognized; or use a wildcard rule (e.g., “%”) to grant access to all vehicles.

Minimum Probability Threshold

Only plates recognized with a confidence above this threshold will trigger check actions, preventing false recognitions from causing unwanted responses. Check action minimum probability (0.1–1.0) sets the minimum confidence required before a recognized license plate is checked against the database for possible actions. In other words, it defines how certain the engine must be that the reading is correct. We recommend a value of 0.6, which typically means the plate has been detected consistently (e.g., in at least two frames) before actions are evaluated. — see Fig.9 Reporting... (3).

Threshold Effect
0.40 (40%) More actions, higher false positive risk
0.60 (60%) Balanced setting
0.90 (90%) Fewer but more accurate actions

Authentication Key

The authkey and ID provide authentication for external server communications — see Fig.9 Reporting... (5). These credentials are obtained from the Metrici web interface where you configure your LPR cameras into the location.

Trigger Output- Send trigger at check action...

When a Check Action returns a positive result, the system can trigger external devices or other Metrici engines by sending a UDP packet to a configured IP address and port. This is typically used to synchronize events between systems—for example, triggering a second camera/engine to start recognition when the first camera detects a vehicle. — see Fig.9 Reporting... (4).

10. GPS Configuration

GPS integration adds location data to every plate detection, useful for mobile installations or when you need to verify where detections occurred.

GPS configuration panel for adding location metadata to plate detections
Fig.10 GPS

GPS Features

Configuration Options

Using GPS Receiver:

  1. Connect a GPS receiver to your system (typically via USB or serial port).
  2. The system automatically detects and connects to GPS devices.
  3. GPS status indicator shows connection quality — see Fig.10 GPS (1).

Using Static Location:

  1. Enter coordinates in Static Latitude and Static Longitude fields — see Fig.10 GPS (2,3).
  2. Use format: decimal degrees (e.g., 44.4268 for Bucharest).
  3. This overrides GPS receiver if both are configured.

GPS Status Indicators

Status Meaning
Unconnected No GPS receiver detected
Error GPS receiver found but communication failed
Low Signal Receiving data but insufficient satellites for accurate fix
Good Signal Accurate position data available

11. Weight Scale and Radar Integration

For commercial vehicle monitoring applications, integrating weight scales and speed radars provides additional data for each detection.

Weight Scale Integration

Connect to weight measurement systems for truck weighing and cargo monitoring:

Weight scale integration panel with scale type selection and connection settings
Fig.11 Weight scale

Supported Weight Scale Types:

Configuration:

  1. In Settings, select "Weight scale" — see Fig.11 Weight scale.
  2. Choose the weight scale type from dropdown — see Fig.11 Weight scale (1).
  3. Enter the IP address of the weight scale controller — see Fig.11 Weight scale (2).
  4. Enter the TCP port number — see Fig.11 Weight scale (3).

Display:

When a weight scale is connected and configured, the measured weight appears on the video display overlay, near the plate detection result.

Radar Speed Detection

Integrate with speed radar devices to capture vehicle speed along with plate recognition:

Speed radar integration panel with radar type and threshold settings
Fig.12 Radar

Supported Radar Types:

Configuration:

  1. In Settings, select "Radar" — see Fig.12 Radar.
  2. Choose the radar type- Observer Radar — see Fig.12 Radar (1).
  3. Enter the IP address of the radar controller — see Fig.12 Radar (2) .
  4. Enter the TCP port number — see Fig.12 Radar (3).

Display:

When connected, detected vehicle speed appears on the video overlay during playback.

Integration Note: Both weight scale and radar use IP connectivity. Ensure both devices are on the same network as your LPR system and that firewall rules allow communication on the configured TCP ports.

12. Barrier and Traffic Light Control

Metrici LPR can automatically control barriers and traffic lights based on plate recognition results. This enables fully automated access control systems.

Barrier and traffic light control panel with output relay and URL configuration options
Fig.13 Barrier and Traffic light

Barrier Control

Configure URLs that the system will call to open and close vehicle barriers:

Configuration Fields:

Example Configuration:

Open barrier URL: http://192.168.1.100/barrier/open
Close barrier URL: http://192.168.1.100/barrier/close
Delay before closing: 10 seconds

Traffic Light Control

Traffic light ON URL is used when a traffic light is installed and configured to switch when a license plate is detected; the light will commute only if this option is enabled for that specific plate number in the Action list, for example in intersection monitoring or traffic management scenarios.

Configuration Fields:

Integration with Check Actions

Barrier and traffic light control is typically triggered by the check action system:

  1. Plate is recognized
  2. System queries check action URL
  3. Check action returns response (allow/deny/action)
  4. System executes configured URLs based on response

13. Troubleshooting

This section covers common issues and their solutions to help you get the most out of your Metrici LPR system.

Camera Connection Issues

Problem: Camera shows "Disconnected" status

Solutions:

Problem: Video is choppy or FPS is low

Solutions:

Recognition Problems

Problem: No plates are being detected

Solutions:

Problem: Recognition accuracy is poor

Solutions:

Problem: False detections (recognizing plates that don't exist)

Solutions:

Problem: Same vehicle detected multiple times

Solutions:

Performance Issues

Problem: System runs slowly or lags

Solutions:

External Integration Issues

Problem: External servers not receiving data

Solutions:

Problem: Barrier/traffic light not responding

Solutions:

GPS Issues

Problem: GPS status shows error or no signal

Solutions:

Getting Help

If you continue to experience issues after trying these solutions:

14. Configuration File (INI)

Metrici LPR stores all its settings in a configuration file called lpr.ini (or numbered variants like 0.ini, 1.ini for multi-camera setups). Understanding this file allows you to:

File Location and Naming

The configuration file is located in the same directory as the application executable. By default, it's named lpr.ini. For multi-camera setups where multiple LPR instances are managed by a central system, files may be numbered:

File Format

The INI file uses standard Windows-style INI format with key-value pairs organized into sections (though Qt's QSettings may flatten sections in some configurations). Here's an example of what the file looks like: 

; Metrici LPR v7.1 Configuration File
; This file contains all settings for the LPR system
; Edit with care - incorrect settings may affect system behavior

[General]
input_stream_type=5
input_stream_address=192.168.1.100
input_stream_tcp_port=80
input_stream_use_ssl=0
input_stream_username=admin
input_stream_password=secret123
input_stream_fps_limit=15

companion_stream_type=0
companion_stream_address=
companion_stream_tcp_port=80
companion_stream_use_ssl=0

[Recognition]
plate_min_length=200
plate_max_length=350
single_plate_mode=0
enhanced_recognition_mode=0
countries=RO,BG
catch_all=0

[Detection]
input_stream_window_active=1
input_stream_window_origx=0.35
input_stream_window_origy=0.45
input_stream_window_resx=0.3
input_stream_window_resy=0.2
virtual_loop_x=0.5
virtual_loop_y=0.6

[Vehicle Analysis]
vehicle_detection=1
maker_detection=0
color_detection=0
red_light_infringement=0

[External Systems]
reporting_url=http://localhost/io/lpr/reporting_event.php
check_action_url=http://localhost/io/lpr/check_action_event.php
check_action_min_probability=0.6
open_barrier_url=http://admin:admin@192.168.1.100/outs.cgi?out0=0
close_barrier_url=http://admin:admin@192.168.1.100/outs.cgi?out0=1
open_close_barrier_delay=10

[GPS]
gps_latitude=44.4268
gps_longitude=26.1025

[Integration]
reporting_check_action_id=1
reporting_check_action_authkey=your_auth_key_here

Complete Settings Reference

Video Stream Settings

Setting Name Default Value Description
input_stream_type 0 Camera type (1=MJPEG HTTP, 2=RTSP H264, etc.) - see stream type codes below
input_stream_address (empty) IP address or hostname of the main camera
input_stream_tcp_port 80 HTTP port for camera connection
input_stream_use_ssl 0 Enable SSL for camera connection (0=disabled, 1=enabled)
input_stream_username (empty) Camera username for authentication
input_stream_password (empty) Camera password for authentication
input_stream_fps_limit 5 Maximum frames per second for main camera (0=unlimited)
companion_stream_type 0 Companion camera type (0=disabled)
companion_stream_address (empty) IP address of companion camera
companion_stream_tcp_port 80 Companion camera port
companion_stream_fps_limit 5 Companion camera FPS limit
rtsp_stream_latency 100 RTSP stream latency in milliseconds (for RTSP streams)
rtsp_stream_protocols tcp RTSP protocol (tcp or udp)

Recognition Settings

Setting Name Default Value Description
plate_min_length 200 Minimum plate width in pixels for detection
plate_max_length 350 Maximum plate width in pixels for detection
single_plate_mode 0 Assume only one plate in view (0=disabled, 1=enabled)
enhanced_recognition_mode 0 Higher accuracy mode (0=disabled, 1=enabled)
countries RO,BG Comma-separated list of country codes to recognize
catch_all 0 Recognize plates from any country (0=disabled, 1=enabled)
same_plate_delay 3 Seconds to wait before reporting same plate again

Detection Window Settings

Setting Name Default Value Description
input_stream_window_active 0 Enable detection window (0=disabled, 1=enabled)
input_stream_window_origx 0.4 Detection window X position as fraction of image width (0.0-1.0)
input_stream_window_origy 0.4 Detection window Y position as fraction of image height (0.0-1.0)
input_stream_window_resx 0.2 Detection window width as fraction of image width (0.0-1.0)
input_stream_window_resy 0.2 Detection window height as fraction of image height (0.0-1.0)
companion_stream_window_active 0 Enable companion camera detection window
companion_window_* 0.4, 0.4, 0.2, 0.2 Companion detection window settings (same format as main)
virtual_loop_x 0.5 Virtual loop X position as fraction of image
virtual_loop_y 0.5 Virtual loop Y position as fraction of image

Vehicle Analysis Settings

Setting Name Default Value Description
vehicle_detection 0 Enable vehicle type classification (0=disabled, 1=enabled)
maker_detection 0 Enable vehicle maker recognition (0=disabled, 1=enabled)
color_detection 0 Enable vehicle color recognition (0=disabled, 1=enabled)
red_light_infringement 0 Enable red light infringement detection (0=disabled, 1=enabled)
full_gpu_algorithm 0 Run full algorithm on GPU (0=disabled, 1=enabled)

Trigger Settings

Setting Name Default Value Description
external_trigger_type 0 Trigger device type (0=None, 1-4=Barionet, 5=Virtual, etc.)
external_trigger_seconds 1 Seconds to analyze after receiving trigger
lpr_engine_working_mode 0 0=Continuous, 1=Triggered-time, 2=Triggered-level
cars_direction 0 Vehicle direction angle (0-359 degrees)
cars_event_type 1 1=Coming, 2=Leaving, 3=Unknown

External Integration Settings

Setting Name Default Value Description
reporting_url http://localhost/io/lpr/reporting_event.php URL for sending detection reports
reporting_duplicate_url (empty) Secondary URL for redundant reporting
check_action_url http://localhost/io/lpr/check_action_event.php URL for checking actions based on plate numbers
check_action_duplicate_url (empty) Secondary check action URL
check_action_min_probability 0.6 Minimum confidence (0.1-1.0) to trigger check action
check_action_send_trigger_address (empty) IP address for sending UDP trigger on check action
check_action_send_trigger_udp_port 0 UDP port for trigger output
check_action_direction_for_sending 0 Direction filter for trigger sending
external_query_url http://localhost/io/lpr/get_info.php?plate_number=#INPUT_VALUE URL for manual plate queries
reporting_check_action_id 0 Camera ID for external system authentication
reporting_check_action_authkey (empty) Authentication key for external systems

Barrier and Traffic Light Control

Setting Name Default Value Description
open_barrier_url (empty) URL to call when opening barrier
close_barrier_url (empty) URL to call when closing barrier
open_close_barrier_delay 10 Seconds to wait before automatically closing barrier
open_barrier2_url (empty) URL to turn traffic light ON (red)
close_barrier2_url (empty) URL to turn traffic light OFF (green)
open_close_barrier2_delay 10 Seconds to maintain red light state

Live View Settings

Setting Name Default Value Description
live_view_active 1 Enable periodic live view snapshots (0=disabled, 1=enabled)
live_view_url http://localhost/io/lpr/live_view.php URL for receiving live view snapshots
live_view_resolution_divider 1 Divide live view resolution by this factor (1=full, 2=half size)

GPS Settings

Setting Name Default Value Description
gps_latitude 0 Static latitude coordinate (decimal degrees)
gps_longitude 0 Static longitude coordinate (decimal degrees)

Hardware Integration Settings

Setting Name Default Value Description
weight_scale_type 0 Weight scale model (0=None, 1=Cantar-I30, 2=Dini Argeo, etc.)
weight_scale_address (empty) IP address of weight scale controller
weight_scale_tcp_port 10001 TCP port for weight scale connection
radar_type 0 Radar type (0=None, 1=Kestrel Pico Basic)
radar_address (empty) IP address of radar controller
radar_tcp_port 10001 TCP port for radar connection

Stream Type Codes Reference

Code Stream Type
0Disabled
1HTTP MJPEG (ACTi)
2RTSP H264 (ACTi)
3HTTP MJPEG (Android)
4HTTP MJPEG (Arecont)
5HTTP MJPEG (Axis)
6RTSP MJPEG (Axis)
7RTSP H264 (Axis)
8RTSP MJPEG (Bosch)
9RTSP H264 (Bosch)
10HTTP MJPEG (Dahua)
11HTTP MJPEG (Diviotec)
12RTSP H264 (Diviotec)
13HTTP MJPEG (Generic)
14RTSP MJPEG (Generic)
15RTSP H264 (Generic)
16RTSP H265 (Generic)
17HTTP JPEG Picture (Generic)
18HTTP MJPEG (Hikvision)
19RTSP H264 (Hikvision)
20HTTP MJPEG (Mobotix)
21HTTP MxPEG (Mobotix)
22RTSP H264 (Mobotix)
23RTSP H264 (Mobotix Move)
24HTTP MJPEG (Novus)
25RTSP H264 (Novus)
26RTSP MJPEG (Pelco)
27Raw (Roseek)
28HTTP MJPEG (Samsung)
29RTSP H264 (Samsung)
30HTTP MJPEG (Sony)
31RTSP H264 (Sony)
32RTSP H264 (Uniview)
33Video File
34HTTP MJPEG (Vivotek)
35HTTP MJPEG (VLC)

Trigger Type Codes

Code Trigger Type
0None
1Barionet 50 Input 1
2Barionet 50 Input 2
3Barionet 50 Input 3
4Barionet 50 Input 4
5Metrici Virtual Trigger-gets command from another engine
6Multicontroller Input 1
7Multicontroller Input 2
8Multicontroller RFID
9Vehicle Detection- Virtual Loop

Weight Scale Type Codes

Code Weight Scale Type
0None (Disabled)
1GenericScale
2Dini Argeo
3Bilancia D400
4Custom STXLF Protocol
5Custom STXETX Protocol

Editing the Configuration File

Manual Editing

  1. Make a backup copy of the current INI file
  2. Open the file in a text editor (Notepad, TextEdit, or any code editor)
  3. Find the setting you want to change
  4. Modify the value after the equals sign
  5. Save the file
  6. Restart the LPR application or reload settings

Important: When editing the INI file manually, be careful to:

Automating Configuration Deployment

For deployments across multiple sites:

  1. Create a "master" INI file with your standard settings
  2. Deploy this file to all installations
  3. Only modify site-specific values (IP addresses, auth keys) per installation
  4. Use version control to track configuration changes

Configuration Backup and Restore

Regular backups ensure you can recover from configuration issues:

What to Include in Backup:

Backup Best Practices:

Troubleshooting Configuration Issues

Settings Not Taking Effect

Possible causes and solutions:

Application Won't Start After Editing INI

Recovery steps:

  1. Rename the problematic INI file to something else
  2. Start the application - it will create a new default INI
  3. Compare the original and new files to identify the error
  4. Copy correct settings from the new file

Common Configuration Mistakes

Advanced: Multiple Camera Setup

For systems managing multiple LPR cameras:

INI File Security Considerations

The INI file may contain sensitive information:

Security recommendations:

15. Appendix: Settings Quick Reference

Recommended Settings by Application

Parking Entry/Exit:

Truck Weighing Station:

Toll Road:

Border Control:

Final Note: Every installation is unique. Use these recommendations as starting points and adjust based on your specific requirements and observed results. Regular monitoring and fine-tuning will optimize performance for your particular situation.

Metrici LPR v7.1

License Plate Recognition System

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