You must install and configure the cameras in such a way that the following requirements are met:
| Type of requirements | Purpose | Requirements for the video image from the camera that is used for detection |
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| Basic requirements | To ensure the recognition of state license plates and vehicles | Camera | - Minimum resolution is 1280*720, recommended resolution is 1920*1080 and more
- Video codec: MJPEG minimum, H.264 or H.265 are recommended, preferably uncompressed
- Bitrate: depends on the frame (license plate must be readable)
- Minimum frame rate: at least five FPS at speed up to 20 km/h (Slow mode), from 20 FPS at speed over 20 km/h (Fast mode)
- Maximum horizontal angle is 30°, recommended angle is 0°
- Maximum vertical angle is 45°, recommended angle is 20°
- Maximum camera rotation angle is 20°, recommended angle is 0°
- In order to recognize state license plates on high-speed roads, the camera must have the Global Shutter mode
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| Lighting | - Illuminated control area. We recommend using conventional spotlights and/or cameras with IR illumination for additional illumination
- Expected image contrast: the contrast difference between characters of the license plate and the background must be at least 20 units with the image brightness scale from 0 to 255
- During daytime and nighttime, we recommend selecting the values of the light sensitivity (ISO) parameter separately with the minimum exposure time (maximum shutter speed)
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| Scene and camera angle | - We recommend installing a camera in such a way that various objects that block the vehicle during its recognition are not in the frame. For example, a barrier or fence
- The state license plate must be readable
- Height of characters (letters and digits) on the state license plates is at least 10px and not more than 60px. Preferably 20px or more
- Width of the dashboard: minimum 80 pixels, recommended 100 pixels
- Thickness of the character line: minimum 1 pixel, recommended 2 pixels
- Vehicles during the passage must be completely within the camera FOV for at least five frames
- The size of the vehicle's bounding rectangle:
- Minimum: height/width is at least 150px and at least 15% of the frame height/width. Recommended: 250px/30%.
- Maximum: height/width isn't limited, but no more than 80% of the height/width of the frame
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| Object images | - To avoid blurring of the image, you must set the camera to a slow shutter speed. We recommend keeping the shutter speed at no more than three ms. The exact value depends on the camera angle and vehicle speed
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| Additional requirements | To determine the speed of the vehicle | - Camera installation height is at least four meters
- The time period when a vehicle is in front of the camera with a fully readable state license plate, or when a vehicle that is fully in the frame and accurately recognized must be at least 500 ms
- Time stamps for frames must not differ from the real time by more than two ms
- When calibrating values, the measured road section must be at least three meters wide and five meters long. In this case, the key points in the image must be at least 300 pixels apart. The measurement error during calibration (difference between actual and entered measured values) must not exceed 1%
- Camera must be rigidly fixed and must not move during gusts of wind and other physical forces
- All of the following rules must be followed by default:
- The bounding rectangle of the state license plates doesn't touch the bottom part of the frame in both selected frames for speed calculation
- The offset of the center of the rectangle between the two selected frames is at least four meters and 100 pixels
- The time difference between two selected frames is at least 100 ms
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| To determine the driving direction of the vehicle | - Camera installation height is at least three meters
- Angle between camera and road direction is not more than 30°
- Minimum camera tilt
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| To recognize the make and model of the vehicle | - Visible width of the vehicle is from 100px
- Color or black and white image
- Front view of the vehicle
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| To recognize the color of the vehicle | - Visible width of the vehicle is from 100px
- The scene illumination must be at least 50 lux. Under low or excessive illumination (night or backlight), the stability of the analytics operation is not guaranteed. There are no abrupt changes in illumination
- Color image with a normal color grade
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| To determine the condition of the headlights | - Visible width of the vehicle is from 100px
- Front view of the vehicle
- Evening, night or foggy shooting conditions are required
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