You must install and configure the cameras in such a way that the following requirements are met:

Type of requirementsPurposeRequirements for the video image from the camera that is used for detection
Basic requirementsTo ensure the recognition of state license plates and vehiclesCamera
  • 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

Correct operation of the detector isn't guaranteed if you use frames that were masked before they got into Axxon One by an IP camera or similar methods.

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)
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:
    1. Minimum: height/width is at least 150px and at least 15% of the frame height/width. Recommended: 250px/30%.
    2. Maximum: height/width isn't limited, but no more than 80% of the height/width of the frame
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
Additional requirementsTo 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