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To ensure the correct recognition of

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the carriage license plates, follow the requirements listed below.

Requirements for video camera selecting, mounting and setup to get the required image quality are follows.

Requirements for video camera characteristics:

characteristics:

1. It is recommended to use the resolution of no more than 800x600, because using a resolution of more than 800x600 does not lead to the recognition quality improvement;
2. use Use black-and-white video cameras of high quallity (570 TVL and higher) because such cameras provides better quality of image at low light conditions.;
3. Rate of the frames arrival is rate should be not less than 24 fps.
4. Possibility of setting the fix exposition value from 1/2000s and less.
5. ;
6. it should be possible to set a fixed exposure value (shutter) on video camera of 1/2000 s or less;
7. the video cameras should have high sensitivity High sensitivity of video cameras (0,01 lx and or more).

Use varifocal lens for settings simplicity. Range of focal distance changing choose for each case of system installation.

It is required to fulfill video camera mounting and setup requirements except requirements for video cameras properties.

Requirements for video camera position:

1. Optimal distance between video camera and railway is 5-7 meters.
2. Height of video camera position is 3-3,5 meters from top of rail.
3. Optical axis of video camera must be perpendicular to the plane of the carriage plate. 
4. Locate infrared sensor and video camera in the same vertical plane.

Image requirements:

Requirements for video camera position:

1. The optimal distance between the video camera and the carriage is 5-7 meters (depends on the focal length of the camera lens);

   Info
   title Note
   To simplify the setting, it is recommended to use the variofocal lenses. The focal length variation range should be selected in each case of the system installation.

   
   

2. the cameras height for reading the side number is 3–3,5 meters, the cameras height for reading the chassis number is 1,5 meters;
3. the width of the carriage plate number in the image should be about 30-35% of the total image width, in most cases this means the width of the camera control zone is 3-5 meters;
4. the optical axis of video camera should be perpendicularly to plane of carriage plate;
5. the position of the carriage in the frame should be strictly horizontal;

6. the infrared sensor and the video camera should be located in the same vertical plane.

   Info
   title Note
   If the analog video camera is used, then to prevent the video signal fading on the transmission line, it is necessary that the distance from the video camera to the digitizing device does not exceed 30 meters.

   
   

Image requirements:

1. The minimum character height in the frame should be 16 pixels, 30–50 pixels are recommended;
2. the geometric distortion by optics ("barrels" and "pillows") should be reduced;
3. the image of the carriage plate numbers should be clear, contrast and readable
4. Position of carriage in the frame should be strictly horizontal.
5. Width of carriage plate in the image should be about 30-35% from the image width.
6. Focal distance of lens is selected in such a way as to hieght of digits in the recognized carriage made about 10% from fame hieght.
7. Geometric distortion by optics should be reduced.

Also it's required while video camera setup:

1. Focus camera exactly to the carriage plate.;
2. Disable disable AGC mode in video camera.;
3. Disable disable modes of adding contrast of video camera.

It's required that distance between video camera and digitizing device won't be more than 30 meters for prevention video signal attenuation.

To provide working of system at night use searchlight flashing of carriages/cisterns. Use usual halogen spotlight with a capacity of 1–1,5 kW while mounting spotlight in distance 5-7 meters from railway. Locate spotlight as shown in the figure below. Such  Such location allows to avoid the following:

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