Video camera mounting and setup requirements for the IntLab-Carriages and ARH Carriages

To ensure the correct recognition of the carriage license plates, follow the requirements listed below.

Requirements for video camera 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 black-and-white video cameras of high quallity because such cameras provides better quality of image at low light conditions;
3. the frames arrival rate should be not less than 24 fps;
4. it should be possible to set a fixed exposure value (shutter) on video camera of 1/2000 s or less;
5. the video cameras should have high sensitivity (0,01 lx or more).

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);

   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.

   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.

Also it's required while video camera setup:

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

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 location allows to avoid the following:

1. Blindness of camera by spotlight directed to it from another site of railway.
2. Image flashing by light reflection from carriage.

Reference image received from correctly mounted and setup video camera is shown in the following figure.