The image received from video cameras must be sharp, contrast and readable for correct recognition of carriages and containers license plates.

Requirements for video camera characteristics:

1. Use video cameras with high resolution (720 p recommended);
2. Frame rate is not less than 24 fps;
3. Possibility of setting the fix exposition value from 1/2000 s and less;
4. High sensitivity of video cameras (0,01 lx and more).

The optical axis of video camera must be perpendicular to the plane of the license plate. Use varifocal lens for settings simplicity. Select the range of focal distance changing individualy for each case of system installation.

Image requirements:

1. Position of carriage or container in the frame must be horizontal;
2. Size of license plate characters in the image must be from 20 to 40 pixels, i.e. from 4% of the image height;
3. Geometric distortion by optics should be reduced.

It is also required while video camera setup:

1. Focus camera exactly to the container or carriage license plate and disable the auto focus; 
2. It is recommended to disable all the video camera forensic features. For instance, the mode of adding contrast.

The sample of mounting video camera for providing the exact recognition of carriage license plates is shown in the following figure.

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