ANPR works properly if the following camera installation requirements are met (for a list of supported countries, visit the web-site of the recognition module's manufacturer):

• character height is at least 15px, stroke width is at least 2px;
• minimum allowable contrast for uniformly contaminated license plates should be at least 10% (contrasting visibility of characters relative to the background is 25 on a 256-point scale);
• maximum allowable non-uniform contamination is no more than 12% (the ratio of the contaminated area to the total area of the license plate);
• the geometric proportions of the image shall not deviate by more than 10% from the real geometric proportions of the license plate.

The camera setup is described in detail in the recognition module manufacturer's documentation.