Head Tracker plugin is a light version of the Queue detector and is designed to define the number of people crossing the preset border line on the camera image in one or other way.
To ensure the stable operation of the plugin the survey coverage and the camera installation location should meet the following requirements.
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Select the camera installation location properly
Table 18.
Requirements CORRECT INCORRECT The camera should be installed above the people passage point. 
No camera tilt is allowed.
The camera lens should be directed vertically down. In this case the image of the camera will run parallel to the floor.
The object size on the image should be 5% at least and 25% at most of the entire frame.
The range of the width of the camera image should be from 600px to 700px.
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Check the lighting conditions
Table 19.
Requirements CORRECT INCORRECT The survey area should be moderately lightened. Insufficient or excessive lighting of the survey area negates the effectiveness of the plugin. 
Prevent any sharp alterations of the lighting conditions. The survey area must not have any specular surfaces. Hard shadows of moving objects interfere with the plugin operation. 
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Disturbances in the survey coverage
Table 20.
Requirements CORRECT INCORRECT Static background without any moving objects (moving stairways or moving walkways) ensure the stable operation of the plugin. 
Constantly opening doors and other objects showing in the survey area decrease the plugin efficiency. 
