In any given camera view, it is usually the case that only part of the area is of interest. During the calibration process the user can define the precise area of interest for counting and analysis. This area becomes the calibrated area used in density calculations.
A polygon drawing tool is used to define the area of interest at floor level and can also be used to mask out areas that need to be excluded. For example, an area covered by another camera to avoid double counting, or to exclude a problematic object like a video advertising screen that may generate false counts. When using a moveable PTZ camera multiple views and calibrated areas can be defined.