We propose an algorithm in ideal case to count a passing object based on video signal processing. The procedure is very simple. The object is tracked whether it has already passed the marker (a virtual line) and made the recording of leftborder (edge of object that will firstly cross the marker) position change. If the object has passed the marker, then it is calculated when the leftborder’s position is increased. The analysis result is also presented to support the validity of the algorithm.

algorithm, count the passing object, video signal processing.