Patent ID: 8766914

Claim:
An apparatus to measure audience size for a digital sign, comprising: a processor; a memory coupled to the processor; a face detection module including machine instructions that when loaded from memory and executed by the processor generate a plurality of paths, one for each face detected in a first sequence of video frames captured by a camera proximate the digital sign; a calibration module including machine instructions that when loaded from memory and executed by the processor generate a zone in the first sequence of video frames through which passes a threshold number of the paths; and a counter module including machine instructions that when loaded from memory and executed by the processor measure motion and direction of motion within the zone in a second sequence of video frames to calculate the audience size that passes through the zone in the second sequence of video frames; wherein the counter module to measure motion and direction of motion within the zone in the second sequence of video frames comprises the counter module to measure average pixel motion and direction of motion within the zone, according to a pixel motion estimation algorithm.