Patent ID: 8320618

Claim:
An object tracker for tracking the movement of an imaged object, comprising: a sampling unit operative to generate particles based on an estimated existence probability distribution of a target object in a first image frame, the particles being used for a particle filter in a parameter space where candidate contours of the object in a second image frame are defined, the first image frame and the second image frame being contained in an image stream forming moving image data obtained as a result of imaging; an observation unit operative to cause the particles generated by the sampling unit to make a transition according to a predetermined motion model and observe a likelihood of each candidate contour defined by the particles; a correction unit operative to compare color information of an area in the second image frame defined by each candidate contour with color information of an area in the first image frame defined by the estimated probability distribution, so as to correct the likelihood observed by the observation unit, based on a result of comparison; and a result obtaining unit operative to estimate the existence probability distribution of the object in the second image frame based on the likelihood corrected by the correction unit.