OBJECT TRACKER AND OBJECT TRACKING METHOD

Referring to FIG. 5, the tracking start-and-stop determining unit 28 of the tracking processing unit 26 determines the starting and stopping of tracking based on predetermined conditions. During the tracking, the sampling unit 29 creates or eliminates particles using the probability density distribution estimated for an immediately preceding image frame. The observation unit causes the particles to make a transition according to a predetermined motion model and observes the likelihoods of a candidate curves defined by the particles. The correction unit 32 compares the color histogram of an area located at a predetermined position relative to the candidate curve with the color histogram of an area similarly located relative to the curve determined as a result of tracking in the immediately preceding image frame. If the matching score is equal to or higher than a predetermined value, the likelihood of the candidate curve is increased by correction. The result obtaining unit 34 estimates the probability density distribution based on the likelihood thus corrected.