In order to track an occluded target in an image sequence

the Bayesian decision theory is

here

introduced to the problem of distinguishing occlusions and appearance changes according to their different risk possibilities.A new target template combining image intensity and histogram is designed.The corresponding updating method is also derived based on particle filter.If the target is totally occluded by another target

the template can be kept unchanged.The occlusion of a target will not influence tracking.Simulation results show that the presented method can efficiently justify whether the occlusion occurs and realize target tracking in image sequences even though the tracked target is totally occluded with long time.