Patent ID: 7817822

Claim:
At least one computer-readable storage medium storing computer-executable instructions for performing a method, the method comprising: determining two keyframes of a video sequence; obtaining a first state for a target object within one of the two keyframes and a second state for the target object within the other keyframe; and tracking the target object in the frames from the one keyframe to the other keyframe based on the first and second state the tracking comprising: performing two-dimensional extraction on the frames to obtain a plurality of local two-dimensional (2D) modes for the target object, the performing two-dimensional extraction including computing an evidence surface and applying a mean shift algorithm to compute a gradient direction of the computed evidence surface that results in the local 2D modes for the target object; performing three-dimensional trajectory segment extraction based on the sparse set of local 2D modes to obtain a plurality of three-dimensional trajectory segments for the target object; and performing trajectory optimization in a coarse to fine manner to obtain an optimal trajectory for the target object based on the trajectory segments.