86. The computer-readable storage medium of claim 85 , further comprising computer program instructions for: tracking the motion of the object across a subset of the plurality of video frames; obtaining estimated motion parameters of the object based on the tracking; refining the estimated motion parameters of the object; and recognizing the visual gesture based at least in part on the detected motion of the object.
86. The computer-readable storage medium of claim 85 , further comprising computer program instructions for: tracking the motion of the object across a subset of the plurality of video frames; obtaining estimated motion parameters of the object based on the tracking; refining the estimated motion parameters of the object; and recognizing the visual gesture based at least in part on the detected motion of the object. 87. The computer-readable storage medium of claim 86 , wherein the computer program instructions for determining motion of the object comprise computer program instructions for: identifying a first instance of the object contained in the ROI in the video frame; and obtaining a center point position of the ROI and a size of the ROI within the video frames.