Patent ID: 7843512

Claim:
A method of identifying a plurality of key video frames in a sequence of image frames, each of said sequence of image frames containing a plurality of pixels, each of said plurality of pixels corresponding to a corresponding point of an area based on which said sequence of image frames are generated, said method comprising: using a processor to determine a rate of change of visual content of each current frame from a corresponding reference frame, each of said current frame and said reference frame being comprised in said sequence of image frames, wherein said rate of change represents a difference of a first value and a second value, said first value representing a change of visual content of a current frame compared to a first frame, said second value representing a change of visual content of said first frame compared to a second frame, wherein said second frame is a reference frame for said first frame and said first frame is a reference frame for said current frame; and using the processor to select said current frame as a corresponding one of a set of potential video frames if said rate exceeds a corresponding first threshold value, wherein said plurality of key video frames are selected from said set of potential video frames, wherein said determining and said selecting are repeated for each of said sequence of image frames as said current frame to form said set of potential video frames, wherein each of the respective first frame and the respective second frame are different for different ones of the current frame in said sequence of image frames; wherein said determining comprises: determining a displacement magnitude of each moved pixel of said current frame compared to the position in said first frame and of said first frame compared to the position in said second frame; and computing a first representative magnitude of said displacement magnitude for said moved pixels of said current frame compared to said first frame, and a second representative magnitude of said displacement magnitude for said moved pixels of said first frame compared to said second frame, wherein said first value and said second value respectively equal said first representative magnitude and said second representative magnitude such that said rate is computed as a difference of said first representative magnitude and said second representative magnitude.