Patent ID: 7203340

Claim:
A method of detecting changes in video, the method comprising: (a) obtaining at least three video frames; (b) selecting one of said at least three video frames as a starting video frame; (c) selecting a second one of said at least three video frames as an ending video frame; (d) selecting a third one of said at least three video frames as a middle video frame, said middle video frame being between said starting video frame and said ending video frame in a time sequence of said at least three video frames; (e) creating a first intermediate image based on differences computed between said starting video frame and said middle video frame; (f) creating a second intermediate image based on differences computed between said middle video frame and said ending video frame; (g) determining a geometric transformation such that when said geometric transformation is applied to said second intermediate image, an overlap between images in said first intermediate image and images in said second intermediate image is maximized; (h) applying said geometric transformation to said second intermediate video frame to result in a transformed image; (i) constructing an end image based on similarities between said first intermediate image and said second intermediate image such that active pixels common to both intermediate images are inactive in said end image.