US Patent 7444018 Method and apparatus for shot detection

A system identifies an abrupt transition in content between two frames, and determines whether the abrupt transition was caused by a shot boundary between the two frames or by a flashlight event. Identification of the abrupt transition in content includes calculating a difference in light intensity histograms between the current frame and a preceding frame, and comparing the histogram difference to a dynamically determined threshold. Further, an average light intensity based method is used to determine whether the abrupt transition was caused by a shot boundary or by a flashlight event.