Patent ID: 7848427

Claim:
An image processing apparatus comprising: effective pixel determining means for determining whether or not each of pixels in an operation block are effective pixels in detecting a motion vector, the pixels being subject to a gradient operation for detecting the motion vector, said effective pixel determining means comprising: time-base temporal difference calculating means for calculating a time-base temporal pixel difference of a pixel in the operation block between a first frame being subject to detection of the motion vector and a second frame following the first frame; based on the time-base temporal pixel difference calculated by said time-base temporal difference calculating means, the pixels in the operation block are detected either as the effective pixels or non-effective pixels in detecting the motion vector; and gradient operation means for performing the gradient operation by using, among the pixels in the operation block, only pixels determined by said effective pixel determining means to be the effective pixels in detecting the motion vector and excluding pixels determined by said effective pixel determining means to be the non-effective pixels in detecting the motion vector; a mode selecting means for selecting a processing mode for the gradient operation, the mode including one of a block-unit processing mode that uses the block from which the motion vector is detected and a pixel-unit processing mode that uses the pixel from which the motion vector is detected, and if the number of effective pixels for the gradient operation in one mode is less than a threshold value, the mode selecting means selects an other mode.