Block matching motion estimation method

A method for detecting motion vectors between a current frame and a previous frame of video signals by using a block matching motion estimation technique, wherein the current frame is divided into a plurality of search blocks of an identical size and the previous frame is divided into a corresponding number of search regions, each search region being divided into a multiplicity of candidate blocks of a size identical to that of the search block, which comprises the steps of:

• (a) producing a plurality of differential search blocks, wherein each differential search block includes differential pixels, each differential pixel in said each differential search block having a difference value between a luminance level of each pixel in a search block and a mean luminance level of the pixels in the search block;
• (b) producing a multiplicity of differential candidate blocks, wherein each differential candidate block includes differential pixels, each differential pixel in said each differential candidate block having a difference value between a luminance level of each pixel in a candidate block and a mean luminance level of the pixels in the candidate block;
• (c) motion-estimating a search block with respect to each of the candidate blocks associated with a corresponding search region to produce displacement vectors corresponding thereto and motion-estimating a differential search block with respect to each of the differential candidate blocks associated with a corresponding search region to produce error functions corresponding thereto, each of the displacement vectors representing displacements between the pixels in the search block and their corresponding pixels in each of the candidate blocks, and each of the error functions being calculated based on differences between luminance levels of the differential pixels in the differential search block and those of their corresponding differential pixels in each of the differential candidate blocks;
• and
• (d) choosing a minimum error function to define a displacement vector corresponding to the minimum error function as a motion vector for the search block.