Patent ID: 7809063

Claim:
A system for adaptive motion estimation, which sets a search range in a previous frame in order to find a corresponding block in the adaptive search range according to each block of a current frame and to accordingly determine a corresponding motion vector, the system comprising: a motion estimation unit, which determines a motion vector by referring to a target block of the current frame and reference blocks in the search range of the previous frame; a mode decision unit, which determines a compression mode according to the target block, the reference blocks and the motion vector and outputs a mode data corresponding to the compression mode; a mode memory unit, which stores the mode data output by the mode decision unit; a motion vector memory unit, which stores the motion vector determined by the motion estimation unit; and a search range specifying unit, which determines the search range according to the mode data stored in the mode memory unit and the motion vector stored in the motion vector memory unit, wherein the search range specifying unit computes an average of motion vectors of the previous frame according to the motion vector stored in the motion vector memory unit and a block number compressed by an intra mode corresponding to the mode data stored in the mode memory unit, and enlarges the search range when the average is greater than a predetermined search range threshold or the block number compressed by the intra mode is greater than predetermined a high motion vector threshold.