MOTION ESTIMATOR

A motion estimator capable of performing fast motion estimation during compression of a moving picture is provided. The motion estimator includes a first memory including a previous search area memory having a plurality of memory areas for storing previous search area data by lines and a current process area memory for storing current process area data by lines; a previous search area data provider; a first switching part for selecting the previous search area data; a second switching part for selecting the current process area data; a calculator comprising a plurality of sum of absolute differences (SAD) calculators connected in parallel, the plurality of SAD calculators calculating SADs of the selected previous search area data and the current process area data; and a shift register for receiving and shifting SAD data and adding the shifted data and SAD data, thereby outputting a partial SAD. Accordingly, the motion estimator can perform a process fast, and particularly, can perform half-pixel based searching fast and effectively.