An electronic circuit includes a block determinator, a candidate selector, and a motion vector generator to perform motion estimation. The block determinator determines a current block and candidate blocks with regard to each of decimated images generated from an original image, wherein the block determinator determines first candidate blocks based on a location of the current block without a full search for all pixels with regard to a first decimated image of the lowest resolution. The candidate selector selects second candidate blocks which are some of the first candidate blocks with regard to a second decimated image of the highest resolution, such that the block determinator determines the second candidate blocks with regard to the original image. The motion vector generator generates a motion vector for the current block based on one reference patch determined from reference patches indicated by candidate motion vectors of the second candidate blocks.