VIDEO PROCESSING WITH REGION-BASED MULTIPLE-PASS MOTION ESTIMATION AND UPDATE OF TEMPORAL MOTION VECTOR CANDIDATES

摘要

The present invention relates to the field of motion estimation in video processing. Specifically the invention relates to a video-processing method and device for ascertaining motion vectors for a plurality of first pixel blocks forming a currently processed image region of a currently processed image of an image sequence. The invention addresses the problem of the impact of region-based motion estimation on the quality of the video output in video applications like picture-rate up conversion. The video-processing device of the invention comprises a processing unit, which is adapted to ascertain motion vectors for a plurality of first pixel blocks (C), which form a currently processed image region (200.1 to 200.14) of a currently processed image (200) of an image sequence, proceeding from image region to image region and processing a respective image region at least twice before proceeding to a next image region. Ascertaining a motion vector for a currently processed first pixel block (C) of the image region is performed by evaluating a respective set of candidate motion vectors containing at least one temporal candidate vector, which is a motion vector that was ascertained for a second pixel block (T) of a preceding image of the image sequence. The video-processing device of the invention is adapted to update, before processing a respective image region (200.2) of the currently processed image a second time, a temporal candidate vector, which was ascertained for a third pixel block located outside the currently processed image region (200.2) in the preceding image, by ascertaining a motion vector for the third pixel block (216) in the currently processed image and replacing the temporal candidate vector with it. By updating temporal motion vector candidates assigned to pixel blocks located outside the currently processed region in a first motion estimation pass, the quality of a motion estimation algorithm after the second or further motion estimation pass is improved in comparison with prior-art solutions.