Multi Resolution Motion Estimation Techniques for Video Compression: a Survey

The discrete wavelet transform has received considerable attention in video processing applications because of its flexibility in representing nonstationary signals. It perfectly provides a multiresolution expression of a signal with localization in both time and frequency. Wavelet transform decomposes a video frame into a set of subframes with different resolutions corresponding to different frequency bands. These multiresolution frames also provide a representation of the global motion structure of the video signal at different scales. The motion activities for a particular subframe at different resolution are different but highly correlated, since they actually represent the same motion structure at different scales. Based on these facts, Multiresolution Motion Estimation (MRME) and Compensation has been reported in literature for the exploitation of temporal redundancy in video compression. This technique estimates the motion vectors hierarchically from lower resolution to higher resolution subimages and thus reduces the complexity significantly. In this paper, the MRME technique and the recent trends for improving the performance of baseline MRME have been presentedf.