US 5,477,272 A · Variable-block size multi-resolution motion estimation scheme for pyramid coding

Abstract

A novel variable-size block multi-resolution motion estimation (MRME) scheme is presented. The motion estimation scheme can be used to estimate motion vectors in subband coding, wavelet coding and other pyramid coding systems for video compression. In the MRME scheme, the motion vectors in the highest layer of the pyramid are first estimated, then these motion vectors are used as the initial estimate for the next layer and gradually refined. A variable block size is used to adapt to its level in the pyramid. This scheme not only considerably reduces the searching and matching time but also provides a meaningful characterization of the intrinsic motion structure. In addition, the variable-MRME approach avoids the drawback of the constant-size MRME in describing small object motion activities. The proposed variable-block size MRME scheme can be used in estimating motion vectors for different video source formats and resolutions including video telephone, NTSC/PAL/SECAM, and HDTV applications.

Claims8

Dependent claims

A method of computing motion vectors for a frame in a full-motion video sequence, comprising the steps of:

transforming said frame into a multifrequency, multiresolution domain representation by decomposing said frame into a plurality of subframes each subframe having an associated resolution m and occupying a respective frequency band, wherein one subframe of said plurality of subframes has the lowest resolution;
dividing each subframe into a set of blocks defining a grid, wherein the size of each block is based on the associated resolution of said subframe;
calculating a first motion vector, relative to a previous frame, for each block of said subframe with the lowest resolution;
calculating a second motion vector by motion compensation for each block of each other subframe of said plurality of subframes, comprising the steps of
scaling said first motion vector corresponding to a respective block of said subframe with the lowest resolution to obtain a scaled motion vector, and
calculating a second motion vector, relative to the previous frame, for each block under motion compensation using the scaled motion vector as an inital bias.

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Variable-block size multi-resolution motion estimation scheme for pyramid coding

Life of this patent

Variable-block size multi-resolution motion estimation scheme for pyramid coding

Life of this patent

Abstract

Claims8