Motion stabilization

A method of jitter compensation for video frames, comprising the steps of:

• providing a resolution hierarchy, F1, F2, . . . FN, for an input frame with N an integer greater than 2 and said input frame equal to FN;
• partitioning said F1 into blocks plus border regions;
• for each of said blocks, (i) computing a block motion vector, (ii) computing prediction errors for said block motion vector and for motion vectors differing by 1 from said block motion vector, and (iii) when a sum of differences of said prediction errors exceeds a first threshold, designating said each of said blocks as a reliable block;
• aggregating said reliable blocks into candidate motion regions according to block motion vectors for said reliable blocks;
• selecting a segmentation for F1 from said candidate motion regions by comparing said regions according to (i) the number of blocks, (ii) the number of blocks corresponding to blocks in a segmentation of a hierarchy of a prior frame, and (iii) an average of relative block motion vectors, wherein said segmentation comprises comparing scores for candidate motion regions where said score for a region includes a difference of an average relative block motion from a maximum, a measure of the number of said reliable blocks in a region, and a measure of the number of said reliable blocks in a region which are also in a segmentation for a low-resolution version of a prior picture;
• for n=2, . . . , N, selecting a segmentation for Fn by repeating the above steps for blocks corresponding to blocks of said segmentation of Fn−1;
• computing a global motion vector from said segmentation of FN;
• and
• using said global motion vector to jitter compensate said input frame.

A video camera, comprising:

• picture capturer;
• a jitter estimator coupled to said picture capturer, said jitter estimator including:
• a resolution hierarchy downsampler;
• a segmenter coupled to said downsampler, said segmenter operable to sequentially find a segmentation plus motion vector for each level of a resolution hierarchy computed from an input picture, wherein said segmentation comprises comparing scores for candidate motion regions where said score for a region includes a difference of an average relative block motion from a maximum, a measure of the number of said reliable blocks in a region, and a measure of the number of said reliable blocks in a region which are also in a segmentation for a low-resolution version of a prior picture;
• a global motion vector determiner coupled to said segmenter;
• a memory for a resolution hierarchy of a prior frame, said memory coupled to said jitter estimator;
• and
• jitter motion compensater coupled to said jitter estimator.