Method and system for digital image stabilization
AssigneeInstitute for Information Industry
InventorsTien-Ying Kuo, Chung-Hsin Wang, Chih-Chun Lai
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Abstract
A method and a system for digital image stabilization are provided for a digital image sequence. The present method calculates local motion vectors between two adjacent images by an interlaced Gray-coded bit-plane matching. An appropriate global motion vector is obtained by weighted accumulation of all local motion vectors. Finally, an accumulated motion vector is obtained by the global motion vector so as to process a motion correction on the digital image sequence and produce a stabile output image.
Claims24
A method for digital image stabilization, applicable to an image sequence, wherein the image sequence comprises a plurality of images conforming to a pixel depth, the method comprising:
- dividing a current image into a plurality of target blocks, and defining a search area corresponding to each of the target blocks in a previous image;
- defining K Gray-coded bit-planes based on a plurality of raw bit-planes corresponding to the current image and defining K Gray-coded bit-planes based on a plurality of raw bit-planes corresponding to the previous image, wherein K is a positive integer smaller than the pixel depth;
- comparing each of the target blocks and the corresponding search area thereof which are respectively formed by interlacing the corresponding K Gray-coded bit-planes, so as to obtain a plurality of correlation measures between each of the target blocks and the corresponding search area thereof;
- estimating a global motion vector indicating a motion of the current image relative to the previous image, based on an average value and a minimum value of the correlation measures of each of the target blocks;
- and
- calculating an accumulated motion vector reflecting a motion of the image sequence based on the global motion vector, and determining an output image from the current image based on the accumulated motion vector.
A system for digital image stabilization, comprising:
- a local motion vector computing device for receiving an image sequence comprising a plurality of images conforming to a pixel depth, dividing the current image into a plurality of target blocks, defining a search area corresponding to each of the target blocks in the previous image, defining K Gray-coded bit-planes based on a plurality of raw bit-planes corresponding to the current image and defining K Gray-coded bit-planes based on a plurality of raw bit-planes corresponding to the previous image, and comparing each of the target blocks and the corresponding search area thereof which are respectively formed by interlacing the corresponding K Gray-coded bit-planes, so as to obtain a plurality of correlation measures of the target blocks and the search area, wherein K is a positive integer smaller than the pixel depth;
- a global motion vector computing device coupled to the local motion vector computing device for estimating a global motion vector indicating a motion of the current image relative to the previous image, based on an average value and a minimum value of all the correlation measures of each target block;
- and
- a motion correction device coupled to the global motion vector computing device for calculating an accumulated motion vector reflecting a motion of the image sequence based on the global motion vector, and determining an output image from the current image according to the accumulated motion vector.
Dependencies are inferred from the claim text.