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US 6,493,039 B1Granted
Method and apparatus for white noise reduction in video images
AssigneeXerox Corporation
InventorSteven J. Harrington
Life of this patent
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Abstract
A method and system for reducing white noise in images. The method does not require knowledge of the image blur or noise statistics, and can remove noise without causing excessive image blur. The image is separated into frequency bands which are then thresholded to remove small image changes, i.e. noise, while maintaining larger changes which are signals. The thresholded components are then recombined to produce an output image with reduced white noise.
Claims10
A method for reducing white noise in an image comprising:
- determining a summed-area table of the image values of the image;
- selecting at least one portion of the image;
- decomposing each selected portion into at least one frequency band;
- filtering the at least one frequency band to remove noise;
- reassembling, for each selected portion, the at least one frequency band into a corresponding filtered portion;
- and
- outputting the filtered image.
4 more elements
A white noise reduction device comprising:
- a decomposer that decomposes the at least one input image into at least one frequency band, the decomposer including at least one summed-area table;
- a threshold comparator that determines white noise in the at least one frequency band and outputs a thresholded frequency band;
- a signal modifier that removes changes in the image that are determined to be white noise;
- and
- a band reassembler that re-combines the at least one thresholded frequency band.
2 more elements
Dependencies are inferred from the claim text.