Enhanced video data compression in intelligent video information management system
First Claim
1. A method of representing video data in compressed form, comprising the steps of:
- dividing into rectangular blocks a present image to be compressed, the present image being formed in an image plane, each of said rectangular blocks consisting of n pixel blocks, each of said pixel blocks corresponding to an m pixel by m pixel segment of said image plane;
n being an integer greater than or equal to 1;
m being an integer greater than 1;
comparing each of said rectangular blocks of the present image with a corresponding rectangular block of a reference image to generate comparison data for the block of the present image;
selecting for representation the rectangular blocks of the present image for which the generated comparison data meets a selection criterion;
generating mapping data indicative of locations in the image plane which correspond to the selected rectangular blocks for the present image; and
representing the present image in compressed form by use of;
(a) header data for identifying the present image;
(b) said mapping data generated for the present image; and
(c) image data representative of the selected rectangular blocks of the present image;
wherein;
said comparing step includes applying an orthogonal transformation to at least one pixel block of the n pixel blocks of each rectangular block of the present image to form coefficient data, and comparing the coefficient data with corresponding coefficient data for a corresponding pixel block in the reference image.
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Accused Products
Abstract
A video image data field to be compression-encoded is divided into rectangular blocks. Each of the rectangular blocks is compared with a corresponding block of a reference image to generate comparison data. The block of the image to be encoded is selected for representation if the comparison data for the block meets a selection criterion. The comparison data is generated on the basis of coefficients formed by applying an orthogonal transform to the blocks of the reference image and to the blocks of the image to be encoded. Mapping data is generated which is indicative of locations in the image plane corresponding to the selected blocks. The image to be encoded is represented in compressed form by header data, the mapping data and image data representative of the selected blocks. When the reference image is compression encoded, the blocks may be expanded in areas of the reference image which correspond to a low information density.
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Citations
35 Claims
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1. A method of representing video data in compressed form, comprising the steps of:
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dividing into rectangular blocks a present image to be compressed, the present image being formed in an image plane, each of said rectangular blocks consisting of n pixel blocks, each of said pixel blocks corresponding to an m pixel by m pixel segment of said image plane;
n being an integer greater than or equal to 1;
m being an integer greater than 1;comparing each of said rectangular blocks of the present image with a corresponding rectangular block of a reference image to generate comparison data for the block of the present image; selecting for representation the rectangular blocks of the present image for which the generated comparison data meets a selection criterion; generating mapping data indicative of locations in the image plane which correspond to the selected rectangular blocks for the present image; and representing the present image in compressed form by use of; (a) header data for identifying the present image; (b) said mapping data generated for the present image; and (c) image data representative of the selected rectangular blocks of the present image; wherein; said comparing step includes applying an orthogonal transformation to at least one pixel block of the n pixel blocks of each rectangular block of the present image to form coefficient data, and comparing the coefficient data with corresponding coefficient data for a corresponding pixel block in the reference image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of representing video data in compressed form, comprising the steps of:
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dividing into rectangular blocks a present image to be compressed, the present image being formed in an image plane, each of said rectangular blocks consisting of n pixel blocks, each of said pixel blocks corresponding to an m pixel by m pixel segment of said image plane;
n being an integer greater than or equal to 1;
m being an integer greater than 1;applying an orthogonal transformation to at least one pixel block of the n pixel blocks of each rectangular block of the present image to form coefficient data; comparing the coefficient data with corresponding coefficient data for a corresponding pixel block in a reference image to generate comparison data for the rectangular block which includes the pixel block of the present image; selecting for representation the rectangular blocks of the present image for which the generated comparison data meets a selection criterion; and generating compressed image data only for the selected rectangular blocks of the present image. - View Dependent Claims (14, 15, 16, 17)
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18. Apparatus for storing compressed video data, comprising:
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means for receiving video signals representing a dynamic sequence of images; means for converting the video signals into a sequence of video data fields; processing means for compressing said video data fields; and means for storing the compressed video data fields; said processing means being programmed to; divide each of said video data fields into pixel blocks each corresponding to an m×
m segment of an image plane, m being an integer greater than 1;apply an orthogonal transformation to each of the pixel blocks to form coefficient data; as to one of said images selected to be a reference image, store at least some of the coefficient data as reference data; as to said reference image, quantize the coefficient data to form quantization data and Huffman-encode the quantization data to form first storage data; cause the means for storing to store the first storage data; as to one of said images subsequent to said reference image, compare the coefficient data corresponding to at least some of the pixel blocks of said subsequent image to the reference data for the corresponding pixel block of the reference image; on the basis of said comparison, select pixel blocks of said subsequent image for further processing and select portions of the reference data for updating; update the selected portions of the reference data using coefficient data corresponding to the selected pixel blocks of said subsequent image; quantize the coefficient data corresponding to the selected pixel blocks and Huffman-encode the resulting quantized coefficient data to form second storage data; and cause the means for storing to store the second storage data. - View Dependent Claims (19)
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20. A method of performing data compression with respect to image data, said image data being representative of pixels arrayed in an image plane, the method comprising the steps of:
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dividing said image data into a plurality of basic data blocks, each of said basic data blocks representing a rectangular part of said image plane, all of said basic data blocks being of equal size; detecting a spatial frequency characteristic of each of a contiguous plurality of said basic data blocks; in dependence upon a result of said detecting step, selectively combining said contiguous plurality of said basic data blocks to form a combined data block; subsampling said combined data block to form a subsampled data block that is equal in size to said basic data blocks; and applying a transformation to said subsampled data block to form a block of coefficient data. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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28. A method of performing data compression with respect to image data, said image data being representative of pixels arrayed in an image plane, the method comprising the steps of:
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dividing said image data into a plurality of m×
m pixel blocks, m being equal to 2p, p being an integer equal to or greater than 1;detecting a spatial frequency characteristic of each of a contiguous plurality of said m×
m pixel blocks;in dependence upon a result of said detecting step, selectively combining said contiguous plurality of m×
m pixel blocks to form an (m·
2q)×
(m·
2q) pixel block, q being an integer equal to or greater than 1;processing said (m·
2q)×
(m·
2q) pixel block to form a processed m×
m data array representative of said (m·
2q)×
(m·
2q) pixel block; andapplying a transformation to said processed m×
m data array to form a block of coefficient data. - View Dependent Claims (29, 30, 31)
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32. A method of performing data compression with respect to image data, said image data being representative of pixels arrayed in an image plane, the method comprising the steps of:
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dividing said image data into a plurality of m×
m pixel blocks, m being equal to 2p, p being an integer equal to or greater than 1;combining a first contiguous plurality of said m×
m pixel blocks to form an (m·
2q)×
(m·
2q) pixel block, q being an integer equal to or greater than 1;processing said (m·
2q)×
(m·
2q) pixel block to form a first processed m×
m data array representative of said (m·
2q)×
(m·
2q) pixel block;transform-encoding said first processed m×
m data array to form compressed image data representative of said (m·
2q)×
(m·
2q) pixel block;combining a second contiguous plurality of said m×
m pixel blocks to form an (m·
2r)×
(m·
2r) pixel block, r being an integer equal to or greater than 1, r≠
q;processing said (m·
2r)×
(m·
2r) pixel block to form a second processed m×
m data array representative of said (m·
2r)×
(m·
2r) pixel block; andtransform-encoding said second processed m×
m data array to form compressed image data representative of said (m·
2r)×
(m·
2r) pixel block. - View Dependent Claims (33, 34, 35)
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Specification