Video telecommunication system and method for compressing and decompressing digital color video data
First Claim
1. A method for compressing digital color video data in a video telecommunication system having means for generating a color video signal for a plurality of video picture frames, with each picture frame comprising a plurality of scan lines composed of a plurality of pixels, and each pixel in said picture frame comprising three digital color components, said method comprising the steps of:
- (a) determining a luminance function for each pixel based upon at least one of said three digital color components;
(b) determining at least one decision parameter for at least a substantial portion of the pixels in the scan lines of a current picture frame based upon the difference of said luminance function between pixels a predetermined distance from at least one other pixel on each scan line;
(c) comparing said at least one decision parameter with a corresponding threshold value to determine starting pixels and ending pixels for run lengths of sequentially related pixels in said scan lines, said run lengths being of a first digital word size, and said three color components being of second, third, and fourth digital word sizes, respectively;
(d) encoding all of said digital color components in said picture frame according to a look up table of digitally compressed color codes of the most visually significant color combinations of a fifth digital word size smaller than the sum of said second, third and fourth digital word sizes;
(e) encoding a plurality of combination of said run lengths and digitally compressed color codes representing at least a portion of said picture frame;
(f) comparing said run lengths and digitally compressed color codes of said current picture frame with the run lengths and digitally compressed color codes of a previous picture frame to determine changes from said previous picture frame to said current frame; and
(g) encoding said changes from said previous picture frame to said current picture frame for at least a portion of said picture frames, whereby once an initial picture frame is encoded, only those changes in subsequent picture frames are encoded.
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Abstract
The method and system of compressing and decompressing digital color video data in a video communication system utilizes a digital color video signal having three video color components, and involves the determination of a predetermined number of the most visually significant combinations of color components in a picture frame, and the encoding of the color components as compressed color codes in a series of run length and compressed color code combinations. Line-to-line differences and movement of edges and segments of the picture frames are determined, and frame-to-frame differences are also encoded to reduce the amount of information to a minimum. Further statistical encoding of at least a portion of the run length and color code combinations is also provided. The digitally compressed color component codes are decoded according to a look up table to form a table of the three digital color components for each run length, and the run lengths and corresponding color components are stored in an array in a buffer memory to represent the scan lines in a video picture frame.
142 Citations
92 Claims
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1. A method for compressing digital color video data in a video telecommunication system having means for generating a color video signal for a plurality of video picture frames, with each picture frame comprising a plurality of scan lines composed of a plurality of pixels, and each pixel in said picture frame comprising three digital color components, said method comprising the steps of:
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(a) determining a luminance function for each pixel based upon at least one of said three digital color components; (b) determining at least one decision parameter for at least a substantial portion of the pixels in the scan lines of a current picture frame based upon the difference of said luminance function between pixels a predetermined distance from at least one other pixel on each scan line; (c) comparing said at least one decision parameter with a corresponding threshold value to determine starting pixels and ending pixels for run lengths of sequentially related pixels in said scan lines, said run lengths being of a first digital word size, and said three color components being of second, third, and fourth digital word sizes, respectively; (d) encoding all of said digital color components in said picture frame according to a look up table of digitally compressed color codes of the most visually significant color combinations of a fifth digital word size smaller than the sum of said second, third and fourth digital word sizes; (e) encoding a plurality of combination of said run lengths and digitally compressed color codes representing at least a portion of said picture frame; (f) comparing said run lengths and digitally compressed color codes of said current picture frame with the run lengths and digitally compressed color codes of a previous picture frame to determine changes from said previous picture frame to said current frame; and (g) encoding said changes from said previous picture frame to said current picture frame for at least a portion of said picture frames, whereby once an initial picture frame is encoded, only those changes in subsequent picture frames are encoded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A system for compressing digital color video data in a video telecommunication system having means for generating a color video signal for a plurality of video picture frames, with each picture frame comprising a plurality of scan lines composed of a plurality of pixels, and each pixel in said picture frame comprising three digital color components, said system comprising:
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(a) means for determining a luminance function for each pixel based upon at least one of said three digital color components; (b) means for determining at least one decision parameter for at least a substantial portion of the pixels in the scan lines of said picture frame based on the difference of said luminance function between pixels a predetermined distance from at least one other pixel on each scan line; (c) means for comparing said at least one decision parameter with a corresponding threshold value to determine starting pixels and ending pixels for run lengths of sequentially related pixels in said scan lines, said run lengths being of a first digital word size, and said three color components being of second, third and fourth digital word sizes, respectively; (d) means for encoding all of said digital color components in said picture frame according to a table of digitally compressed color codes of the most visually significant color combinations of a fifth digital word size smaller than the sum of said second, third and fourth digital word sizes; (e) means for encoding a plurality of said run lengths and digitally compressed color codes representing at least a portion of said picture frame; (f) means for comparing said run lengths and digitally compressed color codes of said current picture frame with the run lengths and digitally compressed color codes of a previous picture frame to determine changes from said previous picture frame to said current frame; and (g) means for encoding said changes from said previous picture frame to said current picture frame for at least a portion of said picture frames, whereby once an initial picture frame is encoded, only those changes in subsequent picture frames are encoded. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A method for decompressing digital color video data in a video telecommunication system having means for receiving a plurality of digitized signals representing changes from a previous picture frame to a current picture frame of combinations of a plurality of pixel run lengths and digitally compressed color component codes of at least a portion of a plurality of scan lines of a video picture frame, and said system including a look up table of digitally compressed color component codes for three corresponding digital color components, said combinations of run length and digitally compressed color component codes having a first digital word size, and said compressed color component codes having a second digital word size, comprising:
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(a) receiving said changes from a previous picture frame to a current picture frame of combinations of run lengths and compressed color component codes to be decompressed and decoded; (b) decoding said digitally compressed color component codes according to said look up table to form a color components table for each of said three digital color components for each said run length, said three decoded color components having third, fourth, and fifth digital word sizes, respectively; (c) storing said changes of said run length and said corresponding color components in an array in a buffer memory means of run length and color component data representing said plurality of scan lines in said picture frame; and (d) generating a color video display signal comprising said three color component data for said picture frame from said run length and associated color components for the scan lines of said picture frame for each pixel of said picture frame by mapping the pixels in said run length from a starting pixel for said run length to an end pixel of said run length to the end of the portion each scan line to be mapped. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39)
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40. A system of decompressing color video data in a video telecommunication system having means for receiving a plurality of digitized signals representing changes from a previous picture frame to a current picture frame of combinations of a plurality of pixel run lengths and digitally compressed color component codes of at least a portion of a plurality of scan lines of a video picture frame and including a look up table of digitally compressed color component codes for three corresponding digital color components, said combinations of run length and digitally compressed color component codes having a first digital word size, and said compressed color component codes having a second digital word size, said system comprising:
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(a) means for receiving said changes from a previous picture frame to a current picture frame of run lengths and compressed color component codes to be decompressed and decoded; (b) means for decoding said digitally compressed color component codes according to said look up table to form a color components table for each of said three digital color components for each said run length, said three decoded color components having third, fourth, and fifth digital word sizes, respectively; (c) means for storing said run lengths and said corresponding color components in an array in buffer memory means of run length and color component data representing said plurality of scan lines in said picture frame; and (d) means for generating a color video display signal comprising said three color component data from said run length and associated color components for the scan lines of said picture frame for each pixel of said picture frame by mapping the pixels in said run length from a starting pixel for said run length to an end pixel of said run length to the end of the portion of each scan line to be mapped. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48)
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49. A method for compressing and decompressing digital color video data in a televideo communication system for transmitting and receiving a plurality of video picture frames, with each picture frame comprising a plurality of scan lines composed of a plurality of pixels, and each pixel in said picture frame comprising three digital color components, said method comprising the steps of:
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(a) determining a luminance function for each pixel based upon at least one of said three digital color components; (b) determining at least one decision parameter for at least a substantial portion of the pixels in the scan lines of said picture frame based upon the difference of said luminance function between pixels a predetermined distance from at least one other pixel on each scan line; (c) comparing said at least one decision parameter a corresponding threshold value to determine starting pixels and ending pixels for run lengths of sequentially related pixels in said scan lines, said run lengths being of a first digital word size, and said three color components being of second, third and fourth digital word sizes, respectively; (d) encoding all of said digital color components in said picture frame according to a look up table of digitally compressed color codes of the most visually significant color combinations of a fifth digital word size smaller than the sum of said second, third and fourth digital word sizes; (e) encoding a plurality of combinations of said run lengths and digitally compressed color coded representing at least a portion of said picture frame; (f) comparing said run lengths and digitally compressed color codes of said current picture frame with the run lengths and digitally compressed color codes of a previous picture frame to determine changes from said previous picture frame to said current frame; and (g) encoding said changes from said previous picture frame to said current picture frame for at least a portion of said picture frames, whereby once an initial picture frame is encoded, only those changes in subsequent picture frames are encoded; (h) transmitting said encoded changes from a previous picture frame to a current picture frame of said run lengths and said digitally compressed color codes; (i) receiving said transmitted encoded changes from a previous picture frame to a current picture frame of said run lengths and compressed color codes to be decompressed and decoded; (j) decoding said digitally compressed color component codes according to said look up table to form a color components table for each of said three digital color components for each said run length, each of said three decoded color components having sixth, seventh, and eighth digital word sizes, respectively; (k) storing said run length and said corresponding color components in an array in a buffer memory means of run length and color component data representing said plurality of scan lines in said picture frame; and (l) generating a color video display signal representing said three color components data from said run length and associated color components for the scan lines of said picture frame for each pixel of said picture frame by mapping the pixels in said run length from a starting pixel for said run length to an end pixel of said run length to the end of the portion each scan line to be mapped. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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71. A system for compressing and decompressing digital color video data in a video telecommunication system for transmitting and receiving signal for a plurality of video picture frames, with each picture frame comprising a plurality of scan lines composed of a plurality of pixels, and each pixel in said picture frame comprising three digital color components, said system comprising:
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(a) means for determining a luminance function for each pixel based upon at least one of said three digital color components; (b) means for determining at least one decision parameter for at least a substantial portion of the pixels in the scan lines of said picture frame based upon the difference of said luminance function between pixels a predetermined distance from at least one other pixel on each scan line; (c) means for comparing said at least one decision parameter with a corresponding threshold value to determine starting pixels and ending pixels for run lengths of sequentially related pixels in said scan lines, said run lengths being of a first digital word size, and said three color components being of second, third and fourth digital word sizes, respectively, for each said run length; (d) means for encoding all of said digital color components in said picture frame according to a look up table of digitally compressed color codes of said most visually significant color combinations of a fifth digital word size smaller than the sum of said second, third and fourth digital word sizes; (e) means for encoding a plurality of combination of said run lengths and digitally compressed color codes representing at least a portion of said picture frame; (f) comparing said run lengths and digitally compressed color codes of said current picture frame with the run lengths and digitally compressed color codes of a previous picture frame to determine changes from said previous picture frame to said current frame; and (g) means for encoding said changes from said previous picture frame to said current picture frame for at least a portion of said picture frame, whereby once an initial picture frame is encoded, only those changes in subsequent picture frames are encoded; (h) means for transmitting said encoded changes from a previous picture frame to a current picture frame of said run lengths and said digitally compressed color codes; (i) means for receiving said encoded changes from a previous picture frame to a current picture frame of said transmitted encoded run lengths and said digitally compressed color codes to be decompressed and decoded; (j) means for decoding said digitally compressed color component codes according to said look up table to form a color components table for each of said three digital color components for each said run length, each of said three decoded color components having sixth, seventh, and eighth digital word sizes, respectively; (k) means for storing said run length and said corresponding color components in an array in a buffer memory means of run length and color component data representing said plurality of scan lines in said picture frame; and (l) means for generating a color video display signal representing said three color component codes from said run length and associated color components for the scan lines of said picture frame for each pixel of said picture frame by mapping the pixels in said run length from a starting pixel for said run length to an end pixel of said run length to the end of the portion each scan line to be mapped. - View Dependent Claims (72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92)
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Specification