EP0339938A2
Expired / Lapsed
EP
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Method and system for compressing colour video encoded data
Assignee: BIL Far East Holdings Ltd
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Filing: 1989-04-25
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Granted: —
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Expires: 2009-04-25
Abstract
Abstract The method and system for compressing color video data in a video communication system utilizes a three color digital signal, and involves the determination of a luminance function for each pixel in a series of video picture frames. One or more decision parameters based upon differences of the luminance function between pixels are compared with corresponding adaptive thresholds to determine decision points in the scan lines, and the digital word size of the three digital color components is reduced before encoding of run lengths between decision points of the color values.
Inventors
- 👤 John Music
- 👤 James L. Thomas
- 👤 Gordon H. Smith
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 18:09
CPC Classifications
H; H04; H04N; H04N11/00; H04N11/04; H04N11/042; G; G06; G06T; G06T9/00; G06T9/005
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
288 words
A method for compressing color video data in a video communication system having means for producing 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, each scan line having a starting pixel and an ending pixel, and each pixel in said picture frame comprising three digital color component signals of first, second and third digital word sizes, respectively, said method comprising the steps of: a) determining a luminance function for each pixel based upon at least one of said three digital color component signals; 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 at least one predetermined distance from at least one other pixel on each scan line; c) determining which of said pixels represent decision points based upon at least one decision parameter and at least one adaptive threshold; d) reducing the word size of at least one of said three reduced digital color components signals to provide one to three digital color component signals of fourth, fifth, and sixth digital word sizes, respectively, for each said pixel; e) coding said plurality of pixels in each scan line as a plurality of combinations of pixel run lengths and said three respective reduced color component signals for each said run length, said run lengths being determined between said starting pixel for each scan line, intermediate points selected from the group of said decision points and points intermediate said decision points, and said ending pixel, and each run length being of a seventh digital word size.
Claim 2
Independent Claim
288 words
A method for compressing color video data in a video communication system having means for producing 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, each scan line having a starting pixel and an ending pixel, and each pixel in said picture frame comprising three digital color component signals of first, second and third digital word sizes, respectively, said method comprising the steps of: a) determining a luminance function for each pixel based upon at least one of said three digital color component signals; 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 at least one predetermined distance from at least one other pixel on each scan line; c) determining which of said pixels represent decision points based upon at least one decision parameter and at least one adaptive threshold; d) reducing the word size of at least one of said three reduced digital color components signals to provide one to three digital color component signals of fourth, fifth, and sixth digital word sizes, respectively, for each said pixel; e) coding said plurality of pixels in each scan line as a plurality of combinations of pixel run lengths and said three respective reduced color component signals for each said run length, said run lengths being determined between said starting pixel for each scan line, intermediate points selected from the group of said decision points and points intermediate said decision points, and said ending pixel, and each run length being of a seventh digital word size.
Claim 3
Dependent Claim
37 words
The method of Claim 1, wherein said step of determining which of said pixels represent decision points comprises comparing the absolute value of said at least one decision parameter with at least one adaptive absolute difference threshold.
Claim 4
Dependent Claim
65 words
The method of Claim 1, wherein said step of determining which of said pixels represent decision points comprises determining the rate of change of said at least one decision parameter for each of said pixels for which said luminance function difference has been determined; and comparing said rate of change of said at least one decision parameter with a corresponding adaptive rate of change threshold.
Claim 5
Dependent Claim
40 words
The method of Claim 1, wherein the step of comparing said rates of change with an adaptive rate of change threshold to determine said decision points includes comparing at least one said decision parameter with an adaptive cumulative difference threshold.
Claim 6
Dependent Claim
23 words
The method of Claim 1, wherein the step of determining said luminance function comprises summing each of said three digital color component signals.
Claim 7
Dependent Claim
38 words
The method of Claim 5, wherein the step of determining said luminance function includes weighting of the sum of said three digital color component signals with respect to one or more of said three digital color component signals.
Claim 8
Dependent Claim
42 words
The method of Claim 1, wherein a first decision parameter is determined from the difference in said luminance function between a first pixel and a second proximate pixel a distance of one pixel away from said first pixel on a scan line.
Claim 9
Dependent Claim
41 words
The method of Claim 1, wherein a first decision parameter is determined from the difference in said luminance function between a first pixel and a second proximate pixel a distance of two pixels away from said first pixel a scan line.
Claim 10
Dependent Claim
20 words
The method of Claim 7 or 8, wherein a cumulative decision parameter is determined from summing said proximate pixel differences.
Claim 11
Dependent Claim
19 words
The method of Claim 14, wherein a second decision parameter is determined from differences between said proximate pixel differences.
Claim 12
Dependent Claim
46 words
The method of Claim 1, further including the step of concatenating run lengths in said plurality of combinations of run lengths and reduced color components in a scan line which are associate with reduced color components whose differences are less than a predetermined color difference threshold.
Claim 13
Independent Claim
298 words
A system for compressing color video data in a video communication system having a camera for producing 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, each scan line having a starting pixel and an ending pixel and each pixel in said frame comprising three digital color component signals of first, second and third digital word sizes, respectively, said system comprising: a) means for determining a luminance function for each pixel based upon at least one of said three digital color component signals; 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 at least one luminance function between pixels at least one predetermined distance from at least one other pixel on each scan line; c) means for determining which of said pixels represent decision points based upon at least one decision parameter and at least one adaptive threshold; d) means for reducing the word size of at least one of said three reduced digital color components signals to provide one to three digital color component signals of fourth, fifth, and sixth digital word sizes, respectively, for each said pixel; e) means for coding said plurality of pixels in each scan line as a plurality of combinations of pixels run lengths and said three respective reduced color component signals for each said run length, said run lengths being determined between said starting pixel for each scan line, intermediate points selected from the group of said decision points and points intermediate said decisicn points, and said ending pixel, and each run length being of a seventh digital word size.
Claim 14
Independent Claim
298 words
A system for compressing color video data in a video communication system having a camera for producing 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, each scan line having a starting pixel and an ending pixel and each pixel in said frame comprising three digital color component signals of first, second and third digital word sizes, respectively, said system comprising: a) means for determining a luminance function for each pixel based upon at least one of said three digital color component signals; 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 at least one luminance function between pixels at least one predetermined distance from at least one other pixel on each scan line; c) means for determining which of said pixels represent decision points based upon at least one decision parameter and at least one adaptive threshold; d) means for reducing the word size of at least one of said three reduced digital color components signals to provide one to three digital color component signals of fourth, fifth, and sixth digital word sizes, respectively, for each said pixel; e) means for coding said plurality of pixels in each scan line as a plurality of combinations of pixels run lengths and said three respective reduced color component signals for each said run length, said run lengths being determined between said starting pixel for each scan line, intermediate points selected from the group of said decision points and points intermediate said decisicn points, and said ending pixel, and each run length being of a seventh digital word size.
Claim 15
Dependent Claim
39 words
The system of Claim 12, wherein said means for determining which of said pixels represents decision points comprises means for comparing the absolute values of said at least one decision parameter with at least one adaptive absolute difference threshold.
Claim 16
Dependent Claim
80 words
The system of Claim 12, wherein said means for determining which of said pixels represent decision points comprises: a) means for determining the rate of change of said at least one decision parameter for each of said pixels for which said luminance function difference has been determined; and b) means for comparing said rate of change of said at least one decision parameter with a corresponding adapative rate of change threshold to determine which of said pixels represent decision points.
Claim 17
Dependent Claim
25 words
The system of Claim 12, wherein said means for determining said luminance function comprises means for summing each of said three digital color component signals.
Claim 18
Dependent Claim
38 words
The system of Claim 15, wherein said means for determining said luminance function includes weighting of the sum of said three digital color component signals with respect to one or more of said three digital color component signals.
Claim 19
Dependent Claim
45 words
The system of Claim 12, further including means for concatenating run lengths in said plurality of combinations of run lengths and reduced color components in a scan line which are associated with reduced color components whose differences are less than a predetermined color difference threshold.
References Cited (Backward Citations)
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