US4862264A
Expired / Lapsed
US
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Method of coding a video signal for transmission in a restricted bandwidth
Assignee: British Broadcasting Corp
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Filing: 1986-12-23
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Granted: 1989-08-29
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Expires: 2006-12-23
Abstract
Abstract A video signal is coded for transmission in a restricted bandwidth by sub-dividing a frame of picture information into a set of constituent blocks, measuring the amount of picture activity in each block, sampling the information in each block at a rate related to the amount of picture activity in that block, and adding to the coded block a supplementary signal indicating the sampling rate used for the block. Thus a decision is made on a block-by-block basis as to whether the block is transmitted with full accuracy or whether it can be adequately reconstructed from the previous frames.
Inventors
- 👤 Nicholas D. Wells
- 👤 Michael J. Knee
- 👤 Charles P. Sandbank
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:19
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/12; H04N7/122; H04N7/125; H04N19/00; H04N19/90; H04N19/98; H04N7/015; H04N7/0152; H04N7/0155
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
106 words
A method of coding a video signal for transmission in a restricted bandwidth, the method comprising the steps of: sub-dividing a frame of picture information of the video signal into a set of constituent blocks; pre-filtering the video signal with a digital anti-aliasing filter; measuring the amount of picture activity in each block; coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; adding to each thus coded block a supplementary signal which is related to the sampling rate used in that block; and transmitting the coded video signal in analogue form.
Claim 2
Independent Claim
106 words
A method of coding a video signal for transmission in a restricted bandwidth, the method comprising the steps of: sub-dividing a frame of picture information of the video signal into a set of constituent blocks; pre-filtering the video signal with a digital anti-aliasing filter; measuring the amount of picture activity in each block; coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; adding to each thus coded block a supplementary signal which is related to the sampling rate used in that block; and transmitting the coded video signal in analogue form.
Claim 3
Dependent Claim
29 words
A method as claimed in claim 1, wherein the signals corresponding to each sampled block are fed into a buffer store for retrieval and transmission at a regular rate.
Claim 4
Dependent Claim
29 words
A method as claimed in claim 1, wherein in blocks where a low sampling rate is used a sample is transmitted representing the mean sample value for that block.
Claim 5
Dependent Claim
36 words
A method as claimed in claim 1, wherein the measurement of picture activity in each block is made on a cummulative basis frame by frame taken from the last frame transmitted at a high sampling rate.
Claim 6
Dependent Claim
31 words
A method as claimed in claim 1, wherein the measurement of picture activity comprises the sum of a function of the difference between successive frames of the samples in a block.
Claim 7
Dependent Claim
18 words
A method as claimed in claim 5, wherein the said function is a power of greater than 2.
Claim 8
Dependent Claim
20 words
A method as claimed in claim 1, wherein at least one motion vector measurement is transmitted for each inactive block.
Claim 9
Dependent Claim
31 words
A method as claimed in claim 7, wherein a set of motion vectors are determined for each frame and one of the set of motion vectors is transmitted for each block.
Claim 10
Dependent Claim
62 words
A method of decoding a video signal encoded according to the method of claim 1, the method comprising: receiving the transmitted sampled video signal in analogue form and receiving associated supplementary signals; separating the supplementary signals; decoding the sampled video signal relating to each block by assuming a sampling rate in accordance with the corresponding supplementary signal; and storing the decoded signals.
Claim 11
Dependent Claim
48 words
A method as claimed in claim 9, wherein in blocks where n low sampling rate is used a sample is received representing the mean value for that block, and the other decoded samples for that block are updated in dependence upon the change in the mean sample value.
Claim 12
Dependent Claim
43 words
A method as claimed in claim 9, wherein at least one motion vector is received, and estimates are formed of sample values written blocks transmitted at a low sampling rate using information from a previous frame shifted in dependence upon the main vector.
Claim 13
Dependent Claim
42 words
A method as claimed in claim 1, wherein those blocks of a frame of picture information having a level of activity above a threshold are sampled at a higher resolution sampling rate than those having a level of activity below the threshold.
Claim 14
Dependent Claim
22 words
A method as claimed in claim 12, wherein the average sample rate of a frame is controlled by adjusting the said threshold.
Claim 15
Dependent Claim
28 words
A method as claimed in claim 13, wherein the threshold level is adjusted according to the measured the activity of those blocks in a frame to be encoded.
Claim 16
Dependent Claim
22 words
A method as claimed in claim 14, wherein the threshold level is variable in inverse relationship to the activity in a block.
Claim 17
Dependent Claim
112 words
Video signal coding apparatus for coding a video signal for transmission in a restricted bandwidth, comprising: digital anti-aliasing filter means for pre-filtering the video signal; means for sub-dividing a frame of picture information of the video signal into a set of constituent blocks: means for measuring the amount of picture activity in each block; means for coding a block by sampling the picture information in a block at a rate related to the amount of measured activity in that block; means for adding to each thus-coded block a supplementary signal which is related to the sampling rate used in that block; and means for transmitting the coded video signal in analogue form.
Claim 18
Dependent Claim
112 words
Video signal coding apparatus for coding a video signal for transmission in a restricted bandwidth, comprising: digital anti-aliasing filter means for pre-filtering the video signal; means for sub-dividing a frame of picture information of the video signal into a set of constituent blocks: means for measuring the amount of picture activity in each block; means for coding a block by sampling the picture information in a block at a rate related to the amount of measured activity in that block; means for adding to each thus-coded block a supplementary signal which is related to the sampling rate used in that block; and means for transmitting the coded video signal in analogue form.
Claim 19
Dependent Claim
33 words
Video signal coding apparatus, as claimed in claim 16 wherein the means for coding a block includes means for deriving a mean sample value for blocks where a low sample rate is used.
Claim 20
Dependent Claim
37 words
Video signal coding apparatus as claimed in claim 16 wherein the activity measuring means comprises means for measuring activity on a cumulative basis frame by frame taken from the last frame transmitted at a high sampling rate.
Claim 21
Dependent Claim
33 words
A video signal coding apparatus as claimed in claim 16 wherein the activity measuring means comprise means for summing a function of the difference between successive frames of the samples in a block.
Claim 22
Dependent Claim
36 words
A video signal coding apparatus as claimed in claim 19 wherein the summing means comprises means for summing a power of greater than two of the difference between successive frames of the samples in a block.
Claim 23
Dependent Claim
25 words
A video signal coding apparatus as claimed in claim 16 comprising means for deriving and transmitting at least one motion vector for each inactive block.
Claim 24
Dependent Claim
33 words
A video signal coding apparatus as claimed in claim 21 comprising means for deriving a set of motion vector for each frame and for selecting and transmitting one of said for each block.
Claim 25
Dependent Claim
68 words
Video signal decoding apparatus for decoding a video signal encoded by the apparatus of claim 16, comprising: means for receiving transmitted sampled video signals in analogue form and associated supplementary signals; means for separating the supplementary signals; means for decoding the sampled video signal relating to each block by assuming a sampling rate indicated by the corresponding supplementary signal; and a frame store for storing the decoded samples.
Claim 26
Dependent Claim
55 words
A video signal decoding apparatus according to claim 23 wherein the receiving means includes means for receiving a sample representative of the mean value for that block and the means for decoding the sampled video signal means for updating the decoded samples for that block in dependence upon the change in the mean sample value.
Claim 27
Dependent Claim
56 words
A video signal decoding apparatus according to claim 24 wherein the receiving means includes means for receiving at least one motion vector and the decoding means includes means for forming estimates of sample values of written blocks transmitted at low sampling rates using information from a previous frame shifted in accordance upon the received motion vector.
Claim 28
Independent Claim
115 words
A method of coding a video signal for transmission in a restricted bandwidth, the method comprising the steps of: sub-dividing a frame of picture information of the video signal into a set of constituent blocks; measuring the amount of picture activity in each block; coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; adding to each thus coded block a supplementary signal which is related to the sampling rate used in that block; transmitting the coded video signal; wherein in blocks where a low sampling rate is used a sample is transmitted representing the mean sample value for that block.
Claim 29
Independent Claim
115 words
A method of coding a video signal for transmission in a restricted bandwidth, the method comprising the steps of: sub-dividing a frame of picture information of the video signal into a set of constituent blocks; measuring the amount of picture activity in each block; coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; adding to each thus coded block a supplementary signal which is related to the sampling rate used in that block; transmitting the coded video signal; wherein in blocks where a low sampling rate is used a sample is transmitted representing the mean sample value for that block.
Claim 30
Dependent Claim
95 words
A method of decoding a video signal encoded according to the method of claim 26, the method comprising: receiving the transmitted sample video signal and receiving associated supplementary signals; separating the supplementary signals; decoding the sampled video signal relating to each block by assuming a sampling rate in accordance with the corresponding supplementary signal; in blocks where a low sample rate is used, receiving a sample representing the mean value for that block and updating other decoded samples for that block in dependence upon the change in mean sample value; and storing the decoded samples.
Claim 31
Independent Claim
107 words
A method of coding a video signal for transmission in a restricted bandwidth, the method comprising the steps of: sub-dividing a frame of picture information of the video signal into a set of constituent blocks; measuring the amount of picture activity in each block on a cumulative basis frame by frame taken from the last frame transmitted at a high sampling rates; coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; and adding to each thus coded block a supplementary signal which is related to the sampling rate used in that block.
Claim 32
Independent Claim
107 words
A method of coding a video signal for transmission in a restricted bandwidth, the method comprising the steps of: sub-dividing a frame of picture information of the video signal into a set of constituent blocks; measuring the amount of picture activity in each block on a cumulative basis frame by frame taken from the last frame transmitted at a high sampling rates; coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; and adding to each thus coded block a supplementary signal which is related to the sampling rate used in that block.
Claim 33
Independent Claim
114 words
A method of coding a video signal for transmission in a restricted bandwidth, the method comprising the steps of: sub-dividing a frame of picture information of the video signal into a set of constituent blocks; measuring the amount of picture activity in each block by summing a function of the difference between successive frames of the samples in a block, the function being a power of greater than 2; coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; and adding to each thus coded block a supplementary signal which is related to the sampling rate used in that block.
Claim 34
Independent Claim
114 words
A method of coding a video signal for transmission in a restricted bandwidth, the method comprising the steps of: sub-dividing a frame of picture information of the video signal into a set of constituent blocks; measuring the amount of picture activity in each block by summing a function of the difference between successive frames of the samples in a block, the function being a power of greater than 2; coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; and adding to each thus coded block a supplementary signal which is related to the sampling rate used in that block.
Claim 35
Independent Claim
104 words
A method of coding a video signal for transmission in a restricted bandwidth, the method comprising the steps of: sub-dividing a frame of picture information of the video signal into a set of constituent blocks; coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; and adding to each thus coded block a supplementary signal which is related to the sampling rate used in that block; determining for each frame, a set of main vectors; and transmitting, for each block measured as inactive, one of the set of motion vectors.
Claim 36
Independent Claim
104 words
A method of coding a video signal for transmission in a restricted bandwidth, the method comprising the steps of: sub-dividing a frame of picture information of the video signal into a set of constituent blocks; coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; and adding to each thus coded block a supplementary signal which is related to the sampling rate used in that block; determining for each frame, a set of main vectors; and transmitting, for each block measured as inactive, one of the set of motion vectors.
Claim 37
Dependent Claim
102 words
A method of decoding a video signal encoded according to the method of claim 30, the method comprising: receiving the transmitted sample video signal in analogue form and receiving associated supplementary signals; separating the supplementary signals including separating for each frame a set of motion vectors; decoding the sampled video signal relating to each block by assuming a sampling rate in accordance with the corresponding supplementary signal; estimating the sample values of written blocks transmitted at a low sampling rate, using information from a previous frame shifted in dependence upon one of the set of motion vectors; and storing the decoded samples.
Claim 38
Dependent Claim
128 words
Video signal coding apparatus for coding a video signal for transmission in a restricted bandwidth, comprising: means for sub-dividing a frame of picture information of the video signal into a set of constituent blocks; means for measuring the amount of picture activity in each block; means for coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; means for adding to each thus-coded block a supplementary signal which is related to the sampling rate used in that block; and means for transmitting the coded video signal; wherein the coding means further comprises means for deriving a mean sample value for a block of transmission if that block is sampled at a low sampling rate.
Claim 39
Dependent Claim
128 words
Video signal coding apparatus for coding a video signal for transmission in a restricted bandwidth, comprising: means for sub-dividing a frame of picture information of the video signal into a set of constituent blocks; means for measuring the amount of picture activity in each block; means for coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; means for adding to each thus-coded block a supplementary signal which is related to the sampling rate used in that block; and means for transmitting the coded video signal; wherein the coding means further comprises means for deriving a mean sample value for a block of transmission if that block is sampled at a low sampling rate.
Claim 40
Dependent Claim
111 words
Video signal coding apparatus for coding a video signal for transmission in a restricted bandwidth, comprising: means for sub-dividing a frame of picture information of the video signal into a set of constituent blocks: means for measuring the amount of picture activity in each block on a cumulative basis frame by frame taken from the best frame transmitted at a high sampling rate; means for coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; and means for adding to each thus-coded block a supplementary signal which is related to the sampling rate used in that block.
Claim 41
Dependent Claim
111 words
Video signal coding apparatus for coding a video signal for transmission in a restricted bandwidth, comprising: means for sub-dividing a frame of picture information of the video signal into a set of constituent blocks: means for measuring the amount of picture activity in each block on a cumulative basis frame by frame taken from the best frame transmitted at a high sampling rate; means for coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; and means for adding to each thus-coded block a supplementary signal which is related to the sampling rate used in that block.
Claim 42
Dependent Claim
100 words
Video signal coding apparatus for coding a video signal for transmission in a restricted bandwidth, comprising: means for measuring the amount of picture activity in each block by summing a function of the difference between successive frames of the samples in a block, the function being a power of greater than 2; means for coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; and means for adding to each thus-coded block a supplementary signal which is related to the sampling rate used in that block.
Claim 43
Dependent Claim
100 words
Video signal coding apparatus for coding a video signal for transmission in a restricted bandwidth, comprising: means for measuring the amount of picture activity in each block by summing a function of the difference between successive frames of the samples in a block, the function being a power of greater than 2; means for coding a block by sampling the picture information in the block at a rate related to the amount of measured activity in that block; and means for adding to each thus-coded block a supplementary signal which is related to the sampling rate used in that block.
Claim 44
Dependent Claim
104 words
Video signal coding apparatus for coding a video signal for transmission in a restricted bandwidth, comprising: means for sub-dividing a frame of picture information of the video signal into a set of constituent blocks; means for measuring the amount of picture activity in each block; means for coding a block by sampling the picture information in the block at a rate related to the sampling rate used in that block; means for determining, for each frame, a set of motion vectors; and transmission means for transmitting the coded video signal and, for each block measured as inactive, one of the set of motion vectors.
Claim 45
Dependent Claim
104 words
Video signal coding apparatus for coding a video signal for transmission in a restricted bandwidth, comprising: means for sub-dividing a frame of picture information of the video signal into a set of constituent blocks; means for measuring the amount of picture activity in each block; means for coding a block by sampling the picture information in the block at a rate related to the sampling rate used in that block; means for determining, for each frame, a set of motion vectors; and transmission means for transmitting the coded video signal and, for each block measured as inactive, one of the set of motion vectors.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |