US4887156A
Expired / Lapsed
US
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Method and system for transform coding of video signals
Assignee: NEC Corp
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Filing: 1988-04-28
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Granted: 1989-12-12
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Expires: 2008-04-28
Abstract
Abstract A coding system in accordance with the present invention includes a control signal generating circuit for generating a control signal indicative of a quantity of band limitation by calculating a ratio of an area of motion from an input video signal. A band limiter band-limits a transform-coded video signal in response to the control signal. For example, when the picture is stationary or little moved, the transform-coded video signal is not band-limited at all; when the area of motion is medium, high frequency components of a part of the video signal are omitted to cope with an increase in the amount of data generated; and when the area of motion is extremely great, many high frequency components are omitted to accommodate a rash of data. A prediction coding circuit predictively codes the band-limited video signal before the latter is sent out to a transmission path.
Inventors
- 👤 Junichi Ohki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:25
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/10; H04N19/102; H04N19/103; H04N19/112; H04N19/60; H04N19/61; H04N19/619; H04N19/124; H04N19/132
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
43 words
A method of coding a video signal by using transform coding, comprising the step of: limiting a signal produced by transform coding to a predetermined band depending upon a ratio of a motion area and a still area within a video signal frame.
Claim 2
Independent Claim
43 words
A method of coding a video signal by using transform coding, comprising the step of: limiting a signal produced by transform coding to a predetermined band depending upon a ratio of a motion area and a still area within a video signal frame.
Claim 3
Independent Claim
163 words
A system for coding a video signal by using transform coding, comprising: calculating means for calculating a ratio of a motion area and a still area within an input video signal frame; means for generating a control signal indicative of a quantity of band limitation on the basis of an output of said calculating means; means for subjecting the input video frame to transform coding to produce a coded video signal; means for band-limiting the coded video signal in response to the control signal to thereby produce a band-limited video signal; means for producing a prediction error signal from the band-limited video signal and a prediction signal; quantitizing means for quanitizing the prediction error signal to produce a quanitized signal; means for generating a locally decoded signal from said quanitized signal and the prediction signal; frame memory means for delaying the locally decoded signal by one frame time before outputting said signal as the prediction signal; and means for variable-length-coding said quanitized signal.
Claim 4
Independent Claim
163 words
A system for coding a video signal by using transform coding, comprising: calculating means for calculating a ratio of a motion area and a still area within an input video signal frame; means for generating a control signal indicative of a quantity of band limitation on the basis of an output of said calculating means; means for subjecting the input video frame to transform coding to produce a coded video signal; means for band-limiting the coded video signal in response to the control signal to thereby produce a band-limited video signal; means for producing a prediction error signal from the band-limited video signal and a prediction signal; quantitizing means for quanitizing the prediction error signal to produce a quanitized signal; means for generating a locally decoded signal from said quanitized signal and the prediction signal; frame memory means for delaying the locally decoded signal by one frame time before outputting said signal as the prediction signal; and means for variable-length-coding said quanitized signal.
Claim 5
Independent Claim
206 words
A system for coding a video signal by using transform coding, comprising: calculating means for calculating a ratio of a motion area and a still area within an input video signal frame; means for producing a control signal indicative of a quantity of band limitation on the basis of an output of said calculating means; means for producing a coded video signal transform coding of the input video signal frame; means for producing a prediction error signal from the coded video signal and the prediction signal; first band limiting means for band-limiting the prediction error signal in response to the control signal to thereby produce a band-limited prediction error signal; quanitizing means for quanitizing the band-limited prediction error signal to produce a quanitized signal; second band limiting means for band-limiting the prediction signal in response to the control signal to thereby produce a band-limited prediction signal; means for producing a locally decoded signal from said quanitized signal and the band-limited prediction signal; a frame memory for delaying the locally decoded signal by one frame time to output the prediction signal; and means for variable-length-coding an output of said quanitized signal to output a coded signal; and means for multiplexing the coded signal and the control signal.
Claim 6
Independent Claim
206 words
A system for coding a video signal by using transform coding, comprising: calculating means for calculating a ratio of a motion area and a still area within an input video signal frame; means for producing a control signal indicative of a quantity of band limitation on the basis of an output of said calculating means; means for producing a coded video signal transform coding of the input video signal frame; means for producing a prediction error signal from the coded video signal and the prediction signal; first band limiting means for band-limiting the prediction error signal in response to the control signal to thereby produce a band-limited prediction error signal; quanitizing means for quanitizing the band-limited prediction error signal to produce a quanitized signal; second band limiting means for band-limiting the prediction signal in response to the control signal to thereby produce a band-limited prediction signal; means for producing a locally decoded signal from said quanitized signal and the band-limited prediction signal; a frame memory for delaying the locally decoded signal by one frame time to output the prediction signal; and means for variable-length-coding an output of said quanitized signal to output a coded signal; and means for multiplexing the coded signal and the control signal.
References Cited (Backward Citations)
US4447886A
Cited
US4541012A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-11 | 1993-06-12 | 1993-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-11 | 1997-06-12 | 1997-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-11 | 2001-06-12 | 2001-12-12 | $7700.00 | Window Closed / Lapsed |