Patent EP0414183A2 successfully refreshed from Google Patents.
EP0414183A2
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EP
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A dynamic video system including automatic contrast and white-stretch processing sections
Assignee: Technicolor USA Inc
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Filing: 1990-08-20
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Granted: —
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Expires: 2010-08-20
Abstract
Abstract A television system is disclosed including sections for limiting peak white drive to a display device (e.g., of the direct view or projection type) while maintaining relatively high subjective image contrast and brightness. Specifically, the system includes an automatic contrast control section (29,31,33,9) for controlling the amplitude of the luminance signal in response to the peak value of a luminance-representative image component signal preceded by a "white-stretch" control section (5) for emphasizing mid-range luminance components relative to high-range luminance components as a function of the average value (35) of the luminance-representative image component. In this was, spot blooming and display driver saturation can be minimized while providing subjectively sharp, bright pictures.
Inventors
- 👤 William Adamson Lagoni
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 20:32
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/20; H04N5/44; H04N5/57; H04N5/52
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
206 words
In a television system, apparatus comprising: input means (1) for providing an input video signal (Yin); output means (12) for utilizing an output video signal (Yout); first (5) and second (9) amplitude control means coupled in cascade between said input means (1) and said output means (12) for controlling the amplitude of said input video signal to produce said output video signal; said amplitude control means having respective first and second gain characteristics controllable in response to respective first and second gain control signals supplied thereto; characterized in that : said first (5) and second (9) amplitude control means are connected in series in the order named between said input and output means; said first gain characteristic including a non-linear gain function having a relatively high gain region followed by a relatively low gain region; said second gain characteristic being a relatively linear gain function compared to said non-linear gain function of said first gain characteristic; said first gain control signal being generated by first gain control means (35,37) in response to the average value of said output video signal; and said second gain control signal being generated by second gain control means (29,31,33) in response to the peak value of said output video signal (YOut).
Claim 2
Dependent Claim
206 words
In a television system, apparatus comprising: input means (1) for providing an input video signal (Yin); output means (12) for utilizing an output video signal (Yout); first (5) and second (9) amplitude control means coupled in cascade between said input means (1) and said output means (12) for controlling the amplitude of said input video signal to produce said output video signal; said amplitude control means having respective first and second gain characteristics controllable in response to respective first and second gain control signals supplied thereto; characterized in that : said first (5) and second (9) amplitude control means are connected in series in the order named between said input and output means; said first gain characteristic including a non-linear gain function having a relatively high gain region followed by a relatively low gain region; said second gain characteristic being a relatively linear gain function compared to said non-linear gain function of said first gain characteristic; said first gain control signal being generated by first gain control means (35,37) in response to the average value of said output video signal; and said second gain control signal being generated by second gain control means (29,31,33) in response to the peak value of said output video signal (YOut).
Claim 3
Dependent Claim
20 words
Apparatus as recited in Claim 1 further characterized in that said second amplitude control means comprises a contrast control section.
Claim 4
Dependent Claim
25 words
Apparatus as recited in Claim 2 further characterized in that said contrast control stage includes manual control means (15) for controlling said second gain characteristic.
Claim 5
Dependent Claim
27 words
Apparatus as recited in Claim 3 further characterized in that said output means includes display means for producing an image in response to said video output signal.
Claim 6
Dependent Claim
31 words
Apparatus as recited in Claim 4 further characterized by brightness control means (11) coupled in cascade with said contrast control means for controlling the DC component of said output video signal.
Claim 7
Dependent Claim
17 words
Apparatus as recited in Claim 1 further characterized in that said output video signal represents luminance information.
Claim 8
Dependent Claim
36 words
Apparatus as recited in Claim 6 further characterized in that said first control means includes an average detector (35) for generating said first control signal in response to the average value of said output luminance signal.
Claim 9
Dependent Claim
62 words
Apparatus as recited in Claim 6 further characterized in that: said first control means includes an average detector (35) for generating said first control signal in response to the average value of said output luminance signal; and said second control means includes peak detector means (29) for generating said second control signal in response to white-going peaks of said output luminance signal.
References Cited (Backward Citations)
No citation records indexed.
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