EP0729273A2
Expired / Lapsed
EP
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Compensation voltage generating apparatus for multipicture display and video display apparatus using it
Assignee: Panasonic Holdings Corp
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Filing: 1995-12-20
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Granted: —
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Expires: 2015-12-20
Abstract
Abstract Average picture levels of a first video signal (for example, a parent picture signal) and a second video signal (for example, a child picture signal) are detected at first and second APL detection circuits, respectively. A compensation voltage sharing circuit inputs a compensation viltage, for example an ABL/ACL compensation voltage and shares the compensation voltage according to a ratio of the APL values detected at the first and the second APL detection circuits and the shared compensation voltages are added to the first and the second video signals at the first and the second video processing circuits, respectively. The processed video signals are synthesized at a synthesizing circuit and the synthesized video signal is displayed on a screen of a display device as a multipicture, in which the first and the second pictures are independently and properly compensated in ABL/ACL function. Thus, a good quality multipicture can be seen.
Inventors
- 👤 Hiroshi Ando
- 👤 Atsuhisa Kageyama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 23:57
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/445; H04N5/45; H04N3/00; H04N3/10; H04N3/16; H04N3/18; H04N3/19; H04N5/14; H04N5/141; H04N5/16; H04N5/165; H04N5/18; H04N5/185; H04N5/20; H04N5/202; H04N5/57
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
95 words
A compensation voltage generating apparatus for multipicture display comprising: compensation voltage generation means for generating picture quality compensation amount for each picture in a multipicture video signal to display a plurality of pictures on a picture display device simultaneously; a plurality of average picture level detection means for detecting average picture level for each of said pictures; and compensation voltage sharing means for sharing picture quality compensation amount of each picture to said multipicture video signal, according to each average picture level of said pictures detected at said plurality of average picture level detection means.
Claim 2
Dependent Claim
44 words
A compensation voltage generating apparatus for multipicture display as recited in claim 1, wherein: said compensation voltage sharing means shares compensation currents corresponding to each average picture level of said pictures using a differential amplifier and generating compensation voltages for each of said pictures.
Claim 3
Dependent Claim
70 words
A compensation voltage generating apparatus for multipicture display as recited in claim 1, wherein: picture quality compensation amount of said compensation voltage sharing means is compensation amount of automatic brightness limiter which automatically controls a black level of said multipicture video signal and compensation amount of automatic contrast limiter which automatically controls the amplitude of said multipicture video signal so that the beam current is smaller than a designated value.
Claim 4
Dependent Claim
35 words
A compensation voltage generating apparatus for multipicture display as recited in claim 1, wherein: picture quality compensation amount of said compensation voltage generation means is gamma compensation amount to compensate gamma of a video signal.
Claim 5
Dependent Claim
37 words
A compensation voltage generating apparatus for multipicture display as recited in claim 1, wherein: picture quality compensation amount of said compensation voltage generation means is black stretch compensation amount to compensate black stretch of a video signal.
Claim 6
Dependent Claim
104 words
A video display apparatus comprising: a cathode ray tube for displaying pictures of a multipicture video signal; drive means for driving said cathode ray tube according to said multipicture video signal; deflection means for deflecting an electron beam in order to display a picture by said electron beam of said cathode ray tube driven by said drive means; extra high tension generation means for supplying an extra high tension to accelerate said electron beam to said cathode ray tube and generating a detection voltage for compensation of automatic brightness limiting and automatic contrast limiting; and compensation voltage generation means as recited in claim 1.
Claim 7
Dependent Claim
104 words
A video display apparatus comprising: a cathode ray tube for displaying pictures of a multipicture video signal; drive means for driving said cathode ray tube according to said multipicture video signal; deflection means for deflecting an electron beam in order to display a picture by said electron beam of said cathode ray tube driven by said drive means; extra high tension generation means for supplying an extra high tension to accelerate said electron beam to said cathode ray tube and generating a detection voltage for compensation of automatic brightness limiting and automatic contrast limiting; and compensation voltage generation means as recited in claim 3.
Claim 8
Dependent Claim
114 words
A video display apparatus comprising: a cathode ray tube for displaying pictures of a multipicture video signal; drive means for driving said cathode ray tube according to said multipicture video signal; deflection means for deflecting an electron beam in order to display a picture by said electron beam of said cathode ray tube driven by said drive means; extra high tension generation means for supplying an extra high tension to accelerate said electron beam to said cathode ray tube and generating a gamma compensation voltage; gamma compensation means for performing gamma compensation for adequately displaying said multipicture video signal on said cathode ray tube; and compensation voltage generation means as recited in claim 4.
Claim 9
Dependent Claim
117 words
A video display apparatus comprising: a cathode ray tube for displaying pictures of a multipicture video signal; drive means for driving said cathode ray tube according to said multipicture video signal; deflection means for deflecting an electron beam in order to display a picture by said electron beam of said cathode ray tube driven by said drive means; extra high tension generation means for supplying an extra high tension to accelerate said electron beam to said cathode ray tube and generating a black stretch compensation voltage; black stretch compensation means for performing black stretch compensation for adequately displaying said multipicture video signal on said cathode ray tube; and compensation voltage generation means as recited in claim 5.
References Cited (Backward Citations)
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