Patent EP0084228A2 successfully refreshed from Google Patents.
EP0084228A2
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EP
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Digital color modification
Assignee: Xerox Corp
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Filing: 1982-12-07
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Granted: —
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Expires: 2002-12-07
Abstract
Abstract A digital display system including a memory containing digital representations of a three color component color image connected through a network of look-up tables and summing circuits to the red, green and blue display drivers of a suitable display. In particular, a first summing circuit is connected to the red display driver, a second summing circuit is connected to the green display driver, and a third summing circuit is connected to the blue display driver. Three look-up tables are connected to the red digital representation in memory with one of the look-up tables being connected to the first summing circuit, another of the look-up tables being connected to the second summing circuit and the third look-up table being connected to the third summing circuits. In a similar manner, groups of three look-up tables are connected to the green and blue digital representations and each look-up table of each group in turn connected to a different summing circuit. The result is nine look-up tables cross-coupled to three summing circuits to provide selected color adjustments and transformations.
Inventors
- 👤 Paul G. Roetling
- 👤 Keith T. Knox
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 18:16
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6027
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
121 words
Apparatus for color correction of digitally displayed color images comprising: a memory (22, 24) having a first color component and a second color component, a first summing circuit (50) providing a first color signal, a second summing circuit (59) providing a second color signal, a first plurality of look-up tables (30, 32) of which one is connected between the first color component and the first summing circuit, and of which the other is connected between the first color component and the second summing circuit, and a second plurality of look-up tables (36, 38) connected between the second color component and the first summing circuitry, and of which the other is connected between the second color component and the second summing circuit.
Claim 2
Dependent Claim
121 words
Apparatus for color correction of digitally displayed color images comprising: a memory (22, 24) having a first color component and a second color component, a first summing circuit (50) providing a first color signal, a second summing circuit (59) providing a second color signal, a first plurality of look-up tables (30, 32) of which one is connected between the first color component and the first summing circuit, and of which the other is connected between the first color component and the second summing circuit, and a second plurality of look-up tables (36, 38) connected between the second color component and the first summing circuitry, and of which the other is connected between the second color component and the second summing circuit.
Claim 3
Dependent Claim
19 words
The apparatus of Claim 1 wherein each look-up table contains 256 bytes of digital information identifying grey scale level.
Claim 4
Dependent Claim
30 words
The apparatus of Claim 1 or 2, wherein each summing circuit provides a signal having a portion of the first color component and a portion of the second color component.
Claim 5
Dependent Claim
83 words
A color correction digital image display system comprising a first memory (22), a second memory (24) and a third memory (26), first summing circuitry (50) providing a first color signal, second summing circuitry (59) providing a second color signal, and third summing circuitry (54) providing a third color signal, and a plurality of look-up tables (30, 32, 34, 36, 38, 40, 42, 44, 46) interconnecting each of the first, second and third memories to each of the first second and third summing circuits.
Claim 6
Dependent Claim
83 words
A color correction digital image display system comprising a first memory (22), a second memory (24) and a third memory (26), first summing circuitry (50) providing a first color signal, second summing circuitry (59) providing a second color signal, and third summing circuitry (54) providing a third color signal, and a plurality of look-up tables (30, 32, 34, 36, 38, 40, 42, 44, 46) interconnecting each of the first, second and third memories to each of the first second and third summing circuits.
Claim 7
Dependent Claim
51 words
The apparatus of Claim 4 wherein the plurality of look-up tables comprises nine look-up tables, of which three interconnect the first memory with each of the summing circuits, three interconnect the second memory with each of the summing circuits, and three interconnect the third memory to each of the summing circuits.
Claim 8
Dependent Claim
31 words
The apparatus of Claim 4 or 5 wherein the summing circuits provide matrix multiplication giving red, green and blue signals, each of the signals having a red, green and blue component.
Claim 9
Independent Claim
53 words
The apparatus of any of Claims 4-6, including a look-up table (56) interconnecting the first summing circuit with the first color signal, a second look-up table (58) interconnecting the second color signal with a second summing circuit, and a third look-up table (60) interconnecting the third color signal with the third summing circuit.
Claim 10
Dependent Claim
16 words
The apparatus of Claim 7 wherein each of the three look-up tables provides an anti-log function.
Claim 11
Dependent Claim
17 words
Apparatus as claimed in any preceding claim, in which each look-up table is substituted by a multiplier.
Claim 12
Independent Claim
83 words
A method of color correction of a color image digitally stored in a memory comprising the steps of providing a summing network (50, 54, 59) for each of the color components of the color image, storing suitable color-correction information in a plurality of look-up tables (30, 32, 34, 36, 38, 40, 42, 44, 46) interconnecting each of the color components of the color image with each of a summing network, and, modifying the information stored in the look-up tables to provide color correction.
Claim 13
Independent Claim
83 words
A method of color correction of a color image digitally stored in a memory comprising the steps of providing a summing network (50, 54, 59) for each of the color components of the color image, storing suitable color-correction information in a plurality of look-up tables (30, 32, 34, 36, 38, 40, 42, 44, 46) interconnecting each of the color components of the color image with each of a summing network, and, modifying the information stored in the look-up tables to provide color correction.
Claim 14
Dependent Claim
25 words
The method of Claim 10, including the step of interconnecting the summing networks to suitable anti-log look-up tables (56, 58, 60) to simulate density correction.
References Cited (Backward Citations)
No citation records indexed.
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