US5270808A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Color image processing with adjustment of computed recording color to match original color
Assignee: Canon Inc
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Filing: 1993-03-01
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Granted: 1993-12-14
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Expires: 2013-03-01
Abstract
Abstract There is disclosed a color image processing method and apparatus therefor, in which the input image data are converted into a color coordinate system represented by luminosity and hue, for example L*a*b* space. The colors reproducible on the output device, for example a printer, are also converted into this coordinate system. An average value is calculated over plural pixels in the vicinity of an object pixel to be digitized, and plural average values are then obtained by including the object pixel selected at each of the reproducible colors. The input image signal is digitized to the closest one of the plural average signals. The digitization error generated upon digitization is distributed to the succeeding pixels with weighted ratios. This method achieves faithful color reproduction, matching the colors reproducible on the recording or display device.
Inventors
- 👤 Hiroshi Tanioka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:56
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/64; H04N1/644; H04N1/52
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
86 words
A color image processing apparatus comprising: first input means for entering a color image in the form of color coordinate data represented by luminosity and hue; second input means for entering representation colors of N kinds to be used in the recording or display, in the form of said color coordinate data; process means for converting the color coordinate data entered by said first input means into one of said representation colors of N kinds; and correction means for correcting an error generated at said conversion.
Claim 2
Dependent Claim
86 words
A color image processing apparatus comprising: first input means for entering a color image in the form of color coordinate data represented by luminosity and hue; second input means for entering representation colors of N kinds to be used in the recording or display, in the form of said color coordinate data; process means for converting the color coordinate data entered by said first input means into one of said representation colors of N kinds; and correction means for correcting an error generated at said conversion.
Claim 3
Dependent Claim
27 words
An apparatus according to claim 1, wherein said first input means receives, as the color coordinate data, L*a*b* data or X 1/3 Y 1/3 Z 1/3 data.
Claim 4
Dependent Claim
39 words
An apparatus according to claim 2, wherein said second input means receives eight representation colors, which are cyan, magenta, yellow, black, red, green, blue and white, in the form of L*a*b* or X 1/3 Y 1/3 Z 1/3 data.
Claim 5
Dependent Claim
38 words
An apparatus according to claim 3, wherein said process means is adapted to convert the L*a*b* or X 1/3 Y 1/3 Z 1/3 data, entered by said first input means, into data of one of said eight colors.
Claim 6
Dependent Claim
32 words
An apparatus according to claim 4, further comprising means for converting data, converted into one of the representation colors of N kinds by said process means, into data for recording or display.
Claim 7
Dependent Claim
54 words
An apparatus according to claim 1, wherein said process means is adapted to calculate an average value on the color coordinate data, based on already converted data in the vicinity of an object pixel, and convert the color image entered by the first input means to a representation color closest to said average value.
Claim 8
Dependent Claim
41 words
An apparatus according to claim 1, wherein said correction means is adapted to correct all the error when it is smaller than a predetermined value, and corrects a predetermined amount of the error when it is larger than said predetermined value.
Claim 9
Dependent Claim
100 words
A color image processing apparatus comprising: means for determining plural average values in a color space represented by luminosity and hue, based on already digitized data in the vicinity of an object pixel and anticipated digitized values of the object pixel; means for determining respective differences between (1) the input image signal and (2) respective ones of said plural anticipated average values; digitization means for selecting the anticipated digitized value giving the smallest one of said respective differences as the digitized value of the object pixel; and conversion means for converting the digitized signal into a record or display signal.
Claim 10
Dependent Claim
100 words
A color image processing apparatus comprising: means for determining plural average values in a color space represented by luminosity and hue, based on already digitized data in the vicinity of an object pixel and anticipated digitized values of the object pixel; means for determining respective differences between (1) the input image signal and (2) respective ones of said plural anticipated average values; digitization means for selecting the anticipated digitized value giving the smallest one of said respective differences as the digitized value of the object pixel; and conversion means for converting the digitized signal into a record or display signal.
Claim 11
Dependent Claim
52 words
An apparatus according to claim 8, further comprising correction means for correcting an error in said respective difference between the anticipated average value selected by said digitization means and the input image signal, which error is generated in digitization of the input image signal of the object pixel by said digitization means.
Claim 12
Dependent Claim
30 words
An apparatus according to claim 9, wherein said correction means is adapted to correct the error up to a predetermined value if said error is larger than a predetermined value.
Claim 13
Dependent Claim
23 words
An apparatus according to claim 8, wherein said average value calculating means is adapted to determine the average value in the L*a*b* space.
Claim 14
Dependent Claim
34 words
An apparatus according to claim 8, wherein said digitization means is adapted to digitize the entered L*a*b* data into one of eight colors, which are yellow, magenta, cyan, black, red, green, blue and white.
Claim 15
Dependent Claim
75 words
A color image processing method comprising the steps of: calculating average values in a color space represented by luminosity and hue, based on plural data already digitized to data of one of plural colors in the vicinity of an object pixel and anticipated digitized values of said object pixel; and digitizing the data of said object pixel, represented by luminosity and hue, into data of one of said plural colors, based on said average values.
Claim 16
Dependent Claim
75 words
A color image processing method comprising the steps of: calculating average values in a color space represented by luminosity and hue, based on plural data already digitized to data of one of plural colors in the vicinity of an object pixel and anticipated digitized values of said object pixel; and digitizing the data of said object pixel, represented by luminosity and hue, into data of one of said plural colors, based on said average values.
Claim 17
Dependent Claim
48 words
A method according to claim 13, further comprising the step of correcting an error generated in said digitizing step in the color space, wherein said correcting step is so performed as to correct the digitization error in an adaptive manner according to the magnitude of the digitization error.
Claim 18
Dependent Claim
73 words
A color image processing apparatus comprising: anticipated average value calculation means for calculating plural average values in a color space, based on plural data already digitized into one of plural colors, in the vicinity of an object pixel, and anticipated digitized values of said object pixel; digitization means for determining the closest color to the input image, among plural average values; and correction means for correcting the digitization error generated in said digitization.
Claim 19
Dependent Claim
73 words
A color image processing apparatus comprising: anticipated average value calculation means for calculating plural average values in a color space, based on plural data already digitized into one of plural colors, in the vicinity of an object pixel, and anticipated digitized values of said object pixel; digitization means for determining the closest color to the input image, among plural average values; and correction means for correcting the digitization error generated in said digitization.
Claim 20
Dependent Claim
13 words
An apparatus according to claim 15, wherein said color space is L*a*b* space.
Claim 21
Dependent Claim
18 words
An apparatus according to claim 15, wherein said color space is X 1/3 Y 1/3 Z 1/3 space.
Claim 22
Dependent Claim
70 words
A color image processing apparatus comprising: calculation means for determining plural weighted average values in anticipation of digitized values of an object pixel, according to the recording characteristics of a recording device; and digitization means for selecting, among the plural weighted average values determined by said calculation means, one closest to input color data, thereby digitizing the input color data into color data reproducible by a recording or displaying device.
Claim 23
Dependent Claim
70 words
A color image processing apparatus comprising: calculation means for determining plural weighted average values in anticipation of digitized values of an object pixel, according to the recording characteristics of a recording device; and digitization means for selecting, among the plural weighted average values determined by said calculation means, one closest to input color data, thereby digitizing the input color data into color data reproducible by a recording or displaying device.
Claim 24
Dependent Claim
26 words
An apparatus according to claim 18, further comprising correction means for correcting an error generated in digitization of the input color data by said digitization means.
Claim 25
Dependent Claim
89 words
A color image processing apparatus comprising: first input means for entering a color image in the form of color coordinate data consisting of of a plurality of color components; second input means for entering representation colors of N kinds to be used in the recording or display, in the form of the color coordinate data; and process means for converting the color coordinate data entered by said first input means into one of said representation color of N kinds, wherein said process means further comprises gamut limitation processing means.
Claim 26
Dependent Claim
89 words
A color image processing apparatus comprising: first input means for entering a color image in the form of color coordinate data consisting of of a plurality of color components; second input means for entering representation colors of N kinds to be used in the recording or display, in the form of the color coordinate data; and process means for converting the color coordinate data entered by said first input means into one of said representation color of N kinds, wherein said process means further comprises gamut limitation processing means.
Claim 27
Dependent Claim
21 words
An apparatus according to claim 20, further comprising correction means for correcting an error generated upon operation by said processing means.
Claim 28
Dependent Claim
26 words
An apparatus according to claim 20, wherein said first input means receives, as the color coordinate data, L*a*b* or X 1/3 Y 1/3 Z 1/3 data.
Claim 29
Dependent Claim
39 words
An apparatus according to claim 22, wherein said second input means receives eight representation colors, which are cyan, magenta, yellow, black, red, green blue and white, in the form of L*a*b* or X 1/3 Y 1/3 Z 1/3 data.
Claim 30
Dependent Claim
38 words
An apparatus according to claim 23, wherein said process means is adapted to convert the L*a*b or X 1/3 Y 1/3 Z 1/3 data, entered by said first input means, into data of one of said eight colors.
Claim 31
Dependent Claim
32 words
An apparatus according to claim 24, further comprising means for converting data, converted into one of the representation colors of N kinds by said process means, into data for recording or display.
Claim 32
Dependent Claim
55 words
An apparatus according to claim 20, wherein said process means is adapted to calculate an average value on the color coordinate data, based on already converted data in the vicinity of an object pixel, and to convert the color image entered by said first input means to a representation color closest to said average value.
Claim 33
Dependent Claim
101 words
A color image processing apparatus comprising: first input means for entering a color image in the form of color coordinate data consisting of of a plurality of color components; second input means for entering representation colors of N kinds to be used in the recording or display, in the form of the color coordinate data; process means for converting the color coordinate data entered by said first input means into one of said representation color of N kinds; and correction means for correcting the color image entered by said first input means, in accordance with a recording characteristic of recording means.
Claim 34
Dependent Claim
101 words
A color image processing apparatus comprising: first input means for entering a color image in the form of color coordinate data consisting of of a plurality of color components; second input means for entering representation colors of N kinds to be used in the recording or display, in the form of the color coordinate data; process means for converting the color coordinate data entered by said first input means into one of said representation color of N kinds; and correction means for correcting the color image entered by said first input means, in accordance with a recording characteristic of recording means.
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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) | 1996-12-13 | 1997-06-14 | 1997-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-12-13 | 2001-06-14 | 2001-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-12-13 | 2005-06-14 | 2005-12-14 | $7700.00 | Window Closed / Lapsed |