US4965663A
Expired / Lapsed
US
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Method for measuring of chromatic optical density
Assignee: Canon Inc
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Filing: 1990-02-20
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Granted: 1990-10-23
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Expires: 2010-02-20
Abstract
Abstract A method of optically measuring chromatic densities of a sample. In the method, three stimulus values, X, Y and Z, of light reflected from the sample, are derived. A cyan density, a magenta density and a yellow density are determined for the sample, using the X, Y and Z stimulus values, and in addition, three stimulus values, Xo, Yo and Zo of a standard color, such as white. With this method, a color image of an original picture may be accurately reproduced with a high fidelity.
Inventors
- 👤 Takashi Sasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:08
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/46; G01J3/02; G01J3/0205; G01J3/0251; G01J3/465; G01J3/50; G01J3/502; H; H04; H04N; H04N1/00; H04N1/46; H04N1/48; H04N1/482; H04N1/56; H04N1/60; H04N1/6016; G01J3/51
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
68 words
A method of optically measuring chromatic densities of a sample, comprising the steps of: deriving three stimulus values X, Y and Z of light reflected by the sample; and determining a cyan density, a magenta density and a yellow density of the sample using said stimulus values X, Y and Z derived and three stimulus values X 0 , Y 0 and Z 0 of a standard color.
Claim 2
Independent Claim
68 words
A method of optically measuring chromatic densities of a sample, comprising the steps of: deriving three stimulus values X, Y and Z of light reflected by the sample; and determining a cyan density, a magenta density and a yellow density of the sample using said stimulus values X, Y and Z derived and three stimulus values X 0 , Y 0 and Z 0 of a standard color.
Claim 3
Dependent Claim
50 words
A method according to claim 1, wherein said deriving step includes the steps of: separating the reflected light into wavelength components with a diffraction grating; detecting intensities of the wavelength components obtained from the separated light; and calculating the three stimulus values X, Y and Z from the detected intensities.
Claim 4
Dependent Claim
12 words
A method according to claim 1, wherein the standard color is white.
Claim 5
Dependent Claim
92 words
A method according to claim 1, wherein said determining step includes the step of: performing the calculations Dc=-log [(a.sub.r X+b.sub.r Y+c.sub.r Z)/(a.sub.r X.sub.0 +b.sub.r Y.sub.0 +c.sub.r Z.sub.0)] Dm=-log [(a.sub.g X+b.sub.g Y+c.sub.g Z)/(a.sub.g X.sub.0 +b.sub.g Y.sub.0 +c.sub.g Z.sub.0)] Dy=-log [(a.sub.b X+b.sub.b Y+c.sub.b Z)/(a.sub.b X.sub.0 +b.sub.b Y.sub.0 +c.sub.b Z.sub.0)] to obtain the cyan density (Dc), the magenta density (Dm) and the yellow density (Dy), wherein a r , b r , c r , a g , b g , c g , a b , b b , c b , are constants.
Claim 6
Independent Claim
99 words
A method of optically measuring chromatic densities of a sample, comprising the steps of: obtaining a photoelectric conversion signal from a light flux from the sample; deriving three stimulus values X, Y and Z from the photoelectric conversion signal obtained by said obtaining step; determining a cyan density, a magenta density and a yellow density of the sample using the derived stimulus values X, Y and Z and three stimulus values X 0 , Y 0 and Z 0 of a standard color; and outputting the cyan density, magenta density and yellow density respectively determined by said determining step.
Claim 7
Independent Claim
99 words
A method of optically measuring chromatic densities of a sample, comprising the steps of: obtaining a photoelectric conversion signal from a light flux from the sample; deriving three stimulus values X, Y and Z from the photoelectric conversion signal obtained by said obtaining step; determining a cyan density, a magenta density and a yellow density of the sample using the derived stimulus values X, Y and Z and three stimulus values X 0 , Y 0 and Z 0 of a standard color; and outputting the cyan density, magenta density and yellow density respectively determined by said determining step.
Claim 8
Dependent Claim
12 words
A method according to claim 5, wherein the standard color is white.
Claim 9
Dependent Claim
92 words
A method according to claim 5, wherein said determining step includes the step of: performing the calculations Dc=-log [(a.sub.r X+b.sub.r Y+c.sub.r Z)/(a.sub.r X.sub.0 +b.sub.r Y.sub.0 +c.sub.r Z.sub.0)] Dm=-log [(a.sub.g X+b.sub.g Y+c.sub.g Z)/(a.sub.g X.sub.0 +b.sub.g Y.sub.0 =c.sub.g Z.sub.0)] Dy=-log [(a.sub.b X+b.sub.b Y+c.sub.b Z)/(a.sub.b X.sub.0 +b.sub.b Y.sub.0 +c.sub.b Z.sub.0)] to obtain the cyan density (Dc), the magenta density (Dm) and the yellow density (Dy), wherein a r , b r , c r , a g , b g , c g , a b , b b , and c b are constants.
Claim 10
Independent Claim
69 words
An apparatus for optically measuring chromatic densities of a sample, comprising: means for deriving three stimulus values X, Y and Z of light reflected by the sample; and means for determining a cyan density, a magenta density and a yellow density of the sample using said derived stimulus values X, Y and Z and three stimulus values X 0 , Y 0 and Z 0 of a standard color.
Claim 11
Independent Claim
69 words
An apparatus for optically measuring chromatic densities of a sample, comprising: means for deriving three stimulus values X, Y and Z of light reflected by the sample; and means for determining a cyan density, a magenta density and a yellow density of the sample using said derived stimulus values X, Y and Z and three stimulus values X 0 , Y 0 and Z 0 of a standard color.
Claim 12
Dependent Claim
53 words
An apparatus according to claim 8, wherein said deriving means includes: means for separating the reflected light into wavelength components with a diffraction grating; means for detecting intensities of the wavelength components obtained from the separated light; and means for calculating the three stimulus values X, Y and Z from the detected intensities.
Claim 13
Dependent Claim
12 words
An apparatus according to claim 8, wherein the standard color is white.
Claim 14
Dependent Claim
92 words
An apparatus according to claim 8, wherein said determining means includes performing means for performing the calculations Dc=-log [(a.sub.r X+b.sub.r Y+c.sub.r Z)/(a.sub.r X.sub.0 +b.sub.r Y.sub.0 +c.sub.r Z.sub.0)] Dm=-log [(a.sub.g X+b.sub.g Y+c.sub.g Z)/(a.sub.g X.sub.0 +b.sub.g Y.sub.0 +c.sub.g Z.sub.0)] Dy=-log [(a.sub.b X+b.sub.b Y+c.sub.b Z)/(a.sub.b X.sub.0 +b.sub.b Y.sub.0 +c.sub.b Z.sub.0)] to obtain the cyan density (Dc), the magenta density (Dm) and the yellow density (Dy), wherein a r , b r , c r , a g , b g , c g , a b , b b , and c b are constants.
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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) | 1993-10-22 | 1994-04-23 | 1994-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-22 | 1998-04-23 | 1998-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-22 | 2002-04-23 | 2002-10-23 | $7700.00 | Window Closed / Lapsed |