EP0168818A2
Expired / Lapsed
EP
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Color image copying apparatus
Assignee: Toshiba Corp
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Filing: 1985-07-16
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Granted: —
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Expires: 2005-07-16
Abstract
Abstract A color copying apparatus includes a color image sensor (1), an image information signal processing unit (3), and a color printer (4) The apparatus converts the three color component signals (R, G, B) from the color image sensor into a luminance signal component (I) and color difference signal components (C1, C2). At least one of the luminance signal component and the color difference signal components is subject to a nonlinear conversion. For density conversion between an input image and an output image, the luminance signal component is subject to a nonlinear conversion in a nonlinear conversion circuit (17).
Inventors
- 👤 Hidekazu Kabushiki Kaisha Toshiba Sekizawa
- 👤 Akito Kabushiki Kaisha Toshiba Iwamoto
- 👤 Naofumi Kabushiki Kaisha Toshiba Yamamoto
- 👤 Hitoshi Kabushiki Kaisha Toshiba Yoneda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 18:40
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6027; H04N1/40; H04N1/407; H04N1/4076; H04N1/6016; H04N1/6019
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
128 words
A color copying apparatus comprising: a color image sensor (1) for scanning an input color image original (2); an image information signal processing unit (3) for processing image information signals from said color image sensor; and a color printer (4) for printing a color image corresponding to the input image in response to output signals from said image information signal processing unit, characterized in that said image information signal processing unit (3) includes means (14) responsive to the color image information signals from said image sensor for producing a luminance signal component (I) and color difference signal components (Cl, C2); and nonlinear conversion means (17, 25, 26, 30) for converting on a nonlinear basis at least one of the luminance signal component and the color difference signal components.
Claim 2
Dependent Claim
128 words
A color copying apparatus comprising: a color image sensor (1) for scanning an input color image original (2); an image information signal processing unit (3) for processing image information signals from said color image sensor; and a color printer (4) for printing a color image corresponding to the input image in response to output signals from said image information signal processing unit, characterized in that said image information signal processing unit (3) includes means (14) responsive to the color image information signals from said image sensor for producing a luminance signal component (I) and color difference signal components (Cl, C2); and nonlinear conversion means (17, 25, 26, 30) for converting on a nonlinear basis at least one of the luminance signal component and the color difference signal components.
Claim 3
Dependent Claim
42 words
A color copying apparatus according to claim 1, characterized in that said nonlinear conversion means includes density conversion means (17) connected to receive the luminance signal component for differing the density of a printed color image from that of the input image.
Claim 4
Dependent Claim
30 words
A color copying apparatus according to claim 2, characterized in that said density conversion means (17) has an input vs. output characteristic given by where n is a positive number.
Claim 5
Dependent Claim
42 words
A color copying apparatus according to claim 3, characterized in that said density conversion means (17) has a plurality of input vs. output characteristics characterized in that n substantially equals 1.5, 1.0, and 0.8, said input vs. output characteristics being externally selectable.
Claim 6
Dependent Claim
36 words
A color copying apparatus according to claim 3, characterized in that the input vs. output characteristic of said density conversion means (17) is combined with a characteristic for the background compensation of the input color image.
Claim 7
Dependent Claim
37 words
A color copying apparatus according to claim 1, characterized in that said nonlinear conversion means includes circuit means (30, 31) for converting the luminance signal component for an achromatic color image portion substantially in bi-level quantizing manner.
Claim 8
Dependent Claim
45 words
A color copying apparatus according to claim 1, characterized in that said nonlinear conversion means includes hue conversion means (25, 26) connected to receive the color difference signal component for differing the hue of the printed color image from that of the input color image.
Claim 9
Dependent Claim
27 words
A color copying apparatus according to claim 7, characterized in that said hue conversion means has a plurality of input vs. output characteristics which are externally selectable.
Claim 10
Dependent Claim
30 words
A color copying apparatus according to claim 8, characterized in that said hue conversion means has an input vs. output characteristic for intensifying the hue of the input color image.
Claim 11
Dependent Claim
113 words
A color copying apparatus according to claim 1, characterized in that said color image sensor (1) is arranged to produce substantially simultaneously three primary color signals (R, G, B) of the input color image by scanning the input color image, said color printer (4) is arranged to print a color output image corresponding to the color input image by superposealy recording color printing signals corresponding respectively to a plurality of ink colors used in printing, and said image information signal processing unit (3) is arranged to produce, on a real time basis, one of the color printing signals (Y, M, C, K) from the three primary color signals from said color image sensor.
Claim 12
Dependent Claim
56 words
A color copying apparatus according to claim 1, characterized in that said color image sensor (1) produces a black reference signal and a white reference signal before the input color original is scanned by said color image sensor, and said reference signals are used for normalizing the three primary color signals from said color image sensor.
Claim 13
Dependent Claim
52 words
A color copying apparatus according to claim 11, characterized in that a black reference plate (6) and a white reference plate (7) are provided, and . said image sensor scans said black and white reference plates before scanning said original, thereby to form the black reference signal and the white reference signal.
Claim 14
Dependent Claim
62 words
A color copying apparatus according to claim 1, characterized in that said image information signal processing unit (3) includes means (16) for converting the luminance signal component (I) and the color difference signal components (Cl, C2) into color- printing signals (Y, M, C, K) respectively corresponding to a plurality of ink colors used in printing a color copy by said color printer.
Claim 15
Dependent Claim
55 words
A color copying apparatus according to claim 13, characterized in that said converting means (16) contains a data table which is prepared allowing for a tonal recording characteristic of said color printer, whereby said conversion means produces the color printing signals which are compensated with respect to the tonal recording characteristic of said color printer.
References Cited (Backward Citations)
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