Image processing apparatus control method and image processing apparatus

• US 20070274586A1
• Filed: 05/21/2007
• Published: 11/29/2007
• Est. Priority Date: 05/26/2006
• Status: Active Grant

• Current Assignee: Konica Minolta Medical & Graphic Incorporated (Konica Minolta Inc.)
• Original Assignee: Konica Minolta Medical & Graphic Incorporated (Konica Minolta Inc.)
• Inventors: Nakazawa, Masayuki, Yamano, Akira
• Granted Patent: US 7,920,145 B2
• Time in Patent Office: Days
• US Class Current: 382/162
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2380/08 Biomedical applications
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 5/028 Circuits for converting colour display signals into monochrome display signals
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables
• CPC Class Codes: H04N 1/644 using a reduced set of representative colours, e.g. each representing a particular range in a colour space

Abstract

There is described an image processing apparatus that converts (n+m)-bit monochromatic image data of a single channel into n-bit color display image data of three channels or more, based on predetermined correlations. The apparatus includes luminance and chromaticity calculating sections to calculate luminance and chromaticity information corresponding to each of monochrome signal values; a signal value determining section to determine each combination of plural-channel color signal values represented by the n-bit color display image data, based on the luminance and chromaticity information, so that each combination of the plural-channel color signal values corresponds to each of the monochrome signal values; and a correlation establishing section to establish the predetermined correlations between the (n+m)-bit monochromatic image data and the n-bit color display image data, so that each combination of the plural-channel color signal values and each of the monochrome signal values are correlated with each other.

Claims

1. A control method, to be employed in an image processing apparatus, for converting (n+m)-bit monochromatic image data represented by a single channel into n-bit color display image data represented by three channels or more channels, based on predetermined correlations between the (n+m)-bit monochromatic image data and the n-bit color display image data, wherein numeral “

n”

indicates a positive integer equal to or greater than 8, while numeral “

m”

indicates a positive integer equal to or greater than 2, the control method comprising;

acquiring luminance information corresponding to each of monochrome signal values represented by the (n+m)-bit monochromatic image data;

acquiring chromaticity information corresponding to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data;

determining each combination of plural-channel color signal values represented by the n-bit color display image data, based on the luminance information and the chromaticity information, so that each combination of the plural-channel color signal values corresponds to each of the monochrome signal values; and

establishing the predetermined correlations between the (n+m)-bit monochromatic image data and the n-bit color display image data, so that each combination of the plural-channel color signal values and each of the monochrome signal values are correlated with each other.

2. The control method of claim 1, further comprising:

selecting a plurality of candidate color display image data having signal values different from each other, with respect to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data; and

calculating a luminance and a chromaticity with respect to each of the plurality of candidate color display image data;

wherein the step of acquiring luminance information includes;

a luminance determining process for determining a target luminance corresponding to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data; and

the step of acquiring chromaticity information includes;

a chromaticity determining process for determining a target chromaticity corresponding to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data; and

wherein, in the determining step, signal values of color display image data are determined, based on a contrast between each luminance of the plurality of candidate color display image data calculated in the calculating step and the target luminance, and another contrast between each chromaticity of the plurality of candidate color display image data calculated in the calculating step and the target chromaticity.

3. The control method of claim 2,

wherein the determining step includes:

a luminance selection process for selecting a plurality of primary-candidate color display image data, based on the contrast between each luminance of the plurality of candidate color display image data and the target luminance; and

a chromaticity selection process for determining signal values of the specific color display image data, based on a contrast between each chromaticity of the plurality of primary-candidate color display image data and the target chromaticity.

4. The control method of claim 3,

wherein, in the chromaticity determining process, a target chromaticity, corresponding to a certain monochrome signal value of the (n+m)-bit monochromatic image data, is set at a chromaticity, determined in the determining step and corresponding to another monochrome signal value of the (n+m)-bit monochromatic image data;

and

wherein, in the chromaticity selection process, signal values of color display image data are determined, based on a contrast between the chromaticity calculated in the calculating step, with respect to each of the primary-candidate color display image data corresponding to a certain monochrome signal value of the (n+m)-bit monochromatic image data, and the target chromaticity.

5. The control method of claim 4,

wherein, in the chromaticity determining process, the target chromaticity, corresponding to signal value “

i”

(“

i”

indicates a positive integer being equal to or greater than 1 and equal to or smaller than (2^n+m−

1)) of the (n+m)-bit monochromatic image data, is employed as a chromaticity of color display image data, which corresponds to (n+m)-bit monochromatic image data of signal value (i−

1); and

wherein, in the chromaticity selection process, signal values of primary-candidate color display image data, which have such a chromaticity that is calculated in the calculating step and makes a color-difference with the target chromaticity minimum, is selected from the plurality of primary-candidate color display image data corresponding to the (n+m)-bit monochromatic image data of the signal value “

i”

.

6. The control method of claim 4,

wherein, in the chromaticity determining process, the target chromaticity, corresponding to signal value “

i”

(“

i”

indicates a positive integer being equal to or greater than 2 and equal to or smaller than (2^n+m−

1)) of the (n+m)-bit monochromatic image data, is employed as a chromaticity of color display image data, which corresponds to (n+m)-bit monochromatic image data of signal value (i−

1) and another chromaticity of the color display image data, which corresponds to (n+m)-bit monochromatic image data of signal value (i−

2); and

wherein, in the chromaticity selection process, primary-candidate color display image data, which have such a chromaticity that is calculated in the calculating step and makes an absolute difference value between color-difference Δ

E(i−

1) and color-difference Δ

E(i−

2) maximum, is selected from the plurality of primary-candidate color display image data corresponding to the (n+m)-bit monochromatic image data of the signal value “

i”

; and

wherein the color-difference Δ

E(i−

1) is defined as a color-difference with color display image data, which corresponds to (n+m)-bit monochromatic image data of signal value (i−

1), while, the color-difference Δ

E(i−

2) is defined as a color-difference with color display image data, which corresponds to (n+m)-bit monochromatic image data of signal value (i−

2).

7. The control method of claim 2,

wherein the determining step includes:

a chromaticity selection process for selecting a plurality of primary-candidate color display image data, based on a contrast between each chromaticity of the plurality of candidate color display image data calculated in the calculating step and the target chromaticity; and

a luminance selection process for determining a signal value of color display image data, based on a contrast between each luminance of the plurality of primary-candidate color display image data and the target luminance.

8. An image processing apparatus that converts (n+m)-bit monochromatic image data represented by a single channel into n-bit color display image data represented by three channels or more channels, based on predetermined correlations between the (n+m)-bit monochromatic image data and the n-bit color display image data, wherein numeral “

n”

indicates a positive integer equal to or greater than 8, while numeral “

m”

indicates a positive integer equal to or greater than 2, the image processing apparatus comprising;

a luminance calculating section to calculate luminance information corresponding to each of monochrome signal values represented by the (n+m)-bit monochromatic image data;

a chromaticity calculating section to calculate chromaticity information corresponding to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data;

a signal value determining section to determine each combination of plural-channel color signal values represented by the n-bit color display image data, based on the luminance information and the chromaticity information, so that each combination of the plural-channel color signal values corresponds to each of the monochrome signal values; and

a correlation establishing section to establish the predetermined correlations between the (n+m)-bit monochromatic image data and the n-bit color display image data, so that each combination of the plural-channel color signal values and each of the monochrome signal values are correlated with each other.

9. The image processing apparatus of claim 8, further comprising:

a candidate-data selecting section to select a plurality of candidate color display image data having signal values different from each other, with respect to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data;

a target luminance determining section to determine a target luminance corresponding to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data; and

a target chromaticity determining section to determine a target chromaticity corresponding to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data;

wherein the luminance calculating section calculates a luminance with respect to each of the plurality of candidate color display image data, and the chromaticity calculating section calculates a chromaticity with respect to each of the plurality of candidate color display image data; and

wherein the signal value determining section selects specific color display image data, based on a contrast between each luminance of the plurality of candidate color display image data and the target luminance, and another contrast between each chromaticity of the plurality of candidate color display image data and the target chromaticity.

10. The image processing apparatus of claim 9,

wherein the signal value determining section includes:

a luminance selection unit to selects a plurality of primary-candidate color display image data, based on the contrast between each luminance of the plurality of candidate color display image data and the target luminance; and

a chromaticity selection unit to determine signal values of the specific color display image data, based on a contrast between each chromaticity of the plurality of primary-candidate color display image data and the target chromaticity.

11. The image processing apparatus of claim 10,

wherein the target chromaticity determining section sets a target chromaticity, corresponding to a certain monochrome signal value of the (n+m)-bit monochromatic image data, at a chromaticity, determined by the signal value determining section and corresponding to another monochrome signal value of the (n+m)-bit monochromatic image data;

and

wherein the chromaticity selection unit determines signal values of the specific color display image data, based on a contrast between the chromaticity, with respect to each of the primary-candidate color display image data corresponding to a certain monochrome signal value of the (n+m)-bit monochromatic image data, and the target chromaticity.

12. The image processing apparatus of claim 11,

wherein the target chromaticity determining section employs the target chromaticity, corresponding to signal value “

i”

(“

i”

indicates a positive integer being equal to or greater than 1 and equal to or smaller than (2^n+m−

1)) of the (n+m)-bit monochromatic image data, as a chromaticity of color display image data, which corresponds to (n+m)-bit monochromatic image data of signal value (i−

1); and

wherein the chromaticity selection unit selects signal values of primary-candidate color display image data, which have such a chromaticity that makes a color-difference with the target chromaticity minimum, from the plurality of primary-candidate color display image data corresponding to the (n+m)-bit monochromatic image data of the signal value “

i”

.

13. The image processing apparatus of claim 11,

wherein the target chromaticity determining section employs the target chromaticity, corresponding to signal value “

i”

(“

i”

indicates a positive integer being equal to or greater than 2 and equal to or smaller than (2^n+m−

1)) of the (n+m)-bit monochromatic image data, as a chromaticity of color display image data, which corresponds to (n+m)-bit monochromatic image data of signal value (i−

1) and another chromaticity of the color display image data, which corresponds to (n+m)-bit monochromatic image data of signal value (i−

2); and

wherein the chromaticity selection unit selects primary-candidate color display image data, which have such a chromaticity that is calculated in the calculating step and makes an absolute difference value between color-difference Δ

E(i−

1) and color-difference Δ

E(i−

2) maximum, from the plurality of primary-candidate color display image data corresponding to the (n+m)-bit monochromatic image data of the signal value “

i”

; and

wherein the color-difference Δ

E(i−

1) is defined as a color-difference with color display image data, which corresponds to (n+m)-bit monochromatic image data of signal value (i−

1), while, the color-difference Δ

E(i−

2) is defined as a color-difference with color display image data, which corresponds to (n+m)-bit monochromatic image data of signal value (i−

2).

14. The image processing apparatus of claim 9,

wherein the signal value determining section includes:

a chromaticity selection unit to selects a plurality of primary-candidate color display image data, based on the contrast between each chromaticity of the plurality of candidate color display image data and the target chromaticity; and

a luminance selection unit to determine signal values of the specific color display image data, based on a contrast between each luminance of the plurality of primary-candidate color display image data and the target luminance.