Tone characteristics-conversion determining apparatus, tone characteristics-conversion determining method, tone characteristics-conversion determining program, image processing apparatus, and image display apparatus

1. A tone-conversion-characteristic determining apparatus for determining tone-conversion characteristic for use in converting tone characteristic of original data so that targeted tone characteristic is obtained when display is performed by a display device, the tone-conversion-characteristic determining apparatus comprising:

a one of tristimulus values X, Y, and Z for one of primary colors included in multiprimary colors

determining unit that, on the basis of tristimulus values X, Y and Z corresponding to a tone characteristic value of the primary color, determines one of tristimulus values X, Y and Z, which is greater than the other tristimulus values; and

a tone-conversion-characteristic determining unit that, on the basis of the tristimulus values determined by one of tristimulus values X, Y and Z determining unit, determines the tone-conversion characteristic so that the targeted tone characteristic is obtained.

2. The tone-conversion-characteristic determining apparatus according to claim 1 , wherein:

the tristimulus values correspond to a maximum tone characteristic value of the primary color; and

the tristimulus value determining unit determines, as the tristimulus value, a greatest tristimulus value among the tristimulus values.

3. The tone-conversion-characteristic determining apparatus according to claim 1 , wherein each of the targeted tone characteristic is such that a tone characteristic value obtained, for a normalized tone characteristic value of the original image data, by normalizing the tristimulus value, is linear.

4. The tone-conversion-characteristic determining apparatus according to claim 1 , wherein each of the targeted tone characteristic is such that a tone value obtained, for a normalized tone characteristic value of the original image data, by normalizing the tristimulus value, is represented by a gamma characteristic prescribed on the basis of a specified gamma value.

5. The tone-conversion-characteristic determining apparatus according to claim 1 , wherein:

the multiprimary colors include red, green, blue, and cyan;

the tristimulus values have value X, value Y, and value Z; and

the tristimulus value determining unit determines, as the tristimulus value, value X for the red, value Y for the green, value Z for the blue, or value Y for the cyan.

6. The tone-conversion-characteristic determining apparatus according to claim 1 , wherein:

the multiprimary colors include red, green, blue, and yellow;

the tristimulus values have value X, value Y, and value Z; and

the tristimulus value determining unit determines, as the tristimulus value, value X for the red, value Y for the green, value Z for the blue, or value Y for the yellow.

7. The tone-conversion-characteristic determining apparatus according to claim 1 , wherein:

the multiprimary colors include red, green, blue, and white;

the tristimulus values have value X, value Y, and value Z; and

the tristimulus value determining unit determines, as the tristimulus value, value X for the red, value Y for the green, value Z for the blue, or value Y for the white.

8. The tone-conversion-characteristic determining apparatus according to claim 1 , wherein colored regions in the colors include, in visible light ranges in which a hue of visible light changes depending on the wavelength of the visible light, a colored region having a hue of a blue range, a colored region having a hue of a red range, and two colored regions respectively having hues selected from hues of blue to yellow.

9. The tone-conversion-characteristic determining apparatus according to claim 1 , wherein colored regions in the colors include a colored region in which a wavelength peak of light passing through the colored region is 415 to 500 nanometers, a colored region in which a wavelength peak of light passing through the colored region is 600 nanometers or greater, a colored region in which a wavelength peak of light passing through the colored region is 485 to 535 nanometers, and a colored region in which a wavelength peak of light passing through the colored region is 500 to 590 nanometers.

10. An image processing apparatus comprising:

a storage unit that stores, as tables, the tone-conversion characteristic determined by the tone-conversion-characteristic determining apparatus according to claim 1 ; and

an image processing unit that uses the tables stored in the storage unit to perform image processing on image data which is obtained such that the display device converts input image data into colors capable of being displayed by the display device.

11. A tone-conversion-characteristic determining method for determining tone-conversion characteristic for use in converting tone characteristic of original data so that targeted tone characteristic is obtained when display is performed by a display device, the tone-conversion-characteristic determining method comprising:

determining, on the basis of tristimulus values X, Y and Z corresponding to a tone characteristic value of one of primary colors included in multiprimary colors, one of tristimulus values X, Y and Z, which is greater than the other tristimulus values; and

determining, on the basis of the determined tristimulus value of the primary color, the tone-conversion characteristic so that the targeted tone characteristic is obtained.

12. A tone-conversion-characteristic computer-readable medium storing a determining program to be executed by a computer, the program allowing the computer to function as:

one of tristimulus values X, Y and Z determining means that, on the basis of tristimulus values X, Y and Z corresponding to a tone value of one of primary colors included in multiprimary colors, determines one of tristimulus values X, Y and Z, which is greater than the other tristimulus values; and

tone-conversion-characteristic determining means that, on the basis of the tristimulus values determined by one of tristimulus values X, Y and Z determining means, determines tone-conversion characteristic for use in converting tone characteristic of the original image data that the targeted tone characteristic is obtained when display is performed by the display device.

13. An image processing apparatus comprising:

a one of tristimulus values X, Y, and Z for one of primary colors included in multiprimary colors determining unit that, on the basis of tristimulus values X, Y and Z corresponding to a tone characteristic value of the primary colors determines one of tristimulus values X, Y and Z, which is greater than the other tristimulus values; and

a tone-conversion-characteristic determining unit that, on the basis of the tristimulus values determined by one of tristimulus values X, Y and Z determining unit, determines tone-conversion characteristic for use in converting tone characteristic of the original image data so that the targeted tone characteristic is obtained when display is performed by the display device; and

an image processing unit that performs image processing by using the tone-conversion characteristic.

14. The image processing apparatus according to claim 13 , wherein:

the tone-conversion-characteristic determining unit determines the tone-conversion characteristic on the basis of a specified gamma value; and

the image processing unit performs gamma correction based on the determined tone-conversion characteristic.

15. An image display apparatus comprising:

the image processing apparatus according to claim 13 ; and

a display device that displays image data which is obtained by the image processing of the image processing apparatus.