Image processing device and image processing method
Provided is an image processing device which enables image display that takes full advantage of a color reproduction performance of a panel without providing a viewer with a feeling of strangeness. An image processing device includes: a color gamut conversion processor configured to convert inputted data into RGB data according to a liquid crystal panel; a weighting factor calculator configured to calculate a weighting factor; a first post-color-gamut-conversion data weighting processor configured to perform weighting processing to the RGB data; an inputted data weighting processor configured to perform weighting processing to the inputted data; and an output adder configured to add data after the weighting processing to generate RGB data to be supplied to the liquid crystal panel. The weighting factor calculator obtains the weighting factor based on a positional relation among a chromaticity coordinate on an xy chromaticity diagram, a color reproduction range for the inputted data, and a boundary line defined so as to include memory colors.
1. An image processing device, comprising:
an RGB data converter configured to perform predetermined conversion processing to first RGB data to generate second RGB data, the first RGB data being externally supplied image data in an RGB colorimetric system;
a weighting factor calculator configured to convert the first RGB data into XYZ data and to calculate a weighting factor based on the XYZ data, the XYZ data being data in an XYZ colorimetric system, the weighting factor being used for performing weighting processing to the first RGB data and the second RGB data;
a first weighting processor configured to perform weighting processing to the first RGB data by multiplying the first RGB data by a first factor obtained based on the weighting factor;
a second weighting processor configured to perform weighting processing to the second RGB data by multiplying the second RGB data by a second factor obtained based on the weighting factor, the second factor increasing and decreasing in an manner opposite to the first factor; and
an output adder configured to generate RGB data for output to be supplied to an external output device by adding data obtained through the weighting processing by first weighting processor and data obtained through the weighting processing by the second weighting processor, wherein
the weighting factor calculator:
obtains a first coordinate, a second coordinate, and a third coordinate for data of each pixel included in the XYZ data, on one of an xy chromaticity diagram and a uv chromaticity diagram, and calculates the weighting factor based on a positional relation among the first coordinate, the second coordinate, and the third coordinate, the first coordinate being a chromaticity coordinate of the corresponding pixel data, the second coordinate being a chromaticity coordinate of an intersection point between a weighting factor calculation line, that is a straight line passing a predetermined reference coordinate and the first coordinate, and a line indicating a color reproduction range obtained by the XYZ data, the third coordinate being a chromaticity coordinate of an intersection point between a boundary line that includes at least three points and defines a closed region and the weighting factor calculation line, and
determines a value of the weighting factor such that a value of the first factor is 0, when the first coordinate is within the boundary line.
2. The image processing device according to claim 1 , wherein
when the first coordinate is outside the boundary line, the weighting factor calculator takes a value obtained by dividing a distance between the third coordinate and the first coordinate by a distance between the third coordinate and the second coordinate as the value of the weighting factor.
3. The image processing device according to claim 1 , wherein
the value of the first factor is equal to the value of the weighting factor.
4. The image processing device according to claim 1 , wherein
the value of the first factor is obtained by an equation,
k 1 =1 −e −kλ ,
wherein, k 1 is the first factor, k is the weighting factor, e is a base of natural logarithm, and λ is a positive factor that is determinable to be any value.
5. The image processing device according to claim 4 , further comprising a look-up table that previously stores a plurality of values of the first factor each in association with a predetermined index, wherein
the weighting factor calculator acquires a value of the first factor from the look-up table by using an index obtained based on the weighting factor.
6. The image processing device according to claim 1 , wherein
the RGB data converter includes a color gamut conversion processor configured to generate the second RGB data such that a color reproduction range to be a reference when the first RGB data is generated is equal to a color reproduction range obtained by supplying the second RGB data to the output device.
7. The image processing device according to claim 1 , wherein
the RGB data converter includes a white balance processor configured to generate the second RGB data by multiplying a value of each color of the first RGB data by a gain that is previously determined for the corresponding color.
8. The image processing device according to claim 1 , wherein
the RGB data converter includes:
a color gamut conversion processor configured to perform conversion processing to the first RGB data to generate the third RGB data such that a color reproduction range obtained by supplying the third RGB data to the output device is equal to a color reproduction range to be a reference when the first RGB data is generated, the third RGB data being data obtained after the conversion of the first RGB data;
a third weighting processor configured to perform weighting processing to the third RGB data by multiplying the third RGB data by a previously determined third factor;
a white balance processor configured to generate fourth RGB data by multiplying a value of each color of the first RGB data by a gain that is previously determined for the corresponding color;
a fourth weighting processor configured to perform weighting processing to the fourth RGB data by multiplying the fourth RGB data by a fourth factor increasing and decreasing in an manner opposite to the third factor; and
a data adder configured to generate the second RGB data by adding data obtained through the weighting processing by the third weighting processor and data obtained through the weighting processing by the fourth weighting processor.
9. The image processing device according to claim 8 , further comprising a scaling processor and a fifth weighting processor, in place of the first weighting processor, the scaling processor generating fifth RGB data by multiplying the value of each color of the first RGB data by a scaling factor that is previously determined for the corresponding color, the fifth weighting processor performing weighting processing to the fifth RGB data by multiplying the fifth RGB data by the first factor, wherein
the output adder adds data obtained through the weighting processing by the fifth weighting processor in place of the first weighting processor and data obtained through the weighting processing by the second weighting processor.
10. The image processing device according to claim 1 , wherein
the boundary line is defined so as to include therein a chromaticity coordinate for D65 which is a standard light source.
11. The image processing device according to claim 1 , wherein
the boundary line is defined so as to include therein chromaticity coordinates of memory color including at least white color and flesh color.
12. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 1 .
13. An image processing method, comprising:
an RGB data converting step of performing predetermined conversion processing to first RGB data to generate second RGB data, the first RGB data being externally supplied image data in an RGB colorimetric system;
a weighting factor calculating step of converting the first RGB data into XYZ data and calculating a weighting factor based on the XYZ data, the XYZ data being data in an XYZ colorimetric system, the weighting factor being used for performing weighting processing to the first RGB data and the second RGB data;
a first weighting processing step of performing weighting processing to the first RGB data by multiplying the first RGB data by a first factor obtained based on the weighting factor;
a second weighting processing step of performing weighting processing to the second RGB data by multiplying the second RGB data by a second factor obtained based on the weighting factor, the second factor increasing and decreasing in an manner opposite to the first factor; and
an output adding step of generating RGB data for output to be supplied to an output device by adding data obtained through the weighting processing in the first weighting processing step and data obtained through the weighting processing in the second weighting processing step, wherein
in the weighting factor calculating step,
a first coordinate, a second coordinate, and a third coordinate are obtained for data of each pixel included in the XYZ data, on one of an xy chromaticity diagram and a uv chromaticity diagram, and the weighting factor is calculated based on a positional relation among the first coordinate, the second coordinate, and the third coordinate, the first coordinate being a chromaticity coordinate of the corresponding pixel data, the second coordinate being a chromaticity coordinate of an intersection point between a weighting factor calculation line, that is a straight line passing a predetermined reference coordinate and the first coordinate, and a line indicating a color reproduction range obtained by the XYZ data, the third coordinate being a chromaticity coordinate of an intersection point between a boundary line that includes at least three points and defines a closed region and the weighting factor calculation line, and
a value of the weighting factor is determined such that a value of the first factor is 0, when the first coordinate is within the boundary line.
14. The image processing method according to claim 13 , wherein
in the weighting factor calculating step, a value obtained by dividing a distance between the third coordinate and the first coordinate by a distance between the third coordinate and the second coordinate is taken as the value of the weighting factor, when the first coordinate is outside the boundary line.
15. The image processing method according to claim 13 , wherein
the value of the first factor is equal to the value of the weighting factor.
16. The image processing method according to claim 13 , wherein
the value of the first factor is obtained by an equation,
k 1 =1 −e −kλ
wherein, k 1 is the first factor, k is the weighting factor, e is a base of natural logarithm, and λ is a positive factor that is determinable to be any value.
17. The image processing method according to claim 16 , wherein
in the weighting factor calculating step, a value of the first factor is acquired from a look-up table by using an index obtained based on the weighting factor, the look-up table previously storing a plurality of values of the first factor each in association with a predetermined index.
18. The image processing method according to claim 13 , wherein
the RGB data converting step includes a color gamut conversion processing step of generating the second RGB data such that a color reproduction range to be a reference when the first RGB data is generated is equal to a color reproduction range obtained by supplying the second RGB data to the output device.
19. The image processing method according to claim 13 , wherein
the RGB data converting step includes a white balance processing step of generating the second RGB data by multiplying a value of each color of the first RGB data by a gain that is previously determined for the corresponding color.
20. The image processing method according to claim 13 , wherein
the RGB data converting step includes:
a color gamut conversion processing step of performing conversion processing to the first RGB data to generate the third RGB data such that a color reproduction range obtained by supplying the third RGB data to the output device is equal to a color reproduction range to be a reference when the first RGB data is generated, the third RGB data being data obtained after the conversion of the first RGB data;
a third weighting processing step of performing weighting processing to the third RGB data by multiplying the third RGB data by a previously determined third factor;
a white balance processing step of generating fourth RGB data by multiplying a value of each color of the first RGB data by a gain that is previously determined for the corresponding color;
a fourth weighting processing step of performing weighting processing to the fourth RGB data by multiplying the fourth RGB data by a fourth factor increasing and decreasing in an manner opposite to the third factor; and
a data adding step of generating the second RGB data by adding data obtained through the weighting processing in the third weighting processing step and data obtained through the weighting processing in the fourth weighting processing step.
21. The image processing method according to claim 20 , further comprising a scaling processing step and a fifth weighting processing step, in place of the first weighting processing step, the scaling processing step being a step of generating fifth RGB data by multiplying the value of each color of the first RGB data by a scaling factor that is previously determined for the corresponding color, the fifth weighting processing step being a step of performing weighting processing to the fifth RGB data by multiplying the fifth RGB data by the first factor, wherein
in the output adding step, data obtained through the weighting processing in the fifth weighting processing step in place of the first weighting processing step and data obtained through the weighting processing in the second weighting processing step are added.
22. The image processing method according to claim 13 , wherein
the boundary line is defined so as to include therein a chromaticity coordinate for D65 which is a standard light source.
23. The image processing method according to claim 13 , wherein
the boundary line is defined so as to include therein chromaticity coordinates of memory color including at least white color and flesh color.
24. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 2 .
25. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 3 .
26. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 4 .
27. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 5 .
28. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 6 .
29. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 7 .
30. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 8 .
31. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 9 .
32. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 10 .
33. A display apparatus having a display panel, as the output device, configured to display an image, the display apparatus comprising:
the image processing device according to claim 11 .