Image processing apparatus, image processing method, and image display device

An apparatus for processing image to supply luminance control signals to light sources corresponding to a plurality of colors and a plurality of divisional regions, and to supply a conversion image to a light modulation device which modulates a transmittance or a reflectance of lights emitted from the light sources, comprising:

• a luminance calculating unit configured to calculate luminances of the light sources for each of the plurality of divisional regions by using an input image;
• a maximum value detecting unit configured to detect a maximum value that is the largest value in the luminances of the plurality of colors, for each of the plurality of divisional regions;
• a luminance correcting unit configured to, for each of the plurality of divisional regions, correct the luminances to obtain corrected luminances so as to reduce the difference among the luminances of the plurality of colors, if the maximum value is smaller than a predetermined threshold value;
• a luminance distribution calculating unit configured to, for each of the plurality of divisional regions, calculate luminance distribution in the light sources by using the corrected luminances;
• a function calculating unit configured to, for each of the plurality of divisional regions, calculate a gradation conversion function applied to the input image corresponding to each of the plurality of colors, by using the luminance distribution;
• and
• a control unit configured to convert the input image into the conversion image by using the gradation conversion function in each divisional region, configured to supply the conversion image to the modulation device, and configured to generate the luminance control signal by using the corrected luminance in each divisional region.

An image processing method, which generates a luminance control signal supplied to light sources corresponding to a plurality of colors and a conversion image supplied to a light modulation device which modulates a transmittance or a reflectance of lights emitted from the light sources, comprising:

• calculating luminances of light sources by using an input image;
• detecting a maximum value that is the largest value in the luminances of the plurality of colors;
• correcting the luminance to obtain corrected luminances so as to reduce the difference among the luminances of the plurality of colors, if the maximum value is smaller than a predetermined threshold value;
• calculating a gradation conversion function applied to the input image corresponding to each of the plurality of colors, by using the corrected luminance;
• converting the input image into the conversion image by using the gradation conversion function;
• and
• generating the luminance control signal by using the corrected luminance.

An image display device comprising:

• a backlight configured to comprise light sources corresponding to a plurality of colors and a plurality of divisional regions, and configured to modulate luminances of the light sources by using a luminance control signal;
• a liquid crystal panel configured to modulate a transmittance or a reflectance of lights emitted from the light sources by using a conversion image;
• a luminance calculating unit configured to calculate luminances of the light sources for each of the plurality of divisional regions by using an input image;
• a maximum value detecting unit configured to detect a maximum value that is the largest value in the luminances of the plurality of colors, for each of the plurality of divisional regions;
• a luminance correcting unit configured to, for each of the plurality of divisional regions, correct the luminances to obtain corrected luminances so as to reduce the difference among the luminances of the plurality of colors, if the maximum value is smaller than a predetermined threshold value;
• a luminance distribution calculating unit configured to, for each of the plurality of divisional regions, calculate luminance distribution in the light sources by using the corrected luminances;
• a function calculating unit configured to, for each of the plurality of divisional regions, calculate a gradation conversion function applied to the input image corresponding to each of the plurality of colors, by using the luminance distribution;
• and
• a control unit configured to convert the input image into the conversion image by using the gradation conversion function in each divisional region, configured to supply the conversion image to the liquid crystal panel, and configured to generate the luminance control signal by using the corrected luminance in each divisional region.