Image processing apparatus, image display apparatus, and image display method
First Claim
1. An image processing apparatus comprising:
- a maximum and minimum color information detection means for detecting a maximum gradation level of color signals constituting an input image signal or a value equivalent to the maximum gradation level and a minimum gradation level of the color signals constituting the input image signal or a value equivalent to the minimum gradation level as maximum and minimum color information of the input image signal;
a correction parameter generating means for setting a correction parameter according to the maximum and minimum color information of the input image signal; and
a gradation correction means for correcting a gradation scale of each color component of the input image signal according to the correction parameter.
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Abstract
A maximum and minimum color information detection means (3, 51, 52) detects a maximum color-signal gradation level or a value equivalent to the maximum gradation level (CMAX) and a minimum color-signal gradation level or a value equivalent to the minimum gradation level (CMIN) as color information for an image signal input to the image processing apparatus, a correction parameter generating means (53) sets correction parameters (Pa) according to the color information (CMAX, CMIN) about the input image signal, and a gradation correction means (6) corrects the gradation scale of each color component of the input image signal according to the correction parameters (Pa). Contrast can thereby be improved without excessive color collapse.
63 Citations
32 Claims
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1. An image processing apparatus comprising:
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a maximum and minimum color information detection means for detecting a maximum gradation level of color signals constituting an input image signal or a value equivalent to the maximum gradation level and a minimum gradation level of the color signals constituting the input image signal or a value equivalent to the minimum gradation level as maximum and minimum color information of the input image signal; a correction parameter generating means for setting a correction parameter according to the maximum and minimum color information of the input image signal; and a gradation correction means for correcting a gradation scale of each color component of the input image signal according to the correction parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 17, 18, 19, 20, 21, 22)
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10. An image processing apparatus comprising:
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a maximum and minimum luminance information detection means for detecting a maximum gradation level of a luminance signal component of an input image signal or a value equivalent to the maximum gradation level and a minimum gradation level of color signals constituting the input image signal or a value equivalent to the minimum gradation level as maximum and minimum luminance information of the input image signal; a correction parameter generating means for setting a correction parameter according to the maximum and minimum luminance information; and a gradation correction means for correcting the gradation scale of a luminance signal and a color difference signal, which are obtained from the image signal, according to the correction parameter. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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23. An image processing apparatus for receiving an image signal and correcting its gradation scale, comprising:
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a color information detection means for detecting a maximum level value of each color component of the image signal and a minimum level value of said each color component as color information of the received image signal; an average luminance information detection means for detecting an average level value of a luminance component of the image signal as average luminance information of the received image signal; a correction control means for outputting a gradation-scale correction signal according to the maximum level value and minimum level value detected by the color information detection means and the average luminance information detected by the average luminance information detection means; and a gradation correction means for correcting the gradation scale of the image signal according to the gradation-scale correction signal output by the correction control means;
whereinthe correction control means obtains first averaged data by averaging the maximum and minimum level values output by the color information detection means over a first time interval and obtains second averaged data by averaging the maximum and minimum level values output by the color information detection means over a second time interval shorter than the first time interval; and obtains average color information by taking a weighted average of the first averaged data and the second averaged data weighted according to the average luminance information detected by the average luminance information detection means, and obtains the gradation correction signal from the average color information. - View Dependent Claims (24, 25, 26, 27, 28)
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29. An image display method for using a gradation correction means to correct a gradation scale of an input image signal, supplying the gradation-scale-corrected image signal to an image display means having a light source with controllable brightness and a light modulation means that changes in optical transmittance or reflectance according to the image signal, and causing the image display means to display the gradation-scale-corrected image signal, the image display method comprising:
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a maximum and minimum color information detection step for detecting a maximum gradation level of the color signals constituting the input image signal or a value equivalent to the maximum gradation level and a minimum gradation level of the color signals constituting the input image signal or a value equivalent to the minimum gradation level as maximum and minimum color information of the input image signal; a maximum and minimum luminance information detection step for detecting a maximum gradation level of a luminance signal component of the input image signal or a value equivalent to the maximum gradation level and a minimum gradation level of the luminance signal component of the input image signal or a value equivalent to the minimum gradation level as maximum and minimum luminance information of the input image signal; a correction control step for setting a correction parameter according to the maximum and minimum color information and the maximum and minimum luminance information detected in the maximum and minimum color information detection step and the maximum and minimum luminance information detection step; a gradation correction step for correcting the gradation scale of the color components of the input image signal according to the correction parameter; an average luminance information detection step for detecting an average luminance gradation value before the gradation-scale correction and an average luminance gradation value after the gradation-scale correction from average values of the gradation values of luminance signals obtained from the image signal before the gradation-scale correction and after the gradation-scale correction in the gradation correction step or from sums of the gradation values of the luminance signals; and a light source control means that controls the brightness of the light source according to the average luminance gradation value after the gradation-scale correction and the average luminance gradation value before the gradation-scale correction. - View Dependent Claims (30, 31, 32)
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Specification