Abstract: Improving the visibility of the dark portion and to prevent the degradation of image quality caused by excessive correction. A reflectance calculation unit is storing a parameter RGain for adjusting the amplitude of a reflectance component R. An illumination light correction unit generates a corrected illumination light component L1 from an illumination light component L and a formula L1=(log(LAmp*L+1))/(log(LAmp+1)). An image resynthesis unit obtains a corrected illumination light component L? from L?=LGain*L1+(1?LGain)*L. The image resynthesis unit also calculates a corrected image Iout from the corrected illumination light component L? and the corrected reflectance R?, as well as from a formula Iout=exp(log L?+RGain(log I?log L)). The value of the corrected illumination light component (L?) is determined based on the ratio (LGain) at which the output value of the correction function (L1) and the original illumination light component (L) are combined.

Abstract: Improving the visibility of the dark portion and to prevent the degradation of image quality caused by excessive correction. A reflectance calculation unit is storing a parameter RGain for adjusting the amplitude of a reflectance component R. An illumination light correction unit generates a corrected illumination light component L1 from an illumination light component L and a formula L1=(log(LAmp*L+1))/(log(LAmp+1)). An image resynthesis unit obtains a corrected illumination light component L? from L?=LGain*L1+(1?LGain)*L. The image resynthesis unit also calculates a corrected image Iout from the corrected illumination light component L? and the corrected reflectance R?, as well as from a formula Iout=exp(log L?+RGain(log I?log L)). The value of the corrected illumination light component (L?) is determined based on the ratio (LGain) at which the output value of the correction function (L1) and the original illumination light component (L) are combined.

Abstract: An object is to correct gradations in such a manner that both halo reduction effect and Retinex calculation effect are satisfied. Each JND value corresponding to each obtained luminance value to be assigned to each unit gradation of a panel is obtained. A pixel value corresponding to the each JND value is obtained for each of the unit gradations of the panel. A threshold ? is obtained by inverse gamma-correcting the ratio between discernible JND values corresponding to the unit gradations of the panel and the maximum output value of the panel. Linear function-based approximations are obtained using least squares. The threshold ? is determined as an increasing function of a pixel value on the basis of the allowable number of JND steps. The threshold ? is changed using this function. The threshold ? can be changed according to the center pixel value.

Abstract: Improving the visibility of the dark portion and to prevent the degradation of image quality caused by excessive correction. A reflectance calculation unit is storing a parameter RGain for adjusting the amplitude of a reflectance component R. An illumination light correction unit generates a corrected illumination light component L1 from an illumination light component L and a formula L1=(log(LAmp*L+1))/(log(LAmp+1)). An image resynthesis unit obtains a corrected illumination light component L? from L?=LGain*L1 +(1?LGain)*L. The image resynthesis unit also calculates a corrected image Tout from the corrected illumination light component L? and the corrected reflectance R?, as well as from a formula Iout=exp(log L?+RGain(log I?log L)). The value of the corrected illumination light component (L?) is determined based on the ratio (LGain) at which the output value of the correction function (L1) and the original illumination light component (L) are combined.

Abstract: An object is to correct gradations in such a manner that both halo reduction effect and Retinex calculation effect are satisfied. Each JND value corresponding to each obtained luminance value to be assigned to each unit gradation of a panel is obtained. A pixel value corresponding to the each JND value is obtained for each of the unit gradations of the panel. A threshold ? is obtained by inverse gamma-correcting the ratio between discernible JND values corresponding to the unit gradations of the panel and the maximum output value of the panel. Linear function-based approximations are obtained using least squares. The threshold ? is determined as an increasing function of a pixel value on the basis of the allowable number of JND steps. The threshold ? is changed using this function. The threshold ? can be changed according to the center pixel value.