Device or method for displaying image

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.

1 - 12 . (canceled) 
     
     
         13 . An image display device for generating output image data by correcting an input image on the basis of Retinex theory, the image display device comprising:
 separation means configured to separate the input image into an illumination light component and a reflected-light component using a filter;   corrected illumination light component calculation means configured to calculate a corrected illumination light component by adjusting the separated illumination light component using a brightness adjustment parameter;   corrected reflectance calculation means configured to calculate corrected reflectance by adjusting the separated reflected-light component using a reflectance adjustment parameter; and   generation means configured to generate the output image data on the basis of the corrected illumination light component and the corrected reflectance.   
     
     
         14 . The image display device of  claim 13 , wherein the corrected illumination light component calculation means adjusts the degree of enhancement of a low-gradation component of the separated illumination light component using a parameter for adjusting the degree of enhancement of the low-gradation component of the illumination light component and subsequently calculates the corrected illumination light component by determining, on the basis of the brightness adjustment parameter, a ratio at which the low-gradation component-adjusted illumination light component and the illumination light component separated by the separation means are combined and summed up. 
     
     
         15 . An image display device for generating output image data by correcting an input image on the basis of Retinex theory, the image display device comprising:
 separation means configured to separate the input image into an illumination light component and a reflected-light component using a filter;   corrected illumination light component calculation means configured to calculate a corrected illumination light component by adjusting the separated illumination light component using an illumination light component brightness adjustment parameter; and   generation means configured to generate the corrected input image on the basis of the corrected illumination light component, wherein   the corrected illumination light component calculation means adjusts the degree of enhancement of a low-gradation component of the separated illumination light component using a parameter for adjusting the degree of enhancement of the low-gradation component of the illumination light component and subsequently calculates the corrected illumination light component by determining, on the basis of the brightness adjustment parameter, a ratio at which the low-gradation component-adjusted illumination light component and the illumination light component separated by the separation means are combined and summed up.   
     
     
         16 . The image display device of  claim 15 , wherein the corrected illumination light component calculation means calculates an average representative value of luminance in a particular region of the input image, and wherein when the average representative value is high, the corrected illumination light component calculation means combines and sums up the illumination light component and the low-gradation component-enhanced illumination light component in such a manner that a content of the low-gradation component-enhanced illumination light component is low. 
     
     
         17 . The image display device of  claim 15 , wherein the corrected illumination light component calculation means calculates the degree of variation of luminance in a particular region of the input image, and
 wherein when the degree of variation is small, the corrected illumination light component calculation means combines and sums up the illumination light component and the low-gradation component-enhanced illumination light component in such a manner that a content of the low-gradation component-enhanced illumination light component is low.   
     
     
         18 . The image display device of any one of  claims 15 , further comprising corrected reflectance calculation means configured to calculate corrected reflectance by adjusting the separated reflected-light component using a reflectance adjustment parameter, wherein
 the corrected illumination light component calculation means generates the output image data on the basis of the corrected illumination light component and the corrected reflectance.   
     
     
         19 . The image display device of  claim 18 , wherein the reflectance amplification coefficient is set such that the reflectance amplification coefficient is reduced as a scale of a low-pass filter used in the separation step is increased and such that the reflectance amplification coefficient is reduced as resolution of a display monitor is reduced. 
     
     
         20 . An image display device for generating output image data by correcting an input image on the basis of Retinex theory, the image display device comprising:
 separation means configured to separate an illumination light component from input image data on the basis of values of a pixel of interest and a pixel region adjacent to the pixel of interest; and   corrected illumination light component calculation means configured to obtain a low-gradation component-enhanced illumination light component by enhancing a low-gradation component of the illumination light component separated by the separation means and to calculate a corrected illumination light component by combining and summing up the low-gradation component-enhanced illumination light component and the illumination light component,   wherein the corrected illumination light component calculation means calculates an average representative value of luminance and/or the degree of variation of luminance in a particular region of the input image, and   wherein when the average representative value is high and/or when degree of variation is low, the corrected illumination light component calculation means combines and sums up the illumination light component and the low-gradation component-enhanced illumination light component in such a manner that a content of the low-gradation component-enhanced illumination light component is low.   
     
     
         21 . The image display device of  claim 20 , wherein the input image data is moving-image data comprising a plurality of frames, and
 wherein the average representative value and/or degree of variation of the luminance are calculated for each frame, and   wherein when the average representative value is high and/or when degree of variation are low, the illumination light component and the low-gradation component-enhanced illumination light component are combined and summed up in such a manner that a content of the low-gradation component-enhanced illumination light component is low.   
     
     
         22 . An image display method for generating output image data by correcting an input image on the basis of Retinex theory, the method comprising:
 separating the input image into an illumination light component and a reflected-light component using a filter;   calculating a corrected illumination light component by adjusting the separated illumination light component using a brightness adjustment parameter;   calculating corrected reflectance by adjusting the separated reflected-light component using a reflectance adjustment parameter; and   generating the output image data on the basis of the corrected illumination light component and the corrected reflectance.   
     
     
         23 . An image display method for generating output image data by correcting an input image on the basis of Retinex theory, the method comprising:
 separating the input image into an illumination light component and a reflected-light component using a filter;   calculating a corrected illumination light component by adjusting the separated illumination light component using an illumination light component brightness adjustment parameter; and   generating the corrected input image on the basis of the corrected illumination light component; and   adjusting the degree of enhancement of a low-gradation component of the separated illumination light component using a parameter for adjusting the degree of enhancement of the low-gradation component of the illumination light component and subsequently calculating the corrected illumination light component by determining, on the basis of the brightness adjustment parameter, a ratio at which the low-gradation component-adjusted illumination light component and the separated illumination light component are combined and summed up.   
     
     
         24 . An image display method for generating output image data by correcting an input image on the basis of Retinex theory, the method comprising:
 separating an illumination light component from input image data on the basis of values of a pixel of interest and a pixel region adjacent to the pixel of interest;   calculating a low-gradation component-enhanced illumination light component by enhancing a low-gradation component of the separated illumination light component and calculating a corrected illumination light component by combining and summing up the low-gradation component-enhanced illumination light component and the illumination light component;   calculating an average representative value of luminance and/or the degree of variation of luminance for each pixel in a particular region of the input image; and   when the average representative value is high and/or when the degree of variation is low, combining and summing up the illumination light component and the low-gradation component-enhanced illumination light component in such a manner that a content of the low-gradation component-enhanced illumination light component is low.