Image display device capable of supporting brightness enhancement and power control and method thereof

Abstract

An image display device capable of supporting brightness enhancement and power control and a method thereof, in which the brightness and contrast are enhanced and the power of a light source is controlled in accordance with the image characteristic. In the image display method, a parameter representative of an input image is calculated from a histogram of the input image, a model corresponding to the input image is selected from a plurality of representative models by analyzing the parameter, and then a brightness controlling function matched with the selected model is selected. The size of each component of a pixel constituting the input image is controlled using the brightness controlling function, and the output image of the pixel whose component size has been controlled is displayed.

1 . A method of displaying an image, comprising: 
 calculating a parameter representative of an input image from a histogram of the input image;    selecting a model corresponding to the input image from a plurality of representative models by analyzing the parameter;    selecting a brightness controlling function matched with the selected model;    controlling the size of each component of a pixel constituting the input image using the brightness controlling function; and    displaying an output image of the pixel whose component size has been controlled.    
   
   
       2 . The method of  claim 1 , wherein the pixel is composed of red (R), green (G), and blue (B) components.  
   
   
       3 . The method of  claim 2 , wherein the histogram is displayed by frequency of a gray scale pixel value that is an average of the R, G, B components of the pixel constituting the input image.  
   
   
       4 . The method of  claim 1 , wherein the parameter includes a number of pixels HighSUM corresponding to a high band, a number of pixels LowSUM corresponding to a low band, a number of pixels MiddleSUM corresponding to a middle band, and an average Mean of a pixel value for the input image.  
   
   
       5 . The method of  claim 4 , wherein the plurality of models include a model representative of an image having a large number of pixels corresponding to the middle band, a model representative of an image having a large number of pixels corresponding to the high band, a model representative of an image having a large number of pixels corresponding to the low band, and a model representative of an image having a small number of pixels corresponding to the middle band.  
   
   
       6 . The method of  claim 1 , wherein the brightness controlling function has an “S”-shaped curve, its independent parameter represents a pixel value, and its dependent parameter represents a brightness increase ratio for the pixel value.  
   
   
       7 . The method of  claim 1 , wherein the controlling the size of each component of the pixel includes: 
 selecting a component of the greatest size among respective components of the pixel constituting the input image;    multiplying a result obtained by substituting the selected component for the brightness controlling function by a predetermined gain and adding the multiplied result to the selected component;    obtaining a ratio between the added result and the selected component; and    increasing the size of each component of the pixel constituting the input image by the ratio.    
   
   
       8 . A method of displaying an image, comprising: 
 controlling the size of each component of a pixel constituting an input image;    calculating a brightness of the input image and a brightness of an output image of the pixel whose size has been controlled;    calculating a power decrease ratio that can offset a luminance difference between the brightness of the input image and the brightness of the output image; and    displaying the output image based on a light source driven by a power decreased by the power decrease ratio.    
   
   
       9 . The method of  claim 8 , wherein the pixel is composed of red (R), green (G), and blue (B) components.  
   
   
       10 . The method of  claim 9 , wherein the brightness is an average value of gray scale pixel values, which are expressed as averages of the components, through the whole image.  
   
   
       11 . The method of  claim 10 , wherein the calculating the power decrease ratio includes: 
 calculating a difference between a luminance value corresponding to the brightness of the input image and a luminance value corresponding to the brightness of the output image; and determining a power required to make the difference equal to a difference between a luminance value corresponding to an initial power and a luminance value corresponding to the power.    
   
   
       12 . The method of  claim 11 , wherein the correlation between the brightness and the luminance value is determined by gamma characteristics of an image display device, and the correlation between the power and the luminance value is determined by power characteristics of the device.  
   
   
       13 . A method of displaying an image, comprising: 
 receiving an input image;    receiving a power decrease ratio from a user;    calculating a brightness of an output image corresponding to the input image, which can offset a luminance decrease ratio decreased depending on the power decrease ratio;    controlling the size of each component of a pixel constituting the input image in accordance with the brightness of the output image; and    displaying the output image of the pixel whose component size has been controlled, based on a light source driven by a power decreased by the power decrease ratio.    
   
   
       14 . The method of  claim 13 , wherein the pixel is composed of red (R), green (G), and blue (B) components.  
   
   
       15 . The method of  claim 13 , wherein the brightness is an average value of gray scale pixel values, which are displayed as averages of the components, through the whole image.  
   
   
       16 . The method of  claim 13 , wherein the calculating the brightness includes: 
 obtaining a difference between a luminance value corresponding an initial power and a luminance value corresponding to the power decreased from the initial power by the power decrease ratio; and    calculating a brightness of the output image to make the difference equal to a difference between a luminance value corresponding to the brightness of the input image and a luminance value corresponding to the brightness of the output image.    
   
   
       17 . The method of  claim 13 , wherein a correlation between the power and the luminance value is determined by power characteristics of an image display device, and a correlation between the brightness and the luminance value is determined by gamma characteristics of the device.  
   
   
       18 . The method of  claim 13 , wherein the controlling the size of each component includes: 
 determining a gain K from the brightness of the output image; and    controlling the size of each component in accordance with the determined gain.    
   
   
       19 . The method of  claim 18 , wherein the determining the gain includes: 
 subtracting the brightness of the input image from the brightness of the output image;    obtaining an average for the input image after substituting a brightness of each pixel constituting the input image for a brightness controlling function; and    dividing the subtracted result by the obtained average.    
   
   
       20 . An image display device comprising: 
 a histogram analyzer calculating a parameter representative of histogram from a gray scale pixel value of an input image;    a model selector selecting a model corresponding to the input image from a plurality of representative models by analyzing the parameter, and selecting a brightness controlling function matched with the selected model;    a pixel controller controlling the size of each component of a pixel constituting the input image using the brightness controlling function; and    an image output unit displaying an output image of the pixel whose component size has been controlled.    
   
   
       21 . An image display device comprising: 
 a pixel controller controlling the size of each component of a pixel constituting an input image and calculating a brightness of the input image and a brightness of an output image of the pixel whose size has been controlled;    a power controller calculating a power decrease ratio that can offset a luminance difference between the brightness of the input image and the brightness of the output image;    a light source unit driven by a power decreased by the power decrease ratio; and    an image output unit displaying the output image based on a light source provided from the light source unit.    
   
   
       22 . An image display device comprising: 
 an image input unit receiving an input image;    a power controller receiving a power decrease ratio from a user and calculating a brightness of an output image corresponding to the input image, which can offset a luminance decrease ratio decreased depending on the power decrease ratio;    a pixel controller controlling the size of each component of a pixel constituting the input image in accordance with the brightness of the output image;    a light source unit driven by a power decreased by the power decrease ratio; and    an image output unit displaying the output image of the pixel whose component size has been controlled, based on a light source from the light source unit.