Patent Publication Number: US-2010128050-A1

Title: Color Correction Method and Related Device for Liquid Crystal Display

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a color correction method for liquid crystal displays (LCDs) and related color correction device, and more particularly, to a color correction method of using gain parameters and gamma parameters of a Gain-Offset-Gamma (GOG) model to measure channel interactions or crosstalk existing among three primary colors for accurately estimating colorimetry of the LCDs and related color correction device. 
     2. Description of the Prior Art 
     For achieving apparatus-independent color reproduction, accurate colorimetry measurement is an important step when establishing color management systems of display devices. Thus, the prior art, based on displaying theory of Cathode Ray Tube (CRT) monitors, provides a Gain-Offset-Gamma (GOG) model to characterize a Tone Reproduction Curve (TRC) or an Electro-Optical Transfer Function (EOTF) of each primary color for estimating colorimetry of the display devices. Regarding the CRT monitors, the GOG model is already effective in characterizing the TRCs. 
     However, as technology has evolved, Liquid Crystal Displays (LCDs) have replaced the CRT monitors and become increasingly popular on the display markets. Since display features of the LCDs differ from the CRT monitors, there usually exist channel interactions, or crosstalk, among three primary colors of the LCDs. Therefore, the GOG model simulated with constant gain parameters and constant gamma parameters can no longer accurately estimate the colorimetry of the LCDs, especially, for Color Sequential Display (CSD) LCDs. In this situation, even after performing color correction on input signals of the LCDs, the LCDs are still not able to have precise color performance due to their inherent colorimetry. 
     To put it simply, the conventional GOG model is not suitable for the LCDs due to presence of channel interactions and color inconstancy. 
     SUMMARY OF THE INVENTION 
     It is therefore an objective of the present invention to provide a color correction method for liquid crystal displays (LCDs) and related color correction device. 
     The present invention discloses a color correction method for eliminating crosstalk between color channels of LCDs. The color correction method includes establishing a channel-dependent Gain-Offset-Gamma (GOG) model to characterize an Electro-Optical Transfer Function (EOTF) of each primary color in which a gain parameter and a gamma parameter of each primary color vary with inputs of other two primary colors due to crosstalk among color channels, measuring the EOTF of each primary color when the other two primary colors are under different input conditions, and simulating the gain parameter and the gamma parameter of each primary color by use of a first surface function and a second surface function, substituting inputs of the three primary colors into the first surface function and the second surface function to calculate the gain parameter and the gamma parameter of each primary color for further estimation of a non-linear EOTF of each primary color and linearizing the non-linear EOTF of each primary color through inverse transformation of the channel-dependent GOG model, and performing color correction according to a target colorimetry to obtain corrected values of the three primary colors. 
     The present invention further discloses a color correction device for eliminating crosstalk among color channels of LCDs. The color correction device includes a quantization unit, an estimation unit, and a correction unit. The quantization unit is used for individually quantizing inputs of three primary colors. The estimation unit is coupled to the quantization unit, and used for performing look-up table operation according to quantization results of the inputs of each primary color to generate a gain parameter and a gamma parameter of each primary color for further estimation of a non-linear EOTF of each primary color. The gain parameter and the gamma parameter of each primary color vary with the inputs of the other two primary colors due to crosstalk among color channels. The estimation unit includes at least one gamma look-up table (LUT) and at least one gain LUT. At least one gamma LUT is used for storing all possible values of the gamma parameter of each primary color under conditions of all possible quantization results of the other two primary colors. At least one gain LUT is used for storing all possible values of the gain parameter of each primary color under conditions of all possible quantization results of the other two primary colors. The correction unit is coupled to input terminals of the quantization unit and the estimation unit, and used for performing color correction on the input of each primary color according to the gain parameter and the gamma parameter of each primary color to generate corrected values of the three primary colors meeting a target colorimetry. The correction unit includes at least one correction LUT which is used for storing all calculation results of the color correction for all possible inputs of the three primary colors. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flowchart of a color correction process for a liquid crystal display (LCD) according to an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of a color correction process according to an embodiment of the present invention. 
         FIG. 3˜FIG .  5  are schematic diagrams of a color correction device for an LCD according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1 , which is a flowchart of a color correction process  10  for a liquid crystal display (LCD) according to an embodiment of the present invention. The color correction process  10  is used for performing color correction for the LCD to eliminate crosstalk among color channels and have predetermined colorimetry. The color correction process  10  includes the following steps: 
     Step  100 : Start. 
     Step  110 : Establish a channel-dependent Gain-Offset-Gamma (GOG) model to characterize an Electro-Optical Transfer Function (EOTF) of each primary color in which a gain parameter and a gamma parameter of each primary color vary with inputs of other two primary colors due to crosstalk among color channels. 
     Step  120 : Measure the EOTF of each primary color when the other two primary colors are under different input conditions, and simulate the gain parameter and the gamma parameter of each primary color by use of a first surface function and a second surface function. 
     Step  130 : Substitute inputs of the three primary colors into the first surface function and the second surface function to calculate the gain parameter and the gamma parameter of each primary color for further estimation of a non-linear EOTF of each primary color. 
     Step  140 : Linearize the non-linear EOTF of each primary color through inverse transformation of the channel-dependent GOG model, and perform color correction according to a target colorimetry to obtain corrected values of the three primary colors. 
     Step  150 : End. 
     According to the color correction process  10 , the present invention firstly establishes the channel-dependent GOG model to characterize the EOTF of each primary color. The gain parameter and the gamma parameter of each primary color vary with inputs of other two primary colors due to crosstalk among color channels in this model. Then, the present invention measures the EOTF of each primary color when the other two primary colors are under different input conditions, and simulates the gain parameter and the gamma parameter of each primary color by use of a first surface function and a second surface function, respectively. In this situation, the present invention can substitute inputs of the three primary colors into the first surface function and the second surface function to calculate the gain parameter and the gamma parameter of each primary color for further estimation of a non-linear EOTF of each primary color. 
     Since different devices possess different display features, the same image may be in different colors on the different devices. Thus, the present invention further linearizes the non-linear EOTF of each primary color through the inverse transformation of the channel-dependent GOG model, to obtain color values which are irrelevant to the display devices. According to the target colorimetry, the color correction is undertaken to convert the linear EOTF to a target EOTF such that the expected color display can be obtained. Regarding detailed operations of the color correction process  10 , please refer to the following statements. 
     Please refer to  FIG. 2 , which is a schematic diagram of an embodiment of the color correction process  10  according to the present invention. In Step  110 , the non-linear EOTF of each primary color is simulated by the channel-dependent GOG model, in which the gain parameter and the gamma parameter of each primary color vary with inputs of the other two primary colors due to crosstalk among color channels. Thus, the channel-dependent GOG model is given by: 
     
       
         
           
             
               
                 
                   
                     
                       R 
                       n 
                     
                     = 
                     
                       
                         [ 
                         
                           
                             
                               
                                 k 
                                 
                                   g 
                                   , 
                                   R 
                                 
                               
                                
                               
                                 ( 
                                 
                                   
                                     d 
                                     G 
                                   
                                   , 
                                   
                                     d 
                                     B 
                                   
                                 
                                 ) 
                               
                             
                              
                             
                               ( 
                               
                                 
                                   d 
                                   R 
                                 
                                 
                                   
                                     2 
                                     N 
                                   
                                   - 
                                   1 
                                 
                               
                               ) 
                             
                           
                           + 
                           
                             ( 
                             
                               1 
                               - 
                               
                                 
                                   k 
                                   
                                     g 
                                     , 
                                     R 
                                   
                                 
                                  
                                 
                                   ( 
                                   
                                     
                                       d 
                                       G 
                                     
                                     , 
                                     
                                       d 
                                       B 
                                     
                                   
                                   ) 
                                 
                               
                             
                             ) 
                           
                         
                         ] 
                       
                       
                         
                           γ 
                           R 
                         
                          
                         
                           ( 
                           
                             
                               d 
                               G 
                             
                             , 
                             
                               d 
                               B 
                             
                           
                           ) 
                         
                       
                     
                   
                   , 
                   
                     0 
                     ≤ 
                     
                       R 
                       n 
                     
                     ≤ 
                     1 
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
             
               
                 
                   
                     
                       G 
                       n 
                     
                     = 
                     
                       
                         [ 
                         
                           
                             
                               
                                 k 
                                 
                                   g 
                                   , 
                                   G 
                                 
                               
                                
                               
                                 ( 
                                 
                                   
                                     d 
                                     R 
                                   
                                   , 
                                   
                                     d 
                                     B 
                                   
                                 
                                 ) 
                               
                             
                              
                             
                               ( 
                               
                                 
                                   d 
                                   G 
                                 
                                 
                                   
                                     2 
                                     N 
                                   
                                   - 
                                   1 
                                 
                               
                               ) 
                             
                           
                           + 
                           
                             ( 
                             
                               1 
                               - 
                               
                                 
                                   k 
                                   
                                     g 
                                     , 
                                     G 
                                   
                                 
                                  
                                 
                                   ( 
                                   
                                     
                                       d 
                                       R 
                                     
                                     , 
                                     
                                       d 
                                       B 
                                     
                                   
                                   ) 
                                 
                               
                             
                             ) 
                           
                         
                         ] 
                       
                       
                         
                           γ 
                           G 
                         
                          
                         
                           ( 
                           
                             
                               d 
                               R 
                             
                             , 
                             
                               d 
                               B 
                             
                           
                           ) 
                         
                       
                     
                   
                   , 
                   
                     0 
                     ≤ 
                     
                       G 
                       n 
                     
                     ≤ 
                     1 
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
             
               
                 
                   
                     
                       B 
                       n 
                     
                     = 
                     
                       
                         [ 
                         
                           
                             
                               
                                 k 
                                 
                                   g 
                                   , 
                                   B 
                                 
                               
                                
                               
                                 ( 
                                 
                                   
                                     d 
                                     R 
                                   
                                   , 
                                   
                                     d 
                                     G 
                                   
                                 
                                 ) 
                               
                             
                              
                             
                               ( 
                               
                                 
                                   d 
                                   B 
                                 
                                 
                                   
                                     2 
                                     N 
                                   
                                   - 
                                   1 
                                 
                               
                               ) 
                             
                           
                           + 
                           
                             ( 
                             
                               1 
                               - 
                               
                                 
                                   k 
                                   
                                     g 
                                     , 
                                     B 
                                   
                                 
                                  
                                 
                                   ( 
                                   
                                     
                                       d 
                                       R 
                                     
                                     , 
                                     
                                       d 
                                       G 
                                     
                                   
                                   ) 
                                 
                               
                             
                             ) 
                           
                         
                         ] 
                       
                       
                         
                           γ 
                           B 
                         
                          
                         
                           ( 
                           
                             
                               d 
                               B 
                             
                             , 
                             
                               d 
                               G 
                             
                           
                           ) 
                         
                       
                     
                   
                   , 
                   
                     0 
                     ≤ 
                     
                       B 
                       n 
                     
                     ≤ 
                     1 
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
     Where d R , d G , d B  denote inputs of the three primary colors, respectively; R n , G n , B n  denote normalized brightness of the three primary colors, respectively; k g,R , k g,G , k g,B  denote the gain parameters of the three primary colors, respectively; γ R , γ G , γ B  denote the gamma parameters of the three primary colors, respectively; and N denotes the number of input bits. 
     Since the gain parameter and the gamma parameter of each primary color vary with inputs of the other two primary colors due to crosstalk among color channels, the gain parameter and the gamma parameter of each primary color can thus be represented by a first surface function and a second surface function (i.e. two dimension function), respectively. In this situation, variance of the gain parameter or the gamma parameter of each primary color on a two dimension plane can be simulated by measuring the EOTF of each primary color when the other two primary colors are under different input conditions, so as to approximate coefficients of the first surface function and the second surface function (Step  120 ). For example, the gain parameter and the gamma parameter of a red primary color are given by: 
       γ R ( d   G   ,d   R )= a+b·d   G   +c·d   B   +d·d   G   2   +e·d   B   2   +f·d   G   ·d   B   (4) 
         k   g,R ( d   G   ,d   R )= g+h·d   G   +i·d   B   +j·d   G   2   +k·d   B   2   +l·d   G   ·d   B   (5) 
     Where a˜f and g˜l are coefficients of the two dimension function optimally approximating to the actual parameter values. Please note that other surface functions can also be used for simulating variance of the gamma parameter and the gain parameter on the two dimension plane as long as differences between estimated parameter values and the actual parameter values are less than a predetermined threshold. Consequently, both of the gamma parameter and the gain parameter of the red primary color can be accurately estimated when the blue and green primary colors are under different input conditions. 
     In other words, after substituting the inputs of the three primary colors into the first surface function and the second surface function, the present invention can calculate the gain parameter and the gamma parameter of each primary color at this time for further characterization of the non-linear EOTF or the TRC of each primary color (Step  130 ), as shown in  FIG. 2 . 
     Due to different displays with different features, the same image may be seen in different colors. Thus, the non-linear EOTF of each primary color can further be linearized through the inverse transformation of the channel-dependent GOG model to obtain color values independent of the display devices. The inverse transformation of the channel-dependent GOG model is given by: 
     
       
         
           
             
               
                 
                   
                     d 
                     
                       R 
                       , 
                       output 
                     
                   
                   = 
                   
                     
                       ( 
                       
                         
                           
                             2 
                             N 
                           
                           - 
                           1 
                         
                         
                           
                             k 
                             
                               g 
                               , 
                               R 
                             
                           
                            
                           
                             ( 
                             
                               
                                 d 
                                 G 
                               
                               , 
                               
                                 d 
                                 B 
                               
                             
                             ) 
                           
                         
                       
                       ) 
                     
                      
                     
                       [ 
                       
                         
                           
                             ( 
                             
                               
                                 d 
                                 R 
                               
                               
                                 
                                   2 
                                   N 
                                 
                                 - 
                                 1 
                               
                             
                             ) 
                           
                           
                             1 
                             
                               
                                 γ 
                                 R 
                               
                                
                               
                                 ( 
                                 
                                   
                                     d 
                                     G 
                                   
                                   , 
                                   
                                     d 
                                     B 
                                   
                                 
                                 ) 
                               
                             
                           
                         
                         - 
                         
                           ( 
                           
                             1 
                             - 
                             
                               
                                 k 
                                 
                                   g 
                                   , 
                                   R 
                                 
                               
                                
                               
                                 ( 
                                 
                                   
                                     d 
                                     G 
                                   
                                   , 
                                   
                                     d 
                                     B 
                                   
                                 
                                 ) 
                               
                             
                           
                           ) 
                         
                       
                       ] 
                     
                   
                 
               
               
                 
                   ( 
                   6 
                   ) 
                 
               
             
             
               
                 
                   
                     d 
                     
                       G 
                       , 
                       output 
                     
                   
                   = 
                   
                     
                       ( 
                       
                         
                           
                             2 
                             N 
                           
                           - 
                           1 
                         
                         
                           
                             k 
                             
                               g 
                               , 
                               G 
                             
                           
                            
                           
                             ( 
                             
                               
                                 d 
                                 R 
                               
                               , 
                               
                                 d 
                                 B 
                               
                             
                             ) 
                           
                         
                       
                       ) 
                     
                      
                     
                       [ 
                       
                         
                           
                             ( 
                             
                               
                                 d 
                                 G 
                               
                               
                                 
                                   2 
                                   N 
                                 
                                 - 
                                 1 
                               
                             
                             ) 
                           
                           
                             1 
                             
                               
                                 γ 
                                 G 
                               
                                
                               
                                 ( 
                                 
                                   
                                     d 
                                     R 
                                   
                                   , 
                                   
                                     d 
                                     B 
                                   
                                 
                                 ) 
                               
                             
                           
                         
                         - 
                         
                           ( 
                           
                             1 
                             - 
                             
                               
                                 k 
                                 
                                   g 
                                   , 
                                   G 
                                 
                               
                                
                               
                                 ( 
                                 
                                   
                                     d 
                                     R 
                                   
                                   , 
                                   
                                     d 
                                     B 
                                   
                                 
                                 ) 
                               
                             
                           
                           ) 
                         
                       
                       ] 
                     
                   
                 
               
               
                 
                   ( 
                   7 
                   ) 
                 
               
             
             
               
                 
                   
                     d 
                     
                       B 
                       , 
                       output 
                     
                   
                   = 
                   
                     
                       ( 
                       
                         
                           
                             2 
                             N 
                           
                           - 
                           1 
                         
                         
                           
                             k 
                             
                               g 
                               , 
                               B 
                             
                           
                            
                           
                             ( 
                             
                               
                                 d 
                                 R 
                               
                               , 
                               
                                 d 
                                 G 
                               
                             
                             ) 
                           
                         
                       
                       ) 
                     
                      
                     
                       [ 
                       
                         
                           
                             ( 
                             
                               
                                 d 
                                 B 
                               
                               
                                 
                                   2 
                                   N 
                                 
                                 - 
                                 1 
                               
                             
                             ) 
                           
                           
                             1 
                             
                               
                                 γ 
                                 B 
                               
                                
                               
                                 ( 
                                 
                                   
                                     d 
                                     R 
                                   
                                   , 
                                   
                                     d 
                                     G 
                                   
                                 
                                 ) 
                               
                             
                           
                         
                         - 
                         
                           ( 
                           
                             1 
                             - 
                             
                               
                                 k 
                                 
                                   g 
                                   , 
                                   B 
                                 
                               
                                
                               
                                 ( 
                                 
                                   
                                     d 
                                     R 
                                   
                                   , 
                                   
                                     d 
                                     G 
                                   
                                 
                                 ) 
                               
                             
                           
                           ) 
                         
                       
                       ] 
                     
                   
                 
               
               
                 
                   ( 
                   8 
                   ) 
                 
               
             
           
         
       
     
     Where d R,output , d G,output , d B,output  denote outputs, individually, generated by inversely transforming the channel-dependent GOG model with the inputs of each primary color, which are irrelevant to the colorimetry of the LCD. 
     Since the linearized EOTF is irrelevant to the colorimetry of the LCD (i.e. the crosstalk existing among the three primary colors has been eliminated), the linear EOTF can then be converted to a target EOTF according to the target colorimetry, as shown in  FIG. 2 , so as to get expected color display on the LCD. That is, for the color correction, the present invention can further substitute the above outputs of each primary color into the target EOTF to obtain corrected values of each primary color. This can be expressed by: 
     
       
         
           
             
               
                 
                   
                     d 
                     R 
                     ′ 
                   
                   = 
                   
                     
                       
                         ( 
                         
                           
                             2 
                             N 
                           
                           - 
                           1 
                         
                         ) 
                       
                        
                       
                         [ 
                         
                           
                             
                               k 
                               
                                 gT 
                                 , 
                                 R 
                               
                             
                              
                             
                               ( 
                               
                                 
                                   d 
                                   
                                     R 
                                     , 
                                     output 
                                   
                                 
                                 
                                   
                                     2 
                                     N 
                                   
                                   - 
                                   1 
                                 
                               
                               ) 
                             
                           
                           + 
                           
                             ( 
                             
                               1 
                               - 
                               
                                 k 
                                 
                                   gT 
                                   , 
                                   R 
                                 
                               
                             
                             ) 
                           
                         
                         ] 
                       
                     
                     
                       γ 
                       
                         T 
                         , 
                         R 
                       
                     
                   
                 
               
               
                 
                   ( 
                   9 
                   ) 
                 
               
             
             
               
                 
                   
                     d 
                     G 
                     ′ 
                   
                   = 
                   
                     
                       
                         ( 
                         
                           
                             2 
                             N 
                           
                           - 
                           1 
                         
                         ) 
                       
                        
                       
                         [ 
                         
                           
                             
                               k 
                               
                                 gT 
                                 , 
                                 G 
                               
                             
                              
                             
                               ( 
                               
                                 
                                   d 
                                   
                                     G 
                                     , 
                                     output 
                                   
                                 
                                 
                                   
                                     2 
                                     N 
                                   
                                   - 
                                   1 
                                 
                               
                               ) 
                             
                           
                           + 
                           
                             ( 
                             
                               1 
                               - 
                               
                                 k 
                                 
                                   gT 
                                   , 
                                   G 
                                 
                               
                             
                             ) 
                           
                         
                         ] 
                       
                     
                     
                       γ 
                       
                         T 
                         , 
                         G 
                       
                     
                   
                 
               
               
                 
                   ( 
                   10 
                   ) 
                 
               
             
             
               
                 
                   
                     d 
                     B 
                     ′ 
                   
                   = 
                   
                     
                       
                         ( 
                         
                           
                             2 
                             N 
                           
                           - 
                           1 
                         
                         ) 
                       
                        
                       
                         [ 
                         
                           
                             
                               k 
                               
                                 gT 
                                 , 
                                 B 
                               
                             
                              
                             
                               ( 
                               
                                 
                                   d 
                                   
                                     B 
                                     , 
                                     output 
                                   
                                 
                                 
                                   
                                     2 
                                     N 
                                   
                                   - 
                                   1 
                                 
                               
                               ) 
                             
                           
                           + 
                           
                             ( 
                             
                               1 
                               - 
                               
                                 k 
                                 
                                   gT 
                                   , 
                                   B 
                                 
                               
                             
                             ) 
                           
                         
                         ] 
                       
                     
                     
                       γ 
                       
                         T 
                         , 
                         B 
                       
                     
                   
                 
               
               
                 
                   ( 
                   11 
                   ) 
                 
               
             
           
         
       
     
     Where k gT,R , k gT,R , k gT,R  denote target gain parameters of each primary color, respectively; γ T,R , γ T,G , γ T,B  denote target gamma parameters of each primary color, respectively; and d R ′, d G ′, d B ′ denote the corrected values of each primary color, respectively. 
     If the colormetry of the LCD is intended to meet the sRGB standard, the target gain parameter and the target gamma parameter are set to 1.0 and 2.2. Then, the aforementioned equations can be rewritten by: 
     
       
         
           
             
               
                 
                   
                     d 
                     R 
                     ′ 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           2 
                           N 
                         
                         - 
                         1 
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           
                             d 
                             
                               R 
                               , 
                               output 
                             
                           
                           
                             
                               2 
                               N 
                             
                             - 
                             1 
                           
                         
                         ) 
                       
                       2.2 
                     
                   
                 
               
               
                 
                   ( 
                   12 
                   ) 
                 
               
             
             
               
                 
                   
                     d 
                     G 
                     ′ 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           2 
                           N 
                         
                         - 
                         1 
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           
                             d 
                             
                               G 
                               , 
                               output 
                             
                           
                           
                             
                               2 
                               N 
                             
                             - 
                             1 
                           
                         
                         ) 
                       
                       2.2 
                     
                   
                 
               
               
                 
                   ( 
                   13 
                   ) 
                 
               
             
             
               
                 
                   
                     d 
                     B 
                     ′ 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           2 
                           N 
                         
                         - 
                         1 
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           
                             d 
                             
                               B 
                               , 
                               output 
                             
                           
                           
                             
                               2 
                               N 
                             
                             - 
                             1 
                           
                         
                         ) 
                       
                       2.2 
                     
                   
                 
               
               
                 
                   ( 
                   14 
                   ) 
                 
               
             
           
         
       
     
     In summary, the non-linear EOTF of the LCD can be accurately estimated by the channel-dependent GOG model when there exists crosstalk among the color channels, so that the non-linear EOTF can be converted to the apparatus-independent linear EOTF and further to the target EOTF for obtaining the expected performance on color display. 
     Please refer to  FIG. 3 , which is a schematic diagram of a color correction device  30  for an LCD according to an embodiment of the present invention. The color correction device  30  is used for realizing the color correction process  10 , and includes a quantization unit  31 , an estimation unit  32  and a correction unit  33 . The quantization unit  31  includes quantizers Q 1 ˜Q 3  for quantizing inputs of the three primary colors to adjust down the resolution for reduction of memory demand. The estimation unit  32  is coupled to the quantization unit  31 , and is used for performing look-up table operations on quantization results of the inputs of each primary color to generate the gain parameter and the gamma parameter of each primary color for estimation of a non-linear EOTF of each primary color. The correction unit  33  is coupled to input terminals of the quantization unit  31  and the estimation unit  32 , and is used for performing color correction on the inputs of the three primary colors according to the gain parameter and the gamma parameter outputted from the estimation unit  32  to generate corrected values of the three primary colors meeting a target colorimetry. 
     The estimation unit  32  further includes gamma look-up tables Gamma_LUT 1 ˜Gamma_LUT 3  and gain look-up tables Gain_LUT 1 ˜Gain_LUT 3 . The gamma look-up tables Gamma_LUT 1 ˜Gamma_LUT 3  are used for storing all possible values of the gamma parameter of each primary color, generated from all possible results of quantizing the other two primary colors. The gain look-up tables Gain_LUT 1 ˜Gain_LUT 3  are used for storing all possible values of the gain parameter of each primary color, generated from all possible results of quantizing the other two primary colors. 
     That is to say, the present invention calculates all possible values of the gain and the gamma parameters in advance by the aforementioned two dimension surface function and stores the quantization results into the gamma look-up tables Gamma_LUT 1 ˜Gamma_LUT 3  and the gain look-up tables Gain_LUT 1 ˜Gain_LUT 3 . Taking the red primary color for example, the contents, stored in the gamma look-up table Gamma_LUT 1 , include values of the gamma parameter corresponding to all possible results of quantizing inputs of the blue and green primary color, which is expressed by: 
       γ R ( {circumflex over (d)}   G   ,{circumflex over (d)}   B )= a+b·{circumflex over (d)}   G   +c·{circumflex over (d)}   B   +d·{circumflex over (d)}   G   2   +e·{circumflex over (d)}   B   2   +f·{circumflex over (d)}   G   ·{circumflex over (d)}   B   (15) 
     Where d{circumflex over ( G )}=Q −1 (Q(d G )) denotes the quantization results of d G ; and Q(d G ) denotes the quantization index of d G . Likewise, the contents, stored in the gain look-up table, include values of the gamma parameter corresponding to all possible results of quantizing inputs of the blue and green primary color, which is expressed by: 
         k   g,R ( {circumflex over (d)}   G   ,{circumflex over (d)}   B )= g+h·{circumflex over (d)}   G   +i·{circumflex over (d)}   B   +j·{circumflex over (d)}   G   2   +k·{circumflex over (d)}   B   2   +l·{circumflex over (d)}   G   ·{circumflex over (d)}   B   (16) 
     On the other hand, the correction unit  33  further includes correction look-up tables Correction_LUT 1 ˜Correction_LUT 3  for storing all calculation results of the color correction for all possible inputs of the three primary colors. Taking the red primary color for example, the correction look-up table Correction_LUT 1  includes all calculation results, provided by linearizing the TRC and modifying the TRC to the target TRC with parameters such as quantization parameters ({circumflex over (γ)} R ({circumflex over (d)} G ,{circumflex over (d)} B ),{circumflex over (k)} g,R ({circumflex over (d)} G ,{circumflex over (d)} B )) outputted from the gamma look-up table Gamma_LUT 1  and the gain look-up table Gain_LUT 1 , all possible inputs of the red primary color d R  and all possible values of the target parameters (k gT,R , γ T,R ), which can be expressed by combining eq. (6) and (9): 
     
       
         
           
             
               
                 
                   
                     d 
                     R 
                     ′ 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           2 
                           N 
                         
                         - 
                         1 
                       
                       ) 
                     
                     × 
                     
                       
                         [ 
                         
                           
                             
                               
                                 k 
                                 
                                   gT 
                                   , 
                                   R 
                                 
                               
                               
                                 
                                   
                                     k 
                                     ^ 
                                   
                                   
                                     g 
                                     , 
                                     R 
                                   
                                 
                                  
                                 
                                   ( 
                                   
                                     
                                       
                                         d 
                                         ^ 
                                       
                                       G 
                                     
                                     , 
                                     
                                       
                                         d 
                                         ^ 
                                       
                                       B 
                                     
                                   
                                   ) 
                                 
                               
                             
                              
                             
                               ( 
                               
                                 
                                   
                                     ( 
                                     
                                       
                                         d 
                                         R 
                                       
                                       
                                         
                                           2 
                                           N 
                                         
                                         - 
                                         1 
                                       
                                     
                                     ) 
                                   
                                   
                                     1 
                                     
                                       
                                         
                                           γ 
                                           ^ 
                                         
                                         R 
                                       
                                        
                                       
                                         ( 
                                         
                                           
                                             
                                               d 
                                               ^ 
                                             
                                             G 
                                           
                                           , 
                                           
                                             
                                               d 
                                               ^ 
                                             
                                             B 
                                           
                                         
                                         ) 
                                       
                                     
                                   
                                 
                                 - 
                                 1 
                                 + 
                                 
                                   
                                     
                                       k 
                                       ^ 
                                     
                                     
                                       g 
                                       , 
                                       R 
                                     
                                   
                                    
                                   
                                     ( 
                                     
                                       
                                         
                                           d 
                                           ^ 
                                         
                                         G 
                                       
                                       , 
                                       
                                         
                                           d 
                                           ^ 
                                         
                                         B 
                                       
                                     
                                     ) 
                                   
                                 
                               
                               ) 
                             
                           
                           + 
                           1 
                           - 
                           
                             k 
                             
                               gT 
                               , 
                               R 
                             
                           
                         
                         ] 
                       
                       
                         γ 
                         
                           T 
                           , 
                           B 
                         
                       
                     
                   
                 
               
               
                 
                     
                 
               
             
           
         
       
     
     For example, if each primary color is quantized to 16 steps (n c =4), each primary color has 256 possible sets of the gain parameter and the gamma parameter which can be calculated in advance by the aforementioned two dimension surface function. Then, calculation results are quantized to n γ  bits and n k  bits, respectively and stored in the gamma look-up tables and the gain look-up tables. In this situation, if the gamma and the gain parameters from the gamma and gain look-up tables are also quantized to 16 steps (n γ =4,n k =4), assuming there are four possible sets of the target gamma and gain parameters (n γT =2,n kT =2), 1 million bytes of memory capacity will be required for the correction look-up table. However, 256 bytes memory is enough for both the gamma look-up table and the gain look-up table when n c =4. 
     If there is only one set of the target gamma and gain parameters, for example, one set meeting the sRGB standard (i.e. the target gain parameter k gT  and the target gamma parameter γ T  of each primary color are set to 1.0 and 2.2, respectively), the color correction device  30  of  FIG. 3  can be simplified as a color correction device  40  shown in  FIG. 4  according to an embodiment of the present invention. In this situation, taking the red primary color for example, the correction look-up table Correction_LUT 1  includes all calculation results, provided by linearizing the TRC and modifying the TRC to the target TRC with parameters such as quantization parameters ({circumflex over (γ)}({circumflex over (d)} G ,{circumflex over (d)} B ), {circumflex over (k)} g,R ({circumflex over (d)} G ,{circumflex over (d)} B )) outputted from the gamma look-up table Gamma_LUT 1  and the gain look-up table Gain_LUT 1  and all possible inputs of the red primary color d R , which can be expressed by combining eq. (6) and (12): 
     
       
         
           
             
               
                 
                   
                     d 
                     R 
                     ′ 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           2 
                           N 
                         
                         - 
                         1 
                       
                       ) 
                     
                     × 
                     
                       
                         [ 
                         
                           
                             1 
                             
                               
                                 
                                   k 
                                   ^ 
                                 
                                 
                                   g 
                                   , 
                                   R 
                                 
                               
                                
                               
                                 ( 
                                 
                                   
                                     
                                       d 
                                       ^ 
                                     
                                     G 
                                   
                                   , 
                                   
                                     
                                       d 
                                       ^ 
                                     
                                     B 
                                   
                                 
                                 ) 
                               
                             
                           
                            
                           
                             ( 
                             
                               
                                 
                                   ( 
                                   
                                     
                                       d 
                                       R 
                                     
                                     
                                       
                                         2 
                                         N 
                                       
                                       - 
                                       1 
                                     
                                   
                                   ) 
                                 
                                 
                                   1 
                                   
                                     
                                       
                                         γ 
                                         ^ 
                                       
                                       R 
                                     
                                      
                                     
                                       ( 
                                       
                                         
                                           
                                             d 
                                             ^ 
                                           
                                           G 
                                         
                                         , 
                                         
                                           
                                             d 
                                             ^ 
                                           
                                           B 
                                         
                                       
                                       ) 
                                     
                                   
                                 
                               
                               - 
                               1 
                               + 
                               
                                 
                                   
                                     k 
                                     ^ 
                                   
                                   
                                     g 
                                     , 
                                     R 
                                   
                                 
                                  
                                 
                                   ( 
                                   
                                     
                                       
                                         d 
                                         ^ 
                                       
                                       G 
                                     
                                     , 
                                     
                                       
                                         d 
                                         ^ 
                                       
                                       B 
                                     
                                   
                                   ) 
                                 
                               
                             
                             ) 
                           
                         
                         ] 
                       
                       2.2 
                     
                   
                 
               
               
                 
                     
                 
               
             
           
         
       
     
     In this situation, if the gamma and gain parameters from the gamma and gain look-up tables are quantized to 16 steps (n γ =4,n k =4), only 64 bytes memory is required for the correction look-up table. 
     Moreover, if the target gamma parameter and the target gain parameter of each primary color are the same and data access time of the LUT memory is less than one-third of each pixel input cycle, the color correction device  40  shown in  FIG. 4  can further be modified as a two-stage pipeline structure as shown in  FIG. 5  according to an embodiment of the present invention. In this case, required memory capacity is only one-third of the embodiment of  FIG. 4 . 
     To sum up, the present invention utilizes the gamma and gain parameters of the GOG model to estimate and model the channel interactions or crosstalk among three primary colors, so that accurate results of the electro-optical conversion can be obtained. Therefore, the color management can be undertaken by using apparatus-independent color values to achieve the expected color display. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.