Methods and apparatus for image adjustment for displays having 2d and 3d display modes

Abstract

Embodiments of the invention relate to a display operable in 2D and 3D display modes. Methods and apparatus are provided for adjusting the colors and brightness of the image data and/or intensity of the display backlight based on the current display mode and/or color-grading of the image data. For example, when switching to a 3D display mode a color mapping may be performed on left and right eye image data to increase color saturation in particular regions, and/or the backlight intensity may be increased in particular regions to compensate for lower light levels in 3D display mode.

What is claimed is: 
     
         1 . A method for operating a display having a 2D display mode and a 3D display mode, the method comprising:
 displaying first image data in the 2D display mode; and,   switching to the 3D display mode wherein switching to the 3D display mode comprises:
 displaying left and right image data for viewing respectively by viewers' left and right eyes; and 
 performing a color mapping on the left and right image data prior to displaying the left and right image data. 
   
     
     
         2 . A method according to  claim 1  wherein performing the color mapping comprises increasing color saturation of the left and right image data. 
     
     
         3 . A method according to  claim 1  or  2  wherein performing the color mapping comprises adjusting colors in the left and right image data to adjust for spectral shifts introduced by viewing eyeglasses used for viewing the left and right image data. 
     
     
         4 . A method according to any one of  claim 3  wherein performing the color mapping comprises transforming the left and right image data to an RGB color space in which primaries are display primaries as modified by the viewing eyeglasses. 
     
     
         5 . A method according to  claim 4  wherein performing the color mapping comprises, for the left and right image data in each of the RGB channels, determining an output value according to a corresponding mapping function. 
     
     
         6 . A method according to  claim 5  wherein the mapping functions are non-linear functions. 
     
     
         7 . A method according to  claim 6  wherein the mapping functions are sigmoid functions. 
     
     
         8 . A method according to  claim 7  wherein each of the sigmoid functions have the equation: 
       
         
           
             
               
                 L 
                 out 
               
               = 
               
                 
                   
                     c 
                     1 
                   
                   + 
                   
                     
                       c 
                       2 
                     
                      
                     
                       L 
                       in 
                       n 
                     
                   
                 
                 
                   1 
                   + 
                   
                     
                       c 
                       3 
                     
                      
                     
                       L 
                       in 
                       n 
                     
                   
                 
               
             
           
         
       
       where c 1 , c 2 , and c 3  are parameters based on one or more of the capabilities of the display and the characteristics of the image data, L in  is the input value, and L out  is the output value. 
     
     
         9 . A method according to any one of  claims 1  to  8  comprising receiving metadata indicating that the first image data has approved colors and, based on the metadata, selecting the color mapping. 
     
     
         10 . A method according to any one of  claims 1  to  9  comprising receiving metadata indicating that the left and right image data has approved colors and, based on the metadata, disabling the color mapping. 
     
     
         11 . A method according to any one of  claims 1  to  10  wherein the display comprises a backlight illuminating a spatial light modulator and switching to the 3D display mode comprises increasing an intensity of the backlight. 
     
     
         12 . A method according to  claim 11  wherein the backlight comprises a plurality of individually controllable light-emitting elements, and displaying the first image data comprises determining drive values for the individually controllable light-emitting elements according to a first algorithm, and displaying the left and right image data comprises determining drive values for the individually controllable light-emitting elements according to a second algorithm, wherein, for the same input, the second algorithm provides greater light output than the first algorithm. 
     
     
         13 . A method according to  claim 11  or  12  wherein switching to the 3D display mode comprises shifting a white point of the backlight to compensate for color shifts introduced by the viewing eyeglasses. 
     
     
         14 . A display comprising:
 an input for receiving image data;   a color mapping unit connected to perform color mapping on received image data;   display driver circuitry connected to display images according to image data processed by the color mapping unit; and   a controller, wherein the controller is configured to control switching between a 2D display mode and a 3D display mode, wherein in controlling switching the controller is configured to:
 change color mapping parameters for the color mapping unit; and 
 switch from displaying first image data to displaying left and right image data for viewing respectively by a viewer's left and right eyes. 
   
     
     
         15 . A display according to  claim 14 , wherein the color mapping unit is configured to increase color saturation of the left and right image data. 
     
     
         16 . A display according to  claim 14  or  15  wherein the color mapping unit is configured to adjust colors in the left and right image data based at least in part on the color mapping parameters. 
     
     
         17 . A display according to  claim 16  wherein the color mapping unit is configured to transform the left and right image data to an RGB color space prior to adjusting colors in the left and right image data. 
     
     
         18 . A display according to  claim 17  wherein, for the left and right image data in each of the RGB channels, the color mapping unit is configured to determine an output value according to a corresponding mapping function. 
     
     
         19 . A display according to  claim 18  wherein, in determining an output value according to a corresponding mapping function, the color mapping unit is configured to apply a non-linear function as the mapping function. 
     
     
         20 . A display according to  claim 19  wherein, in determining an output value according to a corresponding mapping function, the color mapping unit is configured to apply a sigmoid function as the mapping function. 
     
     
         21 . A display according to any one of  claims 14  to  20 , the display comprising a backlight illuminating a spatial light modulator, wherein in controlling switching the controller is configured to generate a backlight control signal to adjust an intensity of the backlight according to whether the display is in the 2D display mode or the 3D display mode. 
     
     
         22 . A display according to  claim 21 , wherein the backlight comprises a plurality of individually controllable light-emitting elements, and generating a backlight control signal for the 2D display mode comprises determining drive values for the individually controllable light-emitting elements according to a first algorithm, and generating a backlight control signal for the 3D display mode comprises determining drive values for the individually controllable light-emitting elements according to a second algorithm, wherein, for the same input, the second algorithm provides greater light output than the first algorithm. 
     
     
         23 . A display according to  claim 21  or  22  wherein in controlling switching the controller is configured to generate a backlight control signal to adjust a white point of the backlight according to whether the display is in the 2D display mode or the 3D display mode. 
     
     
         24 . An image processor for processing input image data for a display capable of switching between a 2D display mode and a 3D display mode, the image processor comprising:
 a transform unit configured to adjust colors in the image data based at least in part on whether the display is in the 2D display mode or the 3D display mode; and   a mapping unit configured to map input values in the image data to output values based on one or more of the capabilities of the display and the characteristics of the image data.   
     
     
         25 . An image processor according to  claim 24 , wherein the input image data comprises left and right image data and when the display is in the 3D display mode, the transform unit is configured to increase color saturation in the left and right image data. 
     
     
         26 . An image processor according to  claim 25 , wherein when the display is in the 3D display mode, the transform unit is configured to adjust colors in the left and right image data to adjust for spectral shifts introduced by viewing eyeglasses used for viewing left and right image data. 
     
     
         27 . An image processor according to  claim 26 , wherein the transform unit is configured to transform the left and right image data to an RGB color space in which primaries are display primaries as modified by the viewing eyeglasses. 
     
     
         28 . An image processor according to  claim 27 , wherein for the left and right image data in each of the RGB channels, the mapping unit is configured to determine an output value according to a corresponding mapping function. 
     
     
         29 . An image processor according to  claim 28  wherein, in determining an output value according to a corresponding mapping function, the mapping unit is configured to apply a non-linear function as the mapping function. 
     
     
         30 . An image processor according to  claim 29  wherein, in determining an output value according to a corresponding mapping function, the color mapping unit is configured to apply a sigmoid function as the mapping function.