System and method for image demosaicing

Abstract

A method of adaptive demosaicing of a mosaiced image includes receiving the mosaiced image having a mosaic pattern with a first color, a second color, and a third color, obtaining a noise level index for the mosaiced image, determining whether the noise level index is greater than a threshold value, and, in response to the noise level index being greater than the threshold value, performing an adaptive demosaicing on the mosaiced image to generate an adaptively demosaiced image. The adaptive demosaicing includes interpolating values of a portion of unknown pixels of the first color in a horizontal or vertical direction, interpolating values of a portion of unknown pixels of the second color in a horizontal or vertical direction, and interpolating values of a portion of unknown pixels of the third color in a horizontal or vertical direction.

What is claimed is: 
     
         1 . A method of adaptive demosaicing of a mosaiced image comprising:
 receiving the mosaiced image having a mosaic pattern with a first color, a second color, and a third color;   obtaining a noise level index for the mosaiced image;   determining whether the noise level index is greater than a threshold value; and   in response to the noise level index being greater than the threshold value, performing an adaptive demosaicing on the mosaiced image to generate an adaptively demosaiced image, the adaptive demosaicing including:
 interpolating values of a portion of unknown pixels of the first color in a horizontal or vertical direction; 
 interpolating values of a portion of unknown pixels of the second color in a horizontal or vertical direction; and 
 interpolating values of a portion of unknown pixels of the third color in a horizontal or vertical direction. 
   
     
     
         2 . The method of  claim 1 , wherein interpolating the values of the portion of unknown pixels of the second color and interpolating the values of the portion of unknown pixels of the third color are based on interpolating the values of the portion of unknown pixels of the first color. 
     
     
         3 . The method of  claim 1 , wherein interpolating the values of the portion of unknown pixels of the second color and interpolating the values of the portion of unknown pixels of the third color occurs after interpolating the values of the portion of unknown pixels of the first color. 
     
     
         4 . The method of  claim 1 , wherein the mosaiced image includes red, green, and blue pixels in a Bayer pattern. 
     
     
         5 . The method of  claim 1 , wherein the first color is green, the second color is red, and the third color is blue. 
     
     
         6 . The method of  claim 1 , wherein horizontal or vertical interpolation is selected based on known color data of a pixel location. 
     
     
         7 . The method of  claim 6 , wherein the horizontal or vertical interpolation is selected based on a respective vertical and horizontal nearest neighbor pixel comparison. 
     
     
         8 . The method of  claim 6 , wherein selecting one of the horizontal interpolation and the vertical interpolation includes calculating a horizontal gradient and calculating a vertical gradient. 
     
     
         9 . The method of  claim 1 , wherein one of a horizontal interpolation and a vertical interpolation is selected for each given pixel location and interpolation of the unknown pixels of the first, second, and third color is performed for that pixel location using the selected interpolation direction. 
     
     
         10 . The method of  claim 9 , wherein selection of the horizontal interpolation or the vertical interpolation for a given pixel location is based on identifying an interpolation direction at that pixel location that has the least change among similar neighboring pixel color values. 
     
     
         11 . The method of  claim 1 , wherein the adaptive demosaicing further includes applying a median filter to the demosaiced image. 
     
     
         12 . The method of  claim 1 , further comprising displaying the demosaiced image on a display. 
     
     
         13 . The method of  claim 1 , wherein receiving the mosaiced image includes receiving the mosaiced image from an image sensor array. 
     
     
         14 . The method of  claim 1 , further comprising generating the mosaiced image based on sensed light that passes through a lens and a mosaicing filter. 
     
     
         15 . The method of  claim 1 , wherein interpolating the values of the portion of unknown pixels of the first color includes interpolating a value of an unknown pixel of the first color based on a low-pass filter, a known value of one of the second color and the third color at the pixel, and known values of the first color at neighboring pixels. 
     
     
         16 . The method of  claim 15 , further comprising obtaining a zero phase finite impulse response filter as the low-pass filter by solving an optimization problem. 
     
     
         17 . A method of adaptive demosaicing of a mosaiced image comprising:
 receiving the mosaiced image having a mosaic pattern with at least one color;   obtaining a noise level index for the mosaiced image;   determining whether the noise level index is greater than a threshold value;   in response to the noise level index being not greater than the threshold value, performing a bilinear demosaicing on the mosaiced image to generate a bilinearly demosaiced image; and   in response to the noise level index being greater than the threshold value, performing an adaptive demosaicing on the mosaiced image to generate an adaptively demosaiced image, the adaptive demosaicing including interpolating values of a portion of unknown pixels of the at least one color in a horizontal or vertical direction.   
     
     
         18 . A method of demosaicing a mosaiced image comprising:
 receiving the mosaiced image having a mosaic pattern with a first, second and third color;   selecting, from a plurality of demosaicing methods, a demosaicing method to be performed on the mosaiced image based on a comparison between a noise level index of the mosaiced image and at least one threshold value; and   demosaicing the mosaiced image using the selected demosaicing method to generate a demosaiced image.   
     
     
         19 . The method of  claim 18 , wherein the mosaiced image comprises red, green and blue pixels in a Bayer pattern. 
     
     
         20 . The method of  claim 18 , further comprising applying a median filter to the demosaiced image.