In a method for processing pixel values of an image in a first representation to a second representation having a yellow-blue axis, a red-green axis, and a luminance axis, the pixel values are converted from the first representation to the second representation by converting the pixel values to a more opponent color encoding using a logical operator to compute a yellowness-blueness value of each of the pixel values and using scaled multiplications to compute a redness-greenness value of each of the pixel values in the second representation. In addition, the converted pixel values are outputted.