1. A method for classifying a pixel in a digital image, said method comprising: a) receiving a first classification map, wherein said first classification map identifies candidate pixels belonging to a first class in a digital image; b) receiving a first pixel location in said first classification map, wherein said first pixel location in said first classification map corresponds to a first pixel location in said digital image; c) calculating a first color estimate corresponding to said first pixel location in said digital image, wherein said first color estimate is a summary of the colors of a plurality of pixels belonging to said first class located in a region proximate to said first pixel location in said digital image; d) calculating a first color difference from said first color estimate and the color of the pixel in said digital image at said first pixel location in said digital image; and e) refining said first classification map at said first pixel location in said first classification map based on said first color difference.