1. A method of processing a digital image comprising a plurality of pixels, the method comprising: (A) deriving a plurality of input channels for said digital image, each input channel in the plurality of input channels representing a visual attribute classification in a plurality of visual attribute classifications, each respective input channel in the plurality of input channels comprising all or a portion of the pixels in the plurality of pixels and, for each respective pixel in the respective input channel, a weight for the respective pixel that represents a similarity between an attribute of the respective pixel and the visual attribute classification of the respective channel; (B) determining, for each respective input channel in the plurality of input channels, one or more heuristic scores for the respective input channel by evaluating a distribution of weighted pixels in the respective input channel against one or more heuristic metrics; (C) forming a plurality of categorical estimates, wherein each categorical estimate in the plurality of categorical estimates comprises a selection of one or more input channels in the plurality of input channels based on the one or more heuristic scores determined for each of the one or more input channels in the determining step (B); (D) merging the plurality of categorical estimates to create a final channel estimate, wherein the final channel estimate categorizes each pixel in the plurality of pixels in the digital image based on a pixel strength of a corresponding pixel in each categorical estimate in the plurality of categorical estimates that is merged to create the final channel estimate; and (E) outputting the final channel estimate or one or more of the plurality of categorical estimates to a display a computer readable memory, or a computer readable medium.