1. A method of labeling digital image data associated with a compound document in a single pass, comprising: receiving image data; distributing the image data to multiple branches, wherein at least two of the multiple branches include filters configured to blur the image data at different resolutions; detecting edges of the blurred image data at the different resolutions; detecting edges of unfiltered image data; combining data output from the at least two of the multiple branches; and determining whether the combined data is to be labeled as a low resolution halftone.