Descreening and detail enhancement for scanned documents

摘要

A method and apparatus for processing a digital image to reduce moiré artifacts while preserving or improving detailed features. Pixels may be categorized as halftone and/or detail pixels and filtered accordingly. A pixel may be categorized as halftone if intensity values over a first window laid over that pixel vary by less than a first predetermined threshold. A descreen filter may be applied to halftone pixels. The remaining pixels that are not categorized as halftone pixels are analyzed as potential text elements. A PTE may be categorized as a detail pixel if intensity values over a second window laid over that pixel vary by more than a second predetermined threshold. The second window may be smaller than the first window. A sharpening filter may be applied to detail pixels.