Patent ID: 7312900

Claim:
A method of descreening a screened image generated from an original image, comprising the steps of: (a) detecting the position of each halftone dot forming said screened image; (b) detecting from said screened image an arrangement of picture-originated pixels in a gradation area of an image from which said screened image is generated; and (c) generating layout data having multi-level gradation from said screened image, said step (c) including the steps of (c-1) bringing predetermined threshold values into correspondence with individual recorder grids constituting each halftone cell determined in said step (a), and (c-2) setting gradation levels in the gradation area for descreened layout data, said gradation levels in the gradation area being set based on a correspondence between said predetermined threshold values and whether or not the recorder grids present in the position of each of said picture-originated pixels contribute to halftone dot formation.