公开(公告)号：JP2002312784A

公开(公告)日：2002-10-25

申请号：JP2002047374

申请日：2002-02-25

Applicant: IBM

Inventor： KUO CHUNGKUI ,  RAO RAVISHANKAR ,  THOMPSON GERHARD R

IPC: G06T5/20 ,  G06T5/00 ,  H04N1/40 ,  H04N1/409

Abstract: PROBLEM TO BE SOLVED: To provide an improved system and method for substantially de- screening any type of color image. SOLUTION: A color image is de-screened by using two-stage sigma filters. The two-stage sigma filters can be used for converting a color halftone image into a continuous tone image regardless of used screening process. The two-stage sigma filters are constituted by using an O (N) algorithm for executing smoothing, and for simultaneously preserving edge information in red/green/ blur(RGB) color spaces. This system and method is able to fulfill double standards for completely removing halftone screen while preserving edge information so that higher performance can be expected than a conventional method using, for example, Gauss blur. When this system and method is combined with a halftone segmentation technology, a complete document processing algorithm for a variable density and color document is generated.