Method and apparatus for generating a half tone halftone image of a compressed image

摘要

PROBLEM TO BE SOLVED: To provide a method for forming a halftone image from an image, compressed by a regional transformation.;SOLUTION: In the method, a halftone image is formed from a compressed image by using transformation, which gives the coefficients for providing a regional factor, and an encoding operation, in which the coefficients are encoded. The method includes a decoding operation S₂₀ for obtaining a decoded coefficient and a thresholding operation S₂₆ for obtaining a bitmap. In the thresholding operation S₂₆, only the decoded coefficient for verifying a selection standard is taken into consideration. A device for forming the halftone image compressed by the regional transformation includes a decoder and a halftone-producing module. In the device, a memory for storing a digital compressed image and a processing unit for processing the digital data are provided. The halftone-producing module is a device for carrying out thresholding operation, by taking into consideration only the decoded coefficients for verifying the selection standard.;COPYRIGHT: (C)2005,JPO&NCIPI