Color halftone image compressing method based on three-dimensional matrix WDCT transformation

Abstract

The invention discloses a color halftone image compressing method based on three-dimensional matrix WDCT transformation. The color halftone image compressing method based on the three-dimensional matrix WDCT transformation comprises the steps that (1) color space transformation is carried out on input color halftone images; (2) three-dimensional matrix WDCT forward transformation is carried out; (3) statistics is carried out, and long run coefficient position scanning rules are established; (4) coefficients are rearranged; (5) run Huffman (RLH) coding is carried out; (6) code streams are output; (7) the code streams are input; (8) RLH decoding is carried out; (9) the coefficients are restored; (10) three-dimensional matrix WDCT inverse transformation is carried out; (11) color space inverse transformation is carried out; (12) decompressed images are output. According to the color halftone image compressing method based on the three-dimensional matrix WDCT transformation, the information redundancy and the correlation, between a space structure and channels, of the color halftone images are taken into consideration, the correlation among all the channels is removed, and the distribution of image energy is made to be relatively concentrated. The long run coefficient position scanning rules are not limited by the content of the images, color representation models of the images and the color halftone technology, and thus the color halftone image compressing method has wide applicability.

Description

technical field [0001] The invention belongs to an image compression method in the technical field of image processing, and specifically relates to a method for compressing a color halftone image after color space conversion and WDCT conversion, and then compressing the statistical coefficient long-run scanning rule, which can support remote printing and faxing. Compression of halftone images. technical background [0002] In the process of remote printing and faxing of color halftone images, in order to reduce the storage space required for image archiving, shorten the transmission time, and effectively solve the contradiction between transmission efficiency and limited bandwidth, it is necessary to compress color halftone images. [0003] At present, the compression techniques of color halftone images mainly include template-based compression algorithm and vector compression algorithm based on color channels. In 2008, Pu Chengfan et al. proposed a compression method for p...

AI Technical Summary

Problems solved by technology

The vectorized color halftone image compression algorithm proposed by Cao Huimin has low complexity and considers the correlation between color channels, but does not consider the correlation between pixels, and can only perform limited compression on ordered dithering color halftone images , when compressing error-dispersed color halftone images, data expansion may also occur, failing to achieve the purpose of image compression

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