Abstract: The color printing is a kind of technology, which uses the yellow, magenta, cyan, black four-colors ink overlap to produce color images. Inverse halftoning is the process that halftone image converts into continuous tone image. It mainly applies in electronic publishing and electronization of printing image. It chooses the LAB color space for inverse halftoning processing. It selects three order B-spline wavelet as wavelet base. And it accords the wavelet decomposition, wavelet coefficients adjustment, reconstruction of wavelet as wavelet transform algorithm. It processes inverse halftoning process to color printing scan image, and gets the inverse halftoning image. The experimental results show that the algorithm avoids to destroy the relevance of the color channel for color image of red, green, and blue color channels. And it has certain theoretical significance and application value to color printing scan images reconstruction and screening image restoration.

Key words: B-spline wavelet, inverse halftoning, wavelet transform, color printing

摘要： 彩色印刷是一种利用黄、品红、青、黑四色油墨叠印产生彩色图像的技术，逆半调是将半色调图像转换成连续调图像的过程，主要应用在电子出版和印刷图像电子化方面。选取LAB颜色空间作为逆半调处理的颜色空间，选择三阶B样条小波作为小波基，遵循小波分解、小波系数调整、小波重构的小波变换算法，对彩色印刷扫描图像进行逆半调处理，得到逆半调图像。实验结果表明，该算法避免了破坏彩色图像红、绿、蓝颜色通道的颜色相关性，对彩色印刷扫描图像的重建和印刷加网图像的恢复具有一定的理论意义和应用价值。

关键词: B样条小波, 逆半调, 小波变换, 彩色印刷