一种改进误差扩散系数的半色调算法

A Halftone Algorithm Improving the Error Diffusion Coefficient

目的为了解决现有半色调算法产生的半色调图像边界模糊以及视觉蠕虫等问题,获得一种人眼视觉感知较好的数字半色调图像。方法在原始经典滤波器的基础上引入α-截尾均值滤波器,得到一种新的基于邻域像素灰度值相关的误差扩散滤波器。结果所提算法相较于传统误差扩散算法能更好地再现半色调图像细节,同时其边界也得到了较好的保持,并且客观评价参数PSNR值、SSIM值均有一定幅度的提高,NSME值也得到了较为理想的结果,不仅解决了传统误差扩散算法中边界模糊现象,同时也更好地表达了半色调图像的细节纹理信息。结论依据提出的算法得到的半色调图像人眼视觉感知效果较好,并且算法简单易行效率高。

The work aims to solve the problem of image boundary blurring and visual worms generated by the existing halftone algorithm and get a better digital halftone image of visual perception. The α-truncated average filter was introduced based on the original classic filter and a new error diffusion filter considering the distance and the grey value similarity between pixels. Compared to the traditional error diffusion algorithm, the proposed algorithm reproduced the halftone image details in a better way and its boundary was also well maintained. Moreover, the PSNR and SSIM values of objective evaluation parameter were increased in some way, and the NSME value also got an ideal result, which not only solved the fuzzy boundary of traditional error diffusion algorithm, but also better expressed the detailed information on texture of the halftone images. The halftone image generated by the proposed algorithm has a better visual effect and the algorithm is simple and effective.