有效抑制黑灰区域噪声的逆半调算法

针对误差分散半调图在黑灰区域的“有界循环”现象,提出了一种基于人眼视觉系统的逆半调算法。该算法利用基于连通区域的分割方法将黑灰区域和非黑灰区域较好分离。然后通过分析均匀灰度图同对应半调图灰度之间的定量关系,设计了去除黑灰区域噪声的有效方法。最后给出了该算法的具体步骤。算法简单易行、速度快,实验证明逆半调图像不仅具有良好的视觉效果,其峰值信噪比等项指标也有较大提高。

Inverse halftoning based on efficient noise removal from dark region

To efficiently remove the limit cycles in dark region of an error-diffused halftone image,an inverse halftoning algorithm based on human visual system is proposed.First,dark regions are separated from non-dark regions with the segmentation method based on connected regions.Then an efficient way to remove the limit cycles in dark rgions is designed upon the study of the quantitative relation between uniform grayscales and their halftones.Finally detailed steps of this algorithm are given.The algorithm has the advantages of good reconstructed visual quality and fast speed.Also an improvement of peak signal-to-noise ratio and other indexes is achieved.