Chung Kuo-Liang, Wu Shih-Tung
Department of Computer Science and Information Engineering National Taiwan University of Science and Technology, Taipei, Taiwan 10672, ROC.
IEEE Trans Image Process. 2005 Oct;14(10):1583-9. doi: 10.1109/tip.2005.854494.
The inverse halftoning algorithm is used to reconstruct a gray image from an input halftone image. Based on the recently published lookup table (LUT) technique, this paper presents a novel edge-based LUT method for inverse halftoning which improves the quality of the reconstructed gray image. The proposed method first uses the LUT-based inverse halftoning method as a preprocessing step to transform the given halftone image to a base gray image, and then the edges are extracted and classified from the base gray image. According to these classified edges, a novel edge-based LUT is built up to reconstruct the gray image. Based on a set of 30 real training images with both low-and high-frequency contents, experimental results demonstrated that the proposed method achieves a better image quality when compared to the currently published two methods, by Chang et al. and Meşe and Vaidyanathan.
逆半色调算法用于从输入的半色调图像重建灰度图像。基于最近发表的查找表（LUT）技术，本文提出了一种新颖的基于边缘的LUT逆半色调方法，该方法提高了重建灰度图像的质量。所提出的方法首先使用基于LUT的逆半色调方法作为预处理步骤，将给定的半色调图像转换为基础灰度图像，然后从基础灰度图像中提取并分类边缘。根据这些分类后的边缘，建立一个新颖的基于边缘的LUT来重建灰度图像。基于一组30幅同时包含低频和高频内容的真实训练图像，实验结果表明，与Chang等人以及Meşe和Vaidyanathan目前发表的两种方法相比，该方法具有更好的图像质量。
