摘要：逆半调技术是半调图像处理中的关键技术之一，近几年来其研究取得了较大的进展。为了使人们对该技术研究现状有个概略了解，首先论述了逆半调技术的原理和主要研究方法；然后重点分析了针对误差分散半调图的滤波方法、机器学习方法和最优化估计方法，并比较了它们的优缺点，通过比较发现，基于模糊技术、人眼视觉特性的自适应滤波方法，在实际应用中有广阔的前景；最后给出误差分散逆半调技术目前存在的问题和进一步的发展方向。

Abstract：Inverse halftoning has been greatly developed recently and it is one of the key techniques in image processing for halftones. First the principles and implementations of inverse halftoning are given. Then the emphasis is put on the analysis of filtering methods, machine-learning based methods and optimum-estimation based methods for error diffusion halftones. Comparisons show that HVS-based fuzzy filtering schemes have a promising application. Finally the open issues and possible future research directions are pointed out.