Abstract: Halftoning is the rendition of continuous-tone pictures on displays，paper or other media that are capable of producing only two levels.The technology has widely applied to typography，printing technology，compression memory of digital image and etc.A review of digital halftoning techniques which are base techniques of image processing is presented.The classical methods and recent advance of digital halftoning are introduced.Several image quality assessment methods are used to evaluate the digital halftoning techniques.Then，the trend of the digital halftoning technology development is described.

Key words: digital halftoning, image quality assessment, image processing

摘要： 数字半色调技术是在二值设备或有限灰度级设备上实现图像再现的一门技术，广泛应用于印刷打印、压缩等领域。针对这一基础性图像处理技术——图像处理支撑技术数字半调技术进行了综述，分析了数字半调技术的现状，对经典算法和最新进展进行了介绍。并通过多种评价方法对半调算法进行了量化比较和分析，展望了数字半色调技术的发展趋势。

关键词: 数字半调, 图像值质量评价, 图像处理