Halftone image areas in the original books cause the most reproduction problems, as there is the potential that moire patterns may form when these image areas are re-screened.
On the basis of which the two dimentional FFT technology is introduced to analyse the quality of error between the halftone image and the original image.
在此基础上，引入二维FFT技术，对半色调误差图象的质量进行了分析研究。
3
Additional to the original methods of digital halftoning, classification and modern digital halftone techniques also included in this paper.