非涂料纸印刷网点尤尔-尼尔逊效应的理论研究

从光信息的传递函数角度，研究了图文复制过程中非涂料纸印刷网点半色调系统的尤尔－ 尼尔逊效应．把非涂料纸表面的印刷网点粗糙墨层等价于随机透射屏；把非涂料纸表面斑点等价于随机吸收屏，分别建立相应的光学传递函数和调制传递函数，以修正受到非涂料纸特性因素影响的半色调系统尤尔－ 尼尔逊效应．

Yule-Nielsen Effect of Noncoated Paper for Printing Dot

The Yule Nielsen effect of noncoated copy paper is studied with the optical information theory in the resolution and tone reproduction characteristics of images printed on paper. This article focuses on the halftone system of the noncoated paper and the rough dot is abstractly taken as the random transparency screen. Similarly, the surface of the noncoated paper on which there are the defect like the dark spot can be abstractly taken as the random absorption screen. The MTF corresponding to the random transparency and absorption screen has been obtained in order to modify the idealized halftone system printed on the surface of the noncoated copy paper. The reflectance of the dots and the paper between the dots with the fractional dot area for the noncoated paper can be obtained respectively based on the idealized halftone line system modified by MTF, and the Yule Nielsen effect for the noncoated copy paper can be modeled.