Abstract: In this paper，color division model and automatic detected method of color registers are proposed for register mark images of four kinds of initial color（cyan，magenta，yellow and black） that overlaps each other.Based on image analysis theory，a color recognition model for cyan pixels，magenta pixels，yellow pixels，black pixels and their complex color pixels is derived.The next step is that edge pixels of color marker are extracted，and their structural lines are approximated by least squares approximations and Hough transforms.Experiments indicate that precision of 20 micron is obtained when this automatic detected method of color register is applied.And this accords with general printing technology standard of china.This method can be applied to two or four color printing system via CMYK combination.

Key words: image analysis, register, least squares approximations, Hough transforms

摘要： 针对彩色印刷领域较常用的四原色（青色C、品红M、黄色Y和黑色B）叠印标记图像，提出了像素分色归类模型和套准偏差计算方法。通过图像分析给出四种原色及其复合色像素的分色归类模型，在此基础上检测四种原色套准标记的边缘像素，结合最小二乘和Hough变换法拟合套准标记的多条边缘直线，在图像中计算四种原色特征直线之间的偏移距离。实验结果表明该方法自动检测套准偏差的精度高于20 ?滋m，符合国家印刷行业标准规定的套准精度要求，适用于以C、M、Y、K合成原理为基础的双色、四色胶印系统。

关键词: 图像分析, 套准, 最小二乘拟合, Hough变换