纸张印刷墨斑检测方法研究

A New Method to Detect Print Mottle of Papers

目的基于扫描仪和STFI-Mottling Expert斑纹测试软件,提出一种使用改进型变异系数Mod Co V表征纸张印刷墨斑的新方法。方法纸张表面的印刷墨斑图像通过扫描仪获取,再经过软件分析,从数字图像处理的角度研究印刷斑纹;实验选用新闻纸、双胶纸、铜版纸和喷墨纸等4种纸张,分析不同波长范围和不同方向的印刷墨斑情况。结果使用改进型变异系数Mod Co V表征印刷墨斑,其视觉判定的相关性比使用变异系数Co V表征印刷墨斑的传统方法更好,在研究不同波长的墨斑水平和墨斑取向问题方面也表现出一定的优越性。结论该方法操作简单,能更加客观地对印刷墨斑进行度量,更加方便地解决印刷墨斑所引起的问题,提高了印品质量。

Based on the scanner and STFI-Mottling Expert testing software, a new method using the COVM（modified coefficient of variation） to characterize the print mottle of papers was introduced. The print mottle image on paper surface was acquired through a scanner, and then studied from the perspective of digital image processing through software analysis. The experiment selected newspaper, offset paper, coated paper and inkjet paper to analyze print mottle in different wavelength ranges and different orientations. The method using the modified COVM proposed in this paper could effectively detect printing mottle. The correlation with visual judgment was better than that of traditional methods using the COVM to characterize the print mottle of papers. There were also some advantages in detecting the print mottle within different wavelength ranges and orientations of mottle. In conclusion, the new method is simpler and more objective as compared to the traditional method. It is more convenient to solve the problems caused by print mottle, and then improve the printing quality.