Research on an Overprinting Accuracy Analysis Algorithm without Color Marks of Multi-color Printings

A new algorithm of overprinting accuracy analysis of multi-color printings with no color marks required is presented in the paper by applying image processing technology and color separation technology to quality inspection of multi-color printings. Firstly the standard image and the images collected from printings waiting for inspection are color-separated, consequently they are registered; then the image registration data can be gotten; finally overprinting error can be obtained by applying the inherent information embodied in inspected images and image registration data. Obviously other than traditional overprinting error analysis methods, with the new algorithm no color marks are necessary to print on the margin of printing media. So printing media can be saved and additional operations such as cutting color marks out can be left out. The experiment shows that accuracy and efficiency of overprinting inspection can completely satisfy the requirement of precise printings with little additional calculation or measurement required.