Quality Detection and Characterization of Star Label Printing Based on Image Processing

This paper is aimed at the quality of star prints used in the quality evaluation of printing and printout industries. Using digital imaging and image processing techniques, we have established quantitative indicators for the quality of star label printing, including star dark line angle width, the shape and size of the fuzzy area, as well as the fill rate in the star label's center. Through the calibration of the light respond of the digital imaging system, the light reflectance gray image of the star print digital image is obtained, and the mass properties of star prints is quantified by light reflectance. The auxiliary line around the star radiant line is used to automatically obtain the center coordinates of the star image. According to setting light reflectance threshold value, the boundary points on both sides of the dark line of the star label and the angle of the radiate line to the center, the visual resolution boundary between the dark lines in the vicinity of the center of the star label and the degree of color ink fill in the 1 mm radius circle of the center of the star label are determined, which have formed a quantitative quality indicator of the star prints. The application results show that the defined quantitative indicators can reflect the transfer performance of the field and small dots in the printing output process. This method can change the current situation where the star label can only be used for visual observation.