Reseach Of Printing Quality Checking And Controlling System Based On Image

In this thesis, the checking methods for printing quality based on image are taken as research objects. On the base of the traditional checking methods of printing quality, combining the method and theory of digital image processing with printing theory in the new domain of image quality checking, We constitute the printing quality checking and controlling system based on image, and expound theory design and model of this system.The checking algorithms of printing quality put forward have been mainly researched by experiments. 1) achieving the location of the image waiting for checking and standard image by template matching method; 2) checking the limitations of printing letter by geometry shape character and texture character; 3) for dot image, two kinds of checking methods have been proposed , one is the checking method using texture character and color correlation in low resolution .another is the checking method using dot area percent of printing colors in high resolution. 4) segmenting dot image and accounting dot area percent using Neural Network pattern recognition method, checking texture character based on Co-occurrence feature and fractal dimensional feature, and checking color correlation based on correlation coefficient of the image waiting for checking and standard image in the corresponding field.Experiment results show that 1) template matching location algorithms can achieve exactitude location of the image waiting for checking and standard image ;2)the checking algorithms for printing letter based on geometry shape character and texture character can detect the limitations of printing letter;3) in the high resolution, Neural Network pattern recognition method can exact-ly recognise-the dots of printing colors; in the low resolution, checking method ,of .texture character based on Co-occurrence feature and fractal dimensional feature can exactly describe the difference between the image waiting for checking and standard image;4)the checking method of the new system is more exactly and efficiently than the traditional checking method.