The Defect Detection System For Color Printings Based On Machine Vision

In this paper,defect detection system for printed matter based on machine vision technology is researched,in which image processing and machine vision and printing basic principle are jointly applied to the printing industry.First of all,based on deeply analyzing and studying theories on color management and device characteristic,The improved tetrahedron interpolation technology is used to achieve the conversion of the color space for image date. The virtual increasing method in sampling volume is applied to the tetrahedron interpolation technology.Therefore the bigger size of 3D-LUT can be obtained and the conversion accuracy of the 3D-LUT can be greatly enhanced.In addition, the tetrahedron that contains the target dot can be ascertained more quickly with the method of distance orientation.Secondly,through studying the principle of color print and analyzing the merits and demerits of traditional method of overprinting error detection,the method based on image information is applied to obtain the overprinting error more quickly by counting the image matching data of single-color plates in the computer..Then some typical defect detection algorithm based on image processing technology is discussed and analyzed.After this a novel defect detection algorithm based on layer-by-layer is proposed.At the same time,this method can detect the location and the size of the defect.Finally,a software of defect detection system for printed matter is developed with Visual C++6.0 platform,which can detect the hackneyed defects without eyes during printing process in real time.When a defect is detected,the defect image is displayed,and the information such as the location and the area of the defect is offered.The defect detection system for printed matter built in this paper meets the real-time requirement.The system function is relatively complete and convenient to be used.