The Print Quality Detection System Based On CCD Line Scanning

The The quality of printed matter is becoming increasingly important in today’s society, for example, consumers can measure the quality of the goods by printing quality. Machine vision based detection system, abandon the traditional manual detection easily missed, presswork quality can not guarantee that these do not meet the development trend of the modern printing market the disadvantages of unified standards, low detection efficiency, high efficiency, accuracy and speediness. Based on the research of domestic and foreign related technologies, this paper studies and designs the on-line inspection system based on line scan CCD printing quality.The collection and processing of the printing image are two important parts of the quality inspection. In image acquisition, the use of industrial camera, usually used in line array or array camera for image acquisition; image processing part mainly includes the image acquisition part of the image registration and comparison. The composition of the quality inspection system based on the CCD line scan print quality detection system consists of image acquisition module and image processing module. Image acquisition module mainly completes the acquisition of the detection and printing image, and the main task of the image processing module is to deal with the last step of the image processing, and finally get the difference between the image and the standard image, so as to achieve the purpose of detection.In this study, the collection of printed matter image is completed by CCD line scan camera. The research and application of CCD scan technology is more and more widely. Especially CCD has the characteristic of self scanning. It can convert the analog image signal into programmable digital image signal, so as to make it possible to process these images. As the CCD linear array camera is used to capture the image as a whole, it is necessary to adopt the driver circuit, which is based on the STC89C51 stepping motor driver, and the power amplifier is used to generate the pulse signal. The pulse signal is amplified by the power amplifier. The power amplifier is used to control the starting and braking of the motor. Compared with the existing technology, the system is more accurate and flexible in the detection system.Image processing part, the main use of image registration algorithm, the acquisition of printed image and standard image registration algorithm. This is a very important step in the quality inspection of the printed image quality. In view of the characteristics of CCD, the registration method is mainly based on the registration of rigid body transformation. The image registration method based on Harris corner feature is used to carry out the registration operation. Then, the registration image and standard image are compared.