On-line System For Inspecting Defects Of Wide Imagesetting Film

Wide imagesetting film has been widely used to print book and newspaper. Therefore, the quality is concerned much. During the process of manufacture, various defects appear stochastically because of processing techniques and production facilities, which directly influence the quality of film. At the same time, there isn't effective quality control during the course of manufacture, even in the last process the conventional inspection manually, which can only seek out severe defects and also miss out much film's inspection, is also used at present. As a result, the quality of film is limited and not perfect. The dissertation introduces an on-line inspection system of wide imagesetting film defects for automatic quality control in finishing process.The inspection system employs the parallel processing architecture with two detection computers and a server. With the infrared uniformity illumination, two high-powered linear CCD Cameras capture images of running film (wide: 1300mm, speed: 90m/min) in real-time, which are then processed by means of the simplified algorithms integrating smooth filter and edge image segmentation. The system uses two summation thresholds to detect existence of defects in time. When a defect appears, the system automatically saves all the information of the defect including its image. The system gets the longitudinal position of defects with encoding module, while the transverse position is calculated from the image. The server can provide defects report of the film detected in order to get the inspection result in time.The system resolution is as high as 80μm in horizontal direction and 500μm in the vertical direction. Having run for several months in the second film factory of Lucky Group, the system shows such performance as steady running status, good anti-jamming ability and reliable inspection results, which fit the production requirement finely, and brings the factory much benefit.