Research On Online Detection System For Printings Based On Lifting Wavelet

With the development of economic and the rapid increase of the level of industrial automation, quality of printing products has been concerned more and more seriously, and quality standard required has also become more and more high. The traditional, manual and low-efficient quality detection methods for printings can not meet the needs of high-speed printing any more. In recent years, research and development of online quality detection system of printings has become a hotspot.Firstly, hardware components for the online quality detection system of printings has been studied and established including strobe lights, linear array CCDs,an image acquisition card, a PC and etc. In the high-speed image acquisition process with CCDs, strobe lights are used as the lighting sources in order to eliminate image blurring and increase the clarity of the collected images.Secondly, on the basis of the deep research and analysis of image processing theory and methods, some algorithms which combine lifting wavelet with image processing algorithms have been studied and applied to detection systems. EZW image compression coding algorithm based on integer lifting wavelet is used to complete image compression coding of collected images more effectively. Harris corner detection algorithm based on lifting wavelet has designed to complete feature corner extraction and image registration. Lifting-wavelet-based selective image fusion algorithm has been presented and used to fuse images that are judged to be necessary.Finally, algorithms described above have been verified by simulating. Experimental results show that these algorithms based on lifting wavelet can reduce time of image processing and improve speed and accuracy to some extend. These algorithms have achieved the desired goals and provided the theoretical basis and experimental data for further study on the detection system.