A Study On Algorithms Of The System For Inspecting And Recognitizing Dot Images In Color Printing

Color Printing is a process of decomposing, transforming, transmitting and reproducing color information, and its purpose is to copy originals faithfully. To get the print with high quality, it is a key to inspect and control the varying trend of dots of each color class.Due to the drawback of methods and devices of inspecting and controlling printing images in current printing industry, a new principle for transforming color spaces and color separation based on digital image processing and pattern recognition is presented, and a system for inspecting and recognizing dots ?DIA (Dot Image Analyzer) system based on colorimetric measurement is designed. With CCD digital camera and optical microscope, DIA carries out measurements directly within images and obtain its RGB information; then recognizes the color pattern of each pixel in micro images (i. e. RGB-CMYK); at last color separating results and some parameters of dots of each color class, which can be used to adjust and control ink amounts of each ink zone of each color on printers. On the basis of the concepts of Divide-and-Conquer and Rough-Fine, DIA build a set of algorithm models including two rough classifiers (i.e. BDT and CMAC) and three fine classifiers (i. e. CLCHFPP, CPN-WED, NNE-IFM) which integrate some techniques such as clustering, decision tree, neural networks, fuzzy logic and information fusion etc. and take advantage of them, so DIA has a high accuracy and speed theoretically. The thesis discussed the building processes and working principles of presented classifiers, and developed the corresponding software for color separation of dot images with the operation system of Microsoft?Window* Me and Microsoft Visual Studio C++ 6. 0. In the end, some experiments were carried out to verify these classifiers and error analysis was given; the next research direction was pointed out.The thesis will directly help to further developing the close looped color control system of modern printers. The principle of transforming color spaces and color separation greatly contributes to the deep research of color reproduction in theory and the software developed has some applied value in printing quality control and image processing.