CCD Subdivision Technology And Its Application Research

Charge Coupled Devices(CCD) is the new type semiconductor integrated photoelectric device developed at the beginning of the seventies of the 20th century. It was put forward at the first of 1970 by W.S.Boyle and GE.Smith from the American Bell telephone laboratory. In the past thirties years, CCD device and its application technology have been developed rapidly with the developed MOS integrated circuit craft. CCD. device falls into linear CCD and matrix CCD according to its sensitization unit permutation way. No matter linear CCD or matrix CCD, the precision of CCD image cell cannot be made very high for the reasons such as its inherent physical characteristic and working mechanism ,etc, or the restrictions as the structure of the chip and manufacture technology ,etc. In order to ensure CCD image cell having adequate sensitization matrix and prevent the commutative disturbing of close image cell, the image cell area and the space of all the CCD devices cannot be so small, in one micron of ranks generally at present. So CCD is restricted to the application of high accuracy measure field.CCD image measure system is composed of lighting system, testee, optic imaging system, signal processing circuit and computer. So, the factors influencing CCD measure accuracy is: the manufacture error of CCD image cell, CCD resolution ratio to the illumination, the accuracy of A/D transforming, the unstability of lighting system, additional noise of CCD driver circuit, focusing error of the imaging system(for instance the sphere error, difference, etc.), the influence of external environment(such as temperature, oscillate, etc.), the image processing level and the goodness or badness of software algorithms, etc. In order to improving the CCD measure level, the high resolution CCD device and high sampling frequency image collecting board is adopted, or the optic enlarging system carried on and the lighting with special lighting source used. But the adoption of these method can be commonly restricted and influenced to some certain degree, such as the precision of CCD image cell not so higher, the imaging quality declined after adopting optic enlarging system, CCD imaging quality affected by the stability and equality oflighting source. But it is simple and effective to improve CCD measure precision by using CCD image processing and soft algorithms. The CCD subdivision subject is put forward and the relative research of CCD subdivision technology and application started at the same time in order to improve the measure precision of CCD application system and meet the demand of CCD application on high precision measure field.With the beginning of introduction on CCD basic structure and working principle in the paper, the various aspects that influence CCD measure precision is analyzed, lighting source and optic processing system, CCD video signal processing and data collection, the noise analysis and processing of CCD working signal, CCD edge detection and image spots location, etc. researched and discussed in detail. Meanwhile, a set of high accuracy micrometer platform and position detection installation is build up. Various CCD subdivision method and technology can be researched and compared by the means of experiment. The academic research and experimental detection of the different CCD subdivision algorithms and subpixel position algorithms is carried on in detail, a series of new subdivision method and technology provided, and the CCD subdivision technology put into the application of high precision measure product development.CCD subdivision can be basically divided into two kinds of research scheme on edge detection subdivision and image spots location subdivision in the paper. Edge is the most principle characteristic of CCD image, the analysis and discussion about two schemes is the main research content of CCD subdivision technology. In the research of CCD edge detection subdivision, the method of dynamic probability > modulation and demodulation> spatial fitting functionn polynominal interpolation, etc. are analyzed theoretically, and the mechanism of these method is inferred on the mathematical aspect, and the advantage and insufficiency summarized. The fuzzy imaging method is introduced fundamentally and checked up experimentally.CCD image spots position subdivision method is introduced between matrix CCD and linear CCD. The matrix CCD subdivision position algorithm is the main method of centroid> power-added centroidx Gauss curve area fittings parabola curve area fitting. The linear CCD subdivision location algorithm have the one-dimension linearity compensation interpolation method, centroid interpolation method, ending voltage method, proportional centrality method, centre of gravity method, step-method, etc. These algorithms is to utilize the high relativity of gray degree value between the image elements for object image spots, and construct mathematics model that reflects accurately the object area image elements gray degree value,...