A Dissertation For Master's Degree Of Science Of Chongqing University

ICT can clearly, directly and accurately show us the structure, density change, character of a absence, position and size of measured profile by computer image. ICT not only has very high-spatial resolution but also has very high-density resolution. So far, ICT has been broadly applicable to various high-tech fields, including aeronautics and astronautics, military industry, shipbuilding, precision instrument, oil reconnaissance, metallurgy and mechanism manufacture, and so on. ICT is considered the best Non-destructive testing technology. But with the development of the high-tech, many of ICT's capabilities can't satisfy the demand of the actual necessary. How improving the capability of ICT has become more and more an important task, for example, improving spatial resolution and density resolution, reducing scan time, enlarging the size of measure space, improving image quality, etc. Moreover the question of the energy spectrum hardening and the photon scattering is one of important bottleneck to restrict the improvement of ICT. So people have paid many attentions to the research of energy spectrum hardening and the photon scattering. Reference to the convention means of the analysis and research for energy spectrum hardening and photon scattering in internal and external, and based on the physical mechanism of radial interacts with matter, this paper approximatively deduce a theoretical formula of correction of energy spectrum hardening and scattered radiation in Transmission Industrial X-ray Computerized Tomography from a ideal model. And presented a correction computer program. Following is our main work and important conclusions:(1) The question of energy spectrum hardening. We used the Klein-Nishina's differential scatter formula, meanwhile utilize the Thaler progression to spread out, and neglected the high-power, and then we deduced a theoretical formula of correction of energy spectrum hardening. The formula show:(a) The attenuation coefficient of X-ray not only connects with matter character, but also is a function with coordinate X. This paper has offered their expression yet.(b) That designing a program to correct the energy spectrum hardening during reconstructing image is feasible.(2) The question of photon scattering. Based on the physical mechanism of scattering phenomenal and the scattering model, we concluded the formal that canapproximatively counts the scattering photons which are detected by detectors. We design a program to calculate the scattering photons and present:(a) After we compared our results with the conclusions which C. J. Leliveld, J. G. Maas drawn through experiments we can find that both are consistent preferably, which show us that our formal is reasonable.(b) Although our correct formulas fit with ideal columniform models, they don't suit erose work pieces. Because of this, those correct formulas have a very big disadvantage, so we should take lots of efforts to improve them in our future work.