Numerical Control System Design And Image Reconstruction Research Of Industrial CT

Owing to the advantages of straight, precise, nondestructive testing and so on. Industrial Computed Tomography (ICT) was widely applied in aviation, spaceflight, national defense, and other fields. Meanwhile, the objects detected by ICT will not be affected by its shape, texture, and so on, thereby, ICT was considered by the international ity to be the optimal nondestructive testing method at present.Based on the research of predecessors, the study of physical design of cone beam CT has been done. The X-ray source system adopted the 225KV X-ray machine. The detector system used the detector array which were composed by the 128×128 detector units with the size of 1.0mm×1.0mm. The control system was built by adopting microcomputer, multiaxial controller, servo drives and motors. The overall layout of cone beam CT was made by setting the distance between ray source and scan center to 240mm as well as the distance between detector and scanning center to 160mm. The simulation results show that the designed ICT system can reach to the presupposed requirement well.The image reconstruction algorithm play an important role in ICT. On the basis of the research achievements of many scholars, a simulation experiment of 2-D and 3-D ICT was carried out by using C++as well as MATLA. Adopting the single detector, single ray source and scanning mode of parallel ray beam as the parameters of simulated ICT as well as the 128×128 classic Shepp-Logan head model as the rebuilded object model, the influences factors of 2-D ART algorithm such as the priori knowledge, the initial value, different projections under different noise levels and projection data with limited angles etc. was studied. The experimental results show that the priori knowledge and the preferable initial value can greatly improve the image quality. At the same time, the priori knowledge and different projections under different noise levels also impact the selection of optimum relaxation parameter. Under the circumstance of a certain range of observation angles unable to scanning, the quality of image can be improved by evenly increasing the projections; The effect produced by the scanning mode to the image reconstruction has been discussed. Experimental results show that the reasonable distribution of radiation source, scanning center and detector as well as scanning 180 degrees uniformly can improve the quality of reconstructed image. Meanwhile, under the circumstances of some angles unable to scan, it will be better as the projections fill the first interval angles range fully with the 1-2 degree scanning and remaining projections evenly to fill the second interval angles range.