Evaluation in Imaging of CT System’s Calculation

Abstract

CT can perform tomography imaging of biological tissue and engineering materials without the destruction of the sample, using the absorption characteristics of the sample to the ray energy, thus obtaining the structural information of the sample. In the background of CT system, four questions are proposed. According to our subject to geometric data, images and other conditions to obtain the CT system, the distance between the center of rotation of the detector unit, the rotation of the 180 directions, and through the CT system parameters to solve information related to two different groups of images of unknown material. For Problem 1, with the Radon function in MATLAB and apply the given CT system parameters and the problems in Appendix 3 and Appendix 5 of the data, we get two 256 * 256 images. Then comparing the 5 given data and annexes 3, the unknown substance absorption rate of each point is sorted out. With proportion calculation, the absorption rate of the 100*100 image is obtained. Absorption rate of the corresponding point is sorted out by comparing with the ten positions in Figure 3. For Problem 2, since the parameters of the CT system have been iteratively iterated in Problem 1, the model is optimized step by step until the four bit after the decimal point does not change any more. Therefore, the accuracy and stability of the model can be guaranteed. The difference between the scanned images is not obvious since the ellipse edge is curve. We choose a diamond and a circle as the template to make the abrupt points of the scan pattern clearer and enhance the calibration coefficient, accuracy and stability.