CT系统参数标定及成像研究

Study on Parameters Calibration and Imaging of CT System

摘要: CT系统安装时存在的误差在一定程度上影响到样品的成像质量，本文提出了一种借助已知结构模板对CT系统进行参数标定后再对未知结构样品进行成像的方法。首先，借助已知结构的模板及其X射线接收信息，基于卷积逆投影图像重建方法讨论了一种已安装好的典型二维CT系统的主要参数标定；然后利用已获得的标定参数，建立基于图像灰度的吸收率计算模型，研究未知结构的样品成像问题；最后对影响标定精度和稳定性的误差因素进行分析，设计新模板以改进标定精度和稳定性。本文的研究对降低CT系统安装误差影响、提高样品成像质量具有一定意义。

Abstract: The errors arising during installation of CT system will affect the imaging quality of the samples to some extent. In this paper, a method is proposed to image the unknown structure samples by cali-brating the parameters of CT system with the known structure template. Firstly, based on convo-lution inverse projection method for image reconstruction, we discuss the main parameters cali-bration of a typical two-dimensional CT system with the help of the known structure template and its X-ray receiving information. Then, based on the obtained calibration parameters, a model for calculating the absorptivity based on image gray level is established to study the imaging problem of unknown structure samples. Finally, the error factors affecting accuracy and stability of the calibration are analyzed, and a new template is designed to improve accuracy and stability. The research in this paper has a certain significance to reduce the influence of CT system installation error and improve the imaging quality of the sample.