部分相干光源微分相衬双图像相位恢复

深圳大学光电工程学院,光电子器件与系统教育部重点实验室,深圳 518060

干涉成像; 相位光栅; 吸收光栅; X射线; 部分相干光源; 相位恢复; 微分相衬成像

Dual-images phase retrieval in differential phase-contrast imaging with partial coherence source
Liu Xin and Guo Jinchuan

Liu Xin and Guo JinchuanCollege of Optoelectronic Engineering, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Shenzhen University, Shenzhen 518060, P.R.China

interferometric imaging; phase grating; absorption grating; X-ray; partially coherent source; phase retrieval; differential phase contrast imaging

DOI: 10.3724/SP.J.1249.2014.02169

备注

基于部分相干光成像理论,结合X射线微分相衬成像特点,给出有限大小焦斑光源物体微分相衬成像干涉条纹强度分布.建立基于吸收光栅微分干涉条纹探测模型,该模型给出可见光探测器探测强度表达式.根据光强分布,提出一种新的相位恢复算法,该算法仅需两幅物体曝光图像,相对旧算法,减少了物体曝光次数,有利于减少物体X射线剂量的吸收.模拟实验验证了该算法的有效性

X-ray phase contrast imaging techniques can directly detect the structure of soft tissues in the medicine, biology and material sciences because those methods can provide higher sensitivity than the conventional X-ray radiography. Based on the partial coherence theory, the intensity distribution of X-ray interferogram with the source of finite focus is presented. The detecting model of visible light detector with absorption grating is built and relative intensity of signal is given also. A new phase retrieval algorithm, which needs only two X-ray images of sample, is proposed according to the detecting model. The new algorithm helps reduce the absorption of X-ray dose. The computer simulation has been performed to verify the feasibility of our proposed algorithm.

·