基于扇束双投影方向的改进迭代层析成像算法  

Improved Iterative Tomography Algorithm Based on Fan-beam Geometry of Double Projections

作　　者：方静[1] 程乐红 张玉萍[1] 罗高鹏[1] 

机构地区：[1]合肥工业大学计算机与信息学院,合肥230009

出　　处：《光子学报》2014年第10期13-20,共8页Acta Photonica Sinica

基　　金：国家自然科学基金(Nos.61102154;41275027)资助

摘　　要：提出一种适用于气体扩散分布重建的改进代数迭代算法.针对投影射线扇束构型及双投影方向,在算法迭代步骤中引入先验矩阵,对迭代结果间隔性地进行中值滤波.以高斯烟羽模型为测试对象,分析迭代次数、松弛因子及不同滤波器使用策略对重建结果的影响,结果表明:迭代次数为500次,松弛因子为2时,均方误差、峰值相对误差基本收敛,并将波峰控制在一定范围内.改进代数迭代算法的均方误差、峰值相对误差重建指标优于传统代数迭代重建算法;同时,改进后算法能够准确定位波峰,完成尾峰重建,具有较强的抗噪性.An improved algebraic iterative algorithm was proposed to solve the problem that reconstruction of gas diffusion can barely be completed by the conventional algebraic iterative algorithm.Under the condition of fan beam geometry and double projections,the prior matrix was introduced in the iteration steps and the results processed by median filter every few iterations.Taking Gaussian plume model as test object,the effect of iterations,relaxation factor and different filter using strategies on the reconstruction results were analyzed.The experimental results shows that the mean square error and peak error reach the basic convergence and the peaks can be controlled in a certain range when the number of iterations is 500 and the relaxation factor is 2.Compared with the conventional algebraic iterative algorithm,the improved algorithm is better on the reconstitution indicators of mean square error and peak error.Furthermore,the peak position can be located more accurately and tail peak can be reconstructed successfully through the improved algorithm and the improved algorithm is robust to noise.

关 键 词：层析成像 迭代算法 中值滤波器 先验知识 遥感 双投影方向 扇束构型 

分 类 号：O439[机械工程—光学工程]