偏折层析的滤波反投影算法及误差分析

对偏折层析投影转换为相位层析投影的转换关系进行了分析,给出明晰的数学关系,并针对偏折层析的滤波反投影算法重建的结果进行误差分析。分析结果表明投影噪声对重建场的作用体现在与由偏折层析滤波反投影算法的滤波器有关的倾斜函数上。因此提出了改进的偏折层析滤波反投影算法,数值模拟表明,改进算法在有效抑制倾斜现象的同时,对重建结果不会造成明显的失真。在此基础上改进的算法被用于真实火箭燃气射流密度场的三维重建中。

Filtered Back-Projection Algorithm of Deflection Tomography and Error Analysis

The conversion from deflection tomography projection to phase tomography projection is analyzed,and an explicit expression corresponding to the conversion is presented.An error analysis is made to the reconstructed fields by filtered back-projection(DFBP) algorithm of deflection tomography.Results show that the effect of projection noise on the reconstructed fields is represented by a slope function related to the filter used in deflection tomographic filtered back-projection algorithm.So the deflection tomographic filtered back-projection algorithm is modified.Numerical simulation shows that the modified algorithm depresses the slope phenomena efficiently,while no obvious distortion is introduced to the reconstruction.Based on the modified algorithm,the three-dimensional reconstruction for density field of the real rocket exhausted plumes is carried out.