基于材料组分先验的X射线多能投影盲分离算法  

Blind Separation Algorithm of X-Ray Polychromatic Projections Based on Material Composition Prior

作　　者：李毅红[1] 屈赵燕 赵晓杰 魏交统[1] 陈平[1] Li Yihong;Qu Zhaoyan;Zhao Xiaojie;Wei Jiaotong;Chen Ping(Shanxi Key Laboratory of Signal Capturing&Processing,North University of China,Taiyuan,Shanxi 030051,China;Department of Physics and Electronic Engineering,Yuncheng University,Yuncheng,Shanxi 044000,China)

机构地区：[1]中北大学信息探测与处理山西省重点实验室,山西太原030051 [2]运城学院物理与电子工程系,山西运城044000

出　　处：《光学学报》2021年第23期77-86,共10页Acta Optica Sinica

基　　金：国家自然科学基金(61801437,61871351,61971381,62122070);山西省自然科学基金(201801D221206,201801D221207)。

摘　　要：能谱计算机断层成像(CT)可以利用多个不同能谱的衰减数据来获取窄能谱投影,窄能谱CT图像能够提高组分定量表征的准确性。鉴于此,基于未知的X射线能谱提出一种获取窄能谱投影的能谱CT盲分离算法。首先建立带有材料先验的X射线多能谱正演模型,其能够为窄能谱投影提供能量指向。其次依据测量数据的泊松统计特性,构建关于能谱拟合系数向量和厚度向量的约束优化问题,并采用块坐标下降算法对其进行求解。该算法在非负矩阵分解和高斯牛顿算法之间可以交替更新。仿真和实际实验结果表明,与已有算法相比,所提算法分解的CT图像具有更少的硬化伪影和噪声,各分解投影图像符合窄能谱投影的特征,能够提高获取窄能谱投影的准确性。Energy spectrum computed tomography(CT)can use attenuated data of multiple different energy spectra to obtain narrow energy spectrum projection,which can improve the accuracy of the quantitative characterization of components.Based on the unknown X-ray energy spectrum,a blind CT separation algorithm is proposed to obtain the projection of narrow energy spectrum.First,the X-ray multi-energy spectrum forward model with material prior is established,which can provide energy direction for narrow energy spectrum projection.Second,according to the Poisson statistical characteristics of the measured data,the constrained optimization problem about the energy spectrum fitting coefficient vector and the thickness vector is constructed,and the block coordinate descent algorithm is used to solve the problem.The algorithm can be updated alternately between non-negative matrix factorization and Gaussian-Newton algorithm.The simulation and experimental results show that compared with the existing algorithms,the CT images decomposed by the proposed algorithm have fewer hardening artifacts and noises,and each decomposed projection image conforms to the characteristics of narrow energy spectrum projections,which can improve the accuracy of obtaining narrow energy spectrum projection.

关 键 词：图像处理 X射线计算机断层成像 多能投影 盲分离 能谱计算断层成像 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]