基于信号子空间主特征向量的心磁源重构-《中国医学物理学杂志》

文章信息/Info

Title:: Magnetocardiogram source reconstruction based on principal eigenvector of signal subspace

Author(s):: LI Haoran; ZHU Junjie; School of Electrical Engineering and Automation, Henan Polytehinc University, Jiaozuo 454000, China

Keywords:: Keywords: cardiac electrical activity magnetocardiogram inverse problem beamforming

摘要:: 利用人体表面测量的磁场数据无创成像心脏电活动中，在信噪比较低时，使用最小方差波束形成（MVB）方法对心磁信号进行源重构，该方法的降噪能力有限。本研究提出基于信号子空间主特征向量的波束形成（ISPEB）方法，该方法在SPEB方法的基础上增加了约束矩阵，采用基于主特征向量的信号子空间投影和噪声空间谱强度归一化的策略，约束空间滤波器输出的噪声功率及其增益，并补偿信号主特征向量对噪声空间谱强度分布均匀性的影响。通过实验比较SPEB、ISPEB、MVB方法的性能，结果表明ISPEB方法的源重构结果优于SPEB方法和MVB方法。最后，采用SPEB、ISPEB和MVB分别对两名健康受试的61通道R波峰时刻心脏磁场数据进行源重构成像，结果表明SPEB方法和ISPEB方法都有较好的源重构效果，源重构的精度较高。

Abstract:: Abstract: In the noninvasive imaging of cardiac electrical activity using magnetic field data measured on human body surface, when the signal-to-noise ratio is low, the minimum variance beamforming (MVB) method has poor ability of noise reduction in the reconstruction of the source of cardiac magnetic signal. Herein an improved beamforming method based on the principal eigenvector of signal subspace (ISPEB) which combines constraint matrix with SPEB method is proposed. The strategies of signal subspace projection and noise spatial spectral intensity normalization based on principal eigenvector are adopted for constraining the noise power and its gain output by spatial filter, and compensating the effect of signal principal eigenvector on the uniformity of noise spatial spectral intensity distribution. By comparing the performance of SPEB, ISPEB and MVB, the results show that ISPEB is superior to SPEB and MVB in source reconstruction. Finally, SPECB, ISPEB and MVB are separately used to conduct source reconstruction imaging on 61 channel R wave peak time cardiac magnetic field data of two healthy individuals, and the results showed that both SPECB and ISPEB perform well in source reconstruction and had high accuracy for source reconstruction.