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心脏磁场源重构,即通过人体胸腔表面的磁场阵列测量信号反演产生该磁场的电流源分布,是一种无创地研究心脏电活动的方法.本文用线性化方程描述测量磁场与心脏内部电流源的关系,并通过一种贪婪优化的方法得到了源重构的稀疏解.通过近似正交化过程和改变迭代算法中原子的选择方式,降低了优化算法的复杂度,可在保证源重构精度的情况下,快速搜索源空间中强度比较大的位置.文中通过一组正常人的心磁测量数据,说明了源重构方法的有效性.这组数据的研究结果表明,强度大于65%的重构电流源的空间移动轨迹与心脏除极和复极电活动的传导过程基本符合.其QRS和ST-T段的实测心磁图与重构电流源产生的磁场图的平均拟合优度分别为99.36%和99.78%.
The reconstruction of cardiac magnetic field source, that is to say, the current source distribution of the magnetic field generated by the magnetic field array measurement signal on the human chest surface is a noninvasive way to study the cardiac electrical activity.In this paper, the linearized equation is used to describe the relationship between the measured magnetic field and the internal current Source, and obtain a sparse solution of source reconstruction through a greedy optimization method.It reduces the complexity of the optimization algorithm by approximating the orthogonalization process and changing the choice of atoms in the iterative algorithm, In this paper, the validity of the source reconstruction method is illustrated by a set of normal human magnetocardiography data.The results of this group of data show that the intensity of the intensity greater than 65 % Of the reconstructed current source spatial movement trajectory and cardiac depolarization and repolarization activity basically consistent with the conduction process.Its QRS and ST-T segment of the measured magnetocardiography and reconstruction of the magnetic field generated by the average of the current map The excellentness was 99.36% and 99.78% respectively.