Calibration of a multichannel MEG system based on the Signal Space Separation method
Calibration of a multichannel MEG system based on the Signal Space Separation method
复制标题
DOI：
10.1088/0031-9155/57/15/4855
复制
发表时间：
2012-08-07
影响因子：
3.5
通讯作者：
Pizzella, V.
中科院分区：
文献类型：
--
作者：
Chella, F.;Zappasodi, F.;Pizzella, V.
为了有效地使用多通道MEG系统，精确的传感器校准是极其重要的。这包括信道灵敏度和信道布置的知识，其可以偏离原始系统计划，例如，因为热应力。在本文中，我们提出了一种新的解决方案的校准的多通道脑磁传感器阵列的信号空间分离（SSS）方法的基础上。已经表明，传感器校准的不准确知识限制了SSS方法的性能，导致测量的神经磁场与其SSS重建之间的不匹配。给定一组已知的磁源，我们表明，一个目标函数，这强烈依赖于传感器的几何形状，可以从测量的矢量信号和SSS基础之间的主要角度。因此，MEG传感器阵列校准是通过标准的大规模优化技术，通过最小化的目标函数。这里介绍了磁源和校准过程的详细信息。最后，安装在基耶蒂大学的153通道全头脑磁图系统的校准的应用进行了讨论。
For an efficient use of multichannel MEG systems, an accurate sensor calibration is extremely important. This includes the knowledge of both channel sensitivities and channel arrangement, which can deviate from original system plans, e.g., because of thermal stresses. In this paper, we propose a new solution to the calibration of a multichannel MEG sensor array based on the signal space separation (SSS) method. It has been shown that an inaccurate knowledge of sensor calibration limits the performances of the SSS method, resulting in a mismatch between the measured neuromagnetic field and its SSS reconstruction. Given a set of known magnetic sources, we show that an objective function, which strongly depends on sensor geometry, can be derived from the principal angle between the measured vector signal and the SSS basis. Hence, the MEG sensor array calibration is carried out by minimizing the objective function through a standard large-scale optimization technique. Details on the magnetic sources and calibration process are presented here. Finally, an application to the calibration of the 153-channel whole-head MEG system installed at the University of Chieti is discussed.