GENERALIZED WIENER ESTIMATION OF 3-DIMENSIONAL CURRENT DISTRIBUTION FROM BIOMAGNETIC MEASUREMENTS

This paper proposes a method for estimating three-dimensional (3-D) bi ocurrent distribution from spatio-temporal biomagnetic data. This meth od is based on the principle of generalized Wiener estimation, and it is formulated based on the assumption that current sources are uncorre lated. Computer simulation demonstrates that the proposed method can r econstruct a 3-D current distribution where the conventional least-squ ares minimum-norm method fails. The influence of noise is also simulat ed, and the results indicate that a signal-to-noise ratio of more than 20 for the uncorrelated sensor noise is needed to implement the propo sed method. The calculated point spread function shows that the propos ed method has very high spatial resolution compared to the conventiona l minimum norm method. The results of computer simulation of the distr ibuted current sources are also presented, including cases where curre nt sources are correlated. These results suggest that no serious error s arise if the source correlation is weak.