Sekihara et. al [50] proposed an 'eigenspace projection' beamformer technique in order to reconstruct source activities at each instant in time. It is assumed that, for a general beamformer, the matrix W = [w x , w y , w z ] where the column weight vectors w x , w y and w z , respectively, detect the x, y and z components of the source moment to be determined and are of the form
