Fig. 3.
Refining the volume conductor eliminates the extra ill-conditioning induced by the discretization. The three meshes have the same boundary resolutions: 105 nodes on the torso and 60 nodes on the heart. (A) Mesh with 1045 elements, 665 nodes. (B) 1325 elements, 805 nodes. (C) 1629 elements, 957 nodes. (D) Singular values of N and AI H. (E) Singular values of K.