Fig. 3
(Top) Picture showing transducer mockup model containing reference plastic hemisphere (red arrow) and ADNI phantom (green arrow). (Middle) Pictures of different copper patterns attached to the outside of the hemisphere: a reference without copper sheet, b solid copper surface (one segment, average surface of segment ≈1413 cm2), c seven-segment clinical pattern (average surface of segments ≈199 cm2), d star pattern (32 segments, average surface of segments ≈37 cm2), e ring pattern (16 segments, average surface of segment ≈92 cm2), and f a combined star-ring pattern (64 segments, average surface of segment ≈27 cm2). (Bottom) Modeled patterns of FEM simulations with 36 (d), 17 (e), and 54 segments, respectively. Black arrows indicate the points of view of the ground planes when plotting the current densities in Fig. 4