A finite element electrical impedance imaging system for binary media: 3. differential discrimination and separate effects for 2-d and 3-d objects

摘要

This paper, the third and final in this series, describes both two- and three- dimensional experimental methods and results. In addition it is shown that differing sensitivity produces differing contrast of similar targets and similar contrast of differing targets, depending on the location in the field being imaged. Furthermore, it has been found that the contrast contour which best describes the area of a target is correlated on the basis of contrast ratio #x2013; the ratio of the maximum target resistivity computed relative to that of the homogeneous background. Both quasi-three-dimensional and two-dimensional targets in both 2-D and 3-D phantoms produce virtually identical results. Truly 3-D targets, however, produce quite different results, presumably due to current flow in the third dimension around the target. Increasing the mesh-size and number of iterations, and utilizing boundary optimization are all shown to improve the resultant images. Finally, we show the ability of the system to image a #x201C;moving#x201D; three-dimensional shape.