Three-dimensional reconstruction algorithm for electrical resistance tomography

Electrical resistance tomography (ERT) is an imaging tool for process and clinical applications in which maps of the electric conductivity distribution of a body are formed from the current-to-voltage map of the body's surface. ERT is inherently a three-mensional problem. The transposition of two-dimensional ERT to three-dimensional (3-D) ERT is a challenging task and imposes significant increase in computational power demands and storage requirements. It is demonstrated that 3-D ERT is a viable offline technique for use today and can be implemented using a low-cost Pentium PC. The 3-D image reconstruction algorithm implemented is based on Newton's method in which optimal experiments are used for the reconstruction process. More importantly, the algorithm incorporates 3-D forward modelling, 3-D data collection and reconstruction. A 'fast' reconstruction algorithm is also implemented and yields a reduced set of equations which has the advantage of no longer being ill-conditioned at the expense of a loss in image resolution.