Status and applications of microelectrical resistance tomography

Electrical resistance tomography (ERT) is part of a suite of real-time low-cost two-dimensional imaging techniques which exploit the differences in the electrical properties of, for example, several flowing particulate systems. A physical sensor typically comprises an annular array of 16 electrodes mounted on a pipe wall such that the electrodes make electrical contact with the measured medium. Although the image fidelity is currently poor compared to X-ray tomography, the sensors can be scaled to suit the application. A microelectric resistance sensory system (MERT) is being developed for on-line interrogating down to 20-1000 μm length scales. This paper reviews the development of microelectrical sensing systems and reconstruction and interpretation methods using as example, a feasibility study on a 56 mm diameter bore sensor. This illustrates the limitations in the widely employed procedure of employing generic tomographic sensors and image feature extraction methods to extract application specific control parameters. (C) 2000 Elsevier Science S.A. All rights reserved.