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 micron 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.