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 th e electrical properties of, for example, several flowing particulate system s. A physical sensor typically comprises an annular array of 16 electrodes mounted on a pipe wall such that the electrodes make electrical contact wit h the measured medium. Although the image fidelity is currently poor compar ed 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 mu m length scales. This paper reviews the development of microelectrical sensing systems and r econstruction and interpretation methods using as example, a feasibility st udy on a 56 mm diameter bore sensor. This illustrates the limitations in th e widely employed procedure of employing generic tomographic sensors and im age feature extraction methods to extract application specific control para meters. (C)2000 Elsevier Science S.A. All rights reserved.