An impedance-analyser-based multi-channel imaging system and its applications

Imaging systems based on impedance measurement are widely used in medical, process monitoring and non-destructive testing, where their hardware designs, measurement range and accuracy are often application-specific. Impedance analysers can deliver excellent performance in terms of reliability, resolution and accuracy. A multi-channel imaging system has been developed using an impedance analyser with a specifically designed multiplexer box, hardware interface and corresponding software to provide flexibility in sensor connection. With a GUI written in Matlab, various algorithms have been implemented and data can be further analysed. We show here that it is a useful tool for a wide range of applications involving impedance measurement, single- or multi-modality 2D or 3D imaging. This system has been used for (a) imaging flow in a porous medium, (b) 3D ECT imaging and (c) security imaging with dual-modality planar capacitive and magnetic sensor arrays.