Image reconstruction for field-focusing capacitance imaging

For online monitoring of multi-phase flows of non-conductive materials, a field-focusing capacitance imaging system has been developed. With a field focusing capacitance sensor, a tomographic image based on capacitance measurements is used directly to map the material distribution. However, it is difficult to achieve a required accuracy for measurement of void fraction from the capacitance image, because of the soft-field effect of the capacitance sensor. In this paper, the forward and inverse problems with a field-focusing capacitance sensor are described. Simulation and experimental results show that deconvolution-based algorithms can reduce the blurring artefact and can reconstruct an image close to the original distribution.