A mathematical model for capacitance tomography

摘要

Capacitance tomography is a relatively new technique for imaging permittivity distribution within process vessels or pipelines. This thesis describes work aimed at modelling the important aspects of a capacitance tomography system. Two areas are considered. Firstly a model, referred to as the M model, is proposed for the first order relationship between capacitance change and local permittivity variation. This model is verified using accurate finite element simulation. A second order model is also introduced to account for the soft-field effect. Secondly an investigation into reconstruction algorithms is reported. The effect of different electrode excitation systems is analysed. The M model is exploited in a simple but quantitative image reconstruction algorithm.