AbstractThe main purpose of this thesis is to develop a better understanding of the interfaces between materials in spatial and time domains via 2D and 3D visualisation and quantitative parameter measurement using Electrical Resistance Tomography (ERT). Some advantages of ERT have been reported as being high temporal resolution, low-cost and non-radiation emitting. The ERT modality is generally used to visualise the interior of a region by mapping the conductivity distribution using potential difference that is measured by electrodes that are attached to the medium. The main algorithm for image reconstruction that has been used is total variation regularisation due to its potential for producing high-quality images with sharp boundaries. In this work, a series of simulation studies and lab-based phantom experimental tests were conducted.
Contributions of this thesis are generally categorised into three aspects. First of all, a spatial-temporal total variation based on the Split Bregman method has been proposed for analysing dynamical movement of a target in a circular tank based on 2D ERT, where spatial and temporal gradients were employed for exploring performance in the space and time domains, and time response of dynamical ERT images has been proposed for the comparison and illustration of advantages of sharp dynamical images. Furthermore, the proposed STTV has extended to 3D ERT visualisation, where a tank with the shape of a vertical pipe has been designed with a dual-plane aiming at representing interior information by producing dynamical images of a moving target inside the pipe. Velocity measurements are feasible based on 2D/3D ERT and the cross correlation method, and the accuracy of these were discussed. Moreover, planar array for 3D ERT visualisation was used to overcome the issue that 3D ERT visualisations based on traditional electrode-ring sensors would suffer from low resolution on the axis-direction along the pipe, especially the region between rings where electrode-ring gaps lead to missing data. Results showed that ERT planar array can extract additional information in its detectable region with a higher 3D spatial resolution, and a combination of planar array and ring-electrode ERT can potentially be made for the purpose of exploring more information in a pipeline.
In general, this thesis represents the research works on improving the performance of static/dynamical ERT visualisation and quantitative parameter measurements. These works have potential applications in flow imaging and tomography-based measurement or control systems in the future. Detailed applications and further work are suggested. Although ERT is a new imaging technique and lots of issues are still preserved to be solved, it is believed that such research would have contributions to the future development of electrical impedance tomography research.
|Date of Award||19 Jun 2019|
|Supervisor||Manuchehr Soleimani (Supervisor) & Biagio Forte (Supervisor)|
- Electrical impedance tomography