An Improved Simultaneous Iterative Reconstruction Technique For Electrical Capacitance Tomography*

Su Bangliang, Peng Lihui, Yao Danya, Zhang Baofen

Department of Automation, Tsinghua University, Beijing 100084, P.R. China Email: subl@263.net; penglihui@hotmail.com; yaody@sist.tsinghua.edu.cn; zbf-dau@mail.tsinghua.edu.cn

Abstract - High-quality reconstruction of capacitance tomography data is important to get the quantitative information from the cross sectional images of the multiphase pipe flow. Because of the complex nature of the capacitance sensors, the reconstruction algorithms well developed for medical tomography are not applicable. The main problems lie in two aspects. One is the "soft-field" effect, the other is the limited number of measurements. To resolve these problems and get high-quality images, a reconstruction algorithm named Simultaneous Iterative Reconstruction Technique (SIRT) often used in geology investigation is introduced. According to the fastness of the process tomography and the smoothing effect of SIRT, some improvements have been made. These methods are compared to the well-known linear back projection algorithm (LBP) and the linear back projection thresholded algorithm widely used in capacitance tomography. A computer simulated eight-electrode capacitance tomography system has been used for the evaluation. Further research will be done on a real eight-electrode capacitance tomography system.

Keywords: Process tomography; image processing; reconstruction algorithm; SIRT