The Research On Image Reconstruction Algorithm For Electromagnetic Tomography

Electromagnetic Tomography (EMT) technology is an industrial process imaging technology that is developed based on the principle of electromagnetic induction in the 1990s. With the characteristics of simple structure, system low cost, fast response, non-invasive and safe, it has broad industrial application prospects. The research of EMT image reconstruction algorithm is the key to its industrial application. However, because of the characteristics of soft fiel and three-dimensional field, it has brought many challenges to the research of EMT image reconstruction algorithm.With studying the electromagnetic field theory, the paper derived the mathematical expression from EMT technology physical meaning. By means of the finite element simulation of EMT forward problem, EMT image reconstruction algorithm was researched in the paper; the contributions of this dissertation are as follows:(1) .By consulting a large number of process tomography papers at domestic andabroad, author used the electromagnetic theory to analyze the EMT sensitive field and made a mathematical modeling from EMT physical model.(2) .The paper used ANSYS parametric modeling language APDL to make amodeling of the EMT forward problem and carry on finite element simulation, and realized ANSYS be called in VC, which made finite element simulation process and image reconstruction operate in an orderly manner.(3) .The image reconstruction algorithm of Electrical Tomography such as ERT, ECT,and EMT has been comprehensively analyzed in the paper.(4) .An improved Landweber algorithm was proposed in the paper, which got rid of the dependence of reference gray matrix, increased iteration speed and improved precision of reconstruction image.(5) .The reconstruction image were realized by the sensitivity coefficient based linear back projection algorithm, Landweber and improved Landweber iterative algorithm with simulation data, and at the same time the image reconstruction results were compared.(6) .The image reconstruction software was optimized for the BJTU-EMT prototype.