Research And Development Of The Sensor System Based On The Electromagnetic Tomographic Technology

Eddy current effects there are many applications in real life, such as motors,transformers and non-destructive testing. Electromagnetic sensor technology based oneddy current effects has advantages in non-interventional, non-contact and no damagedetection, and it can be widely used in industrial process measurement, inspection,geologic exploration and biomedical research and so on. EMT (ElectromagneticTomography) is a new electromagnetic sensing technology, it can also get the distributioninformation of conductivity and permeability of the space field, and it has a wide range inindustrial applications. However, great challenges come forth because of the complexity ofEMT, which including the theoretical solution of its forward and inverse problem, thedevelopment of effective excitation and so on.In this paper, the authour studied the fundamentals of EMT in detail, and inferedmathematical expressions of physical meaning of EMT technology.And the authour alsoresearch on the fast and efficient algorithm for image reconstruction. And introduces thedevelopment of the EMT system and its all aspects of performance testing. The researshworks of this dissertation are as follows:First of all, by consulting a large number of process tomography papers at domesticand abroad, the author used the electromagnetic theory to analyze the EMT sensitive fieldand made a mathematical modeling from EMT physical model.Second, this paper introduced the image reconstruction algorithm of EMT technique,and has a specialty analysis for the main algorithm of EMT such as Linear back projectionalgorithm based on the coefficients of sensitivity, Tikhonov regularization, and Landweberiteration algorithm, Newton-Raphson algorithm, singular value decomposition method(SVD), algebra reconstruction technology (ART) and simultaneous iterative reconstructiontechnique (SIRT) for EMT. Again, the authour designed and developmented a EMT syetem based on8-coilexcitation and detection modes, then introduced the hardware and software modules of thesystem, Make full use of the latest numbers and integrated circuit technology, thecalculation method of high performance,to improve performance of the EMT system.Finally, the authour tested performance of the EMT system, such as the inspection ofsystem noise level, testing ability for simple metal conductor. This research lay a theoryand technology foundation to further develop and perfect the EMT system for conductiveobjects sensor detection.