Research On ECT Image Reconstruction Algorithm Based On The Iterative Principle

Electrical Capacitance Tomography(ECT)is a typical process tomography technology.The main principle is to uniformly install the plates between the measured plates outside the measured pipe,and then use the image reconstruction algorithm.The measured field is reconstructed in 2D or 3D.ECT technology has the advantages of no radiation,fast response,simple structure,non-contact,etc.However,ECT image reconstruction is an inverse problem with "illness" and "morbidity",which will have a certain impact on image reconstruction.In this paper,the ECT image reconstruction algorithm is studied from the perspective of improving the image reconstruction effect and reducing the iterative algorithm step size.The main works are as follows:(1)The ECT system principle is deeply analyzed from the capacitance value measurement and the image reconstruction angle;The ECT model is simulated by the finite element method;Simulate and compare existing algorithms and compare the advantages and disadvantages of each algorithm.(2)For the single image reconstruction criterion,the image reconstruction quality is poor.A multi-criteria based ECT image reconstruction algorithm is proposed.This method combines the least squares criterion,the smoothing criterion and the vector inner product criterion effectively.The new iterative algorithm,image reconstruction results show that the image reconstruction effect is better than the traditional algorithm.(3)Aiming at the problem that most iterative algorithms solve the large-scale equations,the convergence speed is slow and the number of iteration steps is long.Based on the Landweber iterative algorithm,a new image reconstruction algorithm is proposed,which effectively reduces the algorithm.Iterative step size.The image reconstruction results show that the proposed algorithm outperforms the traditional algorithm under the same number of iterations.(4)Aiming at the problems of the traditional Landweber algorithm in the ECT image reconstruction,the number of iteration steps is long and the image quality is not high.The Landweber image reconstruction algorithm based on the improved homotopy perturbation is proposed by adding the constraint factor.Improve image reconstruction quality and reduce iteration steps.Experimental results show that the imaging results of the algorithm are much better than the traditional algorithm under the same number of iterations.