The3D Image Reconstruction Of Tuber Electrical Resistance Tomography System

Electrical Resistance Tomography (ERT) is a hot research field in the area of process tomography, as a result of its non-invasive, no radiation and low cost. Currently, the research on ERT imaging algorithms is usually focused on two-dimensional image. In many cases, we need to extract the geometry of discrete phase, however, these three dimensional information can’t be directly obtained by the two dimensional images, so it will be much more practical to study the three dimensional image reconstruction.In this thesis, we have extended the ERT technology to the field of agriculture and firstly proposed the concept of tuber electrical resistance tomography (TERT). On the basis of studying the forward problem and backward problem of TERT, we have reconstructed the three dimensional image of tuber from two dimensional section images. Concrete research work is as follows:(1) The study of the forward problem and backward problem. In the study of forward problem, the COMSOL Multiphysics software is used to construct and simulate the nearly saturated soil field and tuber model, meanwhile, the C++programming language is used to extract and process the simulation data. In the backward problem, the LBP algorithm is used to reconstruct the2D section image.(2) Preprocessing of3D image. According to the characteristic of TERT system, firstly, the image of tuber is extracted from the section image, then some algorithm is used to detect and match corners, lastly, the tuber’s contour is reconstructed through matched corners.(3)3D images reconstruction. On the basis of3D image reconstruction and study on many image reconstruction algorithms, the marching cubes algorithm is tentatively used to the3D image reconstruction, simultaneously, the NURBS surface fitting algorithm is used to fit the tuber’s3D contour for comparison.(4) Software Development. According to the research result, the tuber’s3D image reconstruction software is developed using OpenCV, OpenGL and VS2010. This software can achieve the reconstruction of tuber’s2D image, images preprocessing, and tuber’s3D image display and so on.