12极板直接三维ECT图像重建仿真

为克服间接三维ECT系统轴向分辨能力低这一缺陷，进行了直接三维ECT重建技术的研究.将12个极板分三层布置，相邻层极板有45°角的相对旋转.不但测量同层极板对的电容值，还要测量不同层极板对的电容值.三维图像直接在重建过程中产生，与经过二维断层图的间接三维重建图像截然不同.建立了传感器的三维有限元模型，分析了传感器的三维敏感场.采用线性反投影算法以及有限元分析法获得的三维灵敏度矩阵和电容测量仿真数据，实现了直接三维ECT图像重建.重建结果显示了直接三维ECT具有良好的轴向分辨能力.

Simulation for direct 3D ECT image reconstruction based on 12 electrode plates

In order to overcome the disadvantage of low axial resolution capability in the indirect 3D ECT system,a direct 3D ECT reconstruction technique was developed.12 electrode plates were arranged in three layers with a relative rotation of 45° between electrod plates in adjacent layers.The capacitance values of electrode plate pairs both in the same layer and in the different layers were measured.Then the 3D images were directly generated in the reconstruction process,and were obviously different from the indirect 3D reconstruction images obtained with 2D tomograms.The 3D finite element model for the sensor was established,and the 3D sensitivity field of the sensor was analyzed.The linear back projection algorithm,the 3D sensitivity matrix and capacitance measurement simulation data obtained with the finite element analysis method were used to realize the direct 3D ECT image reconstruction.The reconstruction results indicate that the direct 3D ECT exhibits good axial resolution capability.