Optimized Design Of FPGA-based ECT/ERT Tomography System

Electrical Capacitance Tomography(ECT) and Electrical Resistance Tomography (ERT), which have lots of advantages such as non-radiation, non-intrusiveness, the more simple structure, the lower cost, the more widely range, the higher speed of the reaction and the better safety performance and so on, are the two main branches of the Electrical Tomography. They play a key role in the process of multiphase flow parameters of industrial measurement. The traditional multiphase flow measurement model has the only way in ECT or ERT, which is hard to meet the measurement requirement in the industry because of the weakness in acquiring enough information, the limited measurement range and higher demanded to the measured material. In order to solve the status, this paper makes many in-depth researches and meticulous experiments.With the background of multiphase flow detection, this paper focuses on digital experiment device design and integrates ECT and ERT in the same test platform. It has completed the ECT/ERT system experimental platform based on the FPGA in addition. At the same time, it makes some measurements and researches preliminarily to two phase flow parameters by Gas-Liquid and Liquid-Liquid. The main research works are as follows:(1) Understanding the characteristics of multiphase flow detection deeply, detailed analysis the digital process and development of ECT/ERT system’s status at home and abroad in the current.(2) Analysising the characteristics of the structure of ECT and ERT sensors, and design the composite sensor structure of ECT/ERT according to the sensor mutual interference problems. Then makeoptimal design to the position, size and some other related parameters of the sensor. (3) Designed the data acquisition and preprocess system based on FPGA, completed its basic module designing, such excitation source, FIR-filter, extracting the information of amplitude and serial communication. It plays a role of controlling FPGA side-by-side and looking-up table by LUT, improves the system’s stability and real-time, and realizes the digital signal processing of system.(4) Analyzed respective advantages and disadvantages by contrasting the single step LBP algorithm, the Landweber algorithm and the Tikhonov regularization algorithm. The system adopts the offline Landweber imaging algorithm and Amendatory Tikhonov algorithm, which combined with Single-step algorithm and Iterative algorithm.(5) Completed the development of PC software platform in the Qt Creator, and some function modules, such as the image reconstruction algorithm, QGraphicView image refresh and the database storage has been realized. Even the Man-machine interface, which based on the signal slot mechanism, has been compiled.(6) Made the primary experiment to this system performance. In the normal work of the system, the data acquisition speed is198.4frames per second, Single-step algorithm for imaging an average speed of67.5frames per second, and the iterative algorithm for imaging the average speed of31.2frames per second. Then made the respective experiment when continuous phase for conductor or not. The error in duty cycle must be controlled within15%on the ensuring that images are not anamorphic.