电容层析成像技术(ECT)是过程层析成像(PT)中发展最为成熟的技术。该技术利用空间敏感电极阵列探测被测物场介质分布变化,通过数据采集单元提取有用信息并传输到上位机进行图像重建,再构物场介质分布图像。该技术具有非侵入、快速响应、成本低廉以及可视化等优点。其中,电容变化信息的提取以及数据采集是该技术的关键环节之一。本文采用一种新型信号解调方法一参数解调,对被调制信号进行处理。该解调方法主要建立在延伸型普朗尼参数识别的基础上,可一次对多频率信号的幅值、相位进行解调,非常适用于多频激励系统的数据采集。仿真实验和图像重建表明,该方法具有计算量小、解调精度高等优点。
Electrical capacitance tomography is the most mature technique developed in progress tomography technology. The technique detects the change in permittivity of materials being imaged using the space sensing array electrodes, obtains the useful information by the data acquisition unit, and sends them to the computer to reconstruct the images. The technique has the advantages of non-intrusion, fast response, visibility and low cost. So the extraction of the capacitance change information and data acquisition are the key links of the technique. The text employed a new signal demodulation method-parametric demodulation to process the modulation signal. Parametric demodulation is mainly based on extended Prony parametric identification. It can obtain the amplitude and phase of the multi-frequency signal through one time, and benefit the data acquisition in the multi-frequency excitation system. The simulation test and reconstructed images show that the technology reduced the operating load and is of high-precision.