基于同步测量的电阻抗层析成像系统研究

摘要

Avoiding the disadvantages of traditional APT-pattern electrical impedance tomography(EIT)systems, such as asynchronous measurement,complex structure and debugging difficulty,a synchronous measuring EIT sys-tem is proposed and designed. This paper introduces an approach of realizing synchronous measuring in terms of hardware and software. The hardware platform consists of PXI-based integrated controller module,switch module, data acquisition module and lab-made current generator. Thishardware scheme simplifiesthe structure and improves the stability and accuracy of the system. A specified software kit is developed by LabVIEW to carry out data syn-chronous collecting and images reconstructing. An improved regularization algorithm is applied to reconstruct the in-ternal conductivity distribution. The comparative experiments are taken to illustrate the differences between syn-chronous and asynchronous measuring. The results show that the images are clearer and the artifacts are less. The average relative error of EIT images based on synchronous measuring is decreased by 48.99%. This paper provides a feasible and available method of synchronous measuring for EIT system,which is suitable for noninvasive imaging applications in numerous electrodes(electrode number≥16)fields.%针对APT模式EIT系统存在的异步测量、结构复杂、调试困难等问题,研究设计了一种基于同步测量的电阻抗层析成像系统,从硬件和软件两个方面阐述了如何实现同步测量.系统硬件由PXI集成控制器、开关模块、数据采集模块和自制电流源组成,简化了系统结构,提高了系统的稳定性和精确度.本系统采用LabVIEW开发了专用软件包,实现了信号的同步采集,并用改进正则化算法重建了电导率分布图像.对比实验显示了同步测量和异步测量的差异,结果表明同步测量EIT系统图像更清晰,伪影更少,平均相对误差降低了48.99%.本文提供了一种可行的EIT系统同步测量方法,该方法适用于多电极(电极数≥16)场域的无损伤成像应用.