Su Mengyue, Song Xizi, Zhou Yijie, Yang Jiajia, Ke Yufeng, Ming Dong
Annu Int Conf IEEE Eng Med Biol Soc. 2020 Jul;2020:988-991. doi: 10.1109/EMBC44109.2020.9176330.
The acoustoelectric (AE) effect is that ultrasonic wave causes the conductivity of electrolyte to change in local position. AE imaging is an imaging method that utilizes AE effect. The decoding accuracy of AE signal is of great significance to improve the decoded signal quality and resolution of AE imaging. At present, the envelope function is adopted to decode AE signal, but the timing characteristics of the decoded signal and the source signal are not very consistent. In order to further improve the decoding accuracy, based on envelope decoding, the decoding process of AE signal is investigated. Considering with the periodic property of AE signal in time series, the upper envelope signal is further fitted by Fourier approximation. Phantom experiment validates the feasibility of AE signal decoding by Fourier approximation. And the time sequence diagram decoded with envelope is also compared. The fitted curve can represent the overall trend curve of low-frequency current signal, which has a significant correspondence with the current source signal. The main performance is of the same frequency and phase. Experiment results validate that the proposed decoding algorithm can improve the decoding accuracy of AE signal and be of potential for the clinical application of AE imaging.
声电（AE）效应是指超声波使电解质的电导率在局部位置发生变化。AE成像是一种利用AE效应的成像方法。AE信号的解码精度对于提高AE成像的解码信号质量和分辨率具有重要意义。目前，采用包络函数对AE信号进行解码，但解码信号与源信号的时间特性不太一致。为了进一步提高解码精度，在包络解码的基础上，对AE信号的解码过程进行了研究。考虑到AE信号在时间序列上的周期性，通过傅里叶逼近对上限包络信号进行进一步拟合。仿体实验验证了通过傅里叶逼近进行AE信号解码的可行性。并与用包络解码得到的时序图进行了比较。拟合曲线能够表征低频电流信号的整体趋势曲线，与电流源信号具有显著的对应关系。主要性能为同频同相。实验结果验证了所提出的解码算法能够提高AE信号的解码精度，在AE成像临床应用中具有潜在价值。
