生物医学工程学杂志

生物医学工程学杂志

编码激励磁声信号处理方法研究

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基于磁声耦合效应的生物组织电特性检测成像方法,在神经电活动监测和肿瘤等疾病早期诊断方面具有重要研究意义。常用的单脉冲激励和接收模式的信噪比低,限制了磁声成像质量;信号平均处理方法则限制了成像速率。本研究提出了一种脉冲编码激励的磁声成像信号处理方法,采用编码序列激励模式和脉冲压缩的检测处理方法以提高信噪比,缩短信号处理时间。本研究通过仿真计算和磁声信号的实验测量,采用 13 位巴克(Barker)编码和 16 位格雷(Golay)编码,对磁声信号的编码激励和脉冲压缩处理方法进行了研究。结果表明,对金属丝模型,在未进行波形叠加平均的条件下,编码激励可明显提高磁声信号信噪比,如 13 位 Barker 脉冲编码和 16 位 Golay 编码处理方法,可分别提高磁声信号信噪比约 20.96 dB 和 20.62 dB。同时处理时间明显缩短:在相同信噪比提升的情况下,13 位 Barker 编码和 16 位 Golay 编码处理方法的整体采集处理时间约缩短为单脉冲激励平均处理方法的 3.62% 和 4.73%。本研究提出的脉冲编码处理方法,对提高磁声信号信噪比、改善成像质量、提高整体成像速率具有重要意义。

Detecting and imaging method of biological electrical characteristics based on magneto-acoustic coupling effect gives valuable information of tissue in early tumor diagnosis and bioelectrical current monitoring. Normal exciting and receiving method is to use single pulse. In this method the signal to noise ratio (SNR) is limited, so the imaging quality and imaging speed are low. In this study, we propose a processing method based on coded excitation to improve SNR and shorten the processing time. The processing method using 13 bit Barker coded excitation and 16 bit Golay code excitation are studied by simulation and experiments. The results show that SNR of magneto-acoustic signal is improved by 20.96 dB and 20.62 dB by using 13 bit Barker coded and 16 bit Golay coded excitation, respectively. It also indicates the processing time is short compare to single pulse mode. In the case of the SNR increasing, the overall acquiring and processing time under 13 bit Barker coded excitation and the 16 bit Golay coded excitation is shortened to 3.62% and 4.73%, respectively, compared to the single pulse excitation with waveform averaging method. In conclusion, the coded excitation will be significant for the improvement of magneto-acoustic signal SNR and imaging quality.

关键词: 磁声耦合效应; 编码激励; 巴克码; 格雷码; 信噪比

Key words: magneto-acoustic coupling effect; coded excitation; Barker code; Golay code; signal-to-noise ratio

引用本文: 张顺起, 殷涛, 刘志朋. 编码激励磁声信号处理方法研究. 生物医学工程学杂志, 2017, 34(5): 653-659. doi: 10.7507/1001-5515.201702042 复制

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