频域磁声耦合成像实验系统研究

System study on magneto-acoustic imaging in frequency domain

目的:研究设计频域磁声耦合成像系统,以实现组织样本的电导率成像。方法:采用连续波正弦信号激励产生磁声信号,利用锁相放大器进行磁声信号的频域幅值和相位的检测,设计基于虚拟仪器的磁声成像实验系统控制程序,进行金属模型的磁声信号实验验证。结果:设计的频域磁声成像实验系统信号幅值检测精度明显提高,达到10-7Pa,实现了磁声信号声源的空间定位,定位精度达到mm级。结论:设计的频域磁声耦合成像系统实现了低频激励下高分辨率声源定位,对于磁声耦合声源理论的研究以及提高磁声成像的精度具有重要意义。

Objective To design a new frequency domain magnato-aoustic imaging system to image the conductivity of medium. Methods A continuous sine wave signal was adopted to stimulate the MAT signal. The lock-in technique was applied to measuring the amplitude and phase of the magneto-acoustic signal. The drive control program of the imaging system was designed using virtual instrument tools. The experiments were conducted on the phantom made of coper wire.Results The amplitude precision was improved up to 10-7Pa, while the system could locate the sonic source with locating precision of millimeter. Conclusion A new magneto-acoustic imaging system is proposed with high locating precision as well as low frequency excitation, which is significative to the study on the sonic source theory and improvement of the imaging precision.