Center for Advanced Diffusion-Wave Technologies (CADIFT), Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, M5S 3G8, Canada.
J Acoust Soc Am. 2011 Sep;130(3):1313-24. doi: 10.1121/1.3605290.
The development of the pulse compression photoacoustic (PA) radar using linear frequency modulation (LFM) demonstrated experimentally that spectral matching of the signal to the ultrasonic transducer bandwidth does not necessarily produce the best PA signal-to-noise ratio, and it was shown that the optical and acoustic properties of the absorber will modify the optimal bandwidth. The effects of these factors are investigated in frequency-domain (FD) PA imaging by employing one-dimensional and axisymmetric models of the PA effect, and a Krimholtz-Leedom-Matthaei model for the employed transducers. LFM chirps with various bandwidths were utilized and transducer sensitivity was measured to ensure the accuracy of the model. The theory was compared with experimental results and it was shown that the PA effect can act as a low-pass filter in the signal generation. Furthermore, with the PA radar, the low-frequency behavior of two-dimensional wave generation can appear as a false peak in the cross correlation signal trace. These effects are important in optimizing controllable features of the FD-PA method to improve image quality.
使用线性调频（LFM）技术开发的脉冲压缩光声（PA）雷达的实验结果表明，信号与超声换能器带宽的频谱匹配不一定能产生最佳的 PA 信噪比，并且证明了吸收体的光学和声学特性会改变最佳带宽。通过采用一维和轴对称的 PA 效应模型以及所使用的换能器的 Krimholtz-Leedom-Matthaei 模型，在频域（FD）PA 成像中研究了这些因素的影响。利用了具有不同带宽的 LFM 啁啾信号，并测量了换能器的灵敏度，以确保模型的准确性。将理论与实验结果进行了比较，结果表明，PA 效应在信号产生中可以起到低通滤波器的作用。此外，对于 PA 雷达，二维波产生的低频行为可能会在互相关信号迹中表现为虚假峰值。这些效应对于优化 FD-PA 方法的可控特性以提高图像质量非常重要。
