│ω│滤波器对光声成像的影响

Influence of │ω│ Filter on Photoacoustic Imaging

光声成像结合了组织纯光学成像和组织纯声学成像的优点,是一种很有潜力的无损伤的医学成像技术。本文研究了四种不同的ω滤波器,即RL滤波器,SL滤波器,改进的SL滤波器和Kwoh-R eed滤波器,利用滤波反投影算法分析了它们对光声图像重建质量的影响,由仿真和实验结果表明,Kwoh-R eed滤波器对强噪音有着很好的抑制作用,能明显的提高图像的对比度。实验所用的光源为YAG激光器,波长为532 nm,重复频率为30 H z,脉宽为7 ns,探测器为针状的PVDF膜水听器,接收面积的直径为1 mm。

Photoacoustic tomography （PAT） combines the advantages of pure optic imaging and pure ultrasound imaging. It has a potential to become a novel noninvasive medical imaging technology. We have explored filters of RL, SL, Modi-SL and Kwoh-Reed, which influences on photoacoustic imaging. The result of simulations and experiments show that Kwoh-Reed can restrain noise effectively and improve the contrast of images. A Q-switched Nd：YAG laser operating at 532 nm was used as light source. The laser had a pulse width of 7 ns and a repetition frequency of 30 Hz. A needle PVDF hydrophone with diameter of 1 mm was used to detect photoacoustic signals.