为了实现高质量的快速光声图像重建, 研究了不同采样率对光声图像重建的影响。由实验表明, 对于mm量级与几百μm量级的吸收体, 将采样率分别调整到5～7 MHz和7～9 MHz时, 其成像质量好, 速度快。实验所用的光源为YAG激光器, 波长为1 064 nm, 重复频率为20 Hz, 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。

In order to attain the reconstruction of photoacoustic images with high-contrast and fast noninvasive features, the effect from different sample rates was studied. The experimental results demonstrate that frequency of sample rate is about 5～7 MHz for the absorber with a few millimeter diameters, and it is 7～9 MHz for hundreds of μm diameter absorber. A Q-switched Nd: YAG laser, which operates at 1 064 nm, was used as light source. The laser has a 7 ns of pulse width and a 20 Hz of repetition frequency. A needle PVDF hydrophone with 1 mm diameter was used to detect photoacoustic signals.