为了进一步提高光声重建图像的质量, 采用滤波反投影算法进行图像重建。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, 接收面的直径为1mm, 得到了4个圆形吸收体和5根头发的光声重建图像。仿真和实验结果表明：通过对信号进行滤波, 能很好地抑制噪声信号, 明显提高图像的对比度和分辨率。

In order to improve the quality of photoacoustic reconstructed image, an algorithm of filter back-projection was adopted. A Q-switched Nd∶YAG laser operating at 1 064nm was used as the light source. The laser had a pulse width of 7ns and a repetition frequency of 20Hz. A needle PVDF hydrophone with a diameter of 1mm was used to detect photoacoustic signals. The photoacoustic reconstructed images of four rounded absorbers and five hairs were obtained. The results of simulations and experiments show that the algorithm restrains noise effectively, and improves the contrast and resolution of images.