利用维纳滤波改善声透镜光声成像系统的分辨率

为了克服衍射效应对光声成像系统分辨率的限制,需要采用逆卷积方法进行图像反演.从理论上分析了声透镜成像原理,模拟仿真了声透镜的点扩展函数对声透镜成像系统分辨率的影响和维纳滤波解卷积方法复原光声成像的过程,并利用自搭建的声透镜光声成像系统进行了深入的实验研究,得到了物平面上相距4 mm和3 mm的两个黑胶带点的直接成像光声...

Resolution Improvement of Photoacoustic Imaging System Based on an Acoustic Lens with Winere Filter

Photoacoustic imaging technique based on an acoustic lens taking advantages of 2-D real time imaging and tomography, can realize fast real time photoacoustic imaging, i.e. an acoustic lens with imaging ability can directly form the image of the initial photoacoustic pressure distribution on the image plan.Photoacoustic imaging includes four steps: light absorption, photoacoustic signal induction, ultrasonic detection and image reconstruction. Studies have shown that photoacoustic image based on an acoustic lens imaging system is the convolution between object’s distribution function and acoustic lens’s point spread function(PSF). Because of acoustic lens’s PSF, that leads the photoacoustic image generated from the photoacoustic imaging system to a degraded image,and then the resolution of the photoacoustic image obained from an acoustic lens imaging system decreases. If the acoustic lens imaging system’s PSF can be measured accurately, objects distribution function can be recovered with digital deconvolution method, and thus improve the resolution of an acoustic lens imaging system. In this paper, by using Fourier transform theory we analyze with details the point spread effect of an acoustic lens, and export its point spread function. Simulation process of recovering photoacoustic imaging using Wiener filter deconvolution is acquired in theory, and take in in-depth experimental study.Simulation results and the experimental results show that: The Wiener filter deconvolution method is workable at improving the resolution of acoustic lens photoacoustic imaging systems.