水下高斯界面背向散射超声散斑场的相位奇异

为了精确描述超声散斑场的特性,提出了采用计算机模拟产生超声散斑场的方法.利用模拟产生的高斯相关随机表面,获得了这类表面远场超声散斑场,同时得到了声强分布和相位分布.与实验产生的散斑场进行对比,建立了超声散斑场接收的实验系统,取与计算模拟相同的参数,获得了实验散斑场.通过对比发现:计算机模拟产生的超声散斑场相位存在奇异点,奇异点周围相位分布类似漩涡,计算机模拟产生的散斑场与实验得到的散斑场强度分布相似,强度值比实验产生的散斑场强度大,携带有用信息的高亮散斑较多,暗点较少,更利于研究和分析.

Phase singularities of an ultrasonic speckle field back-scattered from an underwater Gaussian interface

In order to describe the characteristics of the ultrasonic speckle field accurately, a computation-simulated generation of ultrasonic speckle field is proposed. Using the Gaussian correlation random surfaces that are generated by the simulation, the simulation of the speckle field produced by this kind of surfaces in the far field, the sound intensity distribution, and phase distribution can also be obtained. To compare the difference between speckle field from experiment and that by the simulation, the ultrasonic speckle field receiving experimental system is established, taking the same parameters to calculate and simulate, the experimental speckle field is obtained. By contrast, phase singularity exists in the simulated speckle field and the phase distribution is similar to the swirl around singular points, The intensity distribution of the simulated speckle field and that obtained experimentally are similar, but the former has a bigger strength, more highlight speckles carrying useful information, dark speckle being less, so that it is more conducive to the research and analysis.
Keywords： ultrasonic speckle Gaussian interface phase singularity