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

Abstract

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.