Principles of Designing an “Ideal” System of Imaging Through a Rough Water Surface

Abstract

We propose new principles for designing a system of imaging through a rough water surface. These principles permit one to reduce the negative impact of the surface roughness and multiple scattering in water on the spatial resolution. The system model in which the image of underwater objects is generated by angular scanning with an illumination beam is considered. Image distortions in such a system are due mainly to random variations in the refraction angle of a laser beam on the surface and can be eliminated if the true direction of entry of the beam into water is known. Information on the beam refraction angle is suggested to be taken from the angular distribution of the radiance of the signal backscattered by the subsurface water layer. Reduced impact of multiple scattering in water is reached by high-frequency modulation of the beam power by a complex signal and matched processing in the reception system. It is shown that a combination of proposed imaging techniques gives an essential gain in the resolution of the airborne imaging system.