Recovering the images of underwater objects distorted by rough sea surface

Abstract

A method for approximation of the instantaneous shape of a waved sea surface as a superposition of harmonic waves with unknown amplitudes, wave vectors, and phases is proposed. These unknown parameters are determined using glint characteristics, such as their coordinates and areas. It is shown that for a certain ratio of the number of harmonics and glint, these unknowns can be defined as a solution to the derived system of nonlinear equations. Next, the task of restoring an instant image of an underwater object distorted by surface waves is solved. An algorithm has been developed for reconstructing the original image distorted by the waves, based on the approximation of the instantaneous shape of the waved surface. A full-scale experiment was conducted, the results of which showed the efficiency of the method. The reasons that impede a fairly good recovery, and ways to eliminate these difficulties are noted. It is shown that with an a priori known shape of the object, the depth of its location can be determined by the criterion: “as the depth of the best restoration of the shape of the object”. Adding modules to the developed algorithm that take into account the scattering and absorption of light in the atmosphere and in sea water will make it possible to use it for image corrections of underwater objects taken from aircraft.