Image correction by using adaptive optics in underwater turbulent medium

Optical communication methods are an important communication method due to their high data transmission speed and low latency. Underwater optical communication is an important optical communication method, but imaging is distorted in the underwater medium. Turbulence is a major cause of this distortion, affecting the performance of underwater communication. The propagation of arbitrary optical beams in the underwater environment was investigated by defining known and newly developed source profiles, and their average intensities were obtained and presented. The intensity of arbitrary optical beams in an underwater turbulent environment was analyzed by finding the receiver. Source field profiles of arbitrary optical beams were obtained by dividing the source area into pixels and adding phase and amplitude information to the pixels. The distribution of beam intensities at the receiver plane in an underwater turbulent environment was demonstrated using various beam types, including the familiar Gaussian beam, arbitrary beams shaped like a chess board, and the Ç.Ü. beam, which is derived from the initials of Çankaya University. The effects of underwater turbulence parameters such as wavelength, link length, rate of dissipation of the mean-squared temperature, ratio of temperature and salinity contributions to the refractive index spectrum, the dispersion rate of kinetic energy per unit mass of liquid, inner scale, receiver aperture diameter, and source size on beam intensity were investigated. Piston, tilt, and astigmatism components of adaptive optics correction to correct images distorted by optical beams due to underwater turbulence. The effectiveness of adaptive optics distortion was compared with and without the use of adaptive optics. Calculations were performed using MATLAB, and graphs were obtained. A quality criterion for correcting image distortion caused by underwater turbulence was determined, and the amount of correction was examined to understand how much image correction is achieved by the help of the adaptive optics. This thesis aims to minimize the effect of image distortion caused by turbulence in the underwater environment using adaptive optics correction. The work done in this thesis can be used in areas such as underwater optical imaging systems, underwater wireless optical communication, and improving the underwater performance of electro-optical systems.