Visibility Restoration of Underwater Optical Images using Dehazing Algorithm and Enhancement Techniques

Abstract

We have investigated the problem of underwater hazy image enhancement and restoration in this thesis. Underwater image processing has several applications in the field of oceanic research work and scientific applications such as archaeology, geology, underwater environmental assessment, laying of long distance gas pipelines and communication links across the continents which demand geo-referential surveying of the oceanic bed and prospection of ancient shipwreck. There are many difficulties for undersea optical imaging. The submerging of a camera underwater requires adequate housing. The maneuvering of the camera with the help from remote place or in person at the site is likewise a complex task. However, the major challenge is imposed by underwater medium properties. Underwater haze image enhancement has gained widespread importance with the rapid development of modern imaging equipment. However, the contrast enhancement of single underwater hazy image is a challenging task for scientific exploration and computational applications. At greater depths, due to attenuation in light propagation, the underwater images are prone to inferior visibility. The artificial source of lighting is used to increase the visibility range, resulting in non-uniform illumination pattern. The presence of marine snow and small floating particle in the cone of vision of camera and image plane results in forward and backward scattering of light energy, rendering low contrast and hazy image appearance. Also, light is attenuated with a lateral distance of propagation, reducing the light energy reaching the camera, thus resulting in a loss of the natural color. Thus, the primary goal of underwater image enhancement is the removal of the hazy veil and color compensation using the single underwater image. newlineSo in this study, we are motivated to address the underwater imaging problems like limited visibility, non-uniform illumination, and diminished contrast by developing underwater image enhancement and restoration algorithms by overcoming the