Analysis of underwater image enhancement techniques based on contrast and edge preservation

Abstract

The utilization of underwater imagery has extensive applications in newlinesurveillance and monitoring, including pipeline monitoring, marine newlinearchaeology, and military operations, among others. Marine archaeologists newlineprimarily focus on detecting and examining submerged prehistoric sites newlinethrough image analysis. A preliminary evaluation of the images is essential newlinefor conducting further analysis. Currently, specialized tools such as newlineAutonomous Underwater Vehicles (AUVs) and Remotely Operated Vehicles newline(ROVs) are employed to investigate submerged materials at various depths of newlinethe seafloor. Poor visibility of underwater images results from attenuation of newlinepropagated light, light reflection, and absorption. In the aquatic medium, the newlinechaotic attenuation of the light may result in a foggy and misty appearance newlineand poor contrast in the image of the distant object. The quality of the newlineunderwater image is degraded and distorted in the water medium by light newlineabsorption and scattering. Changes in colour and the bluish hue in the images newlineare due to the refraction and absorption of light by the particles in water. The newlinecolours with larger wavelengths are absorbed more with increasing depth; newlinehence, the perception of colour is related to the depth of the underwater newlinemedium. An important problem that needs to be rectified is the green-bluish newlineappearance of the underwater image in the shallow water region due to the newlineabsorption of red colour in this region. Followed by Red colour; at increased newlinedepths, the green colour is absorbed more than blue, resulting in a bluish tone. newlineWith further increase in depth, only gray-level images are observed. All these newlineissues contribute to blur and degradation in underwater images with respect to newlinecolour distortions and indistinct edge details. Most of the underwater newlineapplications require clear underwater images. newline