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Enhancement of Underwater Images Using Wavelength Compensation Method

R.Sathya, M.Bharathi

Most important source of distortion in underwater environs are Haze and Hue alteration. Haze is produced because of the effect of light scattering by particle present in the underwater environment. Hue alterations occur when light enter deeper in underwater. These two issues make the picture look darker and low luminosity.Haze removal and Hue altered enhancement is important for this kind of low visibility and low contrast underwater images. The existing Dark Channel Prior method effectively removes Haze but color change is not processed. In this paper underwater image enhancement is carried out in two steps. In the first step Haze in the underwater image is removed using dark channel prior. In the second step Hue alterations handled by wavelength compensation. Once depth map is derived, luminance of foreground and background inside the image can be separated and compared. To regulate the Hue alteration wavelength can be compensated using average RGB channels in the image. After computing the scale value of each RGB component, wavelength is compensated together with the average RGB and scale value of each channel in the image. Performance of the proposed method of wavelength compensated image is evaluated using the PSNR, Focus Measurement, Contrast Improvement Index, and Feature Similarity Index. Performance measurement of the wavelength compensation produces better enhancement results than existing method.