Underwater Image Enhancement using Dark Channel Prior and Gamma Correction
Underwater images are usually degraded due to the effects of absorption and scattering. Underwater imaging is
very important in present technology for detecting object like fishes, algae, minor particles etc. Light scattering and color
change are two dominant sources of distortion for underwater imaging that lowers the visibility and contrast of the captured
images, affects ambient underwater environment dominated by a bluish tone. Hence, the presented system demonstrates a
novel approach to enhance underwater images by distance factor estimation along with a dehazing algorithm and histogram
equalization. The noise particles are removed before dehazing by implementing distance factor based on intensities of
different color channels with gamma correction improving the brightness of dimmed images. The dark channel prior
removes haze and noise effect, providing better visual quality with adaptive exposure map estimation for adjusting too dark
and too bright regions of underwater image. At the final stage, the contrast and brightness of dehazed image is recovered by
using contrast limited adaptive histogram equalization. The enhanced haze-free, natural appealing output can be used for
display and analysis purpose.
Keywords - Underwater image dehazing, distance factor, gamma correction, dark channel prior, histogram equalization.