Underwater Image Restoration Based on Dark Channel Prior

Underwater images are usually affected by the turbid water medium and floating particles existed in the water. Thus attenuation, absorption, and scattering happen while light propagates in the water. These phenomena cause low contrast in underwater images, and make them look like covering by a veil. In addition, colors disappear sequentially according to the wavelength while light travels deeper in the water, which makes underwater images blue. On the other hand, we observe that underwater images are similar to haze images because they have the same problems of low contrast and color shifting. This has motivated our use of the haze removal technique, namely, dark channel prior, to dehaze underwater images. Subsequently, we equalize the color mean in each RGB channel to balance the color. Finally, we use CLAHE to enhance the contrast of the images. Experimental results indicate that the proposed method effectively removes the haze in a wide variety of underwater images and successfully recovers the color and contrast.