Underwater Image Enhancement Using Successive Color Correction and Superpixel Dark Channel Prior

Ho Sang Lee,Il Kyu Eom,Sang Whan Moon

doi:10.3390/sym12081220

Abstract

Underwater images generally suffer from quality degradations, such as low contrast, color cast, blurring, and hazy effect due to light absorption and scattering in the water medium. In applying these images to various vision tasks, single image-based underwater image enhancement has been challenging. Thus, numerous efforts have been made in the field of underwater image restoration. In this paper, we propose a successive color correction method with a minimal reddish artifact and a superpixel-based restoration using a color-balanced underwater image. The proposed successive color correction method comprises an effective underwater white balance based on the standard deviation ratio, followed by a new image normalization. The corrected image based on this color balance algorithm barely produces a reddish artifact. The superpixel-based dark channel prior is exploited to enhance the color-corrected underwater image. We introduce an image-adaptive weight factor using the mean of backscatter lights to estimate the transmission map. We perform intensive experiments for various underwater images and compare the performance of the proposed method with those of 10 state-of-the-art underwater image-enhancement methods. The simulation results show that the proposed enhancement scheme outperforms the existing approaches in terms of both subjective and objective quality.

Highlights

Light is attenuated due to the complicated underwater environment and lighting conditions when it propagates through water
Let Ic M (x) this paper, we present an improved underwater white balance (UWB) method using the standard deviation ratio of color be the color-corrected pixel based on the proposed method, which is obtained by channels
5 shows the color correction results obtained for normal underwater images with a Figure shows the color correction for normal underwater images with a moderately weak red channel

Summary

Introduction

Light is attenuated due to the complicated underwater environment and lighting conditions when it propagates through water. Images captured under water have a reduced contrast and hazy effect. Two major factors lead to the degradation of underwater images. The first factor is that reflected light from the underwater object is absorbed and scattered by particles suspended in water, which lowers the image contrast and produces a hazy effect in the underwater image. The second factor is the attenuation of light, which depends on the optical wavelength, dissolved organic compounds and water salinity, which causes various color casts. Because red light has a longer wavelength, most underwater images look bluish or greenish. Color correction is a difficult task because the distortion of color occurs asymmetrically depending on the wavelength of light. Enhancing underwater images is a challenging and important task [1,2,3]

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Conclusion