Underwater Image Restoration and Enhancement Based on a Fusion Algorithm With Color Balance, Contrast Optimization, and Histogram Stretching

Weilin Luo,Jiwen Zheng,Shunqiang Duan

doi:10.1109/access.2021.3060947

Weilin Luo, Jiwen Zheng + Show 1 more

Open Access

https://doi.org/10.1109/access.2021.3060947

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Abstract

A fusion algorithm is proposed for the restoration and enhancement of underwater images. Color balance, contrast optimization and histogram stretching are carried out. To alleviate the effect of color shift in an underwater image, the scalar values of R, G, B channels are renewed so that the distributions of the three channels in histogram are similar. Instead of refining the transmittance in dark channel prior based restoration, an optimized contrast algorithm is employed by which the optimal transmittance is determined. To further improve the brightness and contrast of underwater images, a histogram stretching algorithm based on the red channel is given. To verify the effectiveness of the proposed fusion algorithm, experimental underwater images are treated. Results show that the quality of underwater images is improved significantly, both in term of subjective visual effect and objective evaluation. The proposed underwater image processing strategy is also compared with some popular techniques. Comparison results indicate the advantage of the proposed strategy over others.

Highlights

In the human exploration and exploitation of ocean, the underwater mission is challenging
The images in left column are processed by proposed fusion algorithm in which color balance, optimized contrast and histogram stretching based on red channel are combined
This paper proposes a fusion algorithm for underwater image restoration and enhancement, in which color balance, contrast optimization and histogram stretching based on red channel are combined

Summary

Introduction

In the human exploration and exploitation of ocean, the underwater mission is challenging. The acquisition and analysis of underwater information is vital to accomplish underwater missions like underwater object localization [1], marine life recognition [2], underwater archeology [3], underwater environment monitoring [4], underwater search and salvage [5], underwater maintenance [6], etc. Underwater optical image provides an important source of underwater information. Due to the characteristic attenuation and scattering of light in water, underwater images through camera sensors are apt to degrade. The attenuation results in color shift while scattering of light makes an underwater image blurred and a decrease of contrast. The movement of water or fish shoal can cause so-called motion blur [7].

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