Enhancing underwater images and videos by fusion

TLDR

The paper proposes a novel strategy to enhance underwater videos and images. The method fuses color‑corrected and contrast‑enhanced versions of a degraded underwater image with four weight maps derived solely from the input, enabling a single‑image, hardware‑free enhancement that preserves temporal coherence through edge‑preserving noise reduction. Experiments show the approach reduces noise, improves exposure of dark areas, enhances global contrast and fine details, and proves useful in several challenging applications.

Abstract

This paper describes a novel strategy to enhance underwater videos and images. Built on the fusion principles, our strategy derives the inputs and the weight measures only from the degraded version of the image. In order to overcome the limitations of the underwater medium we define two inputs that represent color corrected and contrast enhanced versions of the original underwater image/frame, but also four weight maps that aim to increase the visibility of the distant objects degraded due to the medium scattering and absorption. Our strategy is a single image approach that does not require specialized hardware or knowledge about the underwater conditions or scene structure. Our fusion framework also supports temporal coherence between adjacent frames by performing an effective edge preserving noise reduction strategy. The enhanced images and videos are characterized by reduced noise level, better exposed-ness of the dark regions, improved global contrast while the finest details and edges are enhanced significantly. In addition, the utility of our enhancing technique is proved for several challenging applications.