Underwater image enhancement based on colour correction and fusion

Underwater image processing has always been a very challenging problem. Under the influence of environmental factors, underwater images are prone to some problems, such as colour cast, low visibility, and few edge details. Here, an image enhancement algorithm is proposed to improve image degradation mainly caused by the absorption of light. First, colour compensation and white balance algorithm are used to restore the natural appearance of the image. Then the improved dark channel prior (DCP) is used to improve the visibility and avoid blocking artifacts which appear in traditional DCP. Unsharp masking (USM) is applied to enhance the texture features of the DCP image. Finally, wavelet fusion is used to fuse the DCP image and DCP + USM image. The fusion algorithm not only further improves the visibility and texture features, but also reduces the noise of DCP + USM. Compared with other methods, quantitative analysis results show that the enhanced images have higher visibility, more details and edge information.