An Integrated Method to Remove Color Cast and Contrast Enhancement for Underwater Image

Abstract

Light scattering and absorption of light in water cause underwater images to be poorly contrasted, haze and dominated by a single color cast. A solution to this is to find methods to improve the quality of the image that eventually leads to better visualization. We propose an integrated approach using Adaptive Gray World (AGW) and Differential Gray-Levels Histogram Equalization for Color Images (DHECI) to remove the color cast as well as improve the contrast and colorfulness of the underwater image. The AGW is an adaptive version of the GW method where apart from computing the global mean, the local mean of each channel of an image is taken into consideration and both are weighted before combining them. It is applied to remove the color cast, thereafter the DHECI is used to improve the contrast and colorfulness of the underwater image. The results of the proposed method are compared with seven state-of-the-art methods using qualitative and quantitative measures. The experimental results showed that in most cases the proposed method produced better quantitative scores than the compared methods.

Underwater Image Enhancement via Higher-Order Moment CLAHE Model and V Channel Substitute

“…The Gray World method, commonly used for color distortion correction in engineering applications [38], often leads to red shading in underwater images when directly applied. This is because the method assumes equal average gray values for the R, G, and B channels.…”