  Underwater images suffer from extremely unfavourable conditions. Light is
heavily attenuated and scattered. Attenuation creates change in hue, scattering
causes so called veiling light. General state of the art methods for enhancing
image quality are either unreliable or cannot be easily used in underwater
operations. On the other hand there is a well known method for haze removal in
air, called Dark Channel Prior. Even though there are known adaptations of this
method to underwater applications, they do not always work correctly. This work
elaborates and improves upon the initial concept presented in [1]. A
modification to the Dark Channel Prior is proposed that allows for an easy
application to underwater images. It is also shown that our method outperforms
competing solutions based on the Dark Channel Prior. Experiments on real-life
data collected within the DexROV project are also presented, showing the
robustness and high performance of the proposed algorithm.
