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A fast enhancing method for non-uniformly illuminated underwater images

Enhancement of underwater images and videos is an important task required in several image-based applications like survey, seafloor mapping, telepresence, documentation etc. Color correction or white balance of underwater images is the most challenging issue because of the highly-variable illumination conditions, increasing bluish shift with the depth. Another problem is the low image contrast with poorly visible details due to the scattering effects. This paper presents a fast enhancement method for non-uniformly illuminated underwater images. The method is based on the gray-world assumption applied in the Ruderman-lαβ opponent color space. The color correction is performed according to locally changing luminance and chrominance by using the summed-area table technique. Due to the low-complexity cost this method is suitable for real-time applications ensuring realistic colors of the objects, more visible details and enhanced visual quality.