This is a video discussing and demonstrating the 'Sea-Thru' (clever!) algorithm developed by oceanographer and engineer Derya Akkaynak that removes the blueish tint to underwater photography that occurs as a result of how sea water "selectively absorbs and scatters light at different wavelengths," making it difficult to discern the true colors of sea life, particularly reds and yellows. Some more info while I speculate if they used this for The Little Mermaid:
Sea-thru's image analysis factors in the physics of light absorption and scattering in the atmosphere, compared with that in the ocean, where the particles that light interacts with are much larger. Then the program effectively reverses image distortion from water pixel by pixel, restoring lost colors.
One caveat is that the process requires distance information to work. Akkaynak takes numerous photographs of the same scene from various angles, which Sea-thru uses to estimate the distance between the camera and objects in the scene--and, in turn, the water's light-attenuating impact. Luckily, many scientists already capture distance information in image data sets by using a process called photogrammetry, and Akkaynak says the program will readily work on those photographs.
Pretty cool. You know what would be even cooler though? "An algorithm that removed all the plastic waste from underwater photography." *touches tip of nose* "You're saying I'm right?" No, I'm saying you've got a boogie. Been there for about an hour, really hard to look away from, can't believe you haven't noticed the stares. But yes also you were right.
Keep going for the video.
Thanks to Caroline, who agrees it was probably either this or draining the oceans.