[jsjw7sbw]

What annoyed me with that answer is they didn't explain why they needed the color chart at all. I would assume it's for training some model, which would lead to this method not working without the chart out of the box for example in muddy waters.

[juliendorra]

The chart is needed to validate that the algorithm works: you need to have known colors in the image, you need a reference. (The chart is the ground truth)

Once the chart is back to its exact color, the image can be considered corrected (at least for this distance, illumination…).

If the algorithm brings the chart back to its true colors at several distances and in various conditions, then it can be applied confidently on images without a chart.

[bayesian_horse]

It might indeed require new training data for substantially different kinds of haze.

They are only talking about reefs though, which means tropical ocean water. Coral don't thrive in muddy water.