Some objects in an image that might be "hidden" because it's to dark could be fixed by e.g. contrast stretching, to increase the intensity values of the pixels. There are more reasons for radiometric corrections, but that is one of the applications. If we talk about passive sensors then it's about measured reflected EM radiation, which can good or bad images depending on the context.
Must be very fascinating to listen to music or watching movies where you can utilize that quality. I haven't had any personal experience with high-end headphones with DACs or AMPs.
You can intrude as much as you want. The course has some elements of that, but mostly of doing thing such as contrast stretching, edge detection, noise removal geometric/radiometric correction and so on.
Would you consider yourself an audiophile? Since you wrote "Anything in the pursuit of better Audio quality.". How do you strive for when you want higher quality in audio? Why do you like aquariums? Do you like anything that has to do with water? What about the ocean specifically? Do enjoy fishing? Do you sea life? If so is there anything you really like in particular? What about coral reefs, do you enjoy those? Do you like animals in general? Is there some predatory animals you really like? Do you have any animals? What games do you like (besides fire emblem and code vein)?