I experience hypnogagic imagery, which is the things you "see" or "dream" when you are kind of falling asleep but aren't asleep. I get these multiple times each day because I often start to fall asleep several times during the day. I think they're kind of cool. They are a very normal part of the sleep process. I'm not sure if that's the same thing you're talking about or not. I don't consider them hallucinations--I think of those as occurring when one is fully awake.