> If going to sleep, these images get more vivid and might classify for something called hypnagogic hallucinations

Try your meditation routine while sitting in a warm shower with a visual focus. That for me gives me the same intensity as the true hypnagogic level visualizations while still having close to full mental faculties.

Some people report being able to use audio patterns as an alternative to visual patterns. I've had mixed success personally but ymmv.