We've all experienced REM. I notice that while awake, with eyes closed (or even open!), I can generate a sequence of images by allowing my eyes to integrate together the present image with my semiconscious lucid thoughts. For instance, I might visualize a vacation spot in the Black Forest and decide to walk to its edge, then shift my eyes to a scene in Connecticut - still associated by the pines and my relatives of German descent who live there. This nonlinear, virtual and intricate processing we use during wakefulness as much as sleep. Please try this method and reply here as to whether it intensifies and modifies your waking imagery.