A hallucination in the broaest sense is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli and that have qualities of real perception in that they are vivid, substantial, and located in external objective space. These definitions distinguish hallucinations from the related phenomena of dreaming (no consciousness), illusion (distorted or misinterpreted real perception), imagery (does not mimick real perception and is under voluntary control), and pseudohallucination (does not mimick real perception, but is not under voluntary control). Hallucinations also differ from "delusional perceptions", in which a correctly sensed and interpreted genuine perception is given some additional (and typically bizarre) significance.