What does illusion mean?

Illusion is distorted perception, that is, the actual thing is distorted and perceived as something completely inconsistent with the actual thing. There are many reasons for the illusion. Poor perceptual conditions, unclear objective stimuli, decline in audio-visual function, strong emotional influence, imagination, suggestion and disturbance of consciousness can all cause illusions. Hard of hearing people often hear what others say wrong; Timid people walk alone in the wilderness at night, afraid in their hearts, and will treat trees as adults and mistake their footsteps for someone is chasing them; Long-term suspense about relatives will mistake the wind for someone knocking at the door. Illusion itself does not necessarily mean illness, because healthy people can have illusions, but healthy people can correct them themselves. Common misconceptions include (1) false vision: for example, taking a coat hanging on a hanger as a person hiding behind a door; The ceiling lamp is considered as a human head hanging from the ceiling. These are all examples of illusions. In addition, there is a special illusion, that is, patients mistakenly perceive the actual thing as a completely different image from the original through their own subjective imagination. For example, patients perceive colorful clouds in the sky as dancing fairies through imagination; Some patients mistakenly perceive the cracks in the wall as some beautiful patterns or ferocious monsters with ferocious faces. (2) Besides wrong vision, there are wrong taste, wrong touch, wrong smell, wrong hearing and inner perceptual illusion.