A visual illusion in which a chequered pattern of small black and white rectangles, containing a circular region in which the rectangles are oriented at right angles to those in the rest of the figure, creates an impression of relative motion when the whole pattern is moved (see illustration), the illusion being caused by the excitation of spatially overlapping ON and OFF regions of centre-surround receptive fields of retinal neurons. Also spelt Ōuchi illusion. Compare Pinna-Brelstaff illusion. [Named after the Japanese graphic artist Hajime Ōuchi who first published it in a book of graphic designs in 1973]
Ouchi illusion. An illusion of relative motion, most vividly seen if the image is moved slowly from side to side or in a circle.