Stereoscopic depth without monocular recognition

The search for stereograms that reveal depth features to two eyes that are concealed from each alone commenced with announcement of the invention of the stereoscope by Wheatstone in 1838. The paired figures he presented to the eyes were mostly simple outline drawings of geometrical objects, in order to reduce or remove monocular indications of depth. One stereogram, consisting of dots, yielded depth without monocular recognition; later others did so with more complex stereograms. Most notably in 1960, Julesz achieved this with computer-generated random-dot stereograms. Prior to Julesz similar patterns were hand-made, photographed and paired to yield stereograms by Cajal, Mobbs, Kompaneysky, and Aschenbrenner. Wheatstone did not recognise the significance of his simple dot stereogram possibly because he was interested in representing objects rather than surfaces stereoscopically. Thus, it can be argued that the precursors of random-dot stereograms were produced by Wheatstone in his article describing the invention of the stereoscope.