Antiquity POCKET STEREOSCOPE Stereo Butterfly With Lea Symbols Stereopsis Test Kit  (Polarized)

Stereoscopy creates the illusion of three-dimensional depth from given two-dimensional images.[5] Human vision, including the perception of depth, is a complex process, which only begins with the acquisition of visual information taken in through the eyes; much processing ensues within the brain, as it strives to make sense of the raw information. One of the functions that occur within the brain as it interprets what the eyes see is assessing the relative distances of objects from the viewer, and the depth dimension of those objects. The cues that the brain uses to gauge relative distances and depth in a perceived scene include