Pocket stereoscope with original test image. Used by military to examine stereoscopic pairs of aerial photographs.Difference in projections of a vertical line in stereoscopy according to distance between left and right eye - animation for eye distance . View of Boston, c. 1860; an early stereoscopic card for viewing a scene from natureStereoscopic image of 787 Orange Street, Addison R. Tinsley house, c. 1890sStereoscopic image of 772 College Street (formerly Johnson Street) in Macon, Ga, c. 1870sKaiserpanorama consists of a multi-station viewing apparatus and sets of stereo slides. Patented by A. Fuhrmann around 1890.[1]A company of ladies looking at stereoscopic views, painting by Jacob Spoel, before 1868. An early depiction of people using a stereoscope.
Stereoscopy (also called stereoscopics, or stereo imaging) is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision.[2] The word stereoscopy derives from Greekστερεός (stereos) 'firm, solid' and σκοπέω (skopeō) 'to look, to see'.[3][4] Any stereoscopic image is called a stereogram. Originally, stereogram referred to a pair of stereo images which could be viewed using a stereoscope.
Most stereoscopic methods present a pair of two-dimensional images to the viewer. The left image is presented to the left eye and the right image is presented to the right eye. When viewed, the human brain perceives the images as a single 3D view, giving the viewer the perception of 3D depth. However, the 3D effect lacks proper focal depth, which gives rise to the Vergence-Accommodation Conflict.
Stereoscopy is distinguished from other types of 3D displays that display an image in three full dimensions, allowing the observer to increase information about the 3-dimensional objects being displayed by head and eye movements.