stereoscopy

Stereoscopy is a technique for creating or perceiving three-dimensional depth by presenting two slightly offset images to the left and right eye. The brain fuses these images into a single perception of depth, relying on binocular disparity, convergence, and other depth cues. In practice, stereoscopic content is captured with two cameras a fixed distance apart or generated digitally by rendering left and right views.

Common formats include side-by-side or over-under image pairs, red–cyan anaglyphs, and polarized or active shutter systems that deliver different images to each eye. Autostereoscopic methods, such as lenticular lenses or parallax barriers, aim for glasses-free 3D but are less widely used for motion content. Stereoscopy can also be produced with virtual reality displays and 3D computer graphics.

Applications span cinema and home theater, virtual reality and simulators, medical imaging, and geographic information systems. In entertainment, stereoscopy enhances spatial realism but can cause discomfort if misaligned, poorly calibrated, or when accommodation-vergence conflicts occur.

History: The concept was demonstrated by Charles Wheatstone in the 1830s with the stereoscope, followed by Sir David Brewster's improvements. Stereoscopy enjoyed periodic revivals through the 20th century with advances in film projection, and is central to modern VR and 3D displays.