Stereografie

Stereografie, or stereography, is the study and practice of representing three-dimensional objects and scenes on two-dimensional media, and of constructing three-dimensional views from multiple images. The term also refers to stereographic projection, a mathematical mapping from a sphere to a plane that preserves angles locally and is widely used in geometry, cartography, and complex analysis. The word stems from Greek stereos meaning “solid” and graphein meaning “to write” or “to draw.”

In imaging contexts, stereography involves capturing two offset images from slightly different viewpoints. When these image pairs are viewed with appropriate equipment or techniques, the viewer perceives depth. Methods include stereo photography viewed with a stereoscope, red–cyan or other colored anaglyphs, polarized 3D systems, and active shutter displays. Autostereograms allow depth perception without specialized eyewear. Stereography has found modern applications in 3D cinema, virtual reality, medical imaging, and architectural visualization.

In mathematics and cartography, stereographic projection maps points on a sphere to a plane by projecting from a fixed point on the sphere onto a plane. This projection is conformal, preserving local angles, and it typically sends circles on the sphere to circles on the plane (or to straight lines). It is a standard tool in the visualization of the Riemann sphere for complex analysis and in the creation of certain types of spherical maps. The concept also underpins various geometric constructions and artistic representations of extended 3D forms on flat media.