Stereoscopic depth rendition

It needs attention to ensure a realistic depiction of the three-dimensionality of viewed scenes and is a specific instance of the more general task of 3D rendering of objects in two-dimensional displays.

The geometric relationship between an object's third dimension and these position differences is presented below and depends on the location of the stereo-camera lenses and the observer's eyes.

[1] The right and left eyes' panels in a stereoscopic reconstruction are created by projection from the principal points of the twin recording camera.

Observers, who can fuse the twin images of the rings by voluntarily changing their convergence, can verify this by moving away and towards the viewing screen.

This particular condition has been termed homeomorphic by Moritz von Rohr and was contrasted by him with the heteromorphic one in which the r values of the stereoscopic and actual views differ.

[2] But homeomorphic rendition with geometrical parameters identical to the original does not assure that an observer's perception of depth in a stereoscopic image is the same as that in the actual three-dimensional structure.

An observer judgment of the apparent disposition of objects in space depends on many factors other than the geometrical ones that pertain to the angles subtended by the components at the two eyes.

[3] Scenes appear flattened through field glasses, even non-prismatic ones without artificial extension of the base, which provide merely overall magnification and leave the r value unchanged.

Geometry of screen view of a small cube at a distance z captured by a twin camera with separation a . Right and left eye images are shown superimposed.
A stereogram of intertwining rings. When fused by an observer, perceived depth increases with viewing distance.