The science and craft of autostereograms.

Autostereograms or SIRDS (Single Image Random-Dot Stereograms) are camouflaged stereograms which combine the Julesz random-dot stereogram principle with the wallpaper effect. They can represent any 3D shape on a single image having a quasi-periodic appearance. Rather large SIRDS can be interpreted in depth with unaided eyes. In the hands of computer graphic designers, SIRDS spread all over the world in 1992-1994, and these images, it was claimed, opened a new era of stereoscopic art. Some scientific, algorithmic and artistic aspects of these images are reviewed here. Scientifically, these images provide interesting cues on stereoscopic memory, and on the roles of monocular regions and texture boundaries in stereopsis. Algorithmically, problems arising with early SIRDS, such as internal texture repeats or ghost images are evoked. Algorithmic recommendations are made for gaining a better control on the construction of SIRDS. Problems of graphic quality (smoothness of the represented surfaces, or elimination of internal texture repeats) are discussed and possible solutions are proposed. Artistically, it is proposed that SIRDS should become less anecdotal, and more oriented towards simple geometric effects, which could be implemented on large panels in natural surrounds.