autostereogramssingleimage

An autostereogram is an image designed to create the illusion of depth from a single picture when viewed with relaxed eyes. The single-image version, commonly called a single-image autostereogram or single-image random dot stereogram, encodes three-dimensional structure into one 2D image without requiring a separate left-right pair. The viewer's brain fuses two offset copies of the repeating texture to reveal a hidden 3D scene.

Autostereograms rely on horizontal disparity. A depth map or depth cue determines, for each horizontal position, how far the pattern must be shifted within the image's repeating texture. Areas that should appear closer in depth are displaced more, while distant areas are displaced less or not at all. The result is a texture that seems visually flat at first glance, but, when the eyes are guided to diverge or converge to the correct distance, a stereoscopic image emerges.

There are different families of single-image autostereograms. The classic form uses a random-dot texture, producing single-image random dot stereograms (SIRDS). Other implementations use decorative textures or repeating patterns. Software and online generators allow users to supply a grayscale depth map and a texture, producing the autostereogram.

Viewing requires practice. Typical methods include parallel viewing or cross-eyed focusing; the required viewing distance is roughly proportional to the image width. Some people experience eye strain or difficulty perceiving depth. Autostereograms are used for entertainment, art, and demonstrations of binocular vision, and they remain a notable example of computational depth encoding in a single image.