Stereoscopic motion, as introduced by

Béla Julesz Béla Julesz (also Bela Julesz in English; February 19, 1928 – December 31, 2003) was a Hungarian-born American visual neuroscientist and experimental psychologist in the fields of visual and auditory perception. Julesz was the originator of ...

in his book ''

Foundations of Cyclopean Perception ''Foundations of Cyclopean Perception'' () is a book by Bela Julesz, published in 1971. Julesz, B. (1971). ''Foundations of Cyclopean Perception''. Chicago: The University of Chicago Press. The Millennium Project ranked it at #57 on a list of t ...

'' of 1971, is a translational motion of figure boundaries defined by changes in

binocular disparity Binocular disparity refers to the difference in image location of an object seen by the left and right eyes, resulting from the eyes’ horizontal separation (parallax). The brain uses binocular disparity to extract depth information from the two-di ...

over time in a real-life 3D scene, a

3D film 3D films are motion pictures made to give an illusion of Three-dimensional space, three-dimensional solidity, usually with the help of Stereoscopy#3D viewers, special glasses worn by viewers. They have existed in some form since 1915, but had been ...

or other stereoscopic scene. This translational motion gives rise to a

mental representation A mental representation (or cognitive representation), in philosophy of mind, cognitive psychology, neuroscience, and cognitive science, is a hypothetical internal cognitive symbol that represents external reality, or else a mental process that ma ...

of three dimensional

motion In physics, motion is the phenomenon in which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed and frame of reference to an observer and mea ...

created in the

brain The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head ( cephalization), usually near organs for special ...

on the basis of the binocular motion stimuli. Whereas the motion stimuli as presented to the eyes have a different direction for each eye, the stereoscopic motion is perceived as yet another direction on the basis of the views of both eyes taken together. Stereoscopic motion, as it is perceived by the brain, is also referred to as ''cyclopean motion'', and the processing of visual input that takes place in the visual system relating to stereoscopic motion is called ''stereoscopic motion processing''. Provided the binocular motion stimuli correspond to a

physical object In common usage and classical mechanics, a physical object or physical body (or simply an object or body) is a collection of matter within a defined contiguous boundary in three-dimensional space. The boundary must be defined and identified by t ...

moving in

3D space Three-dimensional space (also: 3D space, 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called ''parameters'') are required to determine the position of an element (i.e., point). This is the informal ...

, the stereoscopic motion closely represents its actual motion. Alternatively, the images with the binocular motion stimuli can be artificially created, for instance using dynamic random dot stereograms. Cyclopean (stereoscopic) motion and cyclopean images are aspects of so-called ''cyclopean vision'' – named after the mythical giant

Cyclops In Greek mythology and later Roman mythology, the Cyclopes ( ; el, Κύκλωπες, ''Kýklōpes'', "Circle-eyes" or "Round-eyes"; singular Cyclops ; , ''Kýklōps'') are giant one-eyed creatures. Three groups of Cyclopes can be distinguish ...

who had only one eye – involving a mental representation of objects in space as if they were perceived in full depth and from a position of a "cyclopean eye" situated approximately between the two eyes. By definition, individuals who have only monocular vision do not perform stereoscopic motion processing. They rely instead on

monocular depth cues Depth perception is the ability to perceive distance to objects in the world using the visual system and visual perception. It is a major factor in perceiving the world in three dimensions. Depth perception happens primarily due to stereopsis a ...

to perceive motion in space (''see also:'' kinetic depth effect).

Sensing and processing

Stereoscopic motion is sensed in a way that cannot be explained by feature tracking or by inferring the motion from memory of position and time, and it appears to involve specific low-level motion sensing. Purely binocular motion stimuli appear to influence also stereoblind persons as far as their sensation of self-motion is concerned. Using dynamic random dot stereograms presented using a

virtual reality Virtual reality (VR) is a simulated experience that employs pose tracking and 3D near-eye displays to give the user an immersive feel of a virtual world. Applications of virtual reality include entertainment (particularly video games), e ...

head-mounted display A head-mounted display (HMD) is a display device, worn on the head or as part of a helmet (see Helmet-mounted display for aviation applications), that has a small display optic in front of one ( monocular HMD) or each eye (binocular HMD). An ...

, it was demonstrated from subjects' performance on real-world tasks of ball catching and obstacle avoidance that stereoscopic motion can derive from purely binocular stimuli, that is, without requiring any first-order motion perception. In other words, motion can be derived without using retinal flow, instead using

optical flow Optical flow or optic flow is the pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by the relative motion between an observer and a scene. Optical flow can also be defined as the distribution of apparent veloci ...

understood in a more abstract sense. It has been shown that also the adaptation to moving disparity information induces a motion aftereffect. This effect is called the ''stereoscopic motion aftereffect'' to distinguish it from the more well-known luminance

motion aftereffect The motion aftereffect (MAE) is a visual illusion experienced after viewing a moving visual stimulus for a time (tens of milliseconds to minutes) with stationary eyes, and then fixating a stationary stimulus. The stationary stimulus appears to ...

. How the brain combines different cues, including stereo cues, motion cues (both temporal changes in disparity and monocular velocity ratios),

vergence A vergence is the simultaneous movement of both eyes in opposite directions to obtain or maintain single binocular vision. When a creature with binocular vision looks at an object, the eyes must rotate around a vertical axis so that the projec ...

angle and

monocular cues In human species Monocular vision vision is known as seeing and using only one eye in the human species. Depth perception in monocular vision is reduced compared to binocular vision, but still is active primarily due to accommodation of the eye ...

for sensing motion in depth and 3D object position is an area of active research in

vision science Vision science is the scientific study of visual perception. Researchers in vision science can be called vision scientists, especially if their research spans some of the science's many disciplines. Vision science encompasses all studies of vision ...

and neighboring disciplines.For stereo, motion and vergence angle cues, see for example the following article:

References

{{Stereoscopy Stereoscopy Vision Visual perception

Sensing and processing

See also

References