Hence there is the general case of a surface at any angle to the line of displacement, and two special cases (a) the surface parallel to the line of displacement (which yields a sheaf filling only half of the hemisphere) and (b) the surface perpendicular to the line of displacement (which yields a full hemispherical sheaf).
#Motion parallax plane how to
How to describe the differential velocities across the hemispherical sheaf of rays, with reference to the “ information” this contains as regards the distance of the nearest point of the surface, the relative distance of all points of the surface, and the direction of displacement (locomotion) with reference to the surface? What variables (or features) of the ray-sheaf can be specified which reflect (or co-vary with) these tridimensional facts? The pattern of differential velocities will vary with the angle of the surface to the level of displacement. That the eye receives a hemispherical sheaf of rays from the elements of the surface. That the eye is fixated in the direction of its displacement.Ħ. That the eye moves (is displaced) with a unit velocity.ĥ. That the surface is very large (like the terrain).Ĥ. That the surface has “ elements“, of equal size.ģ. A plane surface and an eye (the terrestrial situation, not the astronomical situation).Ģ. The differential apparent velocity of the elements of a plane surface (motion perspective).ġ. Motion parallax = apparent angular velocity of objects, which is inversely proportional to real distance and consequently permits a “safe conclusion” about distance. (Note that all astronomical motions of the observer are rotary not linear).Ģ. Parallax = the “difference in direction of a body caused by difference in position of the observer” (Astronomy). Copies may be circulated if this statement is included on each copy.ġ. The system’s use of a ‘spatially imaged iris plane screen’ and ‘linear blending technology’ enables it to have fewer image sources and projectors than existing multi-view projection systems. References to these essays must cite them explicitly as unpublished manuscripts. This paper describes a glassless 3D screen system we propose that is capable of natural stereoscopic viewing with motion parallax in a wide viewing area. Gibson, Cornell University The World Wide Web distribution of James Gibson’s “Purple Perils” is for scholarly use with the understanding that Gibson did not intend them for publication. © 2013 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.1955 Motion Parallax and Motion Perspective in Visual Perception
#Motion parallax plane code
A simple system is proposed whereby the relative activity in 'near', 'far' and 'on' populations could code depth through motion parallax in a metameric manner similar to that employed to code color vision and stereopsis. Furthermore, some of these neurons preferred backward motion in the visual field and others preferred forward motion, suggesting that they may separately code visual objects 'nearer' and 'farther' than the stabilised ('on') plane during forward translational motion. Their neural responses to these two superimposed planes were facilitated above those produced by a single plane of moving dots and those produced by two layers moving in the same direction. Two large overlapping planes of random dots moving independently were used to simulate motion parallax, in which one with larger dots was moved fast and the other with smaller dots was moved slowly in the opposite direction. Using standard electrophysiological techniques and computer-generated stimuli, we show that some of these flow-field neurons in the pretectal nucleus lentiformis mesencephali in pigeons appear to be processing motion parallax. From their response characteristics, shared frame of reference with the vestibular or inertial system, and anatomical connections, these neurons have been implicated in the stabilisation of retinal images, the control of posture and balance, and the animal's motion trajectories through the world. In the visual system of invertebrates and vertebrates there are specialised groups of motion-sensitive neurons, with large receptive fields, which are optimally tuned to respond to optic flow produced by the animals' movement through the 3-D world.
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