Motion parallax

When a human head moves sidewise, the pupil location changes so that the viewing direction changes accordingly. The closer objects appear to move faster across the field of view than those further away. This effect is, in principle, similar to binocular disparity. The former is a result of the temporal change of viewing points, and the latter is a result of spatially separated 

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Binocular disparity and convergence require the involvement of both eyes, while motion parallax and accommodation could be observed eveu with a single eye. For natural 3-D objects, all the four major depth cues meutioned above should be present at the same lime. Various 3-D display technologies employ at least one of the four major depth cues to geuerate 3-D depth sensation. The more consistent the depth cues are, the more realistic and natural a 3-D image appears. 

Also, because different microlens reproduces the 3-D object from a different perspective, as the viewer move around, motion parallax could be observed. 

The reason for strong depth and distance perception despite missing or limited stereo cues is the capability of the HVS to process additional pictorial as well as dynamic monocular depth cues, which are embedded in the 2D projection of the sensed scene. Dynamic cues arise from apparent motion of the visible objects or ego-motion (motion parallax) as well as the orientation of the eyes (vergence) or focused distance (accommodation). Dynamic cues will not be considered in detail since they do not suit to be manipulated within still images or video sequences to... 

Enzweiler, M., Kanter, P., Gavrila, D. Monocular pedestrian recognition using motion parallax. In Proceedings of IEEE Intelligent Vehicles Symposium, issn 1931-0587 (2008). doi 10.1109/IVS.2008.4621169... 

Something else should be said about the impact of accommodation- When the (general) theory concerned is strongly supported independently of the fact at issue, the accommodation of some fact, even in this ad hoc way, may well still supply the best explanation that science can currently supply for that fact. So, for example, the best explanation in, say, 1700 for the observation of no stellar parallax was surely the Copemican one—that there must in fact be an apparent parallactic motion but that even the nearest stars are so far away as to make the effect too small to be detected by even the best available telescopes. (Here, as before with Ptolemy and with scientific creationism, we use the phenomenon—no observed parallax—to fix (in this case in a rather loose way) an otherwise free parameter in the theory (distance to the nearest star).)... 

Astronomers must use very indirect methods to measure the distances to stars and other astronomical objects. Measuring a star s parallax is a way to find its distance. This method takes advantage of the apparent shift in position of a nearby star as it is observed from different positions as the earth orbits the Sun. Because the parallax effect depends upon the earth s motion about the Sun, it is often referred to as the heliocentric parallax. 

To understand how parallax works, hold your thumb in front of your face. Alternately open and close each eye and notice how your thumb appears to move back and forth with respect to the background wall. Now move your thumb closer to your face and notice how this effect increases as the distance between your eyes and thumb decreases. This apparent motion (you did not really move your thumb) is called the parallax. The brain subconsciously uses information from both eyes to estimate distances. Because the distance estimates require observation from two points, people who have lost an eye will lack this depth perception. A parallax is any apparent shift in the position of an object caused by a change in the observation position. 

The parallax angle is defined as one half of the apparent angular motion of the star as the earth orbits from one side of the Sun to the opposite side. This definition is the same as the apparent motion that would be observed if the two observation points were the Sun and Earth. Once this angle is measured, the distance between the Sun and the star is the earth-Sun distance divided by the tangent of the parallax angle. 

Further concerns regard other technical aspects. For example, out-of-plane motions of the particles caused by normal-to-laser-sheet velocity fluctuations, or the maximum parallax angle related to perspective distortions that grow from fhe confer to the edges of the images. 

The angular displacement in the apparent position of a celestial body when observed from two different points. Diurnal parallax results from the earth s daily rotation, the celestial body being viewed from the surface of the earth rather than from its centre. Annual parallax is caused by the earth s motion round the sun, the celestial body being viewed from the earth rather than from the centre of the sun. Secular parallax is caused by the motion of the solar system relative to the fixed stars. 

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