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Hering–Hillebrand Deviation
The Hering–Hillebrand deviation describes the mismatch between the theoretical and empirical horopter. The horopter is the set of points that projects at the same location in the two retinae (i.e. that have the same visual direction). Geometrically the horopter is a circle passing through the nodal point of the two eyes and through the fixation point. This is known as the horizontal geometrical horopter, or as the Vieth–Müller circle. This is the set of points that correspond ''geometrically'' to the intersection between visual lines at identical eccentricities. There is also a vertical horopter which the a straight line on the sagittal plane and passing through the intersection between the sagittal plane and the Vieth–Müller circle (typically fixation if the observer fixates straight ahead, but not necessarily). An empirical horopter can be defined following different criteria. Following Hering, it is usually meant by empirical horopter the ''equal visual direction'' horop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horopter
The horopter was originally defined in geometric terms as the locus of points in space that make the same angle at each eye with the fixation point, although more recently in studies of binocular vision it is taken to be the locus of points in space that have the same binocular disparity, disparity as fixation. This can be defined theoretically as the points in space that project on corresponding points in the two retinas, that is, on anatomically identical points. The horopter can be measured empirically in which it is defined using some criterion. The concept of horopter can then be extended as a geometrical locus of points in space where a specific condition is met: * the binocular horopter is the locus of iso-disparity points in space; * the oculomotor horopter is the locus of iso-vergence points in space. As other quantities that describe the functional principles of the visual system, it is possible to provide a theoretical description of the phenomenon. The measurement w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hering's Law Of Visual Direction
Hering's law of visual direction describes the perceived visual direction of a point relative to an observer. Because the eyes are horizontally apart in the head, by about 6cm, the visual scene is seen from slightly different point of view by each eye. Thus comes the question of where a point is perceived, relative to the observer, when seen with either eye alone or binocularly. In 1879 Ewald Hering stated the following law: ''"For any given two corresponding lines of direction, or visual lines, there is in visual space a single visual direction upon which appears everything which actually lies in the pair of visual lines"''. Prior to Hering, both Alhazen (1021) and Wells (1792) addressed a similar questions but proposed slightly incorrect laws. Hering's law can be simplified as (1) points falling on the same visual line seem to come from the same location; (2) visual directions are relative to the a unique egocenter (also called cyclopean eye) and (3) the perceived direction of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nodal Point
In Gaussian optics, the cardinal points consist of three pairs of points located on the optical axis of a rotationally symmetric, focal, optical system. These are the '' focal points'', the principal points, and the nodal points. For ''ideal'' systems, the basic imaging properties such as image size, location, and orientation are completely determined by the locations of the cardinal points; in fact only four points are necessary: the focal points and either the principal or nodal points. The only ideal system that has been achieved in practice is the plane mirror, however the cardinal points are widely used to ''approximate'' the behavior of real optical systems. Cardinal points provide a way to analytically simplify a system with many components, allowing the imaging characteristics of the system to be approximately determined with simple calculations. Explanation The cardinal points lie on the optical axis of the optical system. Each point is defined by the effect the opt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittal Plane
The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse and coronal planes. The plane may be in the center of the body and divide it into two equal parts ( mid-sagittal), or away from the midline and divide it into unequal parts (para-sagittal). The term ''sagittal'' was coined by Gerard of Cremona. Variations in terminology Examples of sagittal planes include: * The terms ''median plane'' or ''mid-sagittal plane'' are sometimes used to describe the sagittal plane running through the midline. This plane cuts the body into halves (assuming bilateral symmetry), passing through midline structures such as the navel and spine. It is one of the planes which, combined with the Umbilical plane, defines the four quadrants of the human abdomen. * The term ''parasagittal'' is used to describe any plane parallel or adjacent to a given sagittal plane. Specific named parasa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horopter
The horopter was originally defined in geometric terms as the locus of points in space that make the same angle at each eye with the fixation point, although more recently in studies of binocular vision it is taken to be the locus of points in space that have the same binocular disparity, disparity as fixation. This can be defined theoretically as the points in space that project on corresponding points in the two retinas, that is, on anatomically identical points. The horopter can be measured empirically in which it is defined using some criterion. The concept of horopter can then be extended as a geometrical locus of points in space where a specific condition is met: * the binocular horopter is the locus of iso-disparity points in space; * the oculomotor horopter is the locus of iso-vergence points in space. As other quantities that describe the functional principles of the visual system, it is possible to provide a theoretical description of the phenomenon. The measurement w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vision
Vision, Visions, or The Vision may refer to: Perception Optical perception * Visual perception, the sense of sight * Visual system, the physical mechanism of eyesight * Computer vision, a field dealing with how computers can be made to gain understanding from digital images or videos * Machine vision, technology for imaging-based automatic inspection Perception of the future * Foresight (psychology), in business, the ability to envisage future market trends and plan accordingly * Goal, a desired result ** Vision statement, a declaration of objectives to guide decision-making Other perceptions * Vision (spirituality), a supernatural experience that conveys a revelation * Hallucination, a perception of something that does not exist Arts and media Events * Visions (convention), a science fiction event * Vision Festival, a New York City art festival Film and television * "The Vision", episode of '' Alcoa Presents: One Step Beyond'' * ''The Vision'' (film), 1998 British televisi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
