"Diplopia Diplopia, commonly known as double vision, is the simultaneous perception of two images of a single object that may be displaced horizontally, vertically, diagonally (i.e., both vertically and horizontally), or rotationally in relation to each other. It is usually the result of impaired function of the extraocular muscles (EOMs), where both eyes are still functional but they cannot turn to target the desired object. Problems with EOMs may be due to mechanical problems, disorders of the neuromuscular junction, disorders of the cranial nerves (III, IV, and VI) that stimulate the muscles, and occasionally disorders involving the supranuclear oculomotor pathways"
"vision that possesses information from both eyes which seems to have somehow been 'merged' into a single image. (Consider in a movie, when a character looks through binoculars and the audience is shown what he is looking at, from the character's point of view. The image shown is never made up of two completely separate circular images-- rather the director shows us a single figure-eight shaped region made up of information from each eyepiece.) Descartes noted that information from both eyes seems to have been merged somehow before ""entering"" conscious perception. He also noted similar effects for the other senses."
"Double star In observational astronomy, a double star or visual double is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of optical telescopes. This occurs because the pair either forms a binary star (i.e. a binary system of stars in mutual orbit, gravitationally bound to each other) or is an ""optical double"", a chance line-of-sight alignment of two stars at different distances from the observer. Binary stars are important to stellar astronomers as knowledge of their motions allows direct calculation of stellar mass and other stellar parameters. Since the beginning"
"are open), binocular fusion or singleness of vision (seeing one object with both eyes despite each eye's having its own image of the object), and binocular rivalry (seeing one eye's image alternating randomly with the other when each eye views images that are so different they cannot be fused). Binocular vision helps with performance skills such as catching, grasping, and locomotion. It also allows humans to walk over and around obstacles at greater speed and with more assurance. Optometrists and/or orthoptists are eyecare professionals who fix binocular vision problems. The term ""binocular"" comes from two Latin roots, ""bini"" for double,"
"Stereopsis Stereopsis (from the Greek στερεο- ""stereo-"" meaning ""solid"", and ὄψις ""opsis"", ""appearance, sight"") is a term that is most often used to refer to the perception of depth and 3-dimensional structure obtained on the basis of visual information deriving from two eyes by individuals with normally developed binocular vision. Because the eyes of humans, and many animals, are located at different lateral positions on the head, binocular vision results in two slightly different images projected to the retinas of the eyes. The differences are mainly in the relative horizontal position of objects in the two images. These positional differences"
"Ghost imaging Ghost imaging (also called ""coincidence imaging"", ""two-photon imaging"" or ""correlated-photon imaging"") is a technique that produces an image of an object by combining information from two light detectors: a conventional, ""multi-pixel"" detector that ""doesn't"" view the object, and a ""single-pixel"" (bucket) detector that ""does"" view the object. Two techniques have been demonstrated. A quantum method uses a source of pairs of entangled photons, each pair shared between the two detectors, while a classical method uses a pair of correlated coherent beams without exploiting entanglement. Both approaches may be understood within the framework of a single theory. The first"
"two eyes, the so-called cyclopean eye. The position of the cyclopean eye is not usually exactly centered between the eyes, but tends to be closer to the dominant eye. When very different images are shown to the same retinal regions of the two eyes, perception settles on one for a few moments, then the other, then the first, and so on, for as long as one cares to look. This alternation of perception between the images of the two eyes is called binocular rivalry. Humans have limited capacity to process an image fully at one time. That is why the"
"Binocular vision In biology, binocular vision is a type of vision in which an animal having two eyes is able to perceive a single three-dimensional image of its surroundings. Neurological researcher Manfred Fahle has stated six specific advantages of having two eyes rather than just one: Other phenomena of binocular vision include utrocular discrimination (the ability to tell which of two eyes has been stimulated by light), eye dominance (the habit of using one eye when aiming something, even if both eyes are open), allelotropia (the averaging of the visual direction of objects viewed by each eye when both eyes"
"and insects. Stereopsis Stereopsis (from the Greek στερεο- ""stereo-"" meaning ""solid"", and ὄψις ""opsis"", ""appearance, sight"") is a term that is most often used to refer to the perception of depth and 3-dimensional structure obtained on the basis of visual information deriving from two eyes by individuals with normally developed binocular vision. Because the eyes of humans, and many animals, are located at different lateral positions on the head, binocular vision results in two slightly different images projected to the retinas of the eyes. The differences are mainly in the relative horizontal position of objects in the two images. These"
"Dualphotography Dualphotography is a photographic technique simultaneously taking two photographs (a dualphoto) of one scene, thus photographing a scene from both sides of a photographic device at once. The dualphoto apparatus can be used to simultaneously capture both the subject and the photographer, or both sides of a geographical place at once, thus adding a supplementary narrative layer to that of a single image. Dual photography includes back-to-back photography and portal-plane photography. Stereoscopy is a specific kind of dualphotography, and while it is technically similar and would be compatible with the term, the latter is seldom used for it. The"
"human eye. As the two images captured by each eye is incompatible for stereo processing, they fight for visual dominance over the other eye's side view, resulting in alternating views from the two eyes, where the non-dominant view is almost unseen. This effect often occurs when wearing a monocular HMD. In this setup, researchers also observed objects that completely vanish for several seconds from user’s attention. Describes the phenomenon when both eyes perceive different images that are overlapping, but the brain is not able to distinguish between those. This phenomenon is also known as the inability for visual separation. Describes"
"area of retina stimulated. Thus, when the eyes are misaligned, the brain will perceive two images of one target object, as the target object simultaneously stimulates different, non-corresponding, retinal areas in either eye, thus producing double vision. This correlation of particular areas of the retina in one eye with the same areas in the other is known as retinal correspondence. This relationship also gives rise to an associated phenomenon of binocular diplopia, although one that is rarely noted by those experiencing diplopia: Because the fovea of one eye corresponds to the fovea of the other, images falling on the two"
"“appearance” or “sight”) is the impression of depth that is perceived when a scene is viewed with both eyes by someone with normal binocular vision. Binocular viewing of a scene creates two slightly different images of the scene in the two eyes due to the eyes' different positions on the head. These differences, referred to as binocular disparity, provide information that the brain can use to calculate depth in the visual scene, providing a major means of depth perception. There are two aspects of stereopsis: the nature of the stimulus information specifying stereopsis, and the nature of the brain processes"
"surface reconstruction. Stereopsis, or stereo vision, is the visual blending of two similar but not identical images into one, with resulting visual perception of solidity and depth. In the human brain, stereopsis results from complex mechanisms that form a three-dimensional impression by matching each point (or set of points) in one eye's view with the equivalent point (or set of points) in the other eye's view. Using binocular disparity, the brain derives the points' positions in the otherwise inscrutable ""z""-axis (depth). When the brain is presented with a repeating pattern like wallpaper, it has difficulty matching the two eyes' views"
"Cyclopean image Cyclopean image is a single mental image of a scene created by the brain by combining two images received from the two eyes. The mental process behind construction of the Cyclopean image is crucial to stereo vision. Autostereograms take advantage of this process to trick the brain into forming an apparent Cyclopean image from seemingly random patterns. Cyclopean image is named after the mythical Cyclops with a single eye. Literally it refers to the way stereo sighted viewers perceive the centre of their fused visual field as lying between the two physical eyes, as if seen by a"
"Cerebral polyopia Cerebral diplopia or polyopia describes seeing two or more images arranged in ordered rows, columns, or diagonals after fixation on a stimulus. The polyopic images occur monocular bilaterally (one eye open on both sides) and binocularly (both eyes open), differentiating it from ocular diplopia or polyopia. The number of duplicated images can range from one to hundreds. Some patients report difficulty in distinguishing the replicated images from the real images, while others report that the false images differ in size, intensity, or color. Cerebral polyopia is sometimes confused with palinopsia (visual trailing), in which multiple images appear while"
"Stereoscope A stereoscope is a device for viewing a stereoscopic pair of separate images, depicting left-eye and right-eye views of the same scene, as a single three-dimensional image. A typical stereoscope provides each eye with a lens that makes the image seen through it appear larger and more distant and usually also shifts its apparent horizontal position, so that for a person with normal binocular depth perception the edges of the two images seemingly fuse into one ""stereo window"". In current practice, the images are prepared so that the scene appears to be beyond this virtual window, through which objects"
"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 moving in 3D space, 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"
"see two images created from slightly different positions (points of view). Charles Wheatstone was the first to discuss depth perception being a cue of binocular disparity. He invented the stereoscope, which is an instrument with two eyepieces that displays two photographs of the same location/scene taken at relatively different angles. When observed, separately by each eye, the pairs of images induced a clear sense of depth. By contrast, a telephoto lens—used in televised sports, for example, to zero in on members of a stadium audience—has the opposite effect. The viewer sees the size and detail of the scene as if"
"Monocular vision Monocular vision is vision in which both eyes are used separately. By using the eyes in this way, as opposed by binocular vision, the field of view is increased, while depth perception is limited. The eyes of an animal with monocular vision are usually positioned on opposite sides of the animal's head, giving it the ability to see two objects at once. The word monocular comes from the Greek root, ""mono"" for single, and the Latin root, ""oculus"" for eye. Monocular vision impairment refers to having no vision in one eye with adequate vision in the other. Monopsia"
"Hidden faces People often see hidden faces in things. Depending on the circumstances, this is referred to as pareidolia, the perception or recognition of a specific pattern or form in something essentially different. It is thus also a kind of optical illusion. When an artist notices that two different things have a similar appearance, and draws or paints a picture making this similarity evident he makes images with double meanings. Many of these images are hidden faces or hidden skulls. These illusionistic pictures present the viewer with a mental choice of two interpretations: head or landscape, head or objects, head"
"Dichoptic presentation Dichoptic (from the Greek words δίχα ""dicha"", meaning ""in two,"" and ὀπτικός ""optikos"", ""relating to sight"") is viewing a separate and independent field by each eye. In dichoptic presentation, stimulus A is presented to the left eye and a different stimulus B is presented to the right eye. Dichoptic perceptual training has been tested in order to stimulate the simultaneous use of both eyes. In recent years, efforts have been made to develop methods of perceptual learning in vision therapy for treating interocular suppression and improving binocular vision in patients with anisometropic or strabismic amblyopia. In these methods,"
"have a small area of the retina with very high visual acuity, the fovea centralis. It covers about 2 degrees of visual angle in people. To get a clear view of the world, the brain must turn the eyes so that the image of the object of regard falls on the fovea. Any failure to make eye movements correctly can lead to serious visual degradation. Having two eyes allows the brain to determine the depth and distance of an object, called stereovision, and gives the sense of three-dimensionality to the vision. Both eyes must point accurately enough that the object"
"Binoculars Binoculars or field glasses are two telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. Most are sized to be held using both hands, although sizes vary widely from opera glasses to large pedestal mounted military models. Unlike a (monocular) telescope, binoculars give users a three-dimensional image: for nearer objects the two views, presented to each of the viewer's eyes from slightly different viewpoints, produce a merged view with an impression of depth. Almost from the invention of the telescope in the 17th century"
"one object instead of two, and is referred to as singleness of vision or binocular fusion. The focussing of each eye, its accommodation, is adjusted so the retinal image of the object is as sharp as possible. This is done via contraction of the ciliary muscles controlling the shape of the crystalline lens of the eye. Although convergence and accommodation are separate processes, they normally operate synergistically. When someone looks into an optical instrument, such as a microscope, vision is far from ordinary. A microscope might force the person to use only one eye, it presents the person with a"
"pair of polarizing filters oriented differently (clockwise/counterclockwise with circular polarization or at 90 degree angles, usually 45 and 135 degrees, with linear polarization). As each filter passes only that light which is similarly polarized and blocks the light polarized differently, each eye sees a different image. This is used to produce a three-dimensional effect by projecting the same scene into both eyes, but depicted from slightly different perspectives. Additionally, since both lenses have the same color, people with one dominant eye (amblyopia), where one eye is used more, are able to see the 3D effect, previously negated by the separation"
"to generate a ghost-image basis, enabling proof-of-concept for experimental x-ray ghost imaging. At the same time that this experiment was reported, a Fourier-space variant of x-ray ghost imaging was published. Ghost imaging Ghost imaging (also called ""coincidence imaging"", ""two-photon imaging"" or ""correlated-photon imaging"") is a technique that produces an image of an object by combining information from two light detectors: a conventional, ""multi-pixel"" detector that ""doesn't"" view the object, and a ""single-pixel"" (bucket) detector that ""does"" view the object. Two techniques have been demonstrated. A quantum method uses a source of pairs of entangled photons, each pair shared between the"
"Binocular rivalry Binocular rivalry is a phenomenon of visual perception in which perception alternates between different images presented to each eye. When one image is presented to one eye and a very different image is presented to the other (also known as dichoptic presentation), instead of the two images being seen superimposed, one image is seen for a few moments, then the other, then the first, and so on, randomly for as long as one cares to look. For example, if a set of vertical lines is presented to one eye, and a set of horizontal lines to the same"
"and/or the person has experienced diplopia or doubled vision. Up to a certain extent, binocular disparities can be compensated for by adjustments of the visual system. If, however, defects of binocular vision are too great – for example if they would require the visual system to adapt to overly large horizontal, vertical, torsional or aniseikonic deviations – the eyes tend to avoid binocular vision, ultimately causing or worsening a condition of strabismus. Binocular vision In biology, binocular vision is a type of vision in which an animal having two eyes is able to perceive a single three-dimensional image of its"
"for stereopsis. The Cyclops would not have been able to see a cyclopean stimulus, because having only one eye, he would not have been able to perceive binocular depth cues such as binocular disparity. Cyclopean image Cyclopean image is a single mental image of a scene created by the brain by combining two images received from the two eyes. The mental process behind construction of the Cyclopean image is crucial to stereo vision. Autostereograms take advantage of this process to trick the brain into forming an apparent Cyclopean image from seemingly random patterns. Cyclopean image is named after the mythical"
"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 horizontal axis so that the projection of the image is in the centre of the retina in both eyes. To look at an object closer by, the eyes rotate towards each other (convergence), while for an object farther away they rotate away from each other (divergence). Exaggerated convergence is called ""cross eyed viewing"" (focusing on the nose for example) . When looking into the"
"reality. For example, an image may be split in half, with the top half being enlarged and placed further away from the perceiver in space. This image will be perceived as one complete image from only a single viewpoint in space, rather than the reality of two separate halves of an object. Street artists often use tricks of point-of-view to create 2-dimensional scenes on the ground that appear 3-dimensional. To go further than just perceiving the object is to recognize the object. Recognizing an object plays a crucial role in resolving ambiguous images, and relies heavily on memory and prior"
"scene yielding different retinal images. Normally two images are not observed, but rather a single view of the scene, a phenomenon known as singleness of vision. Nevertheless, stereopsis is possible with double vision. This form of stereopsis was called ""qualitative stereopsis"" by Kenneth Ogle. If the images are very different (such as by going cross-eyed, or by presenting different images in a stereoscope) then one image at a time may be seen, a phenomenon known as binocular rivalry. There is a hysteresis effect associated with stereopsis. Once fusion and stereopsis have stabilized, fusion and stereopsis can be maintained even if"