|
Vergence-accommodation-conflict
Vergence-accommodation conflict (VAC), also known as accommodation-vergence conflict, is a visual phenomenon that occurs when the brain receives mismatching cues between vergence and accommodation of the eye. This commonly occurs in virtual reality devices, augmented reality devices, 3D movies, and other types of stereoscopic displays and autostereoscopic displays. The effect can be unpleasant and cause eye strain. Two main ocular responses can be distinguished - vergence of eyes and accommodation. Both of these mechanisms are crucial in stereoscopic vision. Vergence or independent inward/outward rotation of eyes is engaged to fixate on objects and perceive them as single. Incorrect vergence response can cause double vision. Accommodation is the eye’s focusing mechanism and it is engaged to produce a sharp image on a retina. Both of these mechanisms are neurally linked forming the accommodation-convergence reflex of eyes. One can distinguish vergence distance – a distance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Reality Sickness
Virtual reality sickness, or VR sickness occurs when exposure to a virtual environment causes symptoms that are similar to motion sickness symptoms. The most common symptoms are general discomfort, eye strain, headache, stomach awareness, nausea, vomiting, pallor, sweating, fatigue, drowsiness, disorientation, and apathy. Other symptoms include postural instability and retching. Common causes are low frame rate, input lag, and the vergence-accommodation-conflict. Virtual reality sickness is different from motion sickness in that it can be caused by the visually-induced perception of self-motion; real self-motion is not needed. It is also different from simulator sickness; non-virtual reality simulator sickness tends to be characterized by oculomotor disturbances, whereas virtual reality sickness tends to be characterized by disorientation. Consequences Virtual reality sickness may have undesirable consequences beyond the sickness itself. For example, Crowley (1987) argued th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holographic Display
A holographic display is a type of 3D display that utilizes light diffraction to display a three-dimensional image to the viewer. Holographic displays are distinguished from other forms of 3D displays in that they do not require the viewer to wear any special glasses or use external equipment to be able to see the image, and do not cause the vergence-accommodation conflict. Some commercially available 3D displays are advertised as being holographic, but are actually multiscopic. Timeline 1947 - Hungarian scientist Dennis Gabor first came up with the concept of a hologram while trying to improve the resolution of electron microscopes. He derived the name for holography, with "holos" being the Greek word for "whole," and "gramma" which is the term for "message." 1960 - The world's first laser was developed by Russian scientists Nikolay Basov and Alexander Prokhorov, and American scientist Charles H. Townes. This was a major milestone for holography because laser technology serv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Health Effects Of 3D
The health effects of 3D are the aspects in which the human body is altered after the exposure of three-dimensional (3D) graphics. These health effects typically only occur when viewing stereoscopic, autostereoscopic, and multiscopic displays. Newer types of 3D displays like light field or holographic displays do not cause the same health effects. The viewing of 3D stereoscopic stimuli can cause symptoms related to vision disorders that the individual already had, as a person with a healthy binocular vision shouldn't experience any side effects under three-dimensional exposure. An increase in vergence-accommodation conflict occurs as the eye changes its movement patterns to focus on the position of objects recreated by stereoscopy. One may counter vergence-accommodation conflict when seeing a 3D movie or using a near-eye display system (e.g., augmented reality (AR) and virtual reality (VR)) adapting stereoscopic stimuli without registration function. Adverse health effects, suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depth Perception
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 and accommodation of the eye. Depth sensation is the corresponding term for non-human animals, since although it is known that they can sense the distance of an object, it is not known whether they perceive it in the same way that humans do. Depth perception arises from a variety of depth cues. These are typically classified into binocular cues and monocular cues. Binocular cues are based on the receipt of sensory information in three dimensions from both eyes and monocular cues can be observed with just one eye. Binocular cues include retinal disparity, which exploits parallax and vergence. Stereopsis is made possible with binocular vision. Monocular cues include relative size (distant objects subtend smaller visual angles than near obj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binocular Vision
In biology, binocular vision is a type of vision in which an animal has two eyes capable of facing the same direction to perceive a single three-dimensional image of its surroundings. Binocular vision does not typically refer to vision where an animal has eyes on opposite sides of its head and shares no field of view between them, like in some animals. Neurological researcher Manfred Fahle has stated six specific advantages of having two eyes rather than just one: #It gives a creature a "spare eye" in case one is damaged. #It gives a wider field of view. For example, humans have a maximum horizontal field of view of approximately 190 degrees with two eyes, approximately 120 degrees of which makes up the binocular field of view (seen by both eyes) flanked by two uniocular fields (seen by only one eye) of approximately 40 degrees. #It can give stereopsis in which binocular disparity (or parallax) provided by the two eyes' different positions on the head gives precise depth per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accommodative Convergence
Accommodative convergence is that portion of the range of inward rotation of both eyes (i.e. convergence) that occurs in response to an increase in optical power for focusing by the crystalline lens (i.e. accommodation).Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company, 1990. When the human eye engages the accommodation system to focus on a near object, signal is automatically sent to the extraocular muscles that are responsible for turning their eyes inward. This is helpful for maintaining single, clear, and comfortable vision during reading or similar near tasks. However, errors in this relationship can cause problems, such as hyperopic individuals having a tendency for crossed eyes because of the over exertion of their accommodation system. Clinically, accommodative convergence is measured as a ratio of convergence, measured in prism diopters, to accommodation, measured in diopters of near demand. The patient is ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Of View
The field of view (FoV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation. Humans and animals In the context of human and primate vision, the term "field of view" is typically only used in the sense of a restriction to what is visible by external apparatus, like when wearing spectacles or virtual reality goggles. Note that eye movements are allowed in the definition but do not change the field of view when understood this way. If the analogy of the eye's retina working as a sensor is drawn upon, the corresponding concept in human (and much of animal vision) is the visual field. It is defined as "the number of degrees of visual angle during stable fixation of the eyes".Strasburger, Hans; Pöppel, Ernst (2002). Visual Field. In G. Adelman & B.H. Smith (Eds): ''Encyclopedia of Neuroscience''; 3rd edition, on CD-ROM. El ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Tracking
Eye tracking is the process of measuring either the point of gaze (where one is looking) or the motion of an eye relative to the head. An eye tracker is a device for measuring eye positions and eye movement. Eye trackers are used in research on the visual system, in psychology, in psycholinguistics, marketing, as an input device for human-computer interaction, and in product design. Eye trackers are also being increasingly used for rehabilitative and assistive applications (related,for instance, to control of wheel chairs, robotic arms and prostheses). There are a number of methods for measuring eye movement. The most popular variant uses video images from which the eye position is extracted. Other methods use search coils or are based on the electrooculogram. History In the 1800s, studies of eye movement were made using direct observations. For example, Louis Émile Javal observed in 1879 that reading does not involve a smooth sweeping of the eyes along the text, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of 3D-enabled Mobile Phones
This is a list of 3D-enabled mobile phones. The devices on this list typically use autostereoscopic displays. Some devices may use other kinds of display technology, like holographic displays or multiscopic displays. Some devices employ eye tracking in aiming the 3D effect to the viewer's eye. List of 3D-enabled mobile phones List of 3D Video Players See also *List of mobile phone games with 3D display support *Nintendo 3DS *List of NFC-enabled mobile devices *Projector phone * LEIA Inc *3D Printing 3D printing or additive manufacturing is the Manufacturing, construction of a three-dimensional object from a computer-aided design, CAD model or a digital 3D modeling, 3D model. It can be done in a variety of processes in which material is ... References External links 3D Video Collections For 3D DEVICESDivided by categories (version available for all Desktops, Smartphones, Tablets and above SmartTV 3D) Mobiles by categoriesGlobal 3D-Enabled Smartphones Industry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SeeReal Technologies
SeeReal Technologies GmbH is a Dresden-based company focusing on the development of 3D displays. It is owned by its Luxembourg parent company SeeReal Technologies S.A., which is responsible for marketing, partnering and IP licensing. The firm was founded in 2002 by Dr. Armin Schwerdtner, who had previously headed an optics research group at the Dresden University of Technology (TU Dresden). SeeReal develops technology that is licensed to display manufacturers, including several variants of a tracked autostereoscopic display. The firm has presented a real-time desktop holographic display on the SID 2007 Display Week in Long Beach (California) and thFPD2007 in Yokohama (Japan). The firm owns more than 100 patents in the field of holographic and autostereoscopic 3D displays. SeeReal was awarded the European Information Society Technologies Prize (IST), and the Innovation Prize of the Free State of Saxony in 2007. References {{Reflist Electronics companies of Germany Display te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integral Imaging
Integral imaging is a three-dimensional imaging technique that captures and reproduces a light field by using a two-dimensional array of microlenses (or lenslets), sometimes called a fly's-eye lens, normally without the aid of a larger overall objective or viewing lens. In capture mode, in which a film or detector is coupled to the microlens array, each microlens allows an image of the subject as seen from the viewpoint of that lens's location to be acquired. In reproduction mode, in which an object or source array is coupled to the microlens array, each microlens allows each observing eye to see only the area of the associated micro-image containing the portion of the subject that would have been visible through that space from that eye's location. The optical geometry can perhaps be visualized more easily by substituting pinholes for the microlenses, as has actually been done for some demonstrations and special applications. A display using integral imaging is a type of light field ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
