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Pupillary Distance
Pupillary distance (PD), more correctly known as interpupillary distance (IPD) is the distance in millimeters between the centers of each pupil. Interpupillary Distance Classifications Distance PD is the separation between the visual axes of the eyes in their primary position, as the subject fixates on an infinitely distant object. Near PD is the separation between the visual axes of the eyes, at the plane of the spectacle lenses, as the subject fixates on a near object at the intended working distance. Intermediate PD is at a specified plane in between distance and near. Monocular PD refers to the distance between either the right or left visual axis to the bridge of the nose, which may be slightly different for each eye due to anatomical variations but always sums up to the binocular PD. For people who need to wear prescription glasses, consideration of monocular PD measurement by an optician helps to ensure that the lenses will be located in the optimum position. Whilst PD is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Android (operating System)
Android is an operating system based on a modified version of the Linux kernel and other open-source software, open-source software, designed primarily for touchscreen-based mobile devices such as smartphones and tablet computer, tablets. Android has historically been developed by a consortium of developers known as the Open Handset Alliance, but its most widely used version is primarily developed by Google. First released in 2008, Android is the world's Usage share of operating systems, most widely used operating system; the latest version, released on June 10, 2025, is Android 16. At its core, the operating system is known as the Android Open Source Project (AOSP) and is free and open-source software (FOSS) primarily licensed under the Apache License. However, most devices run the proprietary software, proprietary Android version developed by Google, which ships with additional proprietary closed-source software pre-installed, most notably Google Mobile Services (GMS), which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eyeglass Prescription
An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist, that specifies the value of all parameters the prescriber has deemed necessary to construct and/or dispense corrective lenses appropriate for a patient. If an eye examination indicates that corrective lenses are appropriate, the prescriber generally provides the patient with an eyewear prescription at the conclusion of the exam. The parameters specified on spectacle prescriptions vary, but typically include the patient's name, power of the lenses, any prism to be included, the pupillary distance, expiration date, and the prescriber's signature. The prescription is typically determined during a refraction, using a phoropter and asking the patient which of two lenses is better, or by an automated refractor, or through the technique of retinoscopy. A dispensing optician will take a prescription written by an optometrist and order and/or assemble the frames and lenses to then be dispense ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Reality Headset
A virtual reality headset (or VR headset) is a Head-mounted display, head-mounted device that uses 3D near-eye displays and positional tracking to provide a virtual reality environment for the user. VR headsets are widely used with Virtual reality game, VR video games, but they are also used in other applications, including simulators and trainers. VR headsets typically include a stereoscopic display (providing separate images for each eye), Stereophonic sound, stereo sound, and sensors like accelerometers and gyroscopes for tracking the pose tracking, pose of the user's head to match the orientation of the virtual camera with the user's eye positions in the real world. Augmented reality (AR) headsets are VR headsets that enable the user to see and interact with the outside world. Examples of AR headsets include the Apple Vision Pro and Meta Quest 3. VR headsets typically use at least one MEMS IMU for three degrees of freedom (3DOF) motion tracking, and optionally more tracking t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereoscopy
Stereoscopy, also called stereoscopics or stereo imaging, is a technique for creating or enhancing the depth perception, illusion of depth in an image by means of stereopsis for binocular vision. The word ''stereoscopy'' derives . Any stereoscopic image is called a stereogram. Originally, stereogram referred to a pair of stereo images which could be viewed using a stereoscope. Most stereoscopic methods present a pair of two-dimensional images to the viewer. The left image is presented to the left eye and the right image is presented to the right eye. When viewed, the human brain perceives the images as a single 3D view, giving the viewer the perception of Three-dimensional space, 3D depth. However, the 3D effect lacks proper focal depth, which gives rise to the Vergence-accommodation conflict. Stereoscopy is distinguished from other types of 3d display#3D displays, 3D displays that display an image in Three-dimensional space, three full dimensions, allowing the observer to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haploscope
A haploscope is an optical device for presenting one image to one eye and another image to the other eye. The word derives from two Greek roots: ''haploieides'', single and ''skopeo'', to view. The word is often used interchangeably with stereoscope, but it is more general than that. A stereoscope is a type of haploscope, but not vice versa. The word has more currency in the medical field than elsewhere, where it refers to instruments designed to test binocular vision. These instruments include Worth's amblyoscope and the synoptophore. Commonly haploscopes employ front-surfaced mirrors placed at different angles close to the eyes to reflect the images into the eyes. Reputedly the largest haploscope, with images of over a meter (in fact, 4 feet) square and a viewing distance for each eye of nearly five meters (16 feet), was constructed by Vaegan in about 1975 to research stereoacuity. The large images allowed very small retinal disparities to be presented. See also * Cheir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vision Science
Vision science is the scientific study of visual perception. Researchers in vision science can be called vision scientists, especially if their research spans some of the science's many disciplines. Vision science encompasses all studies of vision, such as how human and non-human organisms process visual information, how conscious visual perception works in humans, how to exploit visual perception for effective communication, and how artificial systems can do the same tasks. Vision science overlaps with or encompasses disciplines such as ophthalmology and optometry, neuroscience(s), psychology (particularly sensation and perception psychology, cognitive psychology, linguistics, biopsychology, psychophysics, and neuropsychology), physics (particularly optics), ethology, and computer science (particularly computer vision, artificial intelligence, and computer graphics), as well as other engineering related areas such as data visualization, user interface design, and human factors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Median
The median of a set of numbers is the value separating the higher half from the lower half of a Sample (statistics), data sample, a statistical population, population, or a probability distribution. For a data set, it may be thought of as the “middle" value. The basic feature of the median in describing data compared to the Arithmetic mean, mean (often simply described as the "average") is that it is not Skewness, skewed by a small proportion of extremely large or small values, and therefore provides a better representation of the center. Median income, for example, may be a better way to describe the center of the income distribution because increases in the largest incomes alone have no effect on the median. For this reason, the median is of central importance in robust statistics. Median is a 2-quantile; it is the value that partitions a set into two equal parts. Finite set of numbers The median of a finite list of numbers is the "middle" number, when those numbers are liste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Deviation
In statistics, the standard deviation is a measure of the amount of variation of the values of a variable about its Expected value, mean. A low standard Deviation (statistics), deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, while a high standard deviation indicates that the values are spread out over a wider range. The standard deviation is commonly used in the determination of what constitutes an outlier and what does not. Standard deviation may be abbreviated SD or std dev, and is most commonly represented in mathematical texts and equations by the lowercase Greek alphabet, Greek letter Sigma, σ (sigma), for the population standard deviation, or the Latin script, Latin letter ''s'', for the sample standard deviation. The standard deviation of a random variable, Sample (statistics), sample, statistical population, data set, or probability distribution is the square root of its variance. (For a finite population, v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Department Of Defense
The United States Department of Defense (DoD, USDOD, or DOD) is an executive department of the U.S. federal government charged with coordinating and supervising the six U.S. armed services: the Army, Navy, Marines, Air Force, Space Force, the Coast Guard for some purposes, and related functions and agencies. As of November 2022, the department has over 1.4 million active-duty uniformed personnel in the six armed services. It also supervises over 778,000 National Guard and reservist personnel, and over 747,000 civilians, bringing the total to over 2.91 million employees. Headquartered at the Pentagon in Arlington County, Virginia, just outside Washington, D.C., the Department of Defense's stated mission is "to provide the military forces needed to deter war and ensure our nation's security". The current Secretary of Defense is Pete Hegseth. The Department of Defense is headed by the secretary of defense, a cabinet-level head who reports directly to the president of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helmet-mounted Display
A helmet-mounted display (HMD) is a headworn device that uses displays and optics to project imagery and/or symbology to the eyes. It provides visual information to the user where head protection is required – most notably in military aircraft. The display-optics assembly can be attached to a helmet or integrated into the design of the helmet. An HMD provides the pilot with situation awareness, an enhanced image of the scene, and in military applications cue weapons systems, to the direction their head is pointing. Applications which allow cuing of weapon systems are referred to as helmet-mounted sight and display (HMSD) or helmet-mounted sights (HMS). Requirement Aviation HMD designs serve these purposes: * using the head angle as a pointer to direct air-to-air and air-to-ground weapons seekers or other sensors (e.g., radar, FLIR) to a target by the pilot merely turning the helmet towards the target and operating a switch via HOTAS. In close combat, without HMDs, pilo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Night Vision Goggle
A night-vision device (NVD), also known as a night optical/observation device (NOD) or night-vision goggle (NVG), is an optoelectronic device that allows visualization of images in low levels of light, improving the user's night vision. The device enhances ambient visible light and converts near-infrared light into visible light which can then be seen by humans; this is known as I2 ( image intensification). By comparison, viewing of infrared thermal radiation is referred to as thermal imaging and operates in a different section of the infrared spectrum. A night vision device usually consists of an image intensifier tube, a protective housing, and an optional mounting system. Many NVDs also include a protective sacrificial lens, mounted over the front/objective lens to prevent damage by environmental hazards, while some incorporate telescopic lenses< ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
