Search results
Results from the WOW.Com Content Network
Prism dioptres. Prism correction is commonly specified in prism dioptres, a unit of angular measurement that is loosely related to the dioptre. Prism dioptres are represented by the Greek symbol delta (Δ) in superscript. A prism of power 1 Δ would produce 1 unit of displacement for an object held 100 units from the prism. [2]
This video demonstrates what is involved when performing a prism cover test. Purpose. measuring strabismus. The prism cover test ( PCT) is an objective measurement and the gold standard in measuring strabismus, i.e. ocular misalignment, or a deviation of the eye. [1] It is used by ophthalmologists and orthoptists in order to measure the ...
Corrective lens. A pair of contact lenses, positioned with the concave side facing upward. A corrective lens is a transmissive optical device that is worn on the eye to improve visual perception. The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia.
OpenCV is an open-source BSD-licensed library for computer vision (multi-language, multi-OS). It features a module for camera calibration. DxO's PhotoLab software can correct complex distortion, and takes into account the focus distance. proDAD Defishr includes an Unwarp-tool and a Calibrator-tool. Due to the distortion of a checkerboard ...
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 ...
In optics, chromatic aberration ( CA ), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. [1] It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light. The refractive index of most transparent materials decreases with increasing ...
The first widely-available fisheye lens for 35mm cameras was the Fisheye-Nikkor 8 mm f /8 from Nikon, released in 1962, which produced circular images similar to those popularized by the LIFE photographers; that lens served as the "eye" of the HAL 9000 computer from the film 2001: A Space Odyssey, although scenes depicting HAL's point of view ...
Gamma correction or gamma is a nonlinear operation used to encode and decode luminance or tristimulus values in video or still image systems. Gamma correction is, in the simplest cases, defined by the following power-law expression:
The history of the single-lens reflex camera (SLR) begins with the use of a reflex mirror in a camera obscura described in 1676, but it took a long time for the design to succeed for photographic cameras. The first patent was granted in 1861, and the first cameras were produced in 1884, but while elegantly simple in concept, they were very ...
Optical aberration. 1: Imaging by a lens with chromatic aberration. 2: A lens with less chromatic aberration. In optics, aberration is a property of optical systems, such as lenses, that causes light to be spread out over some region of space rather than focused to a point. [1]