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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]
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 vertical and horizontal deviation and includes both manifest and latent components. [1]
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 ...
Adobe Photoshop Lightroom and Photoshop CS5 can correct complex distortion. PTlens is a Photoshop plugin or standalone application which corrects complex distortion. It not only corrects for linear distortion, but also second degree and higher nonlinear components. Lensfun is a free to use database and library for correcting lens distortion.
DxO ViewPoint is image geometry and lens defect correction software developed by DxO. It is designed to automatically straighten distorted perspectives caused by the lens used and the position of the photographer.
Photoshop CS2 and subsequent releases includes perspective correction as part of its Lens Distortion Correction Filter; DxO Optics Pro from DxO Labs includes perspective correction; while GIMP (as of 2.6) does not include a specialized tool for correcting perspective, though a plug-in, EZ Perspective, is available.
The Prentice position is an orientation of a prism, used in optics, optometry and ophthalmology. In this position, named after the optician Charles F. Prentice, the prism is oriented such that light enters it at an angle of 90° to the first surface, so that the beam does not refract at that surface. All the deviation caused by the prism takes ...
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.
A Bayer filter mosaic is a color filter array (CFA) for arranging RGB color filters on a square grid of photosensors. Its particular arrangement of color filters is used in most single-chip digital image sensors used in digital cameras, and camcorders to create a color image. The filter pattern is half green, one quarter red and one quarter ...
These reflections are used to determine the size and shape of a ring in the retina which is located in the posterior part of the eye. By measuring this zone, the autorefractor can determine when a patient's eye properly focuses an image. The instrument changes its magnification until the image comes into focus.