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A good procedure is a chart, analogous to the familiar Snellen visual acuity chart, in which one letter in each row differs in depth (front or behind) sequentially increasing in difficulty. For children the fly test is ideal: the image of a fly is transilluminated by polarized light; wearing polarizing glasses the wing appears at a different ...
Atmospheric correction. Atmospheric correction is the process of removing the scattering and absorption effects of the atmosphere on the reflectance values of images taken by satellite or airborne sensors. [1] [2] Atmospheric effects in optical remote sensing are significant and complex, dramatically altering the spectral nature of the ...
Image of Lena Forsén used in many image processing experiments. (Click on the image to access the actual 512×512px standard test version.) Lenna (or Lena) is a standard test image used in the field of digital image processing starting in 1973, [1] but it is no longer considered appropriate by some authors.
Purpose. whether a person has strabismus. In the fields of optometry and ophthalmology, the Hirschberg test, also Hirschberg corneal reflex test, is a screening test that can be used to assess whether a person has strabismus (ocular misalignment). A photographic version of the Hirschberg is used to quantify strabismus. [1]
Amici prism. An Amici prism, named for the astronomer Giovanni Battista Amici, is a type of compound dispersive prism used in spectrometers. The Amici prism consists of two triangular prisms in contact, with the first typically being made from a medium-dispersion crown glass, and the second from a higher-dispersion flint glass.
Prism is the debut album by Canadian rock band Prism, [2] released in May 1977 on the Canadian record label GRT. It was produced primarily by Bruce Fairbairn, and the majority of songs were written by Jim Vallance (who also served as co-producer on three tracks). [3] It achieved platinum status in Canada (in excess of 100,000 units sold). [4]
This variation is called vignetting, and can be corrected by selectively brightening the perimeter of the image. Flat-field correction ( FFC) is a digital imaging technique to mitigate the image detector pixel-to-pixel sensitivity and distortions in the optical path. It is a standard calibration procedure in everything from personal digital ...
Perger prism. A Perger prism or Perger–Porro prism system is a prism, that is used to invert (rotate by 180°) an image. The special feature of this prism is that, like a traditional double Porro prism system, it manages this with only four beam deflections and has neither a roof edge with the accompanying phase correction problems, a ...