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Any two test patterns that are not completely identical can be used to evaluate a contrast between them. When one test pattern comprises the completely bright state (full-white, R=G=B=100%) and the other one the completely dark state (full-black, R=G=B=0%) the resulting contrast is called full-swing contrast. This contrast is the highest ...
Tangent screen The simplest form of perimetry uses a white tangent screen. [3] Vision is tested by presenting different sized pins attached to a black wand, which may be moved, against a black background. [3] This test stimulus (pins) may be white or colored. [3] Goldmann perimeter
SMPTE bars—and several other test cards—include analog black (a flat waveform at 7.5 IRE, or the NTSC setup level), full white (100 IRE), and a "sub-black", or "blacker-than-black" (at 0 IRE), which represents the lowest low-frequency transmission voltage permissible in NTSC broadcasts (though the negative excursions of the colorburst ...
A precursor to the SMPTE test pattern was conceived by Norbert D. Larky (1927–2018) [5] [6] and David D. Holmes (1926–2006) [7] [8] of RCA Laboratories and first published in RCA Licensee Bulletin LB-819 on February 7, 1951. U.S. patent 2,742,525 Color Test Pattern Generator (now expired) was awarded on April 17, 1956, to Larky and Holmes. [9]
A pinhole occluder is an opaque disk with one or more small holes through it, used by ophthalmologists, orthoptists and optometrists to test visual acuity. The occluder is a simple way to focus light, as in a pinhole camera, temporarily removing the effects of refractive errors such as myopia. Because light passes only through the center of the ...
The Indian-head test pattern is a test card that gained widespread adoption during the black-and-white television broadcasting era as an aid in the calibration of television equipment. It features a drawing of a Native American wearing a headdress surrounded by numerous graphic elements designed to test different aspects of broadcast display.
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Test Card W is an updated 16:9 (1.78:1) widescreen version of Test Card F. It first appeared in November 1999 alongside Test Card J, with which it bears some similarities. The colour-bars on the top and right of the image are the full 100 per cent saturation version, unlike Test Cards F and J which use the 95 per cent type. Extra mirrored arrow ...