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A 1951 USAF resolution test chart is a microscopic optical resolution test device originally defined by the U.S. Air Force MIL-STD-150A standard of 1951. The design provides numerous small target shapes exhibiting a stepped assortment of precise spatial frequency specimens.
The bars are generally made of stainless steel or aluminum and touch the chart at each end, while the center is slightly raised to a desired height in order to obtain the desired film thickness. [3] As with the charts, the bars have to be especially resistant to corrosion because of the corrosive nature of some coatings. [ 4 ]
An example of the Landolt C eye chart (also known as the Japanese eye chart). Numerous types of eye charts exist and are used in various situations. For example, the Snellen chart is designed for use at 6 meters or 20 feet, and is thus appropriate for testing distance vision, while the ETDRS chart is designed for use at 4 meters. [16]
The chart was designed by Ian Bailey [5] and Jan E. Lovie-Kitchin at the National Vision Research Institute of Australia. [1] [3] They described their motivation for designing the LogMAR chart as follows: "We have designed a series of near vision charts in which the typeface, size progression, size range, number of words per row and spacings were chosen in an endeavour to achieve a ...
Example of a grouped (clustered) bar chart, one with horizontal bars. A bar chart or bar graph is a chart or graph that presents categorical data with rectangular bars with heights or lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally. A vertical bar chart is sometimes called a column ...
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An extended version of SMPTE Color Bars signal, developed by the Japanese Association of Radio Industries and Businesses as ARIB STD-B28 and standardized as SMPTE RP 219:2002 [15] (High-Definition, Standard-Definition Compatible Color Bar Signal) was introduced to test HDTV signal with an aspect ratio of 16:9 that can be down converted to a ...
A person taking the test covers one eye from 6 metres or 20 feet away, and reads aloud the letters of each row, beginning at the top. The smallest row that can be read accurately indicates the visual acuity in that specific eye. The symbols on an acuity chart are formally known as "optotypes". Variation of Snellen chart with another letter ...