Brightness ratio

Pyrometric thermometers can be of the following types optical (brightness), ratio (two-color), total (wide-band), and narrow-band, whereas the fiber optic designs can be of the light-pipe, black body, dual-wavelength, crystal, gap, and fluoroptic variety. Their temperature ranges are from -40 to 4,000°C (-40 to 7,000°F), and their errors range from 0.25% to 2% FS. 

A difference of 1 magnitude means a brightness ratio of about 2.5. That means we receive about 2.5 times as much light from a star of magnitude 0 as we do from a star of magnitude 1. ... 

A formula describes the relationship between difference in magnitude Am and brightness ratio r. Try plugging numbers in, and you will be amazed. ... 

Downlight sky brightness ratio Ratio of illumination on two sides of vertical plate facing sun or brightest part of sky. 

Effective horizon sky brightness ratio Ratio of brightness of vertical perfect diffuse reflector parallel to ship s axis, to that of horizon sky beyond ship. 

Quality of Lighting The quality of lighting may affect error rates and cause accidents. For many applications control of illumination levels alone is not sufficient. Designs must control illumination quality as well. For example, users of computer screens are more likely to experience eye strain and other visual problems when there are combinations of poor reflectance, brightness ratio, and contrast ratio. 

Brightness Ratio One should also analyze work stations for brightness ratio or luminance ratio. Luminance... 

The color temperature distribution over the whole field-of-view can be obtained with larcsec resolution om color ratios using various combinations of 3.8, 7.8, 12.4 and 20/ m array data. Figure 4 shows the color temperature distribution image from the de-reddened 12/20/xm brightness ratio. The highest color temperatures calculated from the 12/20/im image ratio... 

Contrast. This can be quantified as the ratio of transmitted light intensity in the bright state compared to the dar... 

The Watts Solution, is a relatively cheap, simple solution which is easy to control and keep pure. The nigkel sulphate acts as the main source of nickel ions, though nickel chloride is an additional source. Higher deposition rates can be, used when the ratio of nickel chloride to nickel sulphate is raised and some proprietary bright nickel solutions are available in a high-speed version which contains an increased concentration of nickel chloride. 

In practice a special nickel solution containing the suspended particles is applied over the normal bright nickel deposit. The plating time in this solution is from 20 s to 5 min the most suitable ratio of the two deposits has to be determined in each particular case. 

The upper limit for passive matrix OLEDs thus depends on many factors, including the reverse current of the diodes, the current delivery of the row drivers, the roll-off in OLED power efficiency, and the brightness and contrast ratio requirements of the application. The practical limit is probably less than VGA resolution (480 rows by 640 x 3 columns, where the factor of 3 reflects the RGB subpixels for color) for power-sensitive portable applications. However, such considerations are less important where a wall-plug is available and one company in Japan (Idemitsu Kosan [190]) has demonstrated full color television using passive OLED arrays. 

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