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Topic: Brightness


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  Brightness - Wikipedia, the free encyclopedia
Brightness is an attribute of visual perception in which a source appears to emit a given amount of light.
"Brightness" was formerly used as a synonym for the photometric term luminance and (incorrectly) for the radiometric term radiance.
Brightness is also a color coordinate in HSB color space.
en.wikipedia.org /wiki/Brightness   (191 words)

  
 Surface brightness - Wikipedia, the free encyclopedia
Surface brightness is a concept used in astronomy when describing extended astronomical objects such as galaxies and nebulae.
The apparent magnitude of an astronomical object is generally given as an integrated value - if a galaxy is quoted as having a magnitude of 12.5, it means we see the same total amount of light from the galaxy as we would from a star with magnitude 12.5.
Surface brightness is constant with increasing object luminosity distance.
en.wikipedia.org /wiki/Surface_brightness   (275 words)

  
 Apparent magnitude - Wikipedia, the free encyclopedia
This somewhat crude method of indicating the brightness of stars was popularized by Ptolemy in his Almagest, and is generally believed to have originated with Hipparchus.
The rate at which apparent brightness changes, as the distance from an object increases, is calculated by the inverse-square law (at cosmological distance scales, this is no longer quite true because of the curvature of space).
The second thing to notice is that the scale is logarithmic: the relative brightness of two objects is determined by the difference of their magnitudes.
en.wikipedia.org /wiki/Apparent_magnitude   (1187 words)

  
 Olympus MIC-D: Brightness and Contrast in Digital Images - Interactive Java Tutorial
Moving the brightness slider to the left of center position decreases image brightness and shifts the histogram to lower input pixel brightness values.
Brightness and contrast adjustments that are analogous to those described in the tutorial are available in the Olympus MIC-D digital microscope image processing software, as illustrated in Figure 1.
Brightness should not be confused with intensity (more accurately termed radiant intensity), which refers to the magnitude or quantity of light energy actually reflected from or transmitted through the specimen by the microscope illuminator.
www.olympusmicro.com /primer/java/olympusmicd/digitalimaging/contrast   (1951 words)

  
 THX Ltd. - Brightness Set-Up   (Site not responding. Last check: 2007-11-07)
As with contrast, the brightness adjustment should be made under the viewing conditions you expect at the time you plan to watch the movie.
For the brightness test, THX Optimizer provides a signal that displays two bars containing ten shades of fl at the top and bottom of the screen, the THX logo, and a drop shadow behind the THX logo.
The Brightness adjustment can be very important for some projection televisions since the fl content of the video can contain video noise or hum, which can be detrimental to the picture.
www.thx.com /mod/techlib/brightness.html   (406 words)

  
 Surface Brightness
The concept of surface brightness is crucial for urban and suburban observing, and indeed, for deep-sky observing of all kinds.
When an object is twice as far away, it appears one quarter as bright; however, it also appears to be half as big, or one quarter the area, so the surface brightness, or brightness per unit area, remains the same.
To make matters worse, amateur astronomers frequently use the term brightness to mean both integrated brightness and surface brightness in the same paragraph, and also often use it to denote the subjective impression of brightness, which depends both on surface brightness and on integrated brightness.
mysite.verizon.net /vze55p46/id18.html   (1590 words)

  
 Brightness Contrast: Psychology Department, Langara College
This phenomenon is called simultaneous brightness contrast or lateral brightness adaptation and is explained by the theory of lateral inhibition.
The change in the sensitivity of one part of the retina by the level of brightness excitation in an adjacent retinal area is called lateral inhibition and accounts for most of the contrast effects in FIGURE 1 above.
The observer may note that the gray squares reveal a slightly coloured tint which is complementary to the colour of their backgrounds.
www.langara.bc.ca /psychology/brightness.htm   (1165 words)

  
 Brightness discrimination in the dog
Rockville, MD ——Dogs' ability to discriminate brightness is about half as good as that of humans, according to a study appearing in Volume 4, Issue 3 in the Journal of Vision.
Although the researchers did not test humans in their study, previous studies found that humans need a Weber fraction of 0.14 to be able to discern a brightness difference.
Brightness would be an important cue for such animals.
www.eurekalert.org /pub_releases/2004-06/afri-di062904.php   (448 words)

  
 Brightness (Low, Variable, High) Troubleshooting   (Site not responding. Last check: 2007-11-07)
Also, test the brightness of the broke; it is possible that the level of broke in the paper happens to be high and that the broke has a lower brightness than the supplied pulp.
Some other possible sources of low brightness include (a) humic acids or transition metal compounds in the incoming water, (b) a failure of the filler addition system, (c) excessive addition of dyes, and (d) biological decay.
Sometimes brightness variations can follow the batch-wise preparation cycles of a starch (possibly subject to biological decay), retention aid (possibly related to swings in first-pass retention), or biocide (often added intermittently and also affecting retention efficiency in certain cases).
www4.ncsu.edu:8030 /~hubbe/TShoot/G_Brite.htm   (746 words)

  
 The Brightness of Moonlight
The brightness of moonlight under clear skies is as easily predictable as is the brightness of sunlight under similar conditions.
The brightness of moonlight varies by approximately a factor of 10 between quarter phase and full moon, based on a diffuse reflection and the geometry of the positions of the earth, sun and moon alone.
The brightness is in terms of lunar illumination in foot-candles (divide by 10.76 if you want to use the metric units, which are lux, or meter-candelas).
home.earthlink.net /~kitathome/LunarLight/moonlight_gallery/technique/moonbright.htm   (2046 words)

  
 Brightness
A perceived characteristics of objects which does not vary directly in a simple mathematical relationship with their physical or measured brightness, which is corretly termed their luminance.
The term brightness is often misused to mean luminance.
If so, it should be qualified as "measured" brightness, to distinguish between the absolute attributes ("measured" brightness) and the perceived attributes ("apparent" of "subjective" brightness) of the object in question.
www.schorsch.com /kbase/glossary/brightness.html   (66 words)

  
 Exploratorium: Science Snacks: Solar Brightness
By finding a position at which the sun is as bright as the lamp the power output of the sun can be estimated.
Since the area of a sphere increases as the square of its radius, the intensity of a light source which spreads uniformly decreases as the inverse square of the distance from the center of the source (the radius).
When the photometer indicates that the brightness of the lamp is equal to the brightness of the sun then the intensity of the lamp is approximately equal to the intensity of light from the sun.
www.exploratorium.edu /snacks/solar_brightness   (723 words)

  
 Define hue, saturation, and brightness - a Whatis.com definition - see also: HSB   (Site not responding. Last check: 2007-11-07)
Hue, saturation, and brightness are aspects of color in the red, green, and blue (RGB) scheme.
Brightness is a relative expression of the intensity of the energy output of a visible light source.
It can be expressed as a total energy value (different for each of the curves in the diagram), or as the amplitude at the wavelength where the intensity is greatest (identical for all three curves).
whatis.techtarget.com /definition/0,,sid9_gci212262,00.html   (385 words)

  
 Specs offenders   (Site not responding. Last check: 2007-11-07)
There are a million and one technical issues when testing a projector's brightness, says Barlow, but when all is said and done, commercial and competitive pressures often persuade companies to come up with a higher brightness number than they should.
Brightness, as well as contrast ratio, color saturation, fan noise and other quantitative specs, could be measured and approved by a controlling organization, he suggests.
The consensus among the experts interviewed is that projector brightness and adherence to the advertised brightness spec are still important – but not as important as they used to be.
www.presentations.com /presentations/search/search_display.jsp?vnu_content_id=1000503890   (2856 words)

  
 Neptune's Increased Brightness
This delay in the brightness peak is half the delay in the dynamical response to solar forcing, a consequence of geometric effects.
In this model, dynamic activity that produces brighter cloud features is postulated to increase in proportion to the daily average incident sunlight, thus brightening the hemisphere that is tipped toward the sun and darkening the hemisphere that is tipped away.
This would lead to peaks in disk-averaged brightness at each solstice (maximum latitudinal excursion of the sun), except for one complicating factor.
www.ssec.wisc.edu /media/Neptune2003.htm   (720 words)

  
 Low Surface Brightness Galaxy Gallery   (Site not responding. Last check: 2007-11-07)
LSB disk galaxies have similar structure as high surface brightness galaxies; that is, the light distribution falls of exponentially.
The central surface brightness of this galaxy is 24.28
The high surface brightness knot in one of its spiral arms actually has the same color, luminosity and H-alpha equivalent width as the entire Large Magellanic Cloud.
zebu.uoregon.edu /sb2.html   (506 words)

  
 Cortical processing of a brightness illusion -- Roe et al. 102 (10): 3869 -- Proceedings of the National Academy of ...   (Site not responding. Last check: 2007-11-07)
An illusory brightness contrast is induced by a true contrast difference at an intervening border (16-30% contrast peak to peak at border).
A perceptually matched brightness contrast (8-15% contrast peak to peak at border; cf.
the Cornsweet stimulus is a brightness percept that is induced
www.pnas.org /cgi/content/full/102/10/3869   (3931 words)

  
 Apparent Brightness   (Site not responding. Last check: 2007-11-07)
The apparent brightness is how much energy is coming from the star per square meter per second, as measured on Earth.
A very bright star was called ``first magnitude,'' a pretty bright star is ``second magnitude,''...
The apparent brightness of a star is described by a magnitude that is a positive number for most stars, but can be a negative number for, say, Venus.
zebu.uoregon.edu /~soper/Stars/brightness.html   (140 words)

  
 Large-screen displays, Part Two   (Site not responding. Last check: 2007-11-07)
Display brightness may be important if there is a high amount of ambient light in the room – as is often the case in presentation scenarios – but most of today's displays are plenty bright for presentation purposes.
What this really boils down to is that the relative brightness between displays at any given moment actually depends on the makeup of the image displayed – which is why it is so important to know what will be shown on a display before you buy one.
The DLP is relatively bright, so its grayscale is steeper at low intensities to enhance visual contrast near fl – a plus for video viewing as well.
www.presentations.com /presentations/technology/article_display.jsp?vnu_content_id=1000543355   (2880 words)

  
 Etherington & Roberts. Dictionary--brightness   (Site not responding. Last check: 2007-11-07)
Originally, a judgement of the amount of light reflected to the eye from the surface of a material, regardless of hue or color saturation.
Many factors affect the brightness of a material such as paper, including the degree of bleaching of the pulp, as well as the addition of chemicals.
Chemically treated high-grade text and book papers have a brightness in the range of about 96 (on a scale of 100), coated papers range from about 70 to 85, while mechanical wood machine-coated papers are in the range of about 60 to 75.
palimpsest.stanford.edu /don/dt/dt0478.html   (93 words)

  
 Brightness Variations
In this method, the brightness change of a material point is estimated by tracking the point as it moves.
This algorithm relaxes the brightness constancy assumption of HSOF and allows for a brightness variation modeled by a local linear transformation.
To model the brightness change effects due to tag pattern fading alone, we assume that motion is not present.
iacl.ece.jhu.edu /~gupta/papers/proposal/node6.html   (973 words)

  
 ABC-Dir: Brightness   (Site not responding. Last check: 2007-11-07)
Seeks to capture the brightness and energy of spring and summer.
From NASA Science News, experiment on board shuttle mission STS-107 is monitoring the Sun's variable brightness and its link to...
The BBC report on a theory that Mayan astronomy may have been inspired by fluctations in the brightness of the...
www.abc-directory.com /view/brightness   (235 words)

  
 Amazon.com: Brightness Springs: Books: John Mark Butterworth   (Site not responding. Last check: 2007-11-07)
Brightness Springs is a fantastic parable of the Bright People and the Sleepers.
Curious events and odd disappearances lead Pete and the others to believe that the Bright People, for all their hospitality and kindness, may be hiding something vital and momentous from them; something supernatural and astonishing when at last revealed.
Brightness Springs is a gracious tale of wonder and transformation as if C.S. Lweis and Robert Frost met to compose a modern parable of joy, happiness, love, and compassion in an ever expanding universe of the marvelous, fantastic, srene, and sacred.
www.amazon.com /exec/obidos/tg/detail/-/0967642906?v=glance   (713 words)

  
 brightness control with geforce go 6200 and sony laptop - nV News Forums
I own a sony vaio s3xp (geforce go 6200 tc) and apparently the only way t control lcd brightness (thus increasing battery time) is through the video drivers.
Even in windows you do not obtain brightness control until you install the nvidia driver.
I've found this project today, which focusses on brightness-settings on external display-devices (controlled without buttons); subscribed to their mailing-list a couple of minutes ago, maybe they have a solution.
www.nvnews.net /vbulletin/showthread.php?t=51566   (693 words)

  
 TSU researchers link sun's brightness and life - Monday, 08/09/04   (Site not responding. Last check: 2007-11-07)
But at least the sun's brightness is a lot more consistent than it was once upon a time — say, 600 million years ago — and that's definitely good.
Once the sun's ''brightness variability'' settled down, it got a lot easier for complex life forms — plants and animals — to survive and thrive on Earth, TSU astronomer Greg Henry said.
So the decline in the sun's brightness variability may have been necessary for the emergence of advanced species during the Cambrian explosion.
www.tennessean.com /local/archives/04/08/55599646.shtml?Element_ID=55599646   (789 words)

  
 ESA Portal - Rosetta camera view of Tempel 1 brightness
In this second animation, at left, the brightness of image pixels seen by OSIRIS is plotted 'three-dimensionally', i.e.
The light curve shows that about 30 minutes after impact the brightness of the comet had increased by five times.
After this phase, scientists also noticed that the brightness level fluctuated for about one hour with no overall increase, then seemed to decrease, but much more slowly than the initial increase.
www.esa.int /esaCP/SEMSJ06DIAE_index_0.html   (259 words)

  
 Brightness Temperature
Channel 4 Brightness Temperature - This is the top of the atmosphere brightness temperature, in Kelvin, derived from Channel 4 of the AVHRR (10.3 - 11.3 micrometer).
Channel 5 Brightness Temperature - This is the top of the atmosphere brightness temperature, in Kelvin, derived from Channel 5 of the AVHRR (11.5 - 12.5 micrometer).
A report of the calibration working committee is given in Rao(1993a, 1993b).However, no recommendations were made for the channel 3, so the Pathfinder processing system uses the gains and offsets provided in the NOAA 1b data record and calibrates the radiances using the procedures described in the Polar Orbiter Users Guide (Kidwell 1991).
daac.gsfc.nasa.gov /landbio/btemp.shtml   (237 words)

  
 Tip: PowerBook Brightness flickering? Here's a fix.   (Site not responding. Last check: 2007-11-07)
Situated under each speaker grille, these allow the 'Book to tell how bright its environment is and adjust the screen brightness (and backlit keyboard if you have one) to suit.
Watch the brightness slider in the preference pane while slowly covering then uncovering both speaker grilles.
The brightness should drop right down with the grilles covered, and come back up when they're uncovered, but not jitter when say you wave a hand over the top of them.
www.paulbaily.com /blog/C533025856/E551447606   (590 words)

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