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Topic: Luminance


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Lux

In the News (Sat 20 Jul 19)

  
  More details about Luminance in Histograms
The luminance signal in your TV set uses the same formula, in fact, that was its origin.
So, gray tone range in Luminance values is used by the histogram to map, or to tell us about the actual distribution of, the range of light and dark tones in our color images.
Photographs generally have more nearly all luminance values represented, where both of these samples were intentionally limited, to be able to better show the details better.
www.scantips.com /lumin.html   (1429 words)

  
  Photographing the Moon
The luminance of the moon is the sum of the light from the sky and the light from the moon, and the amount of light in the sky defines three different situations.
Measuring the luminance of the moon with a handheld meter is difficult; because the moon has an angular diameter of approximately 1/2°, even a 1° spot meter won’t suffice.
At an altitude of 5°, the luminance of the moon is 561 cd/m
www.calphoto.com /moon.htm   (2472 words)

  
 Lenovo Healthy Computing - Discussion of illuminance, luminance level, acuity   (Site not responding. Last check: )
Luminance does not follow a square law, but the measurement area must be defined.
The luminance of a wall, for example, is the same whether measured two meters away or four.
The particular luminance of a bright surface is usually referred to as its "brightness" because it is the quality of brightness that we perceive.
www.pc.ibm.com /ww/healthycomputing/vdt19b.html   (653 words)

  
 Color Schemer Forums / Luminance Value
Luminance (aka Lightness, Brightness) is the amount of fl or white in a color (0 to 100%).
Luminance is defined by a numerical value denoting the amount of a shade of grey in a color.
If the luminance was moved to a midpoint of 127 the rgb is then 15,255,15 and hex is #0FFF0F If we move the luminance to a point 75% up the scale at approx 191, you then have values of rgb 151,253,151 with hex of #97FD97.
www.colorschemer.com /forums/viewtopic.php?id=72   (581 words)

  
 Vision Series - darksky.org
Luminance is determined by both the amount of color and light and how sensitive our eyes are to the color of that light.
In the brain, luminance and color vision are separate functions located in separate areas of the visual cortex.
Luminance vision is the most basic type of vision in that without it our sense of the world would be flat or 2-d rather than 3-d.
www.darksky.org /VisionSeries/vs3-3.html   (402 words)

  
 Histograms Tutorial - Luminance and Color
Luminance histograms are more accurate than RGB histograms at describing the perceived brightness distribution or "luminosity" within an image.
Luminance takes into account the fact that the human eye is more sensitive to green light than red or blue light.
Luminance correctly predicts that the following stepped gradient gradually increases in lightness, whereas a simple addition of each RGB value would give the same intensity at each rectangle.
www.cambridgeincolour.com /tutorials/histograms2.htm   (960 words)

  
 Untitled Document
The basic premise of luminance layering is that by combining an unfiltered high resolution and high S/N greyscale image with the weaker color data we can in essense "buy back" the signal and detail lost in our filtered RGB exposures.
What "luminance layering" does in essense is to replace the poor quality, low S/N luminance of the original color data with the new high quality, high S/N luminance image.
In practice this means the luminance is usually a very long unfiltered exposure (or multiple stacked shorter exposures) taken in maximal resolution (unbinned) mode.
www.robgendlerastropics.com /LRGB.html   (1904 words)

  
 Luminance Channel
Simply put this equation say that luminance is equal to a constant times the sum of the spectral radiance times the photopic spectral sensitivity.
The luminance channel is also referred to as the achromatic channel or the spectrally non-opponent channel.
The observer spectral sensitivity is primarily a function of the L and M cone excitation.
www.yorku.ca /eye/luminanc.htm   (218 words)

  
 Face-based Luminance Matching for Perceptual Colormap Generation
That is, the relationship between RGB input levels and perceived luminance is usually not known, due to variations in the monitor, hardware configuration, and the viewing environment.
However, the luminance component of perceptually based colormaps should be controlled, due to the central role that luminance plays in our visual processing.
The method is akin to the minimally distinct border technique (a previous method of luminance matching used for measuring luminous efficiency), but our method relies on the brain's highly developed ability to distinguish human faces.
www.cs.utah.edu /~gk/papers/vis02   (199 words)

  
 Luminance Colorimeter - BOSSTAR Technological Co., Ltd.
Designed for maximum sensitivity in measuring spot toaverage luminance.
The luminance, chromaticity, color temperature, CIELAB, CIELUV, and color difference are measured, and displayed at once.
Because the standard interface is built in, measurements can be performed automatically making it very suitable for inline use.
www.bosstar.com /china/luminance-colorimeter.html   (112 words)

  
 Barco | Barco launches industry-first medical diagnostic luminance color display system
As part of Barco's new Coronis display system family, the Coronis Color 3MP Diagnostic Luminance presents color as well as grayscale images with unprecedented brightness, contrast and DICOM precision over the entire lifetime of the display.
With a calibrated brightness of 500 cd/m2, Barco's Coronis Color 3MP Diagnostic Luminance is the perfect answer to the latest trends in medical diagnostic imaging, such as the rise of color-augmented modalities, 3D imaging, Computer Aided Diagnosis (CAD) and the merge of various types of patient data into one Electronic Medical Record (EMR).
With Barco's Uniform Luminance Technology, radiologists can be sure that their images are DICOM-compliant everywhere on the screen.
www.barco.com /medical/en/Pressreleases/show.asp?index=1663   (554 words)

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