SMPTE Journal ( Volume: 104, Issue: 7, July 1995)
[ACTIVE]
Behind Gamma's Disguise
Metadata
- Publisher
- SMPTE — White Plains, NY, USA
- Doc Type
- Journal Article
- Content Type
- Original Research
- Abbreviated Title
- SMPTE J
- Volume
- 104, No. 7, pp. 452–458
- Abstract
- A simple power law is often used to describe the light output of cathode ray tubes (CRTs). Its exponent gamma (γ) has been measured many times in many ways, with varying results. The failure of this simple formula to accurately characterize high-resolution CRTs used in film recording applications has led to a model that explains the observed light output from very low beam currents to high drive levels. It comprises a cathode model and an anode current “trim” function; the relationship between anode and cathode currents establishes the key parameters. The cathode current is represented by a blend of two power laws. The anode current is a fraction of the cathode current, determined by the intersection of a gaussian beam with a circular aperture. The resulting model successfully predicts the behavior of high-resolution CRTs, even at low output levels. It also explains the many varying results when attempting to measure a single value for gamma.
- Publication Date
- 1995-07-01
- DOI
10.5594/J17709- ISSN
- Print:
0036-1682 - Link
- https://doi.org/10.5594/J17709
- Author(s)
- Thor OlsonManagement Graphics, Inc., Minneapolis, MN 55425
- Copyright
- © 1995 Society of Motion Picture and Television Engineers, Inc.
Bibliographic Reference(s)
- SMPTE Tutorial: “Gamma” and its Disguises: The Nonlinear Mappings of Intensity in Perception, CRTs, Film, and Video [Active]
- 2. Berns R. S. Motta R. J. Gorzynski M. E. , “CRT Colorimetry — Pari I: Theory and Practice,” Color Research and Applications , 18 : 299 – 314 , Oct. 1993 . EXTERNAL
- 3. Ryder J. D. , Electronic Engineering Principles (rev.) , Prentice-Hall Inc. : New York , 1947 . EXTERNAL
- 4. Moss H. , Narrow Angle Electron Guns and Cathode Ray Tubes , Academic Press : New York , 1968 . EXTERNAL
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Thor Olson; Behind Gamma's Disguise, SMPTE Journal ( Volume: 104, Issue: 7, July 1995); SMPTE, 1995. Available at https://doi.org/10.5594/J17709
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Thor Olson; Behind Gamma's Disguise, SMPTE Journal ( Volume: 104, Issue: 7, July 1995); SMPTE, 1995. Available at https://doi.org/10.5594/J17709
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Thor Olson; Behind Gamma's Disguise, SMPTE Journal ( Volume: 104, Issue: 7, July 1995); SMPTE, 1995. Available at https://doi.org/10.5594/J17709
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<span class="citation">Thor Olson; <cite>Behind Gamma's Disguise</cite>, SMPTE Journal ( Volume: 104, Issue: 7, July 1995); SMPTE, 1995. Available at <a href="https://doi.org/10.5594/J17709" target="_blank" rel="noopener">https://doi.org/10.5594/J17709</a></span>
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Thor Olson; Behind Gamma's Disguise, SMPTE Journal ( Volume: 104, Issue: 7, July 1995); SMPTE, 1995
doi: 10.5594/J17709
url: https://doi.org/10.5594/J17709
doi: 10.5594/J17709
url: https://doi.org/10.5594/J17709
Snippet:
<li> Thor Olson; <cite id="bib-10-5594-j17709">Behind Gamma's Disguise</cite>, SMPTE Journal ( Volume: 104, Issue: 7, July 1995); SMPTE, 1995 <span class="doi">10.5594/J17709</span> </li>