| Records |
Author  |
Bará, S.; Nievas, M.; Sanchez de Miguel, A.; Zamorano, J. |
| Title |
Zernike analysis of all-sky night brightness maps |
Type |
Journal Article |
| Year |
2014 |
Publication |
Applied Optics |
Abbreviated Journal |
Appl Opt |
| Volume |
53 |
Issue |
12 |
Pages |
2677-2686 |
| Keywords |
modeling; light at night; light pollution; all-sky; Zernike polynomials; image decomposition; sky brightness |
| Abstract |
All-sky night brightness maps (calibrated images of the night sky with hemispherical field-of-view (FOV) taken at standard photometric bands) provide useful data to assess the light pollution levels at any ground site. We show that these maps can be efficiently described and analyzed using Zernike circle polynomials. The relevant image information can be compressed into a low-dimensional coefficients vector, giving an analytical expression for the sky brightness and alleviating the effects of noise. Moreover, the Zernike expansions allow us to quantify in a straightforward way the average and zenithal sky brightness and its variation across the FOV, providing a convenient framework to study the time course of these magnitudes. We apply this framework to analyze the results of a one-year campaign of night sky brightness measurements made at the UCM observatory in Madrid. |
| Address |
Ãrea de Óptica, Dept. de FÃsica Aplicada, Fac. de FÃsica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain |
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Thesis |
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| Publisher |
Optical Society of America |
Place of Publication |
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Editor |
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| Language |
English |
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Edition |
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| ISSN |
0003-6935 |
ISBN |
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| Notes |
PMID:24787595 |
Approved |
no |
| Call Number |
IDA @ john @ |
Serial |
318 |
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| Author |
Smith, G.; Vingrys, A.J.; Maddocks, J.D.; Hely, C.P. |
| Title |
Color recognition and discrimination under full-moon light |
Type |
Journal Article |
| Year |
1994 |
Publication |
Applied Optics |
Abbreviated Journal |
Appl Opt |
| Volume |
33 |
Issue |
21 |
Pages |
4741-4748 |
| Keywords |
Human Health |
| Abstract |
The ability to recognize and discriminate colors under full-moon light was measured Color naming was performed at three sizes (0.5 degrees , 2 degrees , and 4 degrees ) by the use of one white and six colored chips that spanned the spectrum at two levels of saturation. The results show that correct color recognition is possible under full-moon light. However, the recognition rate depends on a complex interaction between hue, level of saturation, and size of test field. For small fields and desaturated colors, the recognition rate is low. However, for saturated colors, most hues can be recognized at better than chance levels, with red being recognized very accurately. |
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| Language |
English |
Summary Language |
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Original Title |
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Edition |
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| ISSN |
0003-6935 |
ISBN |
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| Notes |
PMID:20935847 |
Approved |
no |
| Call Number |
LoNNe @ christopher.kyba @ |
Serial |
531 |
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| Author |
Zukauskas, A.; Vaicekauskas, R.; Vitta, P. |
| Title |
Optimization of solid-state lamps for photobiologically friendly mesopic lighting |
Type |
Journal Article |
| Year |
2012 |
Publication |
Applied Optics |
Abbreviated Journal |
Appl Opt |
| Volume |
51 |
Issue |
35 |
Pages |
8423-8432 |
| Keywords |
Lighting Systems; Circadian Rhythm; Color; Equipment Design; Humans; Light; *Lighting; Melatonin/metabolism; Photobiology/*methods; Semiconductors; Time Factors; Vision, Ocular |
| Abstract |
The circadian and visual-performance-based mesopic systems of photometry were applied for the optimization of the spectral power distributions (SPDs) of the solid-state sources of light for low-illuminance lighting applications. At mesopic adaptation luminances typical of outdoor lighting (0.1-2 cd/m(2)), the optimal SPDs were obtained through the minimization of the mesopic circadian action factor, which is the ratio of the circadian efficacy of radiation to mesopic luminous efficacy of radiation. For correlated color temperatures below ~3000 K, the optimized dichromatic light-emitting diodes (LEDs) are shown to pose a lower circadian hazard than high-pressure sodium lamps and common warm white LEDs; also they are potentially more efficacious and have acceptable color rendition properties under mesopic conditions. |
| Address |
Institute of Applied Research, Vilnius University, Sauletekio al. 9-III, Vilnius LT-10222, Lithuania. arturas.zukauskas@ff.vu.lt |
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English |
Summary Language |
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| ISSN |
0003-6935 |
ISBN |
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Conference |
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| Notes |
PMID:23262538 |
Approved |
no |
| Call Number |
LoNNe @ christopher.kyba @ |
Serial |
448 |
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