BRDF study of gray-scale Spectralon

Georgiev, G.; Butler, James J.

doi:10.1117/12.795931

Cited by 21 publications

(15 citation statements)

References 11 publications

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“…Whereas reflectance factor monotonically increases with emergence angle at i = 60°and the data show a total increase of 1360% in reflectance factor. This result agrees with the non-polarized measurements presented in Georgiev and Butler (2008), who call the quantity they measure BRDF because they are using different terminology that considers BRDF a measurable quantity (e.g. Hapke 2012); however, in the terminology of Nicodemus, Richmond, and Hsia (1977) they measured biconical reflectance factor /π.…”

Section: S-polarizationsupporting

confidence: 86%

“…Most of these features of Spectralon reflectance factor curves have not been discussed in previous work that looked at large sets of grey-scale Spectralon. However, a careful inspection of the curves presented in Georgiev and Butler (2008) shows that some of the same features visible in the 1064 nm data set presented here are also present in their data set acquired at 900 nm. They provide little discussion of their data, and features at intermediate viewing angles are not visible in their plots for some of the Spectralon targets (possibly due to plot scaling).…”

Section: S-polarizationmentioning

confidence: 77%

“…The data show a total relative decrease in reflectance factor of 44%. Previous works by Parretta and Addonizio (2015) and Georgiev and Butler (2008) did not present separate data sets at s-and p-polarizations.…”

Section: P-polarizationmentioning

confidence: 90%

“…Although many studies have investigated the reflectance properties of the brightest Spectralon standard available (e.g. Jackson, Clarke, and Susan Moran 1992;Bruegge et al 1993;Betty, Fung, and Irons 1996;Georgiev and Butler 2004;Bhandari et al 2011;Svensen et al 2012), there are only a few studies of grey-scale Spectralon in the current literature (Rollin, Milton, and Emery 2000;Maddalena, Tortora, and Parretta 2003;Georgiev and Butler 2008;Parretta and Addonizio 2015).…”

Section: Introductionmentioning

confidence: 98%

“…The study concludes that standards with a higher nominal reflectance exhibit behaviour closer to Lambertian. Georgiev and Butler (2008) also investigate a large set of grey-scale Spectralon targets. The study concludes that the reflectance factor (BRDF in their terminology) of the 40-99% Spectralon targets decreases with increasing viewing angle and the reflectance factor of the 2-20% Spectralon targets increases with increasing viewing angle.…”

Section: Introductionmentioning

confidence: 99%

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Reflectance properties of grey-scale Spectralon® as a function of viewing angle, wavelength, and polarization

Shaw

Daly

Cloutis

et al. 2016

International Journal of Remote Sensing

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The remote-sensing community uses grey-scale Spectralon to evaluate the performance of instruments designed to observe geologic surfaces with a range of reflectance values. This article presents the normalized biconical reflectance factor of a series of grey-scale Spectralon targets taken at viewing angles ranging from 10°to 80°. The darkest Spectralon standard, when illuminated at nadir incidence with s-polarized 1064 nm light, first undergoes a decrease in reflectance factor with increasing viewing angle, then encounters a minimum, after which the reflectance factor increases with increasing viewing angle. When progressively brighter Spectralon samples are measured, the reflectance factor dip at lower emergence angles becomes less pronounced and the slope at higher emergence angles is more gradual until, for the 20% Spectralon sample, the curve dips downward at the highest emergence angles. Measuring the grey-scale Spectralon set of targets using p-polarized incident light, the same trends described above are seen, except for the darkest Spectralon target, which monotonically decreases in reflectance factor. The data show a total decrease of 44%. The reflectance factor curves observed at 852 nm are similar to those seen at 1064 nm in that the same number of inflection points and the same sign of slope is seen at both wavelengths. However, comparing two different incidence angles using 1064 nm s polarized incident light, the slope of the reflectance factor curve does change significantly. For the brightest Spectralon target, the slope is positive for i = 60°and negative for i = 0°at all viewing angles measured. For the darkest Spectralon target, the slope is larger for i = 60°than for i = 0°at all viewing angles measured. At i = 60°, the data show a total increase of 1360% in reflectance factor. ARTICLE HISTORY

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Section: S-polarizationsupporting

confidence: 86%

Section: S-polarizationmentioning

confidence: 77%

Section: P-polarizationmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Reflectance properties of grey-scale Spectralon® as a function of viewing angle, wavelength, and polarization

Shaw

Daly

Cloutis

et al. 2016

International Journal of Remote Sensing

View full text Add to dashboard Cite

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A practical and efficient model for intensity calibration of multi-light image collections

et al. 2021

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We present a novel practical and efficient mathematical formulation for light intensity calibration of Multi Light Image Collections (MLICs). Inspired by existing and orthogonal calibration methods, we design a hybrid solution that leverages their strengths while overcoming most of their weaknesses. We combine the rationale of approaches based on fixed analytical models with the interpolation scheme of image domain methods. This allows us to minimize the final residual error in light intensity estimation, without imposing an overly constraining illuminant type. Unlike previous approaches, the proposed calibration strategy proved to be simpler, more efficient and versatile, and extremely adaptable in different setup scenarios. We conduct an extensive analysis and validation of our new light model compared to several state-of-the-art techniques, and we show how the proposed solution provides a more reliable outcomes in terms of accuracy and precision, and a more stable calibration across different light positions/orientations, and with a more general light form factor.

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