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Spectral goniophotometry: applications to light scattering in paper
Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
2013 (English)Licentiate thesis, comprehensive summary (Other academic)
Place, publisher, year, edition, pages
Örnsköldsvik: Mid Sweden University , 2013. , p. 18
Series
Mid Sweden University licentiate thesis, ISSN 1652-8948 ; 106
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:miun:diva-20950ISBN: 978-91-87557-13-2 (print)OAI: oai:DiVA.org:miun-20950DiVA, id: diva2:683325
Supervisors
Available from: 2014-01-03 Created: 2014-01-03 Last updated: 2014-01-03Bibliographically approved
List of papers
1. Influence of finite-sized detection solid angle on bidirectional reflectance distribution function measurements
Open this publication in new window or tab >>Influence of finite-sized detection solid angle on bidirectional reflectance distribution function measurements
2014 (English)In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 53, no 6, p. 1212-1220Article in journal (Refereed) Published
Abstract [en]

This paper deals with limitations and often overlooked sources of error introduced in compact double-beam goniophotometers. It is shown that relative errors in measured radiance factor, comparable to the total measurement uncertainty, can be introduced if recommended corrections are not carried out. Two different error sources are investigated, both related to the size of the detection solid angle. The first is a geometrical error that occurs when the size of the illuminated area and detector aperture are comparable to the distance between them. The second is a convolution error due to variations in radiant flux over the detector aperture, which is quantified by simulating the full 3D bidirectional reflectance distribution function (BRDF) of a set of samples with different degrees of anisotropic reflectance. The evaluation is performed for a compact double-beam goniophotometer using different detection solid angles, and it is shown that both error sources introduce relative errors of 1%–3%, depending on viewing angle and optical properties of the sample. Commercially available compact goniophotometers, capable of absolute measurements, are becoming more and more common, and the findings in this paper are therefore important for anyone using or planning to use this type of instrument.

Place, publisher, year, edition, pages
Optical Society of America, 2014
Keywords
Reflection, Scattering measurements, BRDF, turbid media
National Category
Natural Sciences
Identifiers
urn:nbn:se:miun:diva-20949 (URN)10.1364/AO.53.001212 (DOI)000331949600027 ()2-s2.0-84942366011 (Scopus ID)
Available from: 2014-01-03 Created: 2014-01-03 Last updated: 2017-12-06Bibliographically approved
2. Separation of surface and bulk reflectance by absorption of bulk scattered light
Open this publication in new window or tab >>Separation of surface and bulk reflectance by absorption of bulk scattered light
2013 (English)In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 52, no 19, p. 4749-4754Article in journal (Refereed) Published
Abstract [en]

A method is proposed for separating light reflected from turbid media with a rough surface into a bulkand a surface component. Dye is added to the sample, thereby increasing absorption and canceling bulkscattering. The remaining reflected light is surface reflectance, which can be subtracted from the totalreflectance of an undyed sample to obtain the bulk component. The method is applied to paper wherethe addition of dye is accomplished by inkjet printing. The results show that the bulk scattered light isefficiently canceled, and that both the spectrally neutral surface reflectance and the surface topographyof the undyed paper is maintained. The proposed method is particularly suitable for characterization ofdielectric, highly randomized materials with significant bulk reflectance and rough surfaces, which aredifficult to analyze with existing methods. A reliable separation method opens up for new ways of analyzing,e.g., biological tissues and optical coatings, and is also a valuable tool in the development of morecomprehensive reflectance models.

Place, publisher, year, edition, pages
Optical Society of America, 2013
Keywords
Reflection, Scattering measurements, Turbid media
National Category
Other Physics Topics
Identifiers
urn:nbn:se:miun:diva-19640 (URN)10.1364/AO.52.004749 (DOI)000321289700043 ()2-s2.0-84879948231 (Scopus ID)
Available from: 2013-09-05 Created: 2013-07-26 Last updated: 2017-12-06Bibliographically approved
3. Angular variations of reflectance and fluorescence from paper - the influence of fluorescent whitening agents and fillers
Open this publication in new window or tab >>Angular variations of reflectance and fluorescence from paper - the influence of fluorescent whitening agents and fillers
2012 (English)In: Final Program and Proceedings - IS and T/SID Color Imaging Conference, Springfield, USA: The Society for Imaging Science and Technology, 2012, p. 236-241Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

It has earlier been shown that light reflected from the bodyof paper exhibit anisotropic behavior. On the other hand, fluores-cence emission is often assumed to be distributed in a Lambertianmanner. The angular behavior of light reflected and fluorescedfrom paper is examined using measurements from a spectral go-niophotometer. The angular dependency of the radiance factorswas measured for a range of excitation wavelengths. Moreover,the influence of fillers and fluorescent whitening agents (FWA)on the anisotropy was studied. The measurements show that theanisotropy of the total radiance factor of paper decreases whenan increasing amount of FWA is added to the paper. The sameeffect was also observed when an increased amount of filler wasadded to the paper. In addition, it was shown that the presenceof fillers reduce the effect of the FWA. The results show that incomparison to the anisotropy of the total radiance factor from thepaper samples, the anisotropy of the fluorescence alone is negligi-ble. Hence, for paper samples containing FWA evenly distributedin the bulk, the fluorescence alone should not induce significantdifferences between color measuring instruments of different mea-surement geometries.

Place, publisher, year, edition, pages
Springfield, USA: The Society for Imaging Science and Technology, 2012
Keywords
reflectance, goniophotometer, fluorescence, anisotropy
National Category
Other Physics Topics
Identifiers
urn:nbn:se:miun:diva-18079 (URN)2-s2.0-84876737413 (Scopus ID)978-0-89208-303-9 (ISBN)
Conference
20th Color and Imaging Conference: Color Science and Engineering Systems, Technologies, and Applications, CIC 2012; Los Angeles, CA; United States; 12 November 2012 through 16 November 2012; Code 96727
Projects
Spektral Goniofotometer
Funder
The Knowledge Foundation
Available from: 2012-12-21 Created: 2012-12-20 Last updated: 2015-05-26Bibliographically approved

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