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1

Comparison of selected methods for measuring the luminous flux of solid-state light sources

Górecki Krzysztof, Kalinowska Aleksandra, Ptak Przemysław

Opto-Electronics Review

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2024

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Vol. 32, No. 1

art. no. ee149234

EN

The paper presents a simple method of measuring the luminous flux value dedicated to LED light sources. This method uses information about a spatial radiation pattern of the lighting source under test and the results of illuminance measurements at the axis of this source. The method is described and the results of the measurements obtained using this method and the classical method are compared and discussed. Tests have been carried out for LED modules of different geometries. The measurement error of the considered method is analysed.

2

Determining the optical properties of blood using He-Ne laser and double integrating sphere set-up

Ashoor Habib E., Jasim Khalil Ebrahim

Polish Journal of Medical Physics and Engineering

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2019

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Vol. 25, Iss. 1

1--5

EN

The behaviour of light interaction with biological tissue is determined by micro-optical parameters: refractive index (n), absorption coefficient (µa), scattering coefficient (µs), and anisotropy (g). The goal of this study is to measure the optical properties of normal whole blood using He-Ne laser (wavelength 632.8 nm). The refractive index is measured using the traveller microscope. The integrating sphere method is used to measure the macro-optical parameters: total diffusive reflectance, transmittance, and collimated transmittance at wavelength 632.8 nm. The macro-optical parameters are fed to Inverse Adding Doubling (IAD) theoretical technique, to estimate the micro-optical parameters (µs, µa, g). An alternative practical method is used to measure the g value based on utilising the goniometric table. The study reveals that the refractive index (n) equals 1.395±0.0547, absorption coefficient (µa) equals 2.37 mm−1, scattering coefficient (µs) equals 55.69 mm−1, and anisotropy (g) equals 0.82. In conclusion, these findings approved, in general, the applicability of the suggested experimental set up. The set up depend on using three devices: the integrating sphere method to estimate (µs, µa, g), traveller microscope (n) and goniometer (g).

3

Ocena przydatności pomiaru reflektancji światła widzialnego z wykorzystaniem sfery integrującej do oznaczania zawartości węgla w lotnych popiołach

Molenda J., Siwiec E., Makowska M.

Chemik

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2011

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Vol. 65, nr 7

615-620

PL

Przeprowadzone badania miały na celu zweryfikowanie przydatności pomiaru reflektancji światła widzialnego, z wykorzystaniem sfery integrującej do badania zawartości niewypalonego węgla w lotnych popiołach. Dokonano szeregu pomiarów spektralnych próbek popiołów lotnych, powstających w konwencjonalnej elektrowni, zasilanej pyłem węglowym. Uzyskane wyniki skorelowano z zawartościami niewypalonego węgla w tych próbkach. Stwierdzono występowanie liniowych zależności, o stosunkowo wysokich współczynnikach korelacji (szczególnie w zakresie światła czerwonego). Próbki o mniejszej zawartości niewypalonego węgla charakteryzowały się wyższymi wartościami reflektancji niż próbki o większej zawartości analitu w matrycy popiołowej. Zastosowana metoda charakteryzowała się wysoką precyzją i czułością, pozwalającą na zidentyfikowanie różnic w zawartości węgla w próbce na poziomie 0,1% m/m.

EN

The investigations performed were aimed at verifying the suitability of visible light reflectance measurement using an integrating sphere to determine unburned carbon content in fly ash. A number of spectral measurements were carried out on samples of fly ash generated in a conventional power station fired with pulverized coal. The results obtained were correlated with the content of unburned carbon in these samples. A linear dependence was found with relatively high correlation coefficients (particularly within the wavelength range of red light). Samples of lower content of unburned carbon showed higher reflectance values than samples of higher analyte content in the ash matrix. The method applied featured high precision and sensitivity, enabling identification of differences in carbon content in sample at a level of 0.1 %wt/wt.

4

Realization of luminous flux unit lumen at National Metrology Institute of Turkey (UME

Samedov F., Durak M.

Optica Applicata

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2004

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Vol. 34, nr 2

265-274

EN

Luminous flux calibration facility with an integrating sphere has been installed at the National Metrology Institute of Turkey (UME) in order to realize lumen. A LabView-based computer-controlled electrical system has been developed to operate light sources and to control electrical parameters. Owing to the corrections of the sphere system, inner coating reflectance, spatial non-uniformity, self-absorption factor and interior temperature variations have been characterized. The overall uncertainty in luminous flux measurement has been determined with an uncertainty of 1.14% (k = 2) in the range between 5–5000 lm