Design of Spectral Transmittance Factor for Sunglasses Using CIECAM02

Thermally induced switching temperature and spectral transmittance of a novel kind of smart thermotropic material developed by a different mixing proportion of hydroxypropyl methyl cellulose (HPMC), sodium chloride ( NaCl ) and pure water was measured. Radiation transmittance measurements were carried out on a thermotropic double glazing window sample, a double glazing window and a low-E double glazing window. Results show that the thermotropic double-glazed window with optimum mixing proportion of HPMC, NaCl and pure water of 2:10:100 by mass-reduces radiation transmittance at fully turbid state by up to 72% and 32% respectively, compared to the ordinary double-glazed window and low-E double-glazed window which do not have adjustable radiation transmittance; its radiation transmittance changed from transparent state to light scattering state up to 60%, indicating a high performance on switching solar radiation and a great potential for energy efficient windows.

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Designing a Color Filter with High Overall Transmittance for Improving the Color Accuracy of Digital Cameras

Color and Imaging Conference ◽

10.2352/issn.2169-2629.2021.29.1 ◽

2021 ◽

Vol 2021 (29) ◽

pp. 1-6

Author(s):

Yuteng Zhu ◽

Graham D. Finlayson

Keyword(s):

White Light ◽

Digital Camera ◽

Color Filter ◽

Digital Cameras ◽

Spectral Transmittance ◽

Optimal Filters ◽

Prior Art ◽

Average Transmittance ◽

Tristimulus Values ◽

Correction Problem

Previously improved color accuracy of a given digital camera was achieved by carefully designing the spectral transmittance of a color filter to be placed in front of the camera. Specifically, the filter is designed in a way that the spectral sensitivities of the camera after filtering are approximately linearly related to the color matching functions (or tristimulus values) of the human visual system. To avoid filters that absorbed too much light, the optimization could incorporate a minimum per wavelength transmittance constraint. In this paper, we change the optimization so that the overall filter transmittance is bounded, i.e. we solve for the filter that (for a uniform white light) transmits (say) 50% of the light. Experiments demonstrate that these filters continue to solve the color correction problem (they make cameras much more colorimetric). Significantly, the optimal filters by restraining the average transmittance can deliver a further 10% improvement in terms of color accuracy compared to the prior art of bounding the low transmittance.

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Investigation of optical glass characteristics under the influence of space factors

Computer Optics ◽

10.18287/2412-6179-2019-43-5-803-809 ◽

2019 ◽

Vol 43 (5) ◽

pp. 803-809

Author(s):

М.P. Kalaev ◽

А.М. Telegin ◽

K.E. Voronov ◽

Jiang Lixiang ◽

Jiao Jilong

Keyword(s):

Experimental Study ◽

Optical Properties ◽

High Speed ◽

Optical Glass ◽

Outer Space ◽

Characteristic Size ◽

Dust Particles ◽

Spectral Transmittance ◽

Ability To Work ◽

High Speed Flows

The paper describes a DF-OPTICS device that the present authors designed for the experimental study of changes in the optical properties of a glass whose surface is exposed to high-speed flows of micron-sized dust particles. The device allows the scattering indicatrix and the spectral transmittance to be automatically measured at each point of the sample with a 0.5-mm increment. Advantages of the developed device include small dimensions and the ability to work in vacuum, allowing it to be used in an accelerator chamber to simulate outer space factors. Experimental results for the K-8 glass put in a microparticle accelerator and bombarded by an aluminum powder PAP-1 with a characteristic size of 1-3 µm and speeds of 2-8 km / s are presented. The device makes it possible to measure the change of the spectral transmittance of transparent materials in the UV and RGB regions with an accuracy of 0.005%, which exceeds the sensitivity of some known spectrophotometers.

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Cloud effects on surface radiation balance at Helheim and Jakobshavn Glaciers (Greenland) using ground-based observations

10.5194/egusphere-egu21-8103 ◽

2021 ◽

Author(s):

Georges Djoumna ◽

Sebastian H. Mernild ◽

David Holland

Keyword(s):

Short Wave ◽

Surface Radiation ◽

Radiation Budget ◽

Wave Radiation ◽

Radiation Balance ◽

Short Wave Radiation ◽

Radiative Fluxes ◽

Long Wave ◽

Transmittance Factor ◽

Cloud Metrics

<p>The surface radiation budget is an essential component of the total energy exchange between the atmosphere and the Earth&#8217;s surface. Measurements of radiative fluxes near/on ice surfaces are sparse in the polar regions, including on the Greenland Ice Sheet (GrIS), and the effects of cloud on radiative fluxes are still poorly studied. In this work, we assess the impacts of cloud on radiative fluxes using two metrics: the longwave-equivalent cloudiness, derived from long-wave radiation measurements, and the cloud transmittance factor, obtained from short-wave radiation. The metrics are applied to radiation data from two automatic weather stations located over the bare ground near the ice front of Helheim (HG) and Jakobshavn Isbr&#230; (JI) on the GrIS. Comparisons of meteorological parameters, surface radiation fluxes, and cloud metrics show significant differences between the two sites. The cloud transmittance factor is higher at HG than at JI, and the incoming short-wave radiation in the summer at HG is 50.0 W m&#8722;2 larger than at JI. Cloud metrics derived at the two sites reveal&#160; &#160;a high dependency on the wind direction. The total cloud radiative effect (CREnet) generally increases during melt season at the two stations due to long-wave CRE enhancement by cloud fraction.&#160;&#160;CREnet decreases from May to June and increases afterward, due to the strengthened short-wave CRE. The annually averaged CREnet were 3.0 &#177; 7.4 W m-2 and 1.9 &#177; 15.1 W m&#8722;2 at JI and HG.&#160; CREnet estimated from AWS indicates that clouds cool the JI and HG during melt season at different rates.</p>

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