scholarly journals Assessing the Stability of Surface Lights for use in Retrievals of Nocturnal Atmospheric Parameters

2019 ◽  
Author(s):  
Jeremy E. Solbrig ◽  
Steven D. Miller ◽  
Jianglong Zhang ◽  
Lewis Grasso ◽  
Anton Kliewer
Keyword(s):  
Near Infrared ◽  
Correlation Coefficients ◽  
Visible Spectrum ◽  
Light Sources ◽  
Infrared Observations ◽  
Spatially Resolved ◽  
Relative Standard ◽  
Geometric Variables ◽  
The Stability

Abstract. Detection and characterization of aerosols is inherently limited at night due to a lack of sensitivity—information typically provided by visible spectrum observations. The VIIRS Day/Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible/near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for retrieval of atmospheric properties including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Timeseries are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially-resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation

scholarly journals Assessing the stability of surface lights for use in retrievals of nocturnal atmospheric parameters

2020 ◽  
Vol 13 (1) ◽  
pp. 165-190 ◽  
Author(s):  
Jeremy E. Solbrig ◽  
Steven D. Miller ◽  
Jianglong Zhang ◽  
Lewis Grasso ◽  
Anton Kliewer
Keyword(s):  
Near Infrared ◽  
Correlation Coefficients ◽  
Visible Spectrum ◽  
Light Sources ◽  
Strongly Correlated ◽  
Spatially Resolved ◽  
Relative Standard ◽  
Geometric Variables ◽  
The Stability

Abstract. The detection and characterization of aerosols are inherently limited at night because the important information provided by visible spectrum observations is not available and infrared bands have limited sensitivity to aerosols. The VIIRS Day–Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible and near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for the retrieval of atmospheric properties, including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Time series are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation <20 %). Additionally, we find that while the radiance variability of surrounding surfaces (i.e., unpopulated land and ocean) is largely dependent on lunar geometry, the anthropogenic light sources are more strongly correlated with satellite viewing geometry. Understanding the spatially resolved relationships between DNB radiance and other parameters is a necessary first step towards characterizing anthropogenic light emissions and establishes a framework for a model to describe variability in a more general sense.

scholarly journals Beyond the visible spectrum – applying 3D multispectral full-body imaging to the VirtoScan system

2021 ◽  
Author(s):  
Sören Kottner ◽  
Martin M. Schulz ◽  
Florian Berger ◽  
Michael Thali ◽  
Dominic Gascho
Keyword(s):  
Near Infrared ◽  
Three Dimensional ◽  
Visible Spectrum ◽  
Image Data ◽  
3D Models ◽  
Light Sources ◽  
Ct Scanner ◽  
Body Imaging ◽  
Wide Range ◽  
Full Body

AbstractMultispectral photography offers a wide range of applications for forensic investigations. It is commonly used to detect latent evidence and to enhance the visibility of findings. Additionally, three-dimensional (3D) full-body documentation has become much easier and more affordable in recent years. However, the benefits of performing 3D imaging beyond the visible (VIS) spectrum are not well known, and the technique has not been widely used in forensic medical investigations. A multicamera setup was used to employ multispectral photogrammetry between 365 and 960 nm in postmortem investigations. The multicamera setup included four modified digital cameras, ultraviolet (UV) and near-infrared (NIR) light sources and supplemental lens filters. Full-body documentation was performed in conjunction with the use of a medical X-ray computed tomography (CT) scanner to automate the imaging procedure. Textured 3D models based on multispectral datasets from four example cases were reconstructed successfully. The level of detail and overall quality of the 3D reconstructions varied depending on the spectral range of the image data. Generally, the NIR datasets showed enhanced visibility of vein patterns and specific injuries, whereas the UV-induced datasets highlighted foreign substances on the skin. Three-dimensional multispectral full-body imaging enables the detection of latent evidence that is invisible to the naked eye and allows visualization, documentation and analysis of evidence beyond the VIS spectrum.

scholarly journals Image-based metric heritage modeling in the near-infrared spectrum

2020 ◽  
Author(s):  
Efstathios Adamopoulos ◽  
Alessandro Bovero ◽  
Fulvio Rinaudo
Keyword(s):  
Near Infrared ◽  
Three Dimensional ◽  
Visible Spectrum ◽  
Lighting Conditions ◽  
Image Based Modeling ◽  
Spectral Models ◽  
Software Implementations ◽  
Automatic Software ◽  
Accuracy Of Results

Abstract Digital photogrammetry and spectral imaging are widely used in heritage sciences, towards the comprehensive recording, understanding, and protection of historical artefacts and artworks. The availability of consumer-grade modified cameras for spectral acquisition, as an alternative to expensive multispectral sensors and multi-sensor apparatuses, along with semi-automatic software implementations of Structure-from-Motion (SfM) and Multiple-View-Stereo (MVS) algorithms, has made more feasible than ever the combination of those techniques. In the research presented here, the authors assess image-based modeling from near-infrared (NIR) imagery acquired with modified sensors, with applications on tangible heritage. Three-dimensional meshes, textured with the non-visible data, are produced and evaluated. Specifically, metric evaluations are conducted through extensive comparisons with models produced with high-resolution visible (VIS) spectrum image-based modeling, to check accuracy of results. Furthermore, the authors observe and discuss, when the implemented NIR modeling approach, enhances the preservation of surface detail on the reconstructed spectral models or counteracts certain problems arising from lighting conditions during VIS acquisition. Radiometric properties of the produced results are evaluated on the capacity to enhance observation towards the characterization of surface and under-surface state of preservation, and consequently, to support conservation interventions, in comparison to the respective results in visible spectrum.

scholarly journals Synthesis and characterization of ZnSe: Ag/SiO2 nanoparticles

2021 ◽  
Vol 261 ◽  
pp. 02063
Author(s):  
Fenghua Huang ◽  
Tao Huang ◽  
Xiangwei Wu ◽  
Wenhui Pang
Keyword(s):  
Visible Spectrum ◽  
Fluorescence Analysis ◽  
Sio2 Nanoparticles ◽  
Fluorescence Properties ◽  
Silicon Dioxide Nanoparticles ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Potential Applications ◽  
The Stability

Argentum-doped zinc selenide/silicon dioxide nanoparticles (expressed as ZnSe: Ag/SiO2) were synthesized by Stöber method. The structure, morphology and fluorescence properties of the quantum dots were characterized by X-ray powder diffraction, transmission electron microscopy, infrared spectrum, ultraviolet-visible spectrum and fluorescence spectrum. The results show that the as-prepared ZnSe: Ag/SiO2 nanoparticles are spherical, most of which are about 30 nm in size, and have good fluorescence properties. Compared with that of ZnSe: Ag nanoparticles, the stability of ZnSe: Ag/SiO2 nanoparticles is enhanced obviously. The ZnSe: Ag/SiO2 nanoparticles will have potential applications in biological fluorescence analysis.

scholarly journals Integrable Near-Infrared Photodetectors Based on Hybrid Erbium/Silicon Junctions

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3755 ◽  
Author(s):  
Mariano Gioffré ◽  
Giuseppe Coppola ◽  
Mario Iodice ◽  
Maurizio Casalino
Keyword(s):  
Silicon Substrate ◽  
Room Temperature ◽  
Reverse Bias ◽  
Near Infrared ◽  
Optical Measurements ◽  
Device Performance ◽  
Light Sources ◽  
Monolithically Integrated ◽  
Fabrication And Characterization

This paper presents the design, fabrication, and characterization of Schottky erbium/silicon photodetectors working at 1.55 µm. These erbium/silicon junctions are carefully characterized using both electric and optical measurements at room temperature. A Schottky barrier ΦB of ~673 meV is extrapolated; the photodetectors show external responsivity of 0.55 mA/W at room temperature under an applied reverse bias of 8 V. In addition, the device performance is discussed in terms of normalized noise and noise-equivalent power. The proposed devices will pave the way towards the development of Er-based photodetectors and light sources to be monolithically integrated in the same silicon substrate, and both operating at 1.55 µm.

scholarly journals Characterization and Evaluation of the Efficiency of TiO2/Zinc Phthalocyanine Nanocomposites as Photocatalysts for Wastewater Treatment Using Solar Irradiation

2008 ◽  
Vol 2008 ◽  
pp. 1-12 ◽  
Author(s):  
Antonio E. H. Machado ◽  
Marcela D. França ◽  
Valdemir Velani ◽  
Gabriel A. Magnino ◽  
Hosana M. M. Velani ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Diffuse Reflectance ◽  
Near Infrared ◽  
Visible Spectrum ◽  
Zinc Phthalocyanine ◽  
Solar Irradiation ◽  
Absorption Bands ◽  
Intense Absorption ◽  
Spectrum Region

This work reports the characterization of composites prepared by the association between zinc phthalocyanine (ZnPc) and titanium dioxide. These composites are better photocatalysts for wastewater decontamination mediated by solar radiation than pureTiO2, performance that remains even when reused. The UV-Vis diffuse reflectance absorption spectra show for these composites two intense absorption bands. The first covers the ultraviolet and part of the visible spectrum region until 460 nm (2.7 eV), whereas the second, nonstructured, goes from 475 nm until the near infrared with an absorption peak at 683 nm attributed to the Q band of ZnPc. The production of additionale−/h+pairs by these aggregates when photoexcited, their capability to act as charge carrier, the thickness and regularity of their distribution on theTiO2surface seem to be important parameters for the performance observed for these composites.

Portable Blood Detection System on the Basis of Dry-Type Chemical Method

2013 ◽  
Vol 321-324 ◽  
pp. 1620-1626
Author(s):  
Xiu Mei Cui ◽  
Feng Chen ◽  
Yao Hua Du ◽  
Chao Li ◽  
Biao Gu ◽  
...  
Keyword(s):  
Digital Signal Processor ◽  
Blood Cells ◽  
Chemical Method ◽  
Detection System ◽  
Correlation Coefficients ◽  
Rapid Test ◽  
Digital Signal ◽  
Test Results ◽  
Relative Standard ◽  
The Stability

This paper presents a portable blood detection system on the basis of dry-type chemical method. Controlled by TM320VC5509A, a high-precision Digital Signal Processor, provided light source by line spot semiconductor laser (LD), converted between light and electricity by photocoupler, the system can fulfill the conventional detection and measurement of blood cells parameters. As for the stability of the system, the test results showed that the relative standard deviation of the parameters of the blood cells were all below 1.7%. The contrast experiment on Sysmex XT-1800i showed that with hematocrit (HCT), hemoglobin (HGB), lymphocytes and moncytes (LM), granulocytes (GRAN), platelets (PLT) and white blood cell (WBC) as contrast items, the correlation coefficients of the system were 0.9910.9720.9520.9860.979 and 0.985 respectively. The volume and time measurements of the system were designed as (25×20×10) cm3and 60s. The system can fulfill some functions such as indicating records, seeking information and deleting. The system will have a wide application prospect in rapid test of blood in field and emergency examination.

scholarly journals Visible and near-infrared observations of interstellar comet 2I/Borisov with the 10.4-m GTC and the 3.6-m TNG telescopes

2020 ◽  
Vol 495 (2) ◽  
pp. 2053-2062 ◽  
Author(s):  
J de León ◽  
J Licandro ◽  
C de la Fuente Marcos ◽  
R de la Fuente Marcos ◽  
L M Lara ◽  
...  
Keyword(s):  
Production Rate ◽  
Heliocentric Distance ◽  
Near Infrared ◽  
Visible Spectrum ◽  
Orbital Evolution ◽  
Gas Production ◽  
Infrared Observations ◽  
La Palma ◽  
Dust Size Distribution ◽  
Visible Spectra

ABSTRACT In this work, we present the results of an observational study of 2I/Borisov carried out with the 10.4-m Gran Telescopio Canarias (GTC) and the 3.6-m Telescopio Nazionale Galileo (TNG), both telescopes located at the Roque de Los Muchachos Observatory, in the island of La Palma (Spain). The study includes images in the visible and near-infrared, as well as visible spectra in the 3600–9200 Å wavelength range. N-body simulations were also performed to explore its orbital evolution and Galactic kinematic context. The comet’s dust continuum and near-infrared colours are compatible with those observed for Solar system comets. From its visible spectrum on the nights of 2019 September 24 and 26, we measured CN gas production rates Q(CN) = (2.3 ± 0.4) × 1024 mol s−1 and Q(CN) = (9.5 ± 0.2) × 1024 mol s−1, respectively, in agreement with measurements reported by other authors on similar nights. We also obtained an upper limit for the C2 production rate of Q(C2) &lt; (4.5 ± 0.1) × 1024 mol s−1. Dust modelling results indicate a moderate dust production rate of ∼50 kg s−1 at heliocentric distance rh = 2.6 au, with a differential power-law dust size distribution of index ∼–3.4, within the range reported for many comet comae. Our simulations show that the Galactic velocity of 2I/Borisov matches well that of known stars in the solar neighbourhood and also those of more distant regions of the Galactic disc.

Spatially resolved near infrared observations of Enceladus’ tiger stripe eruptions from Cassini VIMS

Icarus ◽  
2017 ◽  
Vol 292 ◽  
pp. 1-12 ◽  
Author(s):  
Deepak Dhingra ◽  
Matthew M. Hedman ◽  
Roger N. Clark ◽  
Philip D. Nicholson
Keyword(s):  
Near Infrared ◽  
Infrared Observations ◽  
Spatially Resolved

scholarly journals Tailored polymeric, photovoltaic, and near-infrared-responsive neuroprosthesis

2020 ◽  
Author(s):  
Marta Jole Ildelfonsa Airaghi Leccardi ◽  
Naïg Aurelia Ludmilla Chenais ◽  
Laura Ferlauto ◽  
Maciej Kawecki ◽  
Elodie Geneviève Zollinger ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Organic Semiconductors ◽  
Near Infrared ◽  
Organic Materials ◽  
Visible Spectrum ◽  
Building Blocks ◽  
Aqueous Environment ◽  
Retinal Stimulation ◽  
Neuronal Stimulation ◽  
The Stability

AbstractOrganic materials, such as conjugated polymers, are attractive building blocks for bioelectronic interfaces. In particular, organic semiconductors showed excellent performances in light-mediated excitation and silencing of neuronal cells and tissues. However, the main challenges of these organic photovoltaic interfaces compared to inorganic prostheses are the limited stability of conjugated polymers in the aqueous environment and the exploitation of materials only responsive in the visible spectrum. In this report, we show a new photovoltaic organic interface tailored for neuronal stimulation in the near-infrared spectrum. Also, we adjusted the organic materials by chemical modification in order to improve the stability in aqueous environment and to modulate the photoelectrical stimulation efficiency. As proof of principle, we tested this interface for retinal stimulation. Our results provide an efficient, reliable, and stable implant applicable for neural stimulation.

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