Heteroatom‐Substituted Xanthene Fluorophores Enter the Shortwave‐Infrared Region

2021 ◽  
Author(s):  
Frederik Brøndsted ◽  
Cliff I. Stains
Keyword(s):  
Infrared Region ◽  
Shortwave Infrared

scholarly journals Design and characterization of specMACS, a multipurpose hyperspectral cloud and sky imager

2016 ◽  
Vol 9 (5) ◽  
pp. 2015-2042 ◽  
Author(s):  
Florian Ewald ◽  
Tobias Kölling ◽  
Andreas Baumgartner ◽  
Tobias Zinner ◽  
Bernhard Mayer
Keyword(s):  
Software Design ◽  
Infrared Region ◽  
Central Wavelength ◽  
Laboratory Characterization ◽  
Research Aircraft ◽  
Sky Imager ◽  
Remote Sensing Techniques ◽  
Shortwave Infrared

Abstract. The new spectrometer of the Munich Aerosol Cloud Scanner (specMACS) is a multipurpose hyperspectral cloud and sky imager designated, but is not limited to investigations of cloud–aerosol interactions in Earth's atmosphere. With its high spectral and spatial resolution, the instrument is designed to measure solar radiation in the visible and shortwave infrared region that is reflected from, or transmitted through clouds and aerosol layers. It is based on two hyperspectral cameras that measure in the solar spectral range between 400 and 2500 nm with a spectral bandwidth between 2.5 and 12.0 nm. The instrument was operated in ground-based campaigns as well as aboard the German High Altitude LOng Range (HALO) research aircraft, e.g., during the ACRIDICON-CHUVA campaign in Brazil during summer 2014. This paper describes the specMACS instrument hardware and software design and characterizes the instrument performance. During the laboratory characterization of the instrument, the radiometric response as well as the spatial and spectral resolution was assessed. Since the instrument is primarily intended for retrievals of atmospheric quantities by inversion of radiative models using measured radiances, a focus is placed on the determination of its radiometric response. Radiometric characterization was possible for both spectrometers, with an absolute accuracy of 3 % at their respective central wavelength regions. First measurements are presented which demonstrate the wide applicability of the instrument. They show that key demands are met regarding the radiometric and spectral accuracy which is required for the intended remote sensing techniques.

scholarly journals FIELD SPECTROSCOPY FOR VEGETATION EVALUATION ALONG THE NUTRIENT AND ELEVATION GRADIENT ABOVE THE TREE LINE IN THE KRKONOŠE MOUNTAINS NATIONAL PARK

2016 ◽  
Vol XLI-B6 ◽  
pp. 211-214
Author(s):  
L. Červená ◽  
L. Kupková ◽  
R. Suchá
Keyword(s):  
Plant Cover ◽  
Elevation Gradient ◽  
Vegetation Indices ◽  
Infrared Region ◽  
Spectral Measurements ◽  
Vegetation Height ◽  
Vegetation Water Content ◽  
Red Edge ◽  
Vegetation Water ◽  
Shortwave Infrared

This paper examines the relations between vegetation spectra measured in the field along the nutrient and elevation gradient in the most valuable parts of The Krkonoše Mountains tundra and selected parameters describing vegetation state and condition (fAPAR, plant cover and average vegetation height). The main goal was to find relations and indices based on spectral measurements that could be used for vegetation evaluation and classification in practice and management. The vegetation parameters and spectral properties were also compared for two datasets – one acquired in July and second in August 2015. The best correlations were obtained for plant cover (R<sup>2</sup> above 0.8 for July dataset and above 0.7 for August dataset) and two types of indices – using the wavelengths of red edge, e.g. OSAVI or mND705, and indices for vegetation water content estimates using the wavelengths in shortwave infrared region of the spectra in combination with wavelengths above 800 nm, e. g. NDII. The worst results were found for fAPAR with maximal values of R<sup>2</sup> just above 0.4 with the indices using the wavelengths around 700 nm. For vegetation height the results differ between July and August data – R<sup>2</sup> around 0.62 in July and only 0.47 in August for vegetation indices using the wavelengths of visible and red edge regions.

scholarly journals Shortwave infrared otoscopy for diagnosis of middle ear effusions: a machine-learning-based approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rustin G. Kashani ◽  
Marcel C. Młyńczak ◽  
David Zarabanda ◽  
Paola Solis-Pazmino ◽  
David M. Huland ◽  
...  
Keyword(s):  
Machine Learning ◽  
Otitis Media ◽  
Middle Ear ◽  
Infrared Region ◽  
Common Disease ◽  
Specificity And Sensitivity ◽  
Traditional Approaches ◽  
Shortwave Infrared ◽  
Made In

AbstractOtitis media, a common disease marked by the presence of fluid within the middle ear space, imparts a significant global health and economic burden. Identifying an effusion through the tympanic membrane is critical to diagnostic success but remains challenging due to the inherent limitations of visible light otoscopy and user interpretation. Here we describe a powerful diagnostic approach to otitis media utilizing advancements in otoscopy and machine learning. We developed an otoscope that visualizes middle ear structures and fluid in the shortwave infrared region, holding several advantages over traditional approaches. Images were captured in vivo and then processed by a novel machine learning based algorithm. The model predicts the presence of effusions with greater accuracy than current techniques, offering specificity and sensitivity over 90%. This platform has the potential to reduce costs and resources associated with otitis media, especially as improvements are made in shortwave imaging and machine learning.

scholarly journals INVESTIGATION OF LATENT TRACES USING INFRARED REFLECTANCE HYPERSPECTRAL IMAGING

2016 ◽  
Vol III-7 ◽  
pp. 97-102
Author(s):  
Till Schubert ◽  
Susanne Wenzel ◽  
Ribana Roscher ◽  
Cyrill Stachniss
Keyword(s):  
Hyperspectral Imaging ◽  
Spatial Relation ◽  
Potential Method ◽  
Infrared Region ◽  
Classification Task ◽  
Light Sources ◽  
Main Task ◽  
Distributed Data ◽  
Reduction Methods ◽  
Shortwave Infrared

The detection of traces is a main task of forensics. Hyperspectral imaging is a potential method from which we expect to capture more fluorescence effects than with common forensic light sources. This paper shows that the use of hyperspectral imaging is suited for the analysis of latent traces and extends the classical concept to the conservation of the crime scene for retrospective laboratory analysis. We examine specimen of blood, semen and saliva traces in several dilution steps, prepared on cardboard substrate. As our key result we successfully make latent traces visible up to dilution factor of 1:8000. We can attribute most of the detectability to interference of electromagnetic light with the water content of the traces in the shortwave infrared region of the spectrum. In a classification task we use several dimensionality reduction methods (PCA and LDA) in combination with a Maximum Likelihood classifier, assuming normally distributed data. Further, we use Random Forest as a competitive approach. The classifiers retrieve the exact positions of labelled trace preparation up to highest dilution and determine posterior probabilities. By modelling the classification task with a Markov Random Field we are able to integrate prior information about the spatial relation of neighboured pixel labels.

scholarly journals Comparative analysis of morphological, mineralogical and spectral properties of cryoconite in Jakobshavn Isbræ, Greenland, and Canada Glacier, Antarctica

2013 ◽  
Vol 54 (63) ◽  
pp. 147-157 ◽  
Author(s):  
M. Tedesco ◽  
C.M. Foreman ◽  
J. Anton ◽  
N. Steiner ◽  
T. Schwartzman
Keyword(s):  
Comparative Analysis ◽  
Visible Region ◽  
Mineralogical Composition ◽  
Infrared Region ◽  
Primary Role ◽  
Dry Valleys ◽  
Infrared Wavelengths ◽  
Shortwave Infrared ◽  
The Antarctic

AbstractWe report the results of a comparative analysis focusing on grain size, mineralogical composition and spectral reflectance values (400-2500 nm) of cryoconite samples collected from Jakobshavn Isbræ, West Greenland, and Canada Glacier, McMurdo Dry Valleys, Antarctica. The samples from the Greenland site were composed of small particles clumped into larger rounded agglomerates, while those from the site in Antarctica contained fragments of different sizes and shapes. Mineralogical analysis indicates that the samples from Jakobshavn Isbræ contained a higher percentage of quartz and albite, whereas those from Canada Glacier contained a higher percentage of amphibole, augite and biotite. Spectral measurements confirmed the primary role of organic material in reducing the reflectance over the measured spectrum. The reflectance of the samples from the Antarctic site remained low after the removal of organic matter because of the higher concentration of minerals with low reflectance. The reflectance of dried cryoconite samples in the visible region was relatively low (e.g. between ∼0.1 and ∼0.4) favouring increased absorbed solar radiation. Despite high reflectance values in the shortwave infrared region, the effect of the presence of cryoconite is negligible at infrared wavelengths where ice reflectance is low.

scholarly journals Combination of Cross- and Inter-Band Radiometric Calibrations for a Hyperspectral Sensor Using Model-Based Spectral Band Adjustment

2020 ◽  
Vol 12 (12) ◽  
pp. 2011
Author(s):  
Hiroki Mizuochi ◽  
Satoshi Tsuchida ◽  
Kenta Obata ◽  
Hirokazu Yamamoto ◽  
Satoru Yamamoto
Keyword(s):  
Near Infrared ◽  
Spectral Band ◽  
Space Station ◽  
Infrared Region ◽  
Band Adjustment ◽  
Moderate Resolution ◽  
Satellite Sensors ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Cross Calibration ◽  
Shortwave Infrared

Recently, the growing number of hyperspectral satellite sensors have increased the demand for a flexible and robust approach to their calibration. This paper proposes an operational method for the simultaneous correction of inter-sensor and inter-band biases in hyperspectral sensors via the soil line concept for spectral band adjustment. Earth Observing-1 Hyperion was selected as an example, with the Terra Moderate Resolution Imaging Spectroradiometer (MODIS) as a reference. The results over the Railroad Valley Playa calibration site indicated that the discrepancy in the analogous bands between Hyperion and MODIS during 2001–2008 was approximately 4–6% and 7–9% of the root-mean-square error in the top-of-atmosphere (TOA) radiance at the visible and near-infrared region and shortwave infrared region, respectively. For all Hyperion bands, the relative cross-calibration coefficients during this period were calculated (typically ranging from 0.9 to 1.1) to correct the Hyperion TOA radiance to be consistent with the MODIS and the other Hyperion bands. The application of the proposed approach could allow for more flexible cross-calibration of irregular-orbit sensors aboard the International Space Station.

scholarly journals INVESTIGATION OF LATENT TRACES USING INFRARED REFLECTANCE HYPERSPECTRAL IMAGING

2016 ◽  
Vol III-7 ◽  
pp. 97-102
Author(s):  
Till Schubert ◽  
Susanne Wenzel ◽  
Ribana Roscher ◽  
Cyrill Stachniss
Keyword(s):  
Hyperspectral Imaging ◽  
Spatial Relation ◽  
Potential Method ◽  
Infrared Region ◽  
Classification Task ◽  
Light Sources ◽  
Main Task ◽  
Distributed Data ◽  
Reduction Methods ◽  
Shortwave Infrared

The detection of traces is a main task of forensics. Hyperspectral imaging is a potential method from which we expect to capture more fluorescence effects than with common forensic light sources. This paper shows that the use of hyperspectral imaging is suited for the analysis of latent traces and extends the classical concept to the conservation of the crime scene for retrospective laboratory analysis. We examine specimen of blood, semen and saliva traces in several dilution steps, prepared on cardboard substrate. As our key result we successfully make latent traces visible up to dilution factor of 1:8000. We can attribute most of the detectability to interference of electromagnetic light with the water content of the traces in the shortwave infrared region of the spectrum. In a classification task we use several dimensionality reduction methods (PCA and LDA) in combination with a Maximum Likelihood classifier, assuming normally distributed data. Further, we use Random Forest as a competitive approach. The classifiers retrieve the exact positions of labelled trace preparation up to highest dilution and determine posterior probabilities. By modelling the classification task with a Markov Random Field we are able to integrate prior information about the spatial relation of neighboured pixel labels.

scholarly journals FIELD SPECTROSCOPY FOR VEGETATION EVALUATION ALONG THE NUTRIENT AND ELEVATION GRADIENT ABOVE THE TREE LINE IN THE KRKONOŠE MOUNTAINS NATIONAL PARK

2016 ◽  
Vol XLI-B6 ◽  
pp. 211-214
Author(s):  
L. Červená ◽  
L. Kupková ◽  
R. Suchá
Keyword(s):  
Plant Cover ◽  
Elevation Gradient ◽  
Vegetation Indices ◽  
Infrared Region ◽  
Spectral Measurements ◽  
Vegetation Height ◽  
Vegetation Water Content ◽  
Red Edge ◽  
Vegetation Water ◽  
Shortwave Infrared

This paper examines the relations between vegetation spectra measured in the field along the nutrient and elevation gradient in the most valuable parts of The Krkonoše Mountains tundra and selected parameters describing vegetation state and condition (fAPAR, plant cover and average vegetation height). The main goal was to find relations and indices based on spectral measurements that could be used for vegetation evaluation and classification in practice and management. The vegetation parameters and spectral properties were also compared for two datasets – one acquired in July and second in August 2015. The best correlations were obtained for plant cover (R&lt;sup&gt;2&lt;/sup&gt; above 0.8 for July dataset and above 0.7 for August dataset) and two types of indices – using the wavelengths of red edge, e.g. OSAVI or mND705, and indices for vegetation water content estimates using the wavelengths in shortwave infrared region of the spectra in combination with wavelengths above 800 nm, e. g. NDII. The worst results were found for fAPAR with maximal values of R&lt;sup&gt;2&lt;/sup&gt; just above 0.4 with the indices using the wavelengths around 700 nm. For vegetation height the results differ between July and August data – R&lt;sup&gt;2&lt;/sup&gt; around 0.62 in July and only 0.47 in August for vegetation indices using the wavelengths of visible and red edge regions.

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