scholarly journals Optimization of spatial resolution and scattering effects for biomedical fluorescence imaging by using sub‐regions of the shortwave infrared spectrum

2020 ◽  
Author(s):  
Benjamin Musnier ◽  
Maxime Henry ◽  
Julien Vollaire ◽  
Jean‐Luc Coll ◽  
Yves Usson ◽  
...  
Keyword(s):  
Infrared Spectrum ◽  
Fluorescence Imaging ◽  
Spatial Resolution ◽  
Scattering Effects ◽  
Shortwave Infrared

scholarly journals Mineral Detection Using Sharpened VNIR and SWIR Bands of Worldview-3 Satellite Imagery

2021 ◽  
Vol 13 (10) ◽  
pp. 5518
Author(s):  
Honglyun Park ◽  
Jaewan Choi
Keyword(s):  
Spatial Resolution ◽  
Satellite Imagery ◽  
Near Infrared ◽  
False Negative ◽  
Similarity Score ◽  
Majority Voting ◽  
Similarity Analysis ◽  
Spectral Angle Mapper ◽  
Mineral Detection ◽  
Shortwave Infrared

Worldview-3 satellite imagery provides panchromatic images with a high spatial resolution and visible near infrared (VNIR) and shortwave infrared (SWIR) bands with a low spatial resolution. These images can be used for various applications such as environmental analysis, urban monitoring and surveying for sustainability. In this study, mineral detection was performed using Worldview-3 satellite imagery. A pansharpening technique was applied to the spatial resolution of the panchromatic image to effectively utilize the VNIR and SWIR bands of Worldview-3 satellite imagery. The following representative similarity analysis techniques were implemented for the mineral detection: the spectral angle mapper (SAM), spectral information divergence (SID) and the normalized spectral similarity score (NS3). In addition, pixels that could be estimated to indicate minerals were calculated by applying an empirical threshold to each similarity analysis result. A majority voting technique was applied to the results of each similarity analysis and pixels estimated to indicate minerals were finally selected. The results of each similarity analysis were compared to evaluate the accuracy of the proposed methods. From that comparison, it could be confirmed that false negative and false positive rates decreased when the methods proposed in the present study were applied.

scholarly journals EXTRACTING BUILT-UP FEATURES IN COMPLEX BIOPHYSICAL ENVIRONMENTS BY USING A LANDSAT BANDS RATIO

2020 ◽  
Vol XLIV-M-2-2020 ◽  
pp. 79-85
Author(s):  
A. H. Ngandam Mfondoum ◽  
P. G. Gbetkom ◽  
R. Cooper ◽  
S. Hakdaoui ◽  
M. B. Mansour Badamassi
Keyword(s):  
Remote Sensing ◽  
Spatial Resolution ◽  
Satellite Data ◽  
Kappa Coefficient ◽  
Landsat 8 ◽  
Experimental Site ◽  
Soil Features ◽  
Mixed Pixels ◽  
Shortwave Infrared ◽  
Normalization Process

Abstract. This paper addresses the remote sensing challenging field of urban mixed pixels on a medium spatial resolution satellite data. The tentatively named Normalized Difference Built-up and Surroundings Unmixing Index (NDBSUI) is proposed by using Landsat-8 Operational Land Imager (OLI) bands. It uses the Shortwave Infrared 2 (SWIR2) as the main wavelength, the SWIR1 with the red wavelengths, for the built-up extraction. A ratio is computed based on the normalization process and the application is made on six cities with different urban and environmental characteristics. The built-up of the experimental site of Yaoundé is extracted with an overall accuracy of 95.51% and a kappa coefficient of 0.90. The NDBSUI is validated over five other sites, chosen according to Cameroon’s bioclimatic zoning. The results are satisfactory for the cities of Yokadouma and Kumba in the bimodal and monomodal rainfall zones, where overall accuracies are up to 98.9% and 97.5%, with kappa coefficients of 0.88 and 0.94 respectively, although these values are close to those of three other indices. However, in the cities of Foumban, Ngaoundéré and Garoua, representing the western highlands, the high Guinea savannah and the Sudano-sahelian zones where built-up is more confused with soil features, overall accuracies of 97.06%, 95.29% and 74.86%, corresponding to 0.918, 0.89 and 0.42 kappa coefficients were recorded. Difference of accuracy with EBBI, NDBI and UI are up to 31.66%, confirming the NDBSUI efficiency to automate built-up extraction and unmixing from surrounding noises with less biases.

scholarly journals A Novel TMTP1-modified Theranostic Nanoplatform for Targeted in Vivo NIR-II Fluorescence Imaging-guided Chemotherapy of Cervical Cancer

2021 ◽  
Author(s):  
Alifu Nuernisha ◽  
Rong Ma ◽  
Lijun Zhu ◽  
Zhong Du ◽  
Shuang Chen ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Blood Vessels ◽  
Fluorescence Imaging ◽  
Spatial Resolution ◽  
Self Assembly ◽  
Tumor Targeting ◽  
High Sensitivity ◽  
High Definition ◽  
Targeting Ability

Abstract BackgroundNear-infrared II (NIR-II, 900-1700 nm) fluorescence bioimaging with advantages of good biosafety, excellent spatial resolution, high sensitivity and contrast, has attracted great attentions in biomedical research fields. However, most nanoprobes used for NIR-II fluorescence imaging have poor tumor-targeting ability and therapeutic efficiency. To overcome these limitations, a novel NIR-II-emissive theranostic nanoplatform for imaging and treatment of cervical cancer was designed and prepared. The NIR-II-emissive dye IR-783 and chemotherapy drug doxorubicin (DOX) were encapsulated into liposomes, and the tumor-targeting peptide TMTP1 was conjugated to the surface of the liposomes to form IR-783-DOX-TMTP1 nanoparticles (NPs) via self-assembly methods.ResultsThe IR-783-DOX-TMTP1 NPs showed strong NIR-II emission, excellent biocompatibility, a long lifetime, and low toxicity. Further, high-definition NIR-II fluorescence microscopy images of ear blood vessels and intratumor blood vessels were obtained from IR-783-DOX-TMTP1 NPs-stained mice with high spatial resolution under 808 nm laser excitation. Moreover, IR-783-DOX-TMTP1 NPs showed strong tumor targeting ability and high efficiently chemotherapeutic character towards cervical tumors. ConclusionsThe novel targeting and NIR-II-emissive IR-783-DOX-TMTP1 NPs have potential in diagnosis and therapy for cervical cancer.

scholarly journals Absorption by water increases fluorescence image contrast of biological tissue in the shortwave infrared

2018 ◽  
Vol 115 (37) ◽  
pp. 9080-9085 ◽  
Author(s):  
Jessica A. Carr ◽  
Marianne Aellen ◽  
Daniel Franke ◽  
Peter T. C. So ◽  
Oliver T. Bruns ◽  
...  
Keyword(s):  
Penetration Depth ◽  
Fluorescence Imaging ◽  
Biological Tissue ◽  
Ex Vivo ◽  
Scattered Light ◽  
Image Contrast ◽  
Fluorescence Image ◽  
Tissue Phantoms ◽  
Shortwave Infrared

Recent technology developments have expanded the wavelength window for biological fluorescence imaging into the shortwave infrared. We show here a mechanistic understanding of how drastic changes in fluorescence imaging contrast can arise from slight changes of imaging wavelength in the shortwave infrared. We demonstrate, in 3D tissue phantoms and in vivo in mice, that light absorption by water within biological tissue increases image contrast due to attenuation of background and highly scattered light. Wavelengths of strong tissue absorption have conventionally been avoided in fluorescence imaging to maximize photon penetration depth and photon collection, yet we demonstrate that imaging at the peak absorbance of water (near 1,450 nm) results in the highest image contrast in the shortwave infrared. Furthermore, we show, through microscopy of highly labeled ex vivo biological tissue, that the contrast improvement from water absorption enables resolution of deeper structures, resulting in a higher imaging penetration depth. We then illustrate these findings in a theoretical model. Our results suggest that the wavelength-dependent absorptivity of water is the dominant optical property contributing to image contrast, and is therefore crucial for determining the optimal imaging window in the infrared.

scholarly journals Aerosol direct radiative effect over clouds from synergy of OMI and MODIS reflectance

2019 ◽  
Author(s):  
Martin de Graaf ◽  
L. Gijsbert Tilstra ◽  
Piet Stammes
Keyword(s):  
Spatial Resolution ◽  
Spectral Resolution ◽  
Source Region ◽  
Data Retrieval ◽  
Radiative Effect ◽  
Aerosol Absorption ◽  
Ascension Island ◽  
Microphysical Parameters ◽  
Global Coverage ◽  
Shortwave Infrared

Abstract. The retrieval of geophysical parameters is increasingly dependent on synergistic use of satellite instruments. More sophisticated parameters can be retrieved and the accuracy of retrievals can be increased when more information is combined. In this paper, a synergistic application of OMI/Aura and MODIS/Aqua Level 1B reflectances is described, enabling the retrieval of the aerosol direct radiative effect (DRE) over clouds using the differential aerosol absorption (DAA) technique. This technique was first developed for reflectances from SCIAMACHY/Envisat, which had the unique capability of measuring contiguous radiances from the ultraviolet (UV) at 240 nm to 1750 nm in the shortwave-infrared (SWIR), at a moderate spectral resolution of 0.2–1.5 nm. However, the spatial resolution and global coverage of SCIAMACHY was limited, and Envisat stopped delivering data in 2012. In order to continue the DRE data retrieval, reflectances from OMI and MODIS, flying in formation, were combined from the UV to the SWIR. This resulted in reflectances at a limited but sufficient spectral resolution, available at the OMI pixel grid, which have a much higher spatial resolution and coverage than SCIAMACHY. The combined reflectance spectra allow the retrieval of cloud microphysical parameters in the SWIR, and the subsequent retrieval of aerosol DRE over cloud scenes using the DAA technique. The new aerosol DRE over clouds dataset from OMI/MODIS is compared to the SCIAMACHY dataset for the period 2006–2009, showing a very high correlation. The average aerosol DRE over clouds in August 2006 was 31.5 Wm−2 with a standard deviation of 16 Wm−2. The maximum daily averaged DRE from OMI/MODIS in August 2006 was 75.6 ± 13 Wm−2. Over the Atlantic Ocean, the OMI/MODIS DRE dataset is related to AOT measurements over Ascension Island in 2016, showing the transport of smoke all the way from its source region in Africa over the Atlantic to Ascension and beyond.

scholarly journals Protein enhanced NIR-IIb emission of indocyanine green for functional bioimaging

2020 ◽  
Author(s):  
Mubin He ◽  
Di Wu ◽  
Yuhuang Zhang ◽  
Xiaoxiao Fan ◽  
Hui Lin ◽  
...  
Keyword(s):  
Indocyanine Green ◽  
Fluorescence Imaging ◽  
Clinical Application ◽  
Spatial Resolution ◽  
Near Infrared ◽  
Protein Solutions ◽  
Lymph System ◽  
Fetal Bovine ◽  
Auto Fluorescence

AbstractFluorescence imaging performed in the 1500-1700 nm spectral range (labeled as near-infrared IIb, NIR-IIb) promises high imaging contrast and spatial resolution for its little photon scattering effect and minimum auto-fluorescence. Though inorganic and organic probes have been developed for NIR-IIb bioimaging, most are in preclinical stage, hampering further clinical application. Herein, we showed that indocyanine green (ICG), an US Food and Drug Administration (FDA)-approved agent, exhibited remarkable amount of NIR-IIb emission when dissolved into different protein solutions, including human serum albumin, rat bile, and fetal bovine serum. We performed fluorescence imaging in NIR-IIb window to visualize structures of lymph system, extrahepatic biliary tract and cerebrovascular. Results demonstrated that proteins promoted NIR-IIb emission of ICG in vivo and that NIR-IIb imaging with ICG preserved higher signal-to-background ratio (SBR) and spatial resolution compared with the conventional near-infrared II (NIR-II) fluorescence imaging. Our findings confirm that NIR-IIb fluorescence imaging can be successfully performed using the clinically approved agent ICG. Further clinical application in NIR-IIb region would hopefully be carried out with appropriate ICG-protein solutions.

scholarly journals How the Optical Properties of Leaves Modify the Absorption and Scattering of Energy and Enhance Leaf Functionality

2020 ◽  
pp. 349-384 ◽  
Author(s):  
Susan L. Ustin ◽  
Stéphane Jacquemoud
Keyword(s):  
Optical Properties ◽  
Infrared Spectrum ◽  
Related Species ◽  
Spectral Properties ◽  
Near Infrared ◽  
Solar Spectrum ◽  
Cellular Organization ◽  
Seed Plant ◽  
Or Groups ◽  
Shortwave Infrared

AbstractLeaves absorb, scatter, and transmit sunlight at all wavelengths across the visible, near-infrared, and shortwave-infrared spectrum. The optical properties of a leaf are determined by its biochemical and biophysical characteristics, including its 3-D cellular organization. The absorption and scattering properties of leaves together create the shape of their reflectance spectra. Terrestrial seed plant species share similar physiological and metabolic processes for fluxes of gases (CO2, O2, H2O), nutrients, and energy, while differences are primarily consequences of how these properties are distributed and their physical structures. Related species generally share biochemical and biophysical traits, and their optical properties are also similar, providing a mechanism for identification. However, it is often the minor differences in spectral properties throughout the wavelengths of the solar spectrum that define a species or groups of related species. This chapter provides a review and summary of the most common interactions between leaf properties and light and the physical processes that regulate the outcomes of these interactions.

scholarly journals Water vapour total columns from SCIAMACHY spectra in the 2.36 μm window

2009 ◽  
Vol 2 (3) ◽  
pp. 1453-1485
Author(s):  
H. Schrijver ◽  
A. M. S. Gloudemans ◽  
C. Frankenberg ◽  
I. Aben
Keyword(s):  
Water Vapour ◽  
Weather Forecast ◽  
Mean Value ◽  
Likelihood Method ◽  
Independent Verification ◽  
Scattering Effects ◽  
Spectroscopic Information ◽  
Novel Method ◽  
Iterative Maximum Likelihood ◽  
Shortwave Infrared

Abstract. The potential of the shortwave infrared channel of the atmospheric spectrometer SCIAMACHY on Envisat to provide accurate measurements of total atmospheric water vapour columns is explored. It is shown that good quality results can be obtained for cloud free scenes above the continents using the Iterative Maximum Likelihood Method. In addition to the standard cloud filter employed in this method, further cloud screening is obtained by comparing simultaneously retrieved methane columns with values expected from models. A novel method is used to correct for the scattering effects introduced in the spectra by the ice layer on the detector window. The retrieved water vapour total columns for the period 2003–2007 are compared with spatially and temporally collocated values from the European Centre for Mid-Range Weather Forecast (ECMWF) data. The observed differences for individual measurements have standard deviations not higher than 0.3 g/cm2 and an absolute mean value smaller than 0.01 g/cm2 with some regional excursions. The use of recently published spectroscopic data for water vapour led to a significant improvement in the agreement of the retrieved water vapour total columns and the values derived from ECMWF data. This analysis thus provides independent verification of the new spectroscopic information using atmospheric data.

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