scholarly journals Compact meta-spectral image sensor for mobile applications

Nanophotonics ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Jaesoong Lee ◽  
Yeonsang Park ◽  
Hyochul Kim ◽  
Young-Zoon Yoon ◽  
Woong Ko ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Near Infrared ◽  
High Efficiency ◽  
Infrared Region ◽  
Image Sensor ◽  
High Spectral Resolution ◽  
Infrared Range ◽  
Spectral Image ◽  
Multilayer Filters ◽  
Spectral Imager

Abstract We have demonstrated a compact and efficient metasurface-based spectral imager for use in the near-infrared range. The spectral imager was created by fabricating dielectric multilayer filters directly on top of the CMOS image sensor. The transmission wavelength for each spectral channel was selected by embedding a Si nanopost array of appropriate dimensions within the multilayers on the corresponding pixels, and this greatly simplified the fabrication process by avoiding the variation of the multilayer-film thicknesses. The meta-spectral imager shows high efficiency and excellent spectral resolution up to 2.0 nm in the near-infrared region. Using the spectral imager, we were able to measure the broad spectra of LED emission and obtain hyperspectral images from wavelength-mixed images. This approach provides ease of fabrication, miniaturization, low crosstalk, high spectral resolution, and high transmission. Our findings can potentially be used in integrating a compact spectral imager in smartphones for diverse applications.

The variation of Venus cloud investigated from SOIR onboard Venus Express

2020 ◽  
Author(s):  
Seiko Takagi
Keyword(s):  
Near Infrared ◽  
Cloud Model ◽  
Infrared Region ◽  
High Spectral Resolution ◽  
Atmospheric Transmission ◽  
Infrared Wavelength ◽  
Radiative Transfer Calculation ◽  
Observation Plan ◽  
Venus Express ◽  
Spectral Imager

<p>The Venus cloud consists of a main cloud deck at 47 – 70 km, with thinner hazes above and below. The upper haze on Venus lies above the main cloud surrounding the planet, ranging from the cloud top (70 km) up to as high as 90 km.</p> <p>The Solar Occultation in the InfraRed (SOIR) instrument onboard Venus Express (ESA) was designed to measure the Venusian atmospheric transmission at high altitudes (65 – 220 km) in the infrared wavelength range (2.2 – 4.3 µm) with a high spectral resolution. In Takagi et al. (2019), the optical properties of Venus’s haze layer above 90 km have been investigated using SOIR observations. Vertical and latitudinal profiles of the extinction coefficient, optical thickness, and mixing ratio of aerosols are retrieved.</p> <p>A new cloud model was constructed based on the results of Takagi et al. (2019). In this presentation, I will show the results of a radiative transfer calculation (in the near-infrared region) that incorporates a new cloud model and discuss themeteorological some changes that contribute to cloud variation. Furthermore, I will introduce Venus observation plan using the 1.6 m Pirka telescope and Multi-Spectral Imager (MSI) [Watanabe et al., 2012] mounted on the Cassegrain focus of the telescope at the Nayoro Observatory of Hokkaido University.</p>

Spectrum Filter Performance Analysis on Near-Infrared High-Spectral-Resolution Lidar

2016 ◽  
Vol 43 (4) ◽  
pp. 0414004
Author(s):  
张与鹏 Zhang Yupeng ◽  
刘东 Liu Dong ◽  
杨甬英 Yang Yongying ◽  
罗敬 Luo Jing ◽  
成中涛 Cheng Zhongtao ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Spectral Resolution ◽  
Near Infrared ◽  
High Spectral Resolution ◽  
Filter Performance ◽  
High Spectral Resolution Lidar

Efficient near-infrared luminescence from bis-cyclometalated iridium(iii) complexes with rigid quinoline-derived ancillary ligands

2020 ◽  
Vol 56 (62) ◽  
pp. 8754-8757
Author(s):  
Po-Ni Lai ◽  
Sungwon Yoon ◽  
Thomas S. Teets
Keyword(s):  
Near Infrared ◽  
High Efficiency ◽  
Infrared Region ◽  
Iridium Complexes ◽  
Ancillary Ligands ◽  
Infrared Luminescence ◽  
Near Infrared Region

Rigid bis-cyclometalated iridium complexes with quinoline-based chelating ancillary ligands phosphoresce in the near-infrared region with high efficiency.

scholarly journals Global monitoring of terrestrial chlorophyll fluorescence from moderate spectral resolution near-infrared satellite measurements: methodology, simulations, and application to GOME-2

2013 ◽  
Vol 6 (2) ◽  
pp. 3883-3930 ◽  
Author(s):  
J. Joiner ◽  
L. Guanter ◽  
R. Lindstrot ◽  
M. Voigt ◽  
A. P. Vasilkov ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Spectral Resolution ◽  
Near Infrared ◽  
High Spectral Resolution ◽  
High Signal ◽  
Good Precision ◽  
Atmospheric Absorption ◽  
Red Fluorescence ◽  
Fluorescence Measurements ◽  
Global Mapping

Abstract. Globally mapped terrestrial chlorophyll fluorescence retrievals are of high interest because they can provide information on the functional status of vegetation including light-use efficiency and global primary productivity that can be used for global carbon cycle modeling and agricultural applications. In addition, fluorescence can contaminate photon path estimates from the O2 A-band that has become an integral part of missions to accurately measure greenhouse gas concentrations. Global mapping of far-red (~ 755–770 nm) terrestrial vegetation solar-induced fluorescence from space has been accomplished using the high spectral resolution (ν/Δ ν > 35 000) interferometer on the Japanese Greenhouse gases Observing SATellite (GOSAT). These satellite retrievals of fluorescence rely solely upon the filling-in of solar Fraunhofer lines that are not significantly affected by atmospheric absorption. Although these measurements provide near global coverage on a monthly basis, they suffer from relatively low precision and sparse spatial sampling. Here, we describe a new methodology to retrieve global far-red fluorescence information; we use hyperspectral data to disentangle the spectral signatures of three basic components in and surrounding the O2 A-band: atmospheric absorption, surface reflectance, and fluorescence radiance. Through detailed simulations, we demonstrate the feasibility of the approach and show that moderate spectral resolution measurements with a relatively high signal-to-noise ratio within and outside the O2 A-band can be used to retrieve far-red fluorescence information with good precision and accuracy. The method is then applied to data from the Global Ozone Monitoring Instrument 2 (GOME-2). The GOME-2 fluorescence retrievals display similar spatial structure as compared with GOSAT. GOME-2 enables global mapping of far-red fluorescence with higher precision over smaller spatial and temporal scales than is possible with GOSAT. It should be noted that both GOME-2 and GOSAT were designed to make atmospheric trace gas measurements and were not optimized for fluorescence measurements. Our approach can be applied to other existing and future space-based instruments that provide moderate spectral resolution observations in the near-infrared region.

scholarly journals Wide Swath and High Resolution Airborne HyperSpectral Imaging System and Flight Validation

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1667 ◽  
Author(s):  
Dong Zhang ◽  
Liyin Yuan ◽  
Shengwei Wang ◽  
Hongxuan Yu ◽  
Changxing Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Spectral Resolution ◽  
High Efficiency ◽  
High Spatial Resolution ◽  
Imaging System ◽  
High Sensitivity ◽  
Field Of View ◽  
High Spectral Resolution ◽  
Wide Swath

Wide Swath and High Resolution Airborne Pushbroom Hyperspectral Imager (WiSHiRaPHI) is the new-generation airborne hyperspectral imager instrument of China, aimed at acquiring accurate spectral curve of target on the ground with both high spatial resolution and high spectral resolution. The spectral sampling interval of WiSHiRaPHI is 2.4 nm and the spectral resolution is 3.5 nm (FWHM), integrating 256 channels coving from 400 nm to 1000 nm. The instrument has a 40-degree field of view (FOV), 0.125 mrad instantaneous field of view (IFOV) and can work in high spectral resolution mode, high spatial resolution mode and high sensitivity mode for different applications, which can adapt to the Velocity to Height Ratio (VHR) lower than 0.04. The integration has been finished, and several airborne flight validation experiments have been conducted. The results showed the system’s excellent performance and high efficiency.

Non-Destructive Spectroscopic Investigations on Paintings Using Optical Fibers

1992 ◽  
Vol 267 ◽  
Author(s):  
M. Bacci ◽  
S. Baronti ◽  
A. Casini ◽  
F. Lotti ◽  
M. Picollo ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Near Infrared ◽  
Far Infrared ◽  
Infrared Region ◽  
Infrared Range ◽  
Color Analysis ◽  
Near Infrared Spectra ◽  
Renaissance Period ◽  
Band Pass ◽  
Non Destructive

ABSTRACTThe main objective of our research is the development of totally non-destructive methodologies for the investigation of art works. We propose the use of fiber optic reflectance spectroscopy (FORS) in the visible and near-infrared region as a tool for the identification of the pigments used in painting. We have considered several representative inorganic artists' pigments (mainly till the Renaissance period); powder X-ray diffractograms and diffuse reflectance spectra in the visible, near-, middle- and far-infrared range were recorded for pure pigments. Then we prepared suitable samples with the same pigments using fresco, tempera and oil techniques. The visible and near-infrared spectra of these samples were recorded using an optical fiber spectrum analyzer; color analysis (chromaticity, dominant wavelength and purity) was also performed. The obtained results were used in the interpretation of the spectra obtained from some paintings collected in the Uffizi Gallery, Florence (Giotto and Luca Signorelli). The pointwise information obtained by FORS analysis was also used to calibrate and tune an image spectroscopy system, based on sequences of band-pass filtered images in the near infrared range.

scholarly journals Surface Investigation of Photo-Degraded Wood by Colour Monitoring, Infrared Spectroscopy, and Hyperspectral Imaging

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Giorgia Agresti ◽  
Giuseppe Bonifazi ◽  
Luca Calienno ◽  
Giuseppe Capobianco ◽  
Angela Lo Monaco ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Hyperspectral Imaging ◽  
Near Infrared ◽  
Infrared Region ◽  
Short Wave ◽  
Infrared Range ◽  
Surface Chemical ◽  
Colour Changes ◽  
Short Wave Infrared ◽  
Near Infrared Range

The aim of this investigation is to study the changes occurring on the surface of poplar wood exposed to artificial irradiation in a Solar Box. Colour changes were monitored with a reflectance spectrophotometer. Surface chemical modifications were evaluated by measuring the infrared spectra. Hyperspectral imaging was also applied to study the surface wood changes in the visible-near infrared and the short wave infrared wavelength ranges. The data obtained from the different techniques were compared to find the possible correlations in order to evaluate the applicability of the Hyperspectral imaging to investigate wood modifications in a non-invasive modality. The study of colour changes showed an important variation due to photo-irradiation which is the greatest change occurring within the first 24 hours. Infrared spectroscopy revealed that lignin degrades mainly in the first 48 hours. Concerning Hyperspectral imaging, the spectral features in the visible-near infrared range are mainly linked to the spectral shape, whereas in the short wave infrared cellulose and lignin affect shape and reflectance levels. The proposed approach showed that a correlation can be established between colour variation and wood degradation in the visible-near infrared range; furthermore in the short wave infrared region surface chemical changes can be assessed.

scholarly journals EarthCARE Aerosol and Cloud Layer and Column Products

2018 ◽  
Vol 176 ◽  
pp. 02007 ◽  
Author(s):  
Ulla Wandinger ◽  
Anja Hünerbein ◽  
Stefan Horn ◽  
Florian Schneider ◽  
David Donovan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Spectral Resolution ◽  
Cloud Layer ◽  
High Spectral Resolution ◽  
Aerosol Layer ◽  
Spectral Imager ◽  
Along Track ◽  
High Spectral Resolution Lidar ◽  
Level 2 ◽  
Aerosol Type

We introduce the development of EarthCARE Level 2 layer products derived from profile measurements of the high-spectral-resolution lidar ATLID and column products obtained from combined information of ATLID and the Multi-Spectral Imager (MSI). Layer products include cloud top height as well as aerosol layer boundaries and mean optical properties along the satellite nadir track. Synergistic column products comprise cloud top height, Ångström exponent, and aerosol type both along-track and across the MSI swath.

scholarly journals Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains central facility

2011 ◽  
Vol 4 (3) ◽  
pp. 3097-3145
Author(s):  
S. A. McFarlane ◽  
K. L. Gaustad ◽  
E. J. Mlawer ◽  
C. N. Long ◽  
J. Delamere
Keyword(s):  
Great Plains ◽  
Spectral Resolution ◽  
Surface Albedo ◽  
Vegetation Index ◽  
Near Infrared ◽  
High Spectral Resolution ◽  
Surface Type ◽  
Southern Great Plains ◽  
Green Vegetation ◽  
Visible Wavelengths

Abstract. We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM) facility at the Southern Great Plains (SGP) site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs), four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated) can be identified. A normalized difference vegetation index (NDVI) is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs) and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

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