Spectroscopic photon localization microscopy: breaking the resolution limit of single molecule localization microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Dong, Biqin; Almassalha, Luay Matthew; Urban, Ben E.; Nguyen, The-Quyen; Khuon, Satya; Chew, Teng-Leong; Backman, Vadim; Sun, Cheng; Zhang, Hao F.

2017-02-01

Distinguishing minute differences in spectroscopic signatures is crucial for revealing the fluorescence heterogeneity among fluorophores to achieve a high molecular specificity. Here we report spectroscopic photon localization microscopy (SPLM), a newly developed far-field spectroscopic imaging technique, to achieve nanoscopic resolution based on the principle of single-molecule localization microscopy while simultaneously uncovering the inherent molecular spectroscopic information associated with each stochastic event (Dong et al., Nature Communications 2016, in press). In SPLM, by using a slit-less monochromator, both the zero-order and the first-order diffractions from a grating were recorded simultaneously by an electron multiplying charge-coupled device to reveal the spatial distribution and the associated emission spectra of individual stochastic radiation events, respectively. As a result, the origins of photon emissions from different molecules can be identified according to their spectral differences with sub-nm spectral resolution, even when the molecules are within close proximity. With the newly developed algorithms including background subtraction and spectral overlap unmixing, we established and tested a method which can significantly extend the fundamental spatial resolution limit of single molecule localization microscopy by molecular discrimination through spectral regression. Taking advantage of this unique capability, we demonstrated improvement in spatial resolution of PALM/STORM up to ten fold with selected fluorophores. This technique can be readily adopted by other research groups to greatly enhance the optical resolution of single molecule localization microscopy without the need to modify their existing staining methods and protocols. This new resolving capability can potentially provide new insights into biological phenomena and enable significant research progress to be made in the life sciences.

Time-resolved lidar fluorosensor for sea pollution detection

NASA Technical Reports Server (NTRS)

Ferrario, A.; Pizzolati, P. L.; Zanzottera, E.

1986-01-01

A contemporary time and spectral analysis of oil fluorescence is useful for the detection and the characterization of oil spills on the sea surface. Nevertheless the fluorosensor lidars, which were realized up to now, have only partial capability to perform this double analysis. The main difficulties are the high resolution required (of the order of 1 nanosecond) and the complexity of the detection system for the recording of a two-dimensional matrix of data for each laser pulse. An airborne system whose major specifications were: time range, 30 to 75 ns; time resolution, 1 ns; spectral range, 350 to 700 nm; and spectral resolution, 10 nm was designed and constructed. The designed system of a short pulse ultraviolet laser source and a streak camera based detector are described.

Demonstration of a diode-laser-based high spectral resolution lidar (HSRL) for quantitative profiling of clouds and aerosols.

PubMed

Hayman, Matthew; Spuler, Scott

2017-11-27

We present a demonstration of a diode-laser-based high spectral resolution lidar. It is capable of performing calibrated retrievals of aerosol and cloud optical properties at a 150 m range resolution with less than 1 minute integration time over an approximate range of 12 km during day and night. This instrument operates at 780 nm, a wavelength that is well established for reliable semiconductor lasers and detectors, and was chosen because it corresponds to the D2 rubidium absorption line. A heated vapor reference cell of isotopic rubidium 87 is used as an effective and reliable aerosol signal blocking filter in the instrument. In principle, the diode-laser-based high spectral resolution lidar can be made cost competitive with elastic backscatter lidar systems, yet delivers a significant improvement in data quality through direct retrieval of quantitative optical properties of clouds and aerosols.

HIRIS (High-Resolution Imaging Spectrometer: Science opportunities for the 1990s. Earth observing system. Volume 2C: Instrument panel report

NASA Technical Reports Server (NTRS)

1987-01-01

The high-resolution imaging spectrometer (HIRIS) is an Earth Observing System (EOS) sensor developed for high spatial and spectral resolution. It can acquire more information in the 0.4 to 2.5 micrometer spectral region than any other sensor yet envisioned. Its capability for critical sampling at high spatial resolution makes it an ideal complement to the MODIS (moderate-resolution imaging spectrometer) and HMMR (high-resolution multifrequency microwave radiometer), lower resolution sensors designed for repetitive coverage. With HIRIS it is possible to observe transient processes in a multistage remote sensing strategy for Earth observations on a global scale. The objectives, science requirements, and current sensor design of the HIRIS are discussed along with the synergism of the sensor with other EOS instruments and data handling and processing requirements.

High resolution observations of low contrast phenomena from an Advanced Geosynchronous Platform (AGP)

NASA Technical Reports Server (NTRS)

Maxwell, M. S.

1984-01-01

Present technology allows radiometric monitoring of the Earth, ocean and atmosphere from a geosynchronous platform with good spatial, spectral and temporal resolution. The proposed system could provide a capability for multispectral remote sensing with a 50 m nadir spatial resolution in the visible bands, 250 m in the 4 micron band and 1 km in the 11 micron thermal infrared band. The diffraction limited telescope has a 1 m aperture, a 10 m focal length (with a shorter focal length in the infrared) and linear and area arrays of detectors. The diffraction limited resolution applies to scenes of any brightness but for a dark low contrast scenes, the good signal to noise ratio of the system contribute to the observation capability. The capabilities of the AGP system are assessed for quantitative observations of ocean scenes. Instrument and ground system configuration are presented and projected sensor capabilities are analyzed.

Image simulation and assessment of the colour and spatial capabilities of the Colour and Stereo Surface Imaging System (CaSSIS) on the ExoMars Trace Gas Orbiter

USGS Publications Warehouse

Tornabene, Livio L.; Seelos, Frank P.; Pommerol, Antoine; Thomas, Nicolas; Caudill, Christy M.; Becerra, Patricio; Bridges, John C.; Byrne, Shane; Cardinale, Marco; Chojnacki, Matthew; Conway, Susan J.; Cremonese, Gabriele; Dundas, Colin M.; El-Maarry, M. R.; Fernando, Jennifer; Hansen, Candice J.; Hansen, Kayle; Harrison, Tanya N.; Henson, Rachel; Marinangeli, Lucia; McEwen, Alfred S.; Pajola, Maurizio; Sutton, Sarah S.; Wray, James J.

2018-01-01

This study aims to assess the spatial and visible/near-infrared (VNIR) colour/spectral capabilities of the 4-band Colour and Stereo Surface Imaging System (CaSSIS) aboard the ExoMars 2016 Trace Grace Orbiter (TGO). The instrument response functions for the CaSSIS imager was used to resample spectral libraries, modelled spectra and to construct spectrally (i.e., in I/F space) and spatially consistent simulated CaSSIS image cubes of various key sites of interest and for ongoing scientific investigations on Mars. Coordinated datasets from Mars Reconnaissance Orbiter (MRO) are ideal, and specifically used for simulating CaSSIS. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) provides colour information, while the Context Imager (CTX), and in a few cases the High-Resolution Imaging Science Experiment (HiRISE), provides the complementary spatial information at the resampled CaSSIS unbinned/unsummed pixel resolution (4.6 m/pixel from a 400-km altitude). The methodology used herein employs a Gram-Schmidt spectral sharpening algorithm to combine the ∼18–36 m/pixel CRISM-derived CaSSIS colours with I/F images primarily derived from oversampled CTX images. One hundred and eighty-one simulated CaSSIS 4-colour image cubes (at 18–36 m/pixel) were generated (including one of Phobos) based on CRISM data. From these, thirty-three “fully”-simulated image cubes of thirty unique locations on Mars (i.e., with 4 colour bands at 4.6 m/pixel) were made. All simulated image cubes were used to test both the colour capabilities of CaSSIS by producing standard colour RGB images, colour band ratio composites (CBRCs) and spectral parameters. Simulated CaSSIS CBRCs demonstrated that CaSSIS will be able to readily isolate signatures related to ferrous (Fe2+) iron- and ferric (Fe3+) iron-bearing deposits on the surface of Mars, ices and atmospheric phenomena. Despite the lower spatial resolution of CaSSIS when compared to HiRISE, the results of this work demonstrate that CaSSIS will not only compliment HiRISE-scale studies of various geological and seasonal phenomena, it will also enhance them by providing additional colour and geologic context through its wider and longer full-colour coverage (∼9.4×50">∼9.4×50∼9.4×50 km), and its increased sensitivity to iron-bearing materials from its two IR bands (RED and NIR). In a few examples, subtle surface changes that were not easily detected by HiRISE were identified in the simulated CaSSIS images. This study also demonstrates the utility of the Gram-Schmidt spectral pan-sharpening technique to extend VNIR colour/spectral capabilities from a lower spatial resolution colour/spectral dataset to a single-band or panchromatic image greyscale image with higher resolution. These higher resolution colour products (simulated CaSSIS or otherwise) are useful as means to extend both geologic context and mapping of datasets with coarser spatial resolutions. The results of this study indicate that the TGO mission objectives, as well as the instrument-specific mission objectives, will be achievable with CaSSIS.

Dual-comb spectroscopy of laser-induced plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bergevin, Jenna; Wu, Tsung-Han; Yeak, Jeremy

Dual-comb spectroscopy has become a powerful spectroscopic technique in applications that rely on its broad spectral coverage combined with high frequency resolution capabilities. Experiments to date have primarily focused on detection and analysis of multiple gas species under semi-static conditions, with applications ranging from environmental monitoring of greenhouse gases to high resolution molecular spectroscopy. Here, we utilize dual-comb spectroscopy to demonstrate broadband, high-resolution, and time-resolved measurements in a laser induced plasma for the first time. As a first demonstration, we simultaneously detect trace amounts of Rb and K in solid samples with a single laser ablation shot, with transitions separatedmore » by over 6 THz (13 nm) and spectral resolution sufficient to resolve isotopic and ground state hyperfine splittings of the Rb D2 line. This new spectroscopic approach offers the broad spectral coverage found in the powerful techniques of laser-induced breakdown spectroscopy (LIBS) while providing the high-resolution and accuracy of cw laser-based spectroscopies.« less

High performance multi-spectral interrogation for surface plasmon resonance imaging sensors.

PubMed

Sereda, A; Moreau, J; Canva, M; Maillart, E

2014-04-15

Surface plasmon resonance (SPR) sensing has proven to be a valuable tool in the field of surface interactions characterization, especially for biomedical applications where label-free techniques are of particular interest. In order to approach the theoretical resolution limit, most SPR-based systems have turned to either angular or spectral interrogation modes, which both offer very accurate real-time measurements, but at the expense of the 2-dimensional imaging capability, therefore decreasing the data throughput. In this article, we show numerically and experimentally how to combine the multi-spectral interrogation technique with 2D-imaging, while finding an optimum in terms of resolution, accuracy, acquisition speed and reduction in data dispersion with respect to the classical reflectivity interrogation mode. This multi-spectral interrogation methodology is based on a robust five parameter fitting of the spectral reflectivity curve which enables monitoring of the reflectivity spectral shift with a resolution of the order of ten picometers, and using only five wavelength measurements per point. In fine, such multi-spectral based plasmonic imaging system allows biomolecular interaction monitoring in a linear regime independently of variations of buffer optical index, which is illustrated on a DNA-DNA model case. © 2013 Elsevier B.V. All rights reserved.

Imaging of murine embryonic cardiovascular development using optical coherence tomography (Conference Presentation)

NASA Astrophysics Data System (ADS)

Huang, Yongyang; Degenhardt, Karl R.; Astrof, Sophie; Zhou, Chao

2016-03-01

We have demonstrated the capability of spectral domain optical coherence tomography (SDOCT) system to image full development of mouse embryonic cardiovascular system. Monitoring morphological changes of mouse embryonic heart occurred in different embryonic stages helps identify structural or functional cardiac anomalies and understand how these anomalies lead to congenital heart diseases (CHD) present at birth. In this study, mouse embryo hearts ranging from E9.5 to E15.5 were prepared and imaged in vitro. A customized spectral domain OCT system was used for imaging, with a central wavelength of 1310nm, spectral bandwidth of ~100nm and imaging speed of 47kHz A-scans/s. Axial resolution of this system was 8.3µm in air, and transverse resolution was 6.2 µm with 5X objective. Key features of mouse embryonic cardiovascular development such as vasculature remodeling into circulatory system, separation of atria and ventricles and emergence of valves could be clearly seen in three-dimensional OCT images. Optical clearing was applied to overcome the penetration limit of OCT system. With high resolution, fast imaging speed, 3D imaging capability, OCT proves to be a promising biomedical imaging modality for developmental biology studies, rivaling histology and micro-CT.

Compact full-motion video hyperspectral cameras: development, image processing, and applications

NASA Astrophysics Data System (ADS)

Kanaev, A. V.

2015-10-01

Emergence of spectral pixel-level color filters has enabled development of hyper-spectral Full Motion Video (FMV) sensors operating in visible (EO) and infrared (IR) wavelengths. The new class of hyper-spectral cameras opens broad possibilities of its utilization for military and industry purposes. Indeed, such cameras are able to classify materials as well as detect and track spectral signatures continuously in real time while simultaneously providing an operator the benefit of enhanced-discrimination-color video. Supporting these extensive capabilities requires significant computational processing of the collected spectral data. In general, two processing streams are envisioned for mosaic array cameras. The first is spectral computation that provides essential spectral content analysis e.g. detection or classification. The second is presentation of the video to an operator that can offer the best display of the content depending on the performed task e.g. providing spatial resolution enhancement or color coding of the spectral analysis. These processing streams can be executed in parallel or they can utilize each other's results. The spectral analysis algorithms have been developed extensively, however demosaicking of more than three equally-sampled spectral bands has been explored scarcely. We present unique approach to demosaicking based on multi-band super-resolution and show the trade-off between spatial resolution and spectral content. Using imagery collected with developed 9-band SWIR camera we demonstrate several of its concepts of operation including detection and tracking. We also compare the demosaicking results to the results of multi-frame super-resolution as well as to the combined multi-frame and multiband processing.

Spatial, Temporal and Spectral Satellite Image Fusion via Sparse Representation

NASA Astrophysics Data System (ADS)

Song, Huihui

Remote sensing provides good measurements for monitoring and further analyzing the climate change, dynamics of ecosystem, and human activities in global or regional scales. Over the past two decades, the number of launched satellite sensors has been increasing with the development of aerospace technologies and the growing requirements on remote sensing data in a vast amount of application fields. However, a key technological challenge confronting these sensors is that they tradeoff between spatial resolution and other properties, including temporal resolution, spectral resolution, swath width, etc., due to the limitations of hardware technology and budget constraints. To increase the spatial resolution of data with other good properties, one possible cost-effective solution is to explore data integration methods that can fuse multi-resolution data from multiple sensors, thereby enhancing the application capabilities of available remote sensing data. In this thesis, we propose to fuse the spatial resolution with temporal resolution and spectral resolution, respectively, based on sparse representation theory. Taking the study case of Landsat ETM+ (with spatial resolution of 30m and temporal resolution of 16 days) and MODIS (with spatial resolution of 250m ~ 1km and daily temporal resolution) reflectance, we propose two spatial-temporal fusion methods to combine the fine spatial information of Landsat image and the daily temporal resolution of MODIS image. Motivated by that the images from these two sensors are comparable on corresponding bands, we propose to link their spatial information on available Landsat- MODIS image pair (captured on prior date) and then predict the Landsat image from the MODIS counterpart on prediction date. To well-learn the spatial details from the prior images, we use a redundant dictionary to extract the basic representation atoms for both Landsat and MODIS images based on sparse representation. Under the scenario of two prior Landsat-MODIS image pairs, we build the corresponding relationship between the difference images of MODIS and ETM+ by training a low- and high-resolution dictionary pair from the given prior image pairs. In the second scenario, i.e., only one Landsat- MODIS image pair being available, we directly correlate MODIS and ETM+ data through an image degradation model. Then, the fusion stage is achieved by super-resolving the MODIS image combining the high-pass modulation in a two-layer fusion framework. Remarkably, the proposed spatial-temporal fusion methods form a unified framework for blending remote sensing images with phenology change or land-cover-type change. Based on the proposed spatial-temporal fusion models, we propose to monitor the land use/land cover changes in Shenzhen, China. As a fast-growing city, Shenzhen faces the problem of detecting the rapid changes for both rational city planning and sustainable development. However, the cloudy and rainy weather in region Shenzhen located makes the capturing circle of high-quality satellite images longer than their normal revisit periods. Spatial-temporal fusion methods are capable to tackle this problem by improving the spatial resolution of images with coarse spatial resolution but frequent temporal coverage, thereby making the detection of rapid changes possible. On two Landsat-MODIS datasets with annual and monthly changes, respectively, we apply the proposed spatial-temporal fusion methods to the task of multiple change detection. Afterward, we propose a novel spatial and spectral fusion method for satellite multispectral and hyperspectral (or high-spectral) images based on dictionary-pair learning and sparse non-negative matrix factorization. By combining the spectral information from hyperspectral image, which is characterized by low spatial resolution but high spectral resolution and abbreviated as LSHS, and the spatial information from multispectral image, which is featured by high spatial resolution but low spectral resolution and abbreviated as HSLS, this method aims to generate the fused data with both high spatial and high spectral resolutions. Motivated by the observation that each hyperspectral pixel can be represented by a linear combination of a few endmembers, this method first extracts the spectral bases of LSHS and HSLS images by making full use of the rich spectral information in LSHS data. The spectral bases of these two categories data then formulate a dictionary-pair due to their correspondence in representing each pixel spectra of LSHS data and HSLS data, respectively. Subsequently, the LSHS image is spatially unmixed by representing the HSLS image with respect to the corresponding learned dictionary to derive its representation coefficients. Combining the spectral bases of LSHS data and the representation coefficients of HSLS data, we finally derive the fused data characterized by the spectral resolution of LSHS data and the spatial resolution of HSLS data.

TEMPO Specific Photochemical Reflectance Index for Monitoring Crop Productivity

NASA Astrophysics Data System (ADS)

Wulamu, A.; Fishman, J.; Maimaitiyiming, M.

2016-12-01

Chlorophyll fluorescence and Photochemical Reflectance Index (PRI) are two key indicators of plant functional status used for early stress detection. With its less than one nanometer hyperspectral resolution and hourly revisit capabilities, NASA's Tropospheric Emissions: Monitoring of Pollution (TEMPO) sensor provides new opportunities for monitoring regional food security. Chlorophyll fluorescence can be retrieved by TEMPO using Oxygen B (O2-B) absorption region at 687 nm. The Photochemical Reflectance Index (PRI) is calculated from spectral reflectance at 531 and 570. However, TEMPO spectral range covers from 290 mm - 490 nm and 540 nm -740 nm, does not provide the 531 nm measurement band for PRI. It is imperative to develop alternate wavelengths within the TEMPO spectral range for these early stress indicators so that regional crop health can be observed by TEMPO with unparalleled spectral and temporal resolutions to address food security. Combining field and airborne remote sensing experiments and radiative transfer simulations, this work proposes a TEMPO specific PRI and demonstrates that TEMPO offers a new set of high-resolution spectral data for crop monitoring.

THE IDEA IS TO USEMODIS IN CONJUNCTION WITH THE CURRENT LIMITED LANDSAT CAPABILITY, COMMERCIAL SATELLITES, ANDUNMANNED AERIAL VEHICLES (UAV), IN A MULTI-STAGE APPROACH TO MEET EPA INFORMATION NEEDS.REMOTE SENSING OVERVIEW: EPA CAPABILITIES, PRIORITY AGENCY APPLICATIONS, SENSOR/AIRCRAFT CAPABILITIES, COST CONSIDERATIONS, SPECTRAL AND SPATIAL RESOLUTIONS, AND TEMPORAL CONSIDERATIONS

EPA Science Inventory

EPA remote sensing capabilities include applied research for priority applications and technology support for operational assistance to clients across the Agency. The idea is to use MODIS in conjunction with the current limited Landsat capability, commercial satellites, and Unma...

Enhancing sensitivity of high resolution optical coherence tomography using an optional spectrally encoded extended source (Conference Presentation)

NASA Astrophysics Data System (ADS)

Yu, Xiaojun; Liu, Xinyu; Chen, Si; Wang, Xianghong; Liu, Linbo

2016-03-01

High-resolution optical coherence tomography (OCT) is of critical importance to disease diagnosis because it is capable of providing detailed microstructural information of the biological tissues. However, a compromise usually has to be made between its spatial resolutions and sensitivity due to the suboptimal spectral response of the system components, such as the linear camera, the dispersion grating, and the focusing lenses, etc. In this study, we demonstrate an OCT system that achieves both high spatial resolutions and enhanced sensitivity through utilizing a spectrally encoded source. The system achieves a lateral resolution of 3.1 μm and an axial resolution of 2.3 μm in air; when with a simple dispersive prism placed in the infinity space of the sample arm optics, the illumination beam on the sample is transformed into a line source with a visual angle of 10.3 mrad. Such an extended source technique allows a ~4 times larger maximum permissible exposure (MPE) than its point source counterpart, which thus improves the system sensitivity by ~6dB. In addition, the dispersive prism can be conveniently switched to a reflector. Such flexibility helps increase the penetration depth of the system without increasing the complexity of the current point source devices. We conducted experiments to characterize the system's imaging capability using the human fingertip in vivo and the swine eye optic never disc ex vivo. The higher penetration depth of such a system over the conventional point source OCT system is also demonstrated in these two tissues.

The NPP and J1 CrIS Operational High-Resolution Channel Selection for the NUCAPS algorithm: A demonstration of global applicability to meet users needs

NASA Astrophysics Data System (ADS)

Smith, J.; Gambacorta, A.; Barnet, C.; Smith, N.; Goldberg, M.; Pierce, B.; Wolf, W.; King, T.

2016-12-01

This work presents an overview of the NPP and J1 CrIS high resolution operational channel selection. Our methodology focuses on the spectral sensitivity characteristics of the available channels in order to maximize information content and spectral purity. These aspects are key to ensure accuracy in the retrieval products, particularly for trace gases. We will provide a demonstration of its global optimality by analyzing different test cases that are of particular interests to our JPSS Proving Ground and Risk Reduction user applications. A focus will be on high resolution trace gas retrieval capability in the context of the Alaska fire initiatives.

HazMatID (trademark) Replacement Project

DTIC Science & Technology

2013-05-09

replacement for the Smiths Detection HazMatIDTM on the 886H allowance standard, a search of Fourier transform infrared spectroscopy ( FTIR ) instruments was...uses FTIR spectroscopy. It has the capability to identify chemical warfare agents, explosives , toxic industrial chemicals, narcotics, and...uses FTIR technology , providing a wider spectral coverage and higher spectral resolution. Findings: As I operated the Mobile-IR, I found it to

Vibrational spectral signatures of crystalline cellulose using high resolution broadband sum frequency generation vibrational spectroscopy (HR-BB-SFG-VS)

DOE PAGES

Zhang, Libing; Lu, Zhou; Velarde, Luis; ...

2015-03-03

Both the C–H and O–H region spectra of crystalline cellulose were studied using the sub-wavenumber high-resolution broadband sum frequency generation vibrational spectroscopy (HR-BB-SFG-VS) for the first time. The resolution of HR-BB-SFG-VS is about 10-times better than conventional scanning SFG-VS and has the capability of measuring the intrinsic spectral lineshape and revealing many more spectral details. With HR-BB-SFG-VS, we found that in cellulose samples from different sources, including Avicel and cellulose crystals isolated from algae Valonia (Iα) and tunicates (Iβ), the spectral signatures in the O–H region were unique for the two allomorphs, i.e. Iα and Iβ, while the spectral signaturesmore » in the C–H regions varied in all samples examined. Even though the origin of the different spectral signatures of the crystalline cellulose in the O–H and C–H vibrational frequency regions are yet to be correlated to the structure of cellulose, these results lead to new spectroscopic methods and opportunities to classify and to understand the basic crystalline structures, as well as variations in polymorphism of the crystalline cellulose.« less

Vibrational spectral signatures of crystalline cellulose using high resolution broadband sum frequency generation vibrational spectroscopy (HR-BB-SFG-VS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Libing; Lu, Zhou; Velarde, Luis

Both the C–H and O–H region spectra of crystalline cellulose were studied using the sub-wavenumber high-resolution broadband sum frequency generation vibrational spectroscopy (HR-BB-SFG-VS) for the first time. The resolution of HR-BB-SFG-VS is about 10-times better than conventional scanning SFG-VS and has the capability of measuring the intrinsic spectral lineshape and revealing many more spectral details. With HR-BB-SFG-VS, we found that in cellulose samples from different sources, including Avicel and cellulose crystals isolated from algae Valonia (Iα) and tunicates (Iβ), the spectral signatures in the O–H region were unique for the two allomorphs, i.e. Iα and Iβ, while the spectral signaturesmore » in the C–H regions varied in all samples examined. Even though the origin of the different spectral signatures of the crystalline cellulose in the O–H and C–H vibrational frequency regions are yet to be correlated to the structure of cellulose, these results lead to new spectroscopic methods and opportunities to classify and to understand the basic crystalline structures, as well as variations in polymorphism of the crystalline cellulose.« less

Infrared calibration for climate: a perspective on present and future high-spectral resolution instruments

NASA Astrophysics Data System (ADS)

Revercomb, Henry E.; Anderson, James G.; Best, Fred A.; Tobin, David C.; Knuteson, Robert O.; LaPorte, Daniel D.; Taylor, Joe K.

2006-12-01

The new era of high spectral resolution infrared instruments for atmospheric sounding offers great opportunities for climate change applications. A major issue with most of our existing IR observations from space is spectral sampling uncertainty and the lack of standardization in spectral sampling. The new ultra resolution observing capabilities from the AIRS grating spectrometer on the NASA Aqua platform and from new operational FTS instruments (IASI on Metop, CrIS for NPP/NPOESS, and the GIFTS for a GOES demonstration) will go a long way toward improving this situation. These new observations offer the following improvements: 1. Absolute accuracy, moving from issues of order 1 K to <0.2-0.4 K brightness temperature, 2. More complete spectral coverage, with Nyquist sampling for scale standardization, and 3. Capabilities for unifying IR calibration among different instruments and platforms. However, more needs to be done to meet the immediate needs for climate and to effectively leverage these new operational weather systems, including 1. Place special emphasis on making new instruments as accurate as they can be to realize the potential of technological investments already made, 2. Maintain a careful validation program for establishing the best possible direct radiance check of long-term accuracy--specifically, continuing to use aircraft-or balloon-borne instruments that are periodically checked directly with NIST, and 3. Commit to a simple, new IR mission that will provide an ongoing backbone for the climate observing system. The new mission would make use of Fourier Transform Spectrometer measurements to fill in spectral and diurnal sampling gaps of the operational systems and provide a benchmark with better than 0.1K 3-sigma accuracy based on standards that are verifiable in-flight.

The resolution capability of an irregularly sampled dataset: With application to Geosat altimeter data

NASA Technical Reports Server (NTRS)

Chelton, Dudley B.; Schlax, Michael G.

1994-01-01

A formalism is presented for determining the wavenumber-frequency transfer function associated with an irregularly sampled multidimensional dataset. This transfer function reveals the filtering characteristics and aliasing patterns inherent in the sample design. In combination with information about the spectral characteristics of the signal, the transfer function can be used to quantify the spatial and temporal resolution capability of the dataset. Application of the method to idealized Geosat altimeter data (i.e., neglecting measurement errors and data dropouts) concludes that the Geosat orbit configuration is capable of resolving scales of about 3 deg in latitude and longitude by about 30 days.

Evaluating the capabilities of vegetation spectral indices on chlorophyll content estimation at Sentinel-2 spectral resolutions

NASA Astrophysics Data System (ADS)

Sun, Qi; Jiao, Quanjun; Dai, Huayang

2018-03-01

Chlorophyll is an important pigment in green plants for photosynthesis and obtaining the energy for growth and development. The rapid, nondestructive and accurate estimation of chlorophyll content is significant for understanding the crops growth, monitoring the disease and insect, and assessing the yield of crops. Sentinel-2 equipped with the Multi-Spectral Instrument (MSI), which will provide images with high spatial, spectral and temporal resolution. It covers the VNIR/SWIR spectral region in 13 bands and incorporates two new spectral bands in the red-edge region and a spatial resolution of 20nm, which can be used to derive vegetation indices using red-edge bands. In this paper, we will focus on assessing the potential of vegetation spectral indices for retrieving chlorophyll content from Sentinel-2 at different angles. Subsequently, we used in-situ spectral data and Sentinel-2 data to test the relationship between VIs and chlorophyll content. The REP, MTCI, CIred-edge, CIgreen, Macc01, TCARI/OSAVI [705,750], NDRE1 and NDRE2 were calculated. NDRE2 index displays a strongly similar result for hyperspectral and simulated Sentinel-2 spectral bands (R2 =0.53, R2 =0.51, for hyperspectral and Sentinel-2, respectively). At different observation angles, NDRE2 has the smallest difference in performance (R2 = 0.51, R2 =0.64, at 0° and 15° , respectively).

Three-dimensional nanoscale molecular imaging by extreme ultraviolet laser ablation mass spectrometry

PubMed Central

Kuznetsov, Ilya; Filevich, Jorge; Dong, Feng; Woolston, Mark; Chao, Weilun; Anderson, Erik H.; Bernstein, Elliot R.; Crick, Dean C.; Rocca, Jorge J.; Menoni, Carmen S.

2015-01-01

Analytical probes capable of mapping molecular composition at the nanoscale are of critical importance to materials research, biology and medicine. Mass spectral imaging makes it possible to visualize the spatial organization of multiple molecular components at a sample's surface. However, it is challenging for mass spectral imaging to map molecular composition in three dimensions (3D) with submicron resolution. Here we describe a mass spectral imaging method that exploits the high 3D localization of absorbed extreme ultraviolet laser light and its fundamentally distinct interaction with matter to determine molecular composition from a volume as small as 50 zl in a single laser shot. Molecular imaging with a lateral resolution of 75 nm and a depth resolution of 20 nm is demonstrated. These results open opportunities to visualize chemical composition and chemical changes in 3D at the nanoscale. PMID:25903827

Aerosol Absorption Retrievals from the PACE Broad Spectrum Ocean Color Instrument (OCI)

NASA Technical Reports Server (NTRS)

Mattoo, Shana; Remer, Lorraine A.; Levy, Robert C.; Gupta, Pawan; Ahmad, Ziauddin; Martins, J. Vanderlei; Lima, Adriana Rocha; Torres, Omar

2016-01-01

The PACE (Pre-­Aerosol, Clouds and ocean Ecosystem) mission, anticipated for launch in the early 2020s, is designed to characterize oceanic and atmospheric properties. The primary instrument on-­-board will be a moderate resolution (approximately 1 km nadir) radiometer, called the Ocean Color Instrument (OCI). OCI will provide high spectral resolution (5 nm) from the UV to NIR (350 - 800 nm), with additional spectral bands in the NIR and SWIR. The OCI itself is an excellent instrument for atmospheric objectives, providing measurements across a broad spectral range that in essence combines the capabilities of MODIS and OMI, but with the UV channels from OMI to be available at moderate resolution. (Image credit: PACE Science Definition Team Report). Objective: Can we make use of the UV-­SWIR measurements to derive information about aerosol absorption when aerosol loading is high?

Ground-based eye-safe networkable micro-pulse differential absorption and high spectral resolution lidar for water vapor and aerosol profiling in the lower troposphere

NASA Astrophysics Data System (ADS)

Repasky, K. S.; Spuler, S.; Hayman, M. M.; Bunn, C. E.

2017-12-01

Atmospheric water vapor is a greenhouse gas that is known to be a significant driver of weather and climate. Several National Research Council (NRC) reports have highlighted the need for improved water vapor measurements that can capture its spatial and temporal variability as a means to improve weather predictions. Researchers at Montana State University (MSU) and the National Center for Atmospheric Research (NCAR) have developed an eye-safe diode laser based micro-pulse differential absorption lidar (MP-DIAL) for water vapor profiling in the lower troposphere. The MP-DIAL is capable of long term unattended operation and is capable of monitoring water vapor in the lower troposphere in most weather conditions. Two MP-DIAL instruments are currently operational and have been deployed at the Front Range Air Pollution and Photochemistry Experiment (FRAPPE), the Plains elevated Convection at Night (PECAN) experiment, the Perdigão experiment, and the Land Atmosphere Feedback Experiment (LAFE). For each of these field experiments, the MP-DIAL was run unattended and provided near-continuous water vapor profiles, including periods of bright daytime clouds, from 300 m above the ground level to 4 km (or the cloud base) with 150 m vertical resolution and 5 minute temporal resolution. Three additional MP-DIAL instruments are currently under construction and will result in a network of five eye-safe MP-DIAL instruments for ground based weather and climate research experiments. Taking advantage of the broad spectral coverage and modularity or the diode based architecture, a high spectral resolution lidar (HSRL) measurement capabilities was added to the second MP-DIAL instrument. The HSRL capabilities will be operational during the deployment at the LAFE field experiment. The instrument architecture will be presented along with examples of data collected during recent field experiments.

Semiconductor Laser Multi-Spectral Sensing and Imaging

PubMed Central

Le, Han Q.; Wang, Yang

2010-01-01

Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO). These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers. PMID:22315555

Semiconductor laser multi-spectral sensing and imaging.

PubMed

Le, Han Q; Wang, Yang

2010-01-01

Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO). These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers.

A Compact Airborne High Spectral Resolution Lidar for Observations of Aerosol and Cloud Optical Properties

NASA Technical Reports Server (NTRS)

Hostetler, Chris A.; Hair, John W.; Cook, Anthony L.

2002-01-01

We are in the process of developing a nadir-viewing, aircraft-based high spectral resolution lidar (HSRL) at NASA Langley Research Center. The system is designed to measure backscatter and extinction of aerosols and tenuous clouds. The primary uses of the instrument will be to validate spaceborne aerosol and cloud observations, carry out regional process studies, and assess the predictions of chemical transport models. In this paper, we provide an overview of the instrument design and present the results of simulations showing the instrument's capability to accurately measure extinction and extinction-to-backscatter ratio.

High-Resolution Large Field-of-View FUV Compact Camera

NASA Technical Reports Server (NTRS)

Spann, James F.

2006-01-01

The need for a high resolution camera with a large field of view and capable to image dim emissions in the far-ultraviolet is driven by the widely varying intensities of FUV emissions and spatial/temporal scales of phenomena of interest in the Earth% ionosphere. In this paper, the concept of a camera is presented that is designed to achieve these goals in a lightweight package with sufficient visible light rejection to be useful for dayside and nightside emissions. The camera employs the concept of self-filtering to achieve good spectral resolution tuned to specific wavelengths. The large field of view is sufficient to image the Earth's disk at Geosynchronous altitudes and capable of a spatial resolution of >20 km. The optics and filters are emphasized.

Evaluating the capability of Landsat 8 OLI and SPOT 6 for discriminating invasive alien species in the African Savanna landscape

NASA Astrophysics Data System (ADS)

Kganyago, Mahlatse; Odindi, John; Adjorlolo, Clement; Mhangara, Paidamoyo

2018-05-01

Globally, there is paucity of accurate information on the spatial distribution and patch sizes of Invasive Alien Plants (IAPs) species. Such information is needed to aid optimisation of control mechanisms to prevent further spread of IAPs and minimize their impacts. Recent studies have shown the capability of very high spatial (<1 m) and spectral resolution (<10 nm) data for discriminating vegetation species. However, very high spatial resolution may introduce significant intra-species spectral variability and result in reduced mapping accuracy, while higher spectral resolution data are commonly limited to smaller areas, are costly and computationally expensive. Alternatively, medium and high spatial resolution data are available at low or no cost and have limitedly been evaluated for their potential in determining invasion patterns relevant for invasion ecology and aiding effective IAPs management. In this study medium and high resolution datasets from Landsat Operational Land Imager (OLI) and SPOT 6 sensors respectively, were evaluated for mapping the distribution and patch sizes of IAP, Parthenium hysterophorus in the savannah landscapes of KwaZulu-Natal, South Africa. Support Vector Machines (SVM) classifier was used for classification of both datasets. Results indicated that SPOT 6 had a higher overall accuracy (86%) than OLI (83%) in mapping P. hysterophorus. The study found larger distributions and patch sizes in OLI than in SPOT 6 as a result of possible P. hysterophorus expansion due to temporal differences between images and coarser pixels were insufficient to delineate gaps inside larger patches. On the other hand, SPOT 6 showed better capabilities of delineating gaps and boundaries of patches, hence had better estimates of distribution and patch sizes. Overall, the study showed that OLI may be suitable for mapping well-established patches for the purpose of large scale monitoring, while SPOT 6 can be used for mapping small patches and prioritising them for eradication to prevent further spread at a landscape scale.

The Atacama Large Millimeter/submillimeter Array (alma): Early Results

NASA Astrophysics Data System (ADS)

Wootten, Alwyn

2012-06-01

New radioastronomical instruments, such as ALMA or the Jansky VLA, have increased spectral throughput by orders of magnitude over previously available capabilities. ALMA brings orders of magnitude increases in spectral sensitivity and spatial resolution over what has previously been available. These increased capabilities open new possibilities for studies of complex molecules in the interstellar medium. Complex interstellar molecules may form on the surfaces of interstellar grains, after which they may be liberated into the gas phase by shocks, radiation, or other external influences. Emission from complex molecules may be diluted owing to the large number of transitions large molecules may undergo, particularly in warm regions of interstellar clouds. High sensitivity and spatial resolution are necessary to explore the distributions and relationships of these molecules. Of particular interest are the distributions of large organic molecules. Observations which establish the relationships between various large molecules are now emerging from these new instruments and will be discussed.

Spatial Classification of Orchards and Vineyards with High Spatial Resolution Panchromatic Imagery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warner, Timothy; Steinmaus, Karen L.

2005-02-01

New high resolution single spectral band imagery offers the capability to conduct image classifications based on spatial patterns in imagery. A classification algorithm based on autocorrelation patterns was developed to automatically extract orchards and vineyards from satellite imagery. The algorithm was tested on IKONOS imagery over Granger, WA, which resulted in a classification accuracy of 95%.

Three-dimensional optoacoustic mesoscopy of the tumor heterogeneity in vivo using high depth-to-resolution multispectral optoacoustic tomography

NASA Astrophysics Data System (ADS)

Li, Jiao; Zhang, Songhe; Chekkoury, Andrei; Glasl, Sarah; Vetschera, Paul; Koberstein-Schwarz, Benno; Omar, Murad; Ntziachristos, Vasilis

2017-03-01

Multispectral optoacoustic mesoscopy (MSOM) has been recently introduced for cancer imaging, it has the potential for high resolution imaging of cancer development in vivo, at depths beyond the diffusion limit. Based on spectral features, optoacoustic imaging is capable of visualizing angiogenesis and imaging cancer heterogeneity of malignant tumors through endogenous hemoglobin. However, high-resolution structural and functional imaging of whole tumor mass is limited by modest penetration and image quality, due to the insufficient capability of ultrasound detectors and the twodimensional scan geometry. In this study, we introduce a novel multi-spectral optoacoustic mesoscopy (MSOM) for imaging subcutaneous or orthotopic tumors implanted in lab mice, with the high-frequency ultrasound linear array and a conical scanning geometry. Detailed volumetric images of vasculature and oxygen saturation of tissue in the entire tumors are obtained in vivo, at depths up to 10 mm with the desirable spatial resolutions approaching 70μm. This unprecedented performance enables the visualization of vasculature morphology and hypoxia conditions has been verified with ex vivo studies. These findings demonstrate the potential of MSOM for preclinical oncological studies in deep solid tumors to facilitate the characterization of tumor's angiogenesis and the evaluation of treatment strategies.

Edge technique lidar for high accuracy, high spatial resolution wind measurement in the Planetary Boundary Layer

NASA Technical Reports Server (NTRS)

Korb, C. L.; Gentry, Bruce M.

1995-01-01

The goal of the Army Research Office (ARO) Geosciences Program is to measure the three dimensional wind field in the planetary boundary layer (PBL) over a measurement volume with a 50 meter spatial resolution and with measurement accuracies of the order of 20 cm/sec. The objective of this work is to develop and evaluate a high vertical resolution lidar experiment using the edge technique for high accuracy measurement of the atmospheric wind field to meet the ARO requirements. This experiment allows the powerful capabilities of the edge technique to be quantitatively evaluated. In the edge technique, a laser is located on the steep slope of a high resolution spectral filter. This produces large changes in measured signal for small Doppler shifts. A differential frequency technique renders the Doppler shift measurement insensitive to both laser and filter frequency jitter and drift. The measurement is also relatively insensitive to the laser spectral width for widths less than the width of the edge filter. Thus, the goal is to develop a system which will yield a substantial improvement in the state of the art of wind profile measurement in terms of both vertical resolution and accuracy and which will provide a unique capability for atmospheric wind studies.

Demosaicking for full motion video 9-band SWIR sensor

NASA Astrophysics Data System (ADS)

Kanaev, Andrey V.; Rawhouser, Marjorie; Kutteruf, Mary R.; Yetzbacher, Michael K.; DePrenger, Michael J.; Novak, Kyle M.; Miller, Corey A.; Miller, Christopher W.

2014-05-01

Short wave infrared (SWIR) spectral imaging systems are vital for Intelligence, Surveillance, and Reconnaissance (ISR) applications because of their abilities to autonomously detect targets and classify materials. Typically the spectral imagers are incapable of providing Full Motion Video (FMV) because of their reliance on line scanning. We enable FMV capability for a SWIR multi-spectral camera by creating a repeating pattern of 3x3 spectral filters on a staring focal plane array (FPA). In this paper we present the imagery from an FMV SWIR camera with nine discrete bands and discuss image processing algorithms necessary for its operation. The main task of image processing in this case is demosaicking of the spectral bands i.e. reconstructing full spectral images with original FPA resolution from spatially subsampled and incomplete spectral data acquired with the choice of filter array pattern. To the best of author's knowledge, the demosaicking algorithms for nine or more equally sampled bands have not been reported before. Moreover all existing algorithms developed for demosaicking visible color filter arrays with less than nine colors assume either certain relationship between the visible colors, which are not valid for SWIR imaging, or presence of one color band with higher sampling rate compared to the rest of the bands, which does not conform to our spectral filter pattern. We will discuss and present results for two novel approaches to demosaicking: interpolation using multi-band edge information and application of multi-frame super-resolution to a single frame resolution enhancement of multi-spectral spatially multiplexed images.

Spectral ophthalmoscopy based on supercontinuum

NASA Astrophysics Data System (ADS)

Cheng, Yueh-Hung; Yu, Jiun-Yann; Wu, Han-Hsuan; Huang, Bo-Jyun; Chu, Shi-Wei

2010-02-01

Confocal scanning laser ophthalmoscope (CSLO) has been established to be an important diagnostic tool for retinopathies like age-related macular degeneration, glaucoma and diabetes. Compared to a confocal laser scanning microscope, CSLO is also capable of providing optical sectioning on retina with the aid of a pinhole, but the microscope objective is replaced by the optics of eye. Since optical spectrum is the fingerprint of local chemical composition, it is attractive to incorporate spectral acquisition into CSLO. However, due to the limitation of laser bandwidth and chromatic/geometric aberration, the scanning systems in current CSLO are not compatible with spectral imaging. Here we demonstrate a spectral CSLO by combining a diffraction-limited broadband scanning system and a supercontinuum laser source. Both optical sectioning capability and sub-cellular resolution are demonstrated on zebrafish's retina. To our knowledge, it is also the first time that CSLO is applied onto the study of fish vision. The versatile spectral CSLO system will be useful to retinopathy diagnosis and neuroscience research.

Imaging acoustic vibrations in an ear model using spectrally encoded interferometry

NASA Astrophysics Data System (ADS)

Grechin, Sveta; Yelin, Dvir

2018-01-01

Imaging vibrational patterns of the tympanic membrane would allow an accurate measurement of its mechanical properties and provide early diagnosis of various hearing disorders. Various optical technologies have been suggested to address this challenge and demonstrated in vitro using point scanning and full-field interferometry. Spectrally encoded imaging has been previously demonstrated capable of imaging tissue acoustic vibrations with high spatial resolution, including two-dimensional phase and amplitude mapping. In this work, we demonstrate a compact optical apparatus for imaging acoustic vibrations that could be incorporated into a commercially available digital otoscope. By transmitting harmonic sound waves through the otoscope insufflation port and analyzing the spectral interferograms using custom-built software, we demonstrate high-resolution vibration imaging of a circular rubber membrane within an ear model.

An Airborne A-Band Spectrometer for Remote Sensing Of Aerosol and Cloud Optical Properties

NASA Technical Reports Server (NTRS)

Pitts, Michael; Hostetler, Chris; Poole, Lamont; Holden, Carl; Rault, Didier

2000-01-01

Atmospheric remote sensing with the O2 A-band has a relatively long history, but most of these studies were attempting to estimate surface pressure or cloud-top pressure. Recent conceptual studies have demonstrated the potential of spaceborne high spectral resolution O2 A-band spectrometers for retrieval of aerosol and cloud optical properties. The physical rationale of this new approach is that information on the scattering properties of the atmosphere is embedded in the detailed line structure of the O2 A-band reflected radiance spectrum. The key to extracting this information is to measure the radiance spectrum at very high spectral resolution. Instrument performance requirement studies indicate that, in addition to high spectral resolution, the successful retrieval of aerosol and cloud properties from A-band radiance spectra will also require high radiometric accuracy, instrument stability, and high signal-to-noise measurements. To experimentally assess the capabilities of this promising new remote sensing application, the NASA Langley Research Center is developing an airborne high spectral resolution A-band spectrometer. The spectrometer uses a plane holographic grating with a folded Littrow geometry to achieve high spectral resolution (0.5 cm-1) and low stray light in a compact package. This instrument will be flown in a series of field campaigns beginning in 2001 to evaluate the overall feasibility of this new technique. Results from these campaigns should be particularly valuable for future spaceborne applications of A-band spectrometers for aerosol and cloud retrievals.

An approach for retrieval of atmospheric trace gases CO II, CH 4 and CO from the future Canadian micro earth observation satellite (MEOS)

NASA Astrophysics Data System (ADS)

Trishchenko, Alexander P.; Khlopenkov, Konstantin V.; Wang, Shusen; Luo, Yi; Kruzelecky, Roman V.; Jamroz, Wes; Kroupnik, Guennadi

2007-10-01

Among all trace gases, the carbon dioxide and methane provide the largest contribution to the climate radiative forcing and together with carbon monoxide also to the global atmospheric carbon budget. New Micro Earth Observation Satellite (MEOS) mission is proposed to obtain information about these gases along with some other mission's objectives related to studying cloud and aerosol interactions. The miniature suit of instruments is proposed to make measurements with reduced spectral resolution (1.2nm) over wide NIR range 0.9μm to 2.45μm and with high spectral resolution (0.03nm) for three selected regions: oxygen A-band, 1.5μm-1.7μm band and 2.2μm-2.4μm band. It is also planned to supplement the spectrometer measurements with high spatial resolution imager for detailed characterization of cloud and surface albedo distribution within spectrometer field of view. The approaches for cloud/clear-sky identification and column retrievals of above trace gases are based on differential absorption technique and employ the combination of coarse and high-resolution spectral data. The combination of high and coarse resolution spectral data is beneficial for better characterization of surface spectral albedo and aerosol effects. An additional capability for retrieval of the vertical distribution amounts is obtained from the combination of nadir and limb measurements. Oxygen A-band path length will be used for normalization of trace gas retrievals.

Spectral Resolution and Coverage Impact on Advanced Sounder Information Content

NASA Technical Reports Server (NTRS)

Larar, Allen M.; Liu, Xu; Zhou, Daniel K.; Smith, William L.

2010-01-01

Advanced satellite sensors are tasked with improving global measurements of the Earth s atmosphere, clouds, and surface to enable enhancements in weather prediction, climate monitoring capability, and environmental change detection. Achieving such measurement improvements requires instrument system advancements. This presentation focuses on the impact of spectral resolution and coverage changes on remote sensing system information content, with a specific emphasis on thermodynamic state and trace species variables obtainable from advanced atmospheric sounders such as the Infrared Atmospheric Sounding Interferometer (IASI) and Cross-track Infrared Sounder (CrIS) systems on the MetOp and NPP/NPOESS series of satellites. Key words: remote sensing, advanced sounders, information content, IASI, CrIS

The Multispectral Atmospheric Mapping Sensor (MAMS): Instrument description, calibration and data quality

NASA Technical Reports Server (NTRS)

Jedlovec, G. J.; Menzel, W. P.; Atkinson, R.; Wilson, G. S.; Arvesen, J.

1986-01-01

A new instrument has been developed to produce high resolution imagery in eight visible and three infared spectral bands from an aircraft platform. An analysis of the data and calibration procedures has shown that useful data can be obtained at up to 50 m resolution with a 2.5 milliradian aperture. Single sample standard errors for the measurements are 0.5, 0.2, and 0.9 K for the 6.5, 11.1, and 12.3 micron spectral bands, respectively. These errors are halved when a 5.0 milliradian aperture is used to obtain 100 m resolution data. Intercomparisons with VAS and AVHRR measurements show good relative calibration. MAMS development is part of a larger program to develop multispectral Earth imaging capabilities from space platforms during the 1990s.

Solar flare microwave observations with high spectral resolution

NASA Astrophysics Data System (ADS)

Bruggmann, G.; Magun, A.; Benz, A. O.; Stehling, W.

1990-12-01

The solar flare radio emission in the 6-8 GHz range was observed with a high resolution spectrometer. The observed band corresponds to the plasma frequencies and gyrofrequencies of the transition region and the lowest part of the corona in active regions. Most of the emissions were found to be broadbanded, as expected from the gyrosynchrotron mechanism. In eight out of 46 observed events, spectral structures of three types were detected: spikes below the time resolution of 100 ms, slowly drifting broadband structures, and a narrow bandwidth patch of continuum emission. These first narrowband bursts spectrally recorded in the 6-8 GHz range are generally weak. Slowly drifting structures are the only type compatible with the gyrosynchrotron emission mechanism. A simple argument based on free-free absorption shows that plasma emission can only be propagated if the radiation originates in a dense region with a small density-scale length. The same holds for maser emission at a low harmonic of the electron gyrofrequency. Possible emission mechanisms and diagnostic capabilities are discussed.

Spectral Invariant Behavior of Zenith Radiance Around Cloud Edges Observed by ARM SWS

NASA Technical Reports Server (NTRS)

Marshak, A.; Knyazikhin, Y.; Chiu, J. C.; Wiscombe, W. J.

2009-01-01

The ARM Shortwave Spectrometer (SWS) measures zenith radiance at 418 wavelengths between 350 and 2170 nm. Because of its 1-sec sampling resolution, the SWS provides a unique capability to study the transition zone between cloudy and clear sky areas. A spectral invariant behavior is found between ratios of zenith radiance spectra during the transition from cloudy to cloud-free. This behavior suggests that the spectral signature of the transition zone is a linear mixture between the two extremes (definitely cloudy and definitely clear). The weighting function of the linear mixture is a wavelength-independent characteristic of the transition zone. It is shown that the transition zone spectrum is fully determined by this function and zenith radiance spectra of clear and cloudy regions. An important result of these discoveries is that high temporal resolution radiance measurements in the clear-to-cloud transition zone can be well approximated by lower temporal resolution measurements plus linear interpolation.

Cassini atmospheric chemistry mapper. Volume 1. Investigation and technical plan

NASA Technical Reports Server (NTRS)

Smith, William Hayden; Baines, Kevin Hays; Drossart, Pierre; Fegley, Bruce; Orton, Glenn; Noll, Keith; Reitsema, Harold; Bjoraker, Gordon L.

1990-01-01

The Cassini Atmospheric Chemistry Mapper (ACM) enables a broad range of atmospheric science investigations for Saturn and Titan by providing high spectral and spatial resolution mapping and occultation capabilities at 3 and 5 microns. ACM can directly address the major atmospheric science objectives for Saturn and for Titan, as defined by the Announcement of Opportunity, with pivotal diagnostic measurements not accessible to any other proposed Cassini instrument. ACM determines mixing ratios for atmospheric molecules from spectral line profiles for an important and extensive volume of the atmosphere of Saturn (and Jupiter). Spatial and vertical profiles of disequilibrium species abundances define Saturn's deep atmosphere, its chemistry, and its vertical transport phenomena. ACM spectral maps provide a unique means to interpret atmospheric conditions in the deep (approximately 1000 bar) atmosphere of Saturn. Deep chemistry and vertical transport is inferred from the vertical and horizontal distribution of a series of disequilibrium species. Solar occultations provide a method to bridge the altitude range in Saturn's (and Titan's) atmosphere that is not accessible to radio science, thermal infrared, and UV spectroscopy with temperature measurements to plus or minus 2K from the analysis of molecular line ratios and to attain an high sensitivity for low-abundance chemical species in the very large column densities that may be achieved during occultations for Saturn. For Titan, ACM solar occultations yield very well resolved (1/6 scale height) vertical mixing ratios column abundances for atmospheric molecular constituents. Occultations also provide for detecting abundant species very high in the upper atmosphere, while at greater depths, detecting the isotopes of C and O, constraining the production mechanisms, and/or sources for the above species. ACM measures the vertical and horizontal distribution of aerosols via their opacity at 3 microns and, particularly, at 5 microns. ACM recovers spatially-resolved atmospheric temperatures in Titan's troposphere via 3- and 5-microns spectral transitions. Together, the mixing ratio profiles and the aerosol distributions are utilized to investigate the photochemistry of the stratosphere and consequent formation processes for aerosols. Finally, ring opacities, observed during solar occultations and in reflected sunlight, provide a measurement of the particle size and distribution of ring material. ACM will be the first high spectral resolution mapping spectrometer on an outer planet mission for atmospheric studies while retaining a high resolution spatial mapping capability. ACM, thus, opens an entirely new range of orbital scientific studies of the origin, physio-chemical evolution and structure of the Saturn and Titan atmospheres. ACM provides high angular resolution spectral maps, viewing nadir and near-limb thermal radiation and reflected sunlight; sounds planetary limbs, spatially resolving vertical profiles to several atmospheric scale heights; and measures solar occultations, mapping both atmospheres and rings. ACM's high spectral and spatial resolution mapping capability is achieved with a simplified Fourier Transform spectrometer with a no-moving parts, physically compact design. ACM's simplicity guarantees an inherent stability essential for reliable performance throughout the lengthy Cassini Orbiter mission.

A Petascale Non-Hydrostatic Atmospheric Dynamical Core in the HOMME Framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tufo, Henry

The High-Order Method Modeling Environment (HOMME) is a framework for building scalable, conserva- tive atmospheric models for climate simulation and general atmospheric-modeling applications. Its spatial discretizations are based on Spectral-Element (SE) and Discontinuous Galerkin (DG) methods. These are local methods employing high-order accurate spectral basis-functions that have been shown to perform well on massively parallel supercomputers at any resolution and scale particularly well at high resolutions. HOMME provides the framework upon which the CAM-SE community atmosphere model dynamical-core is constructed. In its current incarnation, CAM-SE employs the hydrostatic primitive-equations (PE) of motion, which limits its resolution to simulations coarser thanmore » 0.1 per grid cell. The primary objective of this project is to remove this resolution limitation by providing HOMME with the capabilities needed to build nonhydrostatic models that solve the compressible Euler/Navier-Stokes equations.« less

High Spectral Resolution Lidar for atmospheric temperature profiling.

NASA Astrophysics Data System (ADS)

Razenkov, I.; Eloranta, E. W.

2017-12-01

The High Spectral Resolution Lidar (HSRL) designed at the University of Wisconsin-Madison is equipped with two iodine absorption filters with different line widths (1.8 GHz and 2.85 GHz). The filters are implemented to discriminate between Mie and Rayleigh backscattering and to resolve temperature sensitive changes in Rayleigh spectrum for atmospheric temperature profile measurements. This measurement capability makes the instrument intrinsically and absolutely calibrated. HSRL has a shared transmitter-receiver telescope and operates in the eye-safe mode with the product of laser average power and telescope aperture less than 0.025 𝑊𝑚2 at 532 nm. With this low-power prototype instrument we have achieved temperature profile measurements extending above tropopause with a time resolution of several hours. Further instrument optimizations will reduce systematic measurement errors and will improve a signal-to-noise ratio providing temperature data comparable to a standard radiosonde with higher time resolution.

LANDSAT D to test thematic mapper, inaugurate operational system

NASA Technical Reports Server (NTRS)

1982-01-01

NASA will launch the Landsat D spacecraft on July 9, 1982 aboard a new, up-rated Delta 3920 expendable launch vehicle. LANDSAT D will incorporate two highly sophisticated sensors; the flight proven multispectral scanner; and a new instrument expected to advance considerably the remote sensing capabilities of Earth resources satellites. The new sensor, the thematic mapper, provides data in seven spectral (light) bands with greatly improved spectral, spatial and radiometric resolution.

Evolution of miniature detectors and focal plane arrays for infrared sensors

NASA Astrophysics Data System (ADS)

Watts, Louis A.

1993-06-01

Sensors that are sensitive in the infrared spectral region have been under continuous development since the WW2 era. A quest for the military advantage of 'seeing in the dark' has pushed thermal imaging technology toward high spatial and temporal resolution for night vision equipment, fire control, search track, and seeker 'homing' guidance sensing devices. Similarly, scientific applications have pushed spectral resolution for chemical analysis, remote sensing of earth resources, and astronomical exploration applications. As a result of these developments, focal plane arrays (FPA) are now available with sufficient sensitivity for both high spatial and narrow bandwidth spectral resolution imaging over large fields of view. Such devices combined with emerging opto-electronic developments in integrated FPA data processing techniques can yield miniature sensors capable of imaging reflected sunlight in the near IR and emitted thermal energy in the Mid-wave (MWIR) and longwave (LWIR) IR spectral regions. Robotic space sensors equipped with advanced versions of these FPA's will provide high resolution 'pictures' of their surroundings, perform remote analysis of solid, liquid, and gas matter, or selectively look for 'signatures' of specific objects. Evolutionary trends and projections of future low power micro detector FPA developments for day/night operation or use in adverse viewing conditions are presented in the following test.

Evolution of miniature detectors and focal plane arrays for infrared sensors

NASA Technical Reports Server (NTRS)

Watts, Louis A.

1993-01-01

Sensors that are sensitive in the infrared spectral region have been under continuous development since the WW2 era. A quest for the military advantage of 'seeing in the dark' has pushed thermal imaging technology toward high spatial and temporal resolution for night vision equipment, fire control, search track, and seeker 'homing' guidance sensing devices. Similarly, scientific applications have pushed spectral resolution for chemical analysis, remote sensing of earth resources, and astronomical exploration applications. As a result of these developments, focal plane arrays (FPA) are now available with sufficient sensitivity for both high spatial and narrow bandwidth spectral resolution imaging over large fields of view. Such devices combined with emerging opto-electronic developments in integrated FPA data processing techniques can yield miniature sensors capable of imaging reflected sunlight in the near IR and emitted thermal energy in the Mid-wave (MWIR) and longwave (LWIR) IR spectral regions. Robotic space sensors equipped with advanced versions of these FPA's will provide high resolution 'pictures' of their surroundings, perform remote analysis of solid, liquid, and gas matter, or selectively look for 'signatures' of specific objects. Evolutionary trends and projections of future low power micro detector FPA developments for day/night operation or use in adverse viewing conditions are presented in the following test.

NASA's Far-IR/Submillimeter Roadmap Missions SAFIR and SPECS

NASA Technical Reports Server (NTRS)

Leisawitz, David

2003-01-01

The far-IR is rich with information about star, disk and planet formation because protostars emit predominantly in this spectral range, and the radiation can escape from the inherently dusty stellar birth sites. Spectral lines contain particularly valuable information about the cooling, collapse, and chemistry of molecular cloud cores and protostars. However, the interpretation of line intensities and profiles is model-dependent; ultimately, high angular resolution is needed to break model degeneracy and definitively characterize the source. Processes occurring on scales smaller than 10,000 AU (72 arcsec at 140 pc, where the nearest protostellar objects are found) likely affect the stellar initial mass function and determine the product of cloud collapse (Binary star or planetary system? How many planets, and what kind will they be?) The next-generation far-IR observatories SIRTF, SOFIA, and Herschel will revolutionize star formation studies and leave the community yearning for telescopes that operate in this spectral region but provide many orders of magnitude better angular resolution. NASA's space science roadmap includes the JWST-scale Single Aperture Far-IR (SAFIR) telescope and the 1 km maximum baseline far-IR interferometer, SPECS (the Submillimeter Probe of the Evolution of Cosmic Structure). I will give the scientific motivation for these missions, describe mission concepts and telescope measurement capabilities, and compare these capabilities with those of the next-generation IR telescopes and with the complementary JWST and ALMA. I will also describe the Space Infrared Interferometric Telescope (SPIRIT), a science and technology pathfinder for SPECS, which could be ready to launch in about a decade. At 100 microns, SAFIR will provide 2.5 arcsec resolution (10 times better than SIRTF), SPIRIT will provide 0.25 arcsec resolution, and SPECS will provide 10 milli-arcsec resolution, which is comparable to that of the Hubble Space Telescope.

iCATSI: multi-pixel imaging differential spectroradiometer for standoff detection and quantification of chemical threats

NASA Astrophysics Data System (ADS)

Prel, Florent; Moreau, Louis; Lavoie, Hugo; Bouffard, François; Thériault, Jean-Marc; Vallieres, Christian; Roy, Claude; Dubé, Denis

2011-11-01

Homeland security and first responders are often faced with safety situations involving the identification of unknown volatile chemicals. Examples include industrial fires, chemical warfare, industrial leak, etc. The Improved Compact ATmospheric Sounding Interferometer (iCATSI) sensor has been developed to investigate the standoff detection and identification of toxic industrial chemicals (TICs), chemical warfare agents (CWA) and other chemicals. iCATSI is a combination of the CATSI instrument, a standoff differential FTIR optimised for the characterization of chemicals and the MR-i, the hyperspectral imaging spectroradiometer of ABB Bomem based on the proven MR spectroradiometers. The instrument is equipped with a dual-input telescope to perform optical background subtraction. The resulting signal is the difference between the spectral radiance entering each input port. With that method, the signal from the background is automatically removed from the signal of the target of interest. The iCATSI sensor is able to detect, spectrally resolve and identify 5 meters plumes up to 5 km range. The instrument is capable of sensing in the VLWIR (cut-off near 14 μm) to support research related to standoff chemical detection. In one of its configurations, iCATSI produces three 24 × 16 spectral images per second from 5.5 to 14 μm at a spectral resolution of 16 cm-1. In another configuration, iCATSI produces from two to four spectral images per second of 256 × 256 pixels from 8 to 13 μm with the same spectral resolution. Overview of the capabilities of the instrument and results from tests and field trials will be presented.

Performance and applications of a hypertemporal hyperspectral Fourier-transform infrared spectroradiometer

NASA Astrophysics Data System (ADS)

King, Bruce H.; Ellis, Thomas; Old, Tom E.

2009-05-01

A fast-scanning, high-resolution FTIR spectroradiometer has been designed and built for use in remote sensing, stand-off detection, and spectral-temporal characterization of fast, energetic infrared events. The instrument design uses a Michelson-type interferometer with a rotary modulator which is capable of continuous measurement of infrared spectra at a rate of 1000 scans per second with 4 cm-1 resolution in the 2 - 25 micron spectral range. Sensitivity, spectral accuracy, and radiometric precision are discussed along with specific design parameters. This instrument can be used for passive sensing as a stand-alone sensor, or for active sensing as a receiver when used in conjunction with a highenergy excitation source such as a laser. Applications include muzzle flash signature measurement, ordnance detonation characterization, missile plume identification, and rocket motor combustion diagnostics.

Spectral-Temporal Modulated Ripple Discrimination by Children With Cochlear Implants.

PubMed

Landsberger, David M; Padilla, Monica; Martinez, Amy S; Eisenberg, Laurie S

A postlingually implanted adult typically develops hearing with an intact auditory system, followed by periods of deafness (or near deafness) and adaptation to the implant. For an early implanted child whose brain is highly plastic, the auditory system matures with consistent input from a cochlear implant. It is likely that the auditory system of early implanted cochlear implant users is fundamentally different than postlingually implanted adults. The purpose of this study is to compare the basic psychophysical capabilities and limitations of these two populations on a spectral resolution task to determine potential effects of early deprivation and plasticity. Performance on a spectral resolution task (Spectral-temporally Modulated Ripple Test [SMRT]) was measured for 20 bilaterally implanted, prelingually deafened children (between 5 and 13 years of age) and 20 hearing children within the same age range. Additionally, 15 bilaterally implanted, postlingually deafened adults, and 10 hearing adults were tested on the same task. Cochlear implant users (adults and children) were tested bilaterally, and with each ear alone. Hearing listeners (adults and children) were tested with the unprocessed SMRT and with a vocoded version that simulates an 8-channel cochlear implant. For children with normal hearing, a positive correlation was found between age and SMRT score for both the unprocessed and vocoded versions. Older hearing children performed similarly to hearing adults in both the unprocessed and vocoded test conditions. However, for children with cochlear implants, no significant relationship was found between SMRT score and chronological age, age at implantation, or years of implant experience. Performance by children with cochlear implants was poorer than performance by cochlear implanted adults. It was also found that children implanted sequentially tended to have better scores with the first implant compared with the second implant. This difference was not observed for adults. An additional finding was that SMRT score was negatively correlated with age for adults with implants. Results from this study suggest that basic psychophysical capabilities of early implanted children and postlingually implanted adults differ when assessed in the sound field using their personal implant processors. Because spectral resolution does not improve with age for early implanted children, it seems likely that the sparse representation of the signal provided by a cochlear implant limits spectral resolution development. These results are supported by the finding that postlingually implanted adults, whose auditory systems matured before the onset of hearing loss, perform significantly better than early implanted children on the spectral resolution test.

Evaluation of multi-resolution satellite sensors for assessing water quality and bottom depth of Lake Garda.

PubMed

Giardino, Claudia; Bresciani, Mariano; Cazzaniga, Ilaria; Schenk, Karin; Rieger, Patrizia; Braga, Federica; Matta, Erica; Brando, Vittorio E

2014-12-15

In this study we evaluate the capabilities of three satellite sensors for assessing water composition and bottom depth in Lake Garda, Italy. A consistent physics-based processing chain was applied to Moderate Resolution Imaging Spectroradiometer (MODIS), Landsat-8 Operational Land Imager (OLI) and RapidEye. Images gathered on 10 June 2014 were corrected for the atmospheric effects with the 6SV code. The computed remote sensing reflectance (Rrs) from MODIS and OLI were converted into water quality parameters by adopting a spectral inversion procedure based on a bio-optical model calibrated with optical properties of the lake. The same spectral inversion procedure was applied to RapidEye and to OLI data to map bottom depth. In situ measurements of Rrs and of concentrations of water quality parameters collected in five locations were used to evaluate the models. The bottom depth maps from OLI and RapidEye showed similar gradients up to 7 m (r = 0.72). The results indicate that: (1) the spatial and radiometric resolutions of OLI enabled mapping water constituents and bottom properties; (2) MODIS was appropriate for assessing water quality in the pelagic areas at a coarser spatial resolution; and (3) RapidEye had the capability to retrieve bottom depth at high spatial resolution. Future work should evaluate the performance of the three sensors in different bio-optical conditions.

Parallel-multiplexed excitation light-sheet microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xu, Dongli; Zhou, Weibin; Peng, Leilei

2017-02-01

Laser scanning light-sheet imaging allows fast 3D image of live samples with minimal bleach and photo-toxicity. Existing light-sheet techniques have very limited capability in multi-label imaging. Hyper-spectral imaging is needed to unmix commonly used fluorescent proteins with large spectral overlaps. However, the challenge is how to perform hyper-spectral imaging without sacrificing the image speed, so that dynamic and complex events can be captured live. We report wavelength-encoded structured illumination light sheet imaging (λ-SIM light-sheet), a novel light-sheet technique that is capable of parallel multiplexing in multiple excitation-emission spectral channels. λ-SIM light-sheet captures images of all possible excitation-emission channels in true parallel. It does not require compromising the imaging speed and is capable of distinguish labels by both excitation and emission spectral properties, which facilitates unmixing fluorescent labels with overlapping spectral peaks and will allow more labels being used together. We build a hyper-spectral light-sheet microscope that combined λ-SIM with an extended field of view through Bessel beam illumination. The system has a 250-micron-wide field of view and confocal level resolution. The microscope, equipped with multiple laser lines and an unlimited number of spectral channels, can potentially image up to 6 commonly used fluorescent proteins from blue to red. Results from in vivo imaging of live zebrafish embryos expressing various genetic markers and sensors will be shown. Hyper-spectral images from λ-SIM light-sheet will allow multiplexed and dynamic functional imaging in live tissue and animals.

A review of future remote sensing satellite capabilities

NASA Technical Reports Server (NTRS)

Calabrese, M. A.

1980-01-01

Existing, planned and future NASA capabilities in the field of remote sensing satellites are reviewed in relation to the use of remote sensing techniques for the identification of irrigated lands. The status of the currently operational Landsat 2 and 3 satellites is indicated, and it is noted that Landsat D is scheduled to be in operation in two years. The orbital configuration and instrumentation of Landsat D are discussed, with particular attention given to the thematic mapper, which is expected to improve capabilities for small field identification and crop discrimination and classification. Future possibilities are then considered, including a multi-spectral resource sampler supplying high spatial and temporal resolution data possibly based on push-broom scanning, Shuttle-maintained Landsat follow-on missions, a satellite to obtain high-resolution stereoscopic data, further satellites providing all-weather radar capability and the Large Format Camera.

Simulating PACE Global Ocean Radiances

NASA Technical Reports Server (NTRS)

Gregg, Watson W.; Rousseaux, Cecile S.

2017-01-01

The NASA PACE mission is a hyper-spectral radiometer planned for launch in the next decade. It is intended to provide new information on ocean biogeochemical constituents by parsing the details of high resolution spectral absorption and scattering. It is the first of its kind for global applications and as such, poses challenges for design and operation. To support pre-launch mission development and assess on-orbit capabilities, the NASA Global Modeling and Assimilation Office has developed a dynamic simulation of global water-leaving radiances, using an ocean model containing multiple ocean phytoplankton groups, particulate detritus, particulate inorganic carbon (PIC), and chromophoric dissolved organic carbon (CDOC) along with optical absorption and scattering processes at 1 nm spectral resolution. The purpose here is to assess the skill of the dynamic model and derived global radiances. Global bias, uncertainty, and correlation are derived using available modern satellite radiances at moderate spectral resolution. Total chlorophyll, PIC, and the absorption coefficient of CDOC (aCDOC), are simultaneously assimilated to improve the fidelity of the optical constituent fields. A 5-year simulation showed statistically significant (P < 0.05) comparisons of chlorophyll (r = 0.869), PIC (r = 0.868), and a CDOC (r =0.890) with satellite data. Additionally, diatoms (r = 0.890), cyanobacteria (r = 0.732), and coccolithophores (r = 0.716) were significantly correlated with in situ data. Global assimilated distributions of optical constituents were coupled with a radiative transfer model (Ocean-Atmosphere Spectral Irradiance Model, OASIM) to estimate normalized water-leaving radiances at 1 nm for the spectral range 250-800 nm. These unassimilated radiances were within 0.074 mW/sq cm/micron/sr of MODIS-Aqua radiances at 412, 443, 488, 531, 547, and 667 nm. This difference represented a bias of 10.4% (model low). A mean correlation of 0.706 (P < 0.05) was found with global distributions of MODIS radiances. These results suggest skill in the global assimilated model and resulting radiances. The reported error characterization suggests that the global dynamical simulation can support some aspects of mission design and analysis. For example, the high spectral resolution of the simulation supports investigations of band selection. The global nature of the radiance representations supports investigations of satellite observing scenarios. Global radiances at bands not available in current and past missions support investigations of mission capability. PACE, ocean color, water-leaving radiances, biogeochemical model, radiative transfer model

Simulating PACE Global Ocean Radiances

PubMed Central

Gregg, Watson W.; Rousseaux, Cécile S.

2017-01-01

The NASA PACE mission is a hyper-spectral radiometer planned for launch in the next decade. It is intended to provide new information on ocean biogeochemical constituents by parsing the details of high resolution spectral absorption and scattering. It is the first of its kind for global applications and as such, poses challenges for design and operation. To support pre-launch mission development and assess on-orbit capabilities, the NASA Global Modeling and Assimilation Office has developed a dynamic simulation of global water-leaving radiances, using an ocean model containing multiple ocean phytoplankton groups, particulate detritus, particulate inorganic carbon (PIC), and chromophoric dissolved organic carbon (CDOC) along with optical absorption and scattering processes at 1 nm spectral resolution. The purpose here is to assess the skill of the dynamic model and derived global radiances. Global bias, uncertainty, and correlation are derived using available modern satellite radiances at moderate spectral resolution. Total chlorophyll, PIC, and the absorption coefficient of CDOC (aCDOC), are simultaneously assimilated to improve the fidelity of the optical constituent fields. A 5-year simulation showed statistically significant (P <0.05) comparisons of chlorophyll (r = 0.869), PIC (r = 0.868), and aCDOC (r = 0.890) with satellite data. Additionally, diatoms (r = 0.890), cyanobacteria (r = 0.732), and coccolithophores (r = 0.716) were significantly correlated with in situ data. Global assimilated distributions of optical constituents were coupled with a radiative transfer model (Ocean-Atmosphere Spectral Irradiance Model, OASIM) to estimate normalized water-leaving radiances at 1 nm for the spectral range 250–800 nm. These unassimilated radiances were within −0.074 mW cm−2 μm1 sr−1 of MODIS-Aqua radiances at 412, 443, 488, 531, 547, and 667 nm. This difference represented a bias of −10.4% (model low). A mean correlation of 0.706 (P < 0.05) was found with global distributions of MODIS radiances. These results suggest skill in the global assimilated model and resulting radiances. The reported error characterization suggests that the global dynamical simulation can support some aspects of mission design and analysis. For example, the high spectral resolution of the simulation supports investigations of band selection. The global nature of the radiance representations supports investigations of satellite observing scenarios. Global radiances at bands not available in current and past missions support investigations of mission capability. PMID:29292403

Snapshot Imaging Spectrometry in the Visible and Long Wave Infrared

NASA Astrophysics Data System (ADS)

Maione, Bryan David

Imaging spectrometry is an optical technique in which the spectral content of an object is measured at each location in space. The main advantage of this modality is that it enables characterization beyond what is possible with a conventional camera, since spectral information is generally related to the chemical composition of the object. Due to this, imaging spectrometers are often capable of detecting targets that are either morphologically inconsistent, or even under resolved. A specific class of imaging spectrometer, known as a snapshot system, seeks to measure all spatial and spectral information simultaneously, thereby rectifying artifacts associated with scanning designs, and enabling the measurement of temporally dynamic scenes. Snapshot designs are the focus of this dissertation. Three designs for snapshot imaging spectrometers are developed, each providing novel contributions to the field of imaging spectrometry. In chapter 2, the first spatially heterodyned snapshot imaging spectrometer is modeled and experimentally validated. Spatial heterodyning is a technique commonly implemented in non-imaging Fourier transform spectrometry. For Fourier transform imaging spectrometers, spatial heterodyning improves the spectral resolution trade space. Additionally, in this chapter a unique neural network based spectral calibration is developed and determined to be an improvement beyond Fourier and linear operator based techniques. Leveraging spatial heterodyning as developed in chapter 2, in chapter 3, a high spectral resolution snapshot Fourier transform imaging spectrometer, based on a Savart plate interferometer, is developed and experimentally validated. The sensor presented in this chapter is the highest spectral resolution sensor in its class. High spectral resolution enables the sensor to discriminate narrowly spaced spectral lines. The capabilities of neural networks in imaging spectrometry are further explored in this chapter. Neural networks are used to perform single target detection on raw instrument data, thereby eliminating the need for an explicit spectral calibration step. As an extension of the results in chapter 2, neural networks are once again demonstrated to be an improvement when compared to linear operator based detection. In chapter 4 a non-interferometric design is developed for the long wave infrared (wavelengths spanning 8-12 microns). The imaging spectrometer developed in this chapter is a multi-aperture filtered microbolometer. Since the detector is uncooled, the presented design is ultra-compact and low power. Additionally, cost effective polymer absorption filters are used in lieu of interference filters. Since, each measurement of the system is spectrally multiplexed, an SNR advantage is realized. A theoretical model for the filtered design is developed, and the performance of the sensor for detecting liquid contaminants is investigated. Similar to past chapters, neural networks are used and achieve false detection rates of less than 1%. Lastly, this dissertation is concluded with a discussion on future work and potential impact of these devices.

Retrievals with the Infrared Atmospheric Sounding Interferometer

NASA Technical Reports Server (NTRS)

Zhou, Daniel K.; Liu, Xu; Larar, Allen M.; Smith, William L.; Taylor, Jonathan P.; Schlussel, Peter; Strow, L. Larrabee; Calbet, Xavier; Mango, Stephen A.

2007-01-01

The Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite was launched on October 19, 2006. The Joint Airborne IASI Validation Experiment (JAIVEx) was conducted during April 2007 mainly for validation of the IASI on the MetOp satellite. IASI possesses an ultra-spectral resolution of 0.25/cm and a spectral coverage from 645 to 2760/cm. Ultraspectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. An advanced retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. Preliminary retrievals of atmospheric soundings, surface properties, and cloud optical/microphysical properties with the IASI observations during the JAIVEx are obtained and presented. These retrievals are further inter-compared with those obtained from airborne FTS system, such as the NPOESS Airborne Sounder Testbed Interferometer (NAST-I), dedicated dropsondes, radiosondes, and ground based Raman Lidar. The capabilities of satellite ultra-spectral sounder such as the IASI are investigated.

Hyperspectral imaging of the human iris

NASA Astrophysics Data System (ADS)

Di Cecilia, Luca; Marazzi, Francesco; Rovati, Luigi

2017-07-01

We describe an optical system and a method for measuring the human iris spectral reflectance in vivo by hyperspectral imaging analysis. It is important to monitor age-related changes in the reflectance properties of the iris as they are a prognostic factor for several eye pathologies. In this paper, we report the outcomes of our most recent research, resulting from the improvement of our imaging system. In particular, a custom tunable light source was developed: the images are now acquired in the spectral range 440 - 900 nm. With this system, we are able to obtain a spectral resolution of 20nm, while each image of 2048 x 1536 pixels has a spatial resolution of 10.7 μm. The results suggest that the instrument could be exploited for measuring iris pigmentation changes over time. These measurements could provide new diagnostic capabilities in ophthalmology. Further studies are required to determine the measurements' repeatability and to develop a spectral library for results evaluation and to detect differences among subsequent screenings of the same subject.

The BATSE experiment on the Gamma Ray Observatory: Solar flare hard x ray and gamma-ray capabilities

NASA Technical Reports Server (NTRS)

Fishman, G. J.; Meegan, C. A.; Wilson, R. B.; Parnell, T. A.; Paciesas, W. S.; Pendleton, G. N.; Hudson, H. S.; Matteson, J. L.; Peterson, L. E.; Cline, T. L.

1989-01-01

The Burst and Transient Source Experiment (BATSE) for the Gamma Ray Observatory (GRO) consists of eight detector modules that provide full-sky coverage for gamma-ray bursts and other transient phenomena such as solar flares. Each detector module has a thin, large-area scintillation detector (2025 sq cm) for high time-resolution studies, and a thicker spectroscopy detector (125 sq cm) to extend the energy range and provide better spectral resolution. The total energy range of the system is 15 keV to 100 MeV. These 16 detectors and the associated onboard data system should provide unprecedented capabilities for observing rapid spectral changes and gamma-ray lines from solar flares. The presence of a solar flare can be detected in real-time by BATSE; a trigger signal is sent to two other experiments on the GRO. The launch of the GRO is scheduled for June 1990, so that BATSE can be an important component of the Max '91 campaign.

Next Generation Instrumentation for the Very Large Telescope Interferometer

NASA Astrophysics Data System (ADS)

Quirrenbach, A.

The scientific capabilities of the VLT Interferometer can be substantially enhanced through new focal-plane instruments. Many interferometric techniques - astrometry, phase-referenced imaging, nulling, and differential phase measurements - require control of the phase to <~ 1 rad; this capability will be provided at the VLTI by the PRIMA facility. Phase-coherent operation of the VLTI will also make it possible to perform interferometry with spectral resolution up to R ~ 100,000 by building fiber links to the high-resolution spectrographs UVES and CRIRES. These developments will open new approaches to fundamental problems in fields as diverse as extrasolar planets, stellar atmospheres, circumstellar matter, and active galactic nuclei.

UVMAS: Venus ultraviolet-visual mapping spectrometer

NASA Astrophysics Data System (ADS)

Bellucci, G.; Zasova, L.; Altieri, F.; Nuccilli, F.; Ignatiev, N.; Moroz, V.; Khatuntsev, I.; Korablev, O.; Rodin, A.

This paper summarizes the capabilities and technical solutions of an Ultraviolet Visual Mapping Spectrometer designed for remote sensing of Venus from a planetary orbiter. The UVMAS consists of a multichannel camera with a spectral range 0.19 << 0.49 μm which acquires data in several spectral channels (up to 400) with a spectral resolution of 0.58 nm. The instantaneous field of view of the instrument is 0.244 × 0.244 mrad. These characteristics allow: a) to study the upper clouds dynamics and chemistry; b) giving constraints on the unknown absorber; c) observation of the night side airglow.

Lunar UV-visible-IR mapping interferometric spectrometer

NASA Technical Reports Server (NTRS)

Smith, W. Hayden; Haskin, L.; Korotev, R.; Arvidson, R.; Mckinnon, W.; Hapke, B.; Larson, S.; Lucey, P.

1992-01-01

Ultraviolet-visible-infrared mapping digital array scanned interferometers for lunar compositional surveys was developed. The research has defined a no-moving-parts, low-weight and low-power, high-throughput, and electronically adaptable digital array scanned interferometer that achieves measurement objectives encompassing and improving upon all the requirements defined by the LEXSWIG for lunar mineralogical investigation. In addition, LUMIS provides a new, important, ultraviolet spectral mapping, high-spatial-resolution line scan camera, and multispectral camera capabilities. An instrument configuration optimized for spectral mapping and imaging of the lunar surface and provide spectral results in support of the instrument design are described.

High Vertically Resolved Atmospheric State Revealed with IASI Single FOV Retrievals under All-weather Conditions

NASA Technical Reports Server (NTRS)

Zhou, Daniel K.; Liu, Xu; Larar, Allen M.; Smith, William L.; Taylor, Jonathan P.; Schluessel, L. Peter; Strow, Larrybee; Mango, Stephen A.

2008-01-01

The Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite was launched on October 19, 2006. The Joint Airborne IASI Validation Experiment (JAIVEx) was conducted during April 2007 mainly for validation of the IASI on the MetOp satellite. IASI possesses an ultra-spectral resolution of 0.25 cm(exp -1) and a spectral coverage from 645 to 2760 cm(exp -1). Ultra-spectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. An advanced retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. Preliminary retrievals of atmospheric soundings, surface properties, and cloud optical/microphysical properties with the IASI observations are obtained and presented. These retrievals are further inter-compared with those obtained from airborne FTS system, such as the NPOESS Airborne Sounder Testbed - Interferometer (NAST-I), dedicated dropsondes, radiosondes, and ground based Raman Lidar. The capabilities of satellite ultra-spectral sounder such as the IASI are investigated to benefit future NPOESS operation.

Visible light spectral domain optical coherence microscopy system for ex vivo imaging

NASA Astrophysics Data System (ADS)

Lichtenegger, Antonia; Harper, Danielle J.; Augustin, Marco; Eugui, Pablo; Fialová, Stanislava; Woehrer, Adelheid; Hitzenberger, Christoph K.; Baumann, Bernhard

2017-02-01

A visible light spectral domain optical coherence microscopy system operating in the wavelength range of 450-680 nm was developed. The resulting large wavelength range of 230 nm enabled an ultrahigh axial resolution of 0.88μm in tissue. The setup consisted of a Michelson interferometer combined with a homemade spectrometer with a spectral resolution of 0.03 nm. Scanning of 1 x 1 mm2 and 0.5 x 0.5 mm2 areas was performed by an integrated microelectromechanical mirror. After scanning the light beam is focused onto the tissue by a commercial objective with a 10 x magnification, resulting in a transverse resolution of 2 μm . Specification measurements showed that a -89 dB sensitivity with a 24 dB/mm roll-off could be achieved with the system. First of all the capabilities of the system were tested by investigating millimeter paper, tape and the USAF (US Air Force) 1951 resolution test target. Finally cerebral tissues from non-pathological and Alzheimer's disease affected brains were investigated. The results showed that structures, such as white and gray matter, could be distinguished. Furthermore a first effort was made to differentiate Alzheimer's disease from healthy brain tissue.

High spectral resolution studies of gamma ray bursts on new missions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desai, U. D.; Acuna, M. H.; Cline, T. L.

1996-08-01

Two new missions will be launched in 1996 and 1997, each carrying X-ray and gamma ray detectors capable of high spectral resolution at room temperature. The Argentine Satelite de Aplicaciones Cientificas (SAC-B) and the Small Spacecraft Technology Initiative (SSTI) Clark missions will each carry several arrays of X-ray detectors primarily intended for the study of solar flares and gamma-ray bursts. Arrays of small (1 cm{sup 2}) cadmium zinc telluride (CZT) units will provide x-ray measurements in the 10 to 80 keV range with an energy resolution of {approx_equal}6 keV. Arrays of both silicon avalanche photodiodes (APD) and P-intrinsic-N (PIN) photodiodesmore » (for the SAC-B mission only) will provide energy coverage from 2-25 keV with {approx_equal}1 keV resolution. For SAC-B, higher energy spectral data covering the 30-300 keV energy range will be provided by CsI(Tl) scintillators coupled to silicon APDs, resulting in similar resolution but greater simplicity relative to conventional CsI/PMT systems. Because of problems with the Pegasus launch vehicle, the launch of SAC-B has been delayed until 1997. The launch of the SSTI Clark mission is scheduled for June 1996.« less

The "+" for CRIRES: enabling better science at infrared wavelength and high spectral resolution at the ESO VLT

NASA Astrophysics Data System (ADS)

Dorn, Reinhold J.; Follert, Roman; Bristow, Paul; Cumani, Claudio; Eschbaumer, Siegfried; Grunhut, Jason; Haimerl, Andreas; Hatzes, Artie; Heiter, Ulrike; Hinterschuster, Renate; Ives, Derek J.; Jung, Yves; Kerber, Florian; Klein, Barbara; Lavaila, Alexis; Lizon, Jean Louis; Löwinger, Tom; Molina-Conde, Ignacio; Nicholson, Belinda; Marquart, Thomas; Oliva, Ernesto; Origlia, Livia; Pasquini, Luca; Paufique, Jérôme; Piskunov, Nikolai; Reiners, Ansgar; Seemann, Ulf; Stegmeier, Jörg; Stempels, Eric; Tordo, Sebastien

2016-08-01

The adaptive optics (AO) assisted CRIRES instrument is an IR (0.92 - 5.2 μm) high-resolution spectrograph was in operation from 2006 to 2014 at the Very Large Telescope (VLT) observatory. CRIRES was a unique instrument, accessing a parameter space (wavelength range and spectral resolution) up to now largely uncharted. It consisted of a single-order spectrograph providing long-slit (40 arcsecond) spectroscopy with a resolving power up to R=100 000. However the setup was limited to a narrow, single-shot, spectral range of about 1/70 of the central wavelength, resulting in low observing efficiency for many scientific programmes requiring a broad spectral coverage. The CRIRES upgrade project, CRIRES+, transforms this VLT instrument into a cross-dispersed spectrograph to increase the simultaneously covered wavelength range by a factor of ten. A new and larger detector focal plane array of three Hawaii 2RG detectors with 5.3 μm cut-off wavelength will replace the existing detectors. For advanced wavelength calibration, custom-made absorption gas cells and an etalon system will be added. A spectro-polarimetric unit will allow the recording of circular and linear polarized spectra. This upgrade will be supported by dedicated data reduction software allowing the community to take full advantage of the new capabilities offered by CRIRES+. CRIRES+ has now entered its assembly and integration phase and will return with all new capabilities by the beginning of 2018 to the Very Large Telescope in Chile. This article will provide the reader with an update of the current status of the instrument as well as the remaining steps until final installation at the Paranal Observatory.

Improved Cloud and Snow Screening in MAIAC Aerosol Retrievals Using Spectral and Spatial Analysis

NASA Technical Reports Server (NTRS)

Lyapustin, A.; Wang, Y.; Laszlo, I.; Kokrkin, S.

2012-01-01

An improved cloud/snow screening technique in the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm is described. It is implemented as part of MAIAC aerosol retrievals based on analysis of spectral residuals and spatial variability. Comparisons with AERONET aerosol observations and a large-scale MODIS data analysis show strong suppression of aerosol optical thickness outliers due to unresolved clouds and snow. At the same time, the developed filter does not reduce the aerosol retrieval capability at high 1 km resolution in strongly inhomogeneous environments, such as near centers of the active fires. Despite significant improvement, the optical depth outliers in high spatial resolution data are and will remain the problem to be addressed by the application-dependent specialized filtering techniques.

Propane spectral resolution enhancement by the maximum entropy method

NASA Technical Reports Server (NTRS)

Bonavito, N. L.; Stewart, K. P.; Hurley, E. J.; Yeh, K. C.; Inguva, R.

1990-01-01

The Burg algorithm for maximum entropy power spectral density estimation is applied to a time series of data obtained from a Michelson interferometer and compared with a standard FFT estimate for resolution capability. The propane transmittance spectrum was estimated by use of the FFT with a 2 to the 18th data sample interferogram, giving a maximum unapodized resolution of 0.06/cm. This estimate was then interpolated by zero filling an additional 2 to the 18th points, and the final resolution was taken to be 0.06/cm. Comparison of the maximum entropy method (MEM) estimate with the FFT was made over a 45/cm region of the spectrum for several increasing record lengths of interferogram data beginning at 2 to the 10th. It is found that over this region the MEM estimate with 2 to the 16th data samples is in close agreement with the FFT estimate using 2 to the 18th samples.

Sub-10 fs Time-Resolved Vibronic Optical Microscopy

PubMed Central

2016-01-01

We introduce femtosecond wide-field transient absorption microscopy combining sub-10 fs pump and probe pulses covering the complete visible (500–650 nm) and near-infrared (650–950 nm) spectrum with diffraction-limited optical resolution. We demonstrate the capabilities of our system by reporting the spatially- and spectrally-resolved transient electronic response of MAPbI3–xClx perovskite films and reveal significant quenching of the transient bleach signal at grain boundaries. The unprecedented temporal resolution enables us to directly observe the formation of band-gap renormalization, completed in 25 fs after photoexcitation. In addition, we acquire hyperspectral Raman maps of TIPS pentacene films with sub-400 nm spatial and sub-15 cm–1 spectral resolution covering the 100–2000 cm–1 window. Our approach opens up the possibility of studying ultrafast dynamics on nanometer length and femtosecond time scales in a variety of two-dimensional and nanoscopic systems. PMID:27934055

SpIOMM and SITELLE: Wide-field Imaging FTS for the Study of Galaxy Evolution

NASA Astrophysics Data System (ADS)

Drissen, Laurent; Bernier, Anne-Pier; Robert, Carmelle; Robert

2011-12-01

SpIOMM, a wide-field Imaging Fourier Transform Spectrometer attached to the Mont Mégantic 1.6-m telescope, is capable of obtaining the visible spectrum of every source of light in a 12 arcminute field of view, with a spectral resolution ranging from R = 1 (wide-band image) to R = 25 000, resulting in 1.7 million spectra with a spatial resolution of one arcsecond. SITELLE will be a similar instrument attached to the Canada-France-Hawaii telescope, and will be in operation in early 2013. We present a short description of these instruments and illustrate their capabilities to study nearby galaxies with the results of a data cube of M51.

Evaluation on Radiometric Capability of Chinese Optical Satellite Sensors

PubMed Central

Yang, Aixia; Zhong, Bo; Wu, Shanlong; Liu, Qinhuo

2017-01-01

The radiometric capability of on-orbit sensors should be updated on time due to changes induced by space environmental factors and instrument aging. Some sensors, such as Moderate Resolution Imaging Spectroradiometer (MODIS), have onboard calibrators, which enable real-time calibration. However, most Chinese remote sensing satellite sensors lack onboard calibrators. Their radiometric calibrations have been updated once a year based on a vicarious calibration procedure, which has affected the applications of the data. Therefore, a full evaluation of the sensors’ radiometric capabilities is essential before quantitative applications can be made. In this study, a comprehensive procedure for evaluating the radiometric capability of several Chinese optical satellite sensors is proposed. In this procedure, long-term radiometric stability and radiometric accuracy are the two major indicators for radiometric evaluation. The radiometric temporal stability is analyzed by the tendency of long-term top-of-atmosphere (TOA) reflectance variation; the radiometric accuracy is determined by comparison with the TOA reflectance from MODIS after spectrally matching. Three Chinese sensors including the Charge-Coupled Device (CCD) camera onboard Huan Jing 1 satellite (HJ-1), as well as the Visible and Infrared Radiometer (VIRR) and Medium-Resolution Spectral Imager (MERSI) onboard the Feng Yun 3 satellite (FY-3) are evaluated in reflective bands based on this procedure. The results are reasonable, and thus can provide reliable reference for the sensors’ application, and as such will promote the development of Chinese satellite data. PMID:28117745

Evaluation on Radiometric Capability of Chinese Optical Satellite Sensors.

PubMed

Yang, Aixia; Zhong, Bo; Wu, Shanlong; Liu, Qinhuo

2017-01-22

The radiometric capability of on-orbit sensors should be updated on time due to changes induced by space environmental factors and instrument aging. Some sensors, such as Moderate Resolution Imaging Spectroradiometer (MODIS), have onboard calibrators, which enable real-time calibration. However, most Chinese remote sensing satellite sensors lack onboard calibrators. Their radiometric calibrations have been updated once a year based on a vicarious calibration procedure, which has affected the applications of the data. Therefore, a full evaluation of the sensors' radiometric capabilities is essential before quantitative applications can be made. In this study, a comprehensive procedure for evaluating the radiometric capability of several Chinese optical satellite sensors is proposed. In this procedure, long-term radiometric stability and radiometric accuracy are the two major indicators for radiometric evaluation. The radiometric temporal stability is analyzed by the tendency of long-term top-of-atmosphere (TOA) reflectance variation; the radiometric accuracy is determined by comparison with the TOA reflectance from MODIS after spectrally matching. Three Chinese sensors including the Charge-Coupled Device (CCD) camera onboard Huan Jing 1 satellite (HJ-1), as well as the Visible and Infrared Radiometer (VIRR) and Medium-Resolution Spectral Imager (MERSI) onboard the Feng Yun 3 satellite (FY-3) are evaluated in reflective bands based on this procedure. The results are reasonable, and thus can provide reliable reference for the sensors' application, and as such will promote the development of Chinese satellite data.

Incorporation of satellite remote sensing pan-sharpened imagery into digital soil prediction and mapping models to characterize soil property variability in small agricultural fields

NASA Astrophysics Data System (ADS)

Xu, Yiming; Smith, Scot E.; Grunwald, Sabine; Abd-Elrahman, Amr; Wani, Suhas P.

2017-01-01

Soil prediction models based on spectral indices from some multispectral images are too coarse to characterize spatial pattern of soil properties in small and heterogeneous agricultural lands. Image pan-sharpening has seldom been utilized in Digital Soil Mapping research before. This research aimed to analyze the effects of pan-sharpened (PAN) remote sensing spectral indices on soil prediction models in smallholder farm settings. This research fused the panchromatic band and multispectral (MS) bands of WorldView-2, GeoEye-1, and Landsat 8 images in a village in Southern India by Brovey, Gram-Schmidt and Intensity-Hue-Saturation methods. Random Forest was utilized to develop soil total nitrogen (TN) and soil exchangeable potassium (Kex) prediction models by incorporating multiple spectral indices from the PAN and MS images. Overall, our results showed that PAN remote sensing spectral indices have similar spectral characteristics with soil TN and Kex as MS remote sensing spectral indices. There is no soil prediction model incorporating the specific type of pan-sharpened spectral indices always had the strongest prediction capability of soil TN and Kex. The incorporation of pan-sharpened remote sensing spectral data not only increased the spatial resolution of the soil prediction maps, but also enhanced the prediction accuracy of soil prediction models. Small farms with limited footprint, fragmented ownership and diverse crop cycle should benefit greatly from the pan-sharpened high spatial resolution imagery for soil property mapping. Our results show that multiple high and medium resolution images can be used to map soil properties suggesting the possibility of an improvement in the maps' update frequency. Additionally, the results should benefit the large agricultural community through the reduction of routine soil sampling cost and improved prediction accuracy.

Demonstration of the Wide-Field Imaging Interferometer Testbed Using a Calibrated Hyperspectral Image Projector

NASA Technical Reports Server (NTRS)

Bolcar, Matthew R.; Leisawitz, David; Maher, Steve; Rinehart, Stephen

2012-01-01

The Wide-field Imaging Interferometer testbed (WIIT) at NASA's Goddard Space Flight Center uses a dual-Michelson interferometric technique. The WIIT combines stellar interferometry with Fourier-transform interferometry to produce high-resolution spatial-spectral data over a large field-of-view. This combined technique could be employed on future NASA missions such as the Space Infrared Interferometric Telescope (SPIRIT) and the Sub-millimeter Probe of the Evolution of Cosmic Structure (SPECS). While both SPIRIT and SPECS would operate at far-infrared wavelengths, the WIIT demonstrates the dual-interferometry technique at visible wavelengths. The WIIT will produce hyperspectral image data, so a true hyperspectral object is necessary. A calibrated hyperspectral image projector (CHIP) has been constructed to provide such an object. The CHIP uses Digital Light Processing (DLP) technology to produce customized, spectrally-diverse scenes. CHIP scenes will have approximately 1.6-micron spatial resolution and the capability of . producing arbitrary spectra in the band between 380 nm and 1.6 microns, with approximately 5-nm spectral resolution. Each pixel in the scene can take on a unique spectrum. Spectral calibration is achieved with an onboard fiber-coupled spectrometer. In this paper we describe the operation of the CHIP. Results from the WIIT observations of CHIP scenes will also be presented.

Covariance J-resolved spectroscopy: Theory and application in vivo.

PubMed

Iqbal, Zohaib; Verma, Gaurav; Kumar, Anand; Thomas, M Albert

2017-08-01

Magnetic resonance spectroscopy (MRS) is a powerful tool capable of investigating the metabolic status of several tissues in vivo. In particular, single-voxel-based 1 H spectroscopy provides invaluable biochemical information from a volume of interest (VOI) and has therefore been used in a variety of studies. Unfortunately, typical one-dimensional MRS data suffer from severe signal overlap and thus important metabolites are difficult to distinguish. One method that is used to disentangle overlapping resonances is the two-dimensional J-resolved spectroscopy (JPRESS) experiment. Due to the long acquisition duration of the JPRESS experiment, a limited number of points are acquired in the indirect dimension, leading to poor spectral resolution along this dimension. Poor spectral resolution is problematic because proper peak assignment may be hindered, which is why the zero-filling method is often used to improve resolution as a post-processing step. However, zero-filling leads to spectral artifacts, which may affect visualization and quantitation of spectra. A novel method utilizing a covariance transformation, called covariance J-resolved spectroscopy (CovJ), was developed in order to improve spectral resolution along the indirect dimension (F 1 ). Comparison of simulated data demonstrates that peak structures remain qualitatively similar between JPRESS and the novel method along the diagonal region (F 1 = 0 Hz), whereas differences arise in the cross-peak (F 1 ≠0 Hz) regions. In addition, quantitative results of in vivo JPRESS data acquired on a 3T scanner show significant correlations (r 2 >0.86, p<0.001) when comparing the metabolite concentrations between the two methods. Finally, a quantitation algorithm, 'COVariance Spectral Evaluation of 1 H Acquisitions using Representative prior knowledge' (Cov-SEHAR), was developed in order to quantify γ-aminobutyric acid and glutamate from the CovJ spectra. These preliminary findings indicate that the CovJ method may be used to improve spectral resolution without hindering metabolite quantitation for J-resolved spectra. Copyright © 2017 John Wiley & Sons, Ltd.

Evaluating Sentinel-2 for Lakeshore Habitat Mapping Based on Airborne Hyperspectral Data.

PubMed

Stratoulias, Dimitris; Balzter, Heiko; Sykioti, Olga; Zlinszky, András; Tóth, Viktor R

2015-09-11

Monitoring of lakeshore ecosystems requires fine-scale information to account for the high biodiversity typically encountered in the land-water ecotone. Sentinel-2 is a satellite with high spatial and spectral resolution and improved revisiting frequency and is expected to have significant potential for habitat mapping and classification of complex lakeshore ecosystems. In this context, investigations of the capabilities of Sentinel-2 in regard to the spatial and spectral dimensions are needed to assess its potential and the quality of the expected output. This study presents the first simulation of the high spatial resolution (i.e., 10 m and 20 m) bands of Sentinel-2 for lakeshore mapping, based on the satellite's Spectral Response Function and hyperspectral airborne data collected over Lake Balaton, Hungary in August 2010. A comparison of supervised classifications of the simulated products is presented and the information loss from spectral aggregation and spatial upscaling in the context of lakeshore vegetation classification is discussed. We conclude that Sentinel-2 imagery has a strong potential for monitoring fine-scale habitats, such as reed beds.

Calibrated infrared ground/air radiometric spectrometer

NASA Astrophysics Data System (ADS)

Silk, J. K.; Schildkraut, Elliot Robert; Bauldree, Russell S.; Goodrich, Shawn M.

1996-06-01

The calibrated infrared ground/air radiometric spectrometer (CIGARS) is a new high performance, multi-purpose, multi- platform Fourier transform spectrometer (FPS) sensor. It covers the waveband from 0.2 to 12 micrometer, has spectral resolution as fine as 0.3 cm-1, and records over 100 spectra per second. Two CIGARS units are being used for observations of target signatures in the air or on the ground from fixed or moving platforms, including high performance jet aircraft. In this paper we describe the characteristics and capabilities of the CIGARS sensor, which uses four interchangeable detector modules (Si, InGaAs, InSb, and HgCdTe) and two optics modules, with internal calibration. The data recording electronics support observations of transient events, even without precise information on the timing of the event. We present test and calibration data on the sensitivity, spectral resolution, stability, and spectral rate of CIGARS, and examples of in- flight observations of real targets. We also discuss plans for adapting CIGARS for imaging spectroscopy observations, with simultaneous spectral and spatial data, by replacing the existing detectors with a focal plane array (FPA).

Evaluating Sentinel-2 for Lakeshore Habitat Mapping Based on Airborne Hyperspectral Data

PubMed Central

Stratoulias, Dimitris; Balzter, Heiko; Sykioti, Olga; Zlinszky, András; Tóth, Viktor R.

2015-01-01

Monitoring of lakeshore ecosystems requires fine-scale information to account for the high biodiversity typically encountered in the land-water ecotone. Sentinel-2 is a satellite with high spatial and spectral resolution and improved revisiting frequency and is expected to have significant potential for habitat mapping and classification of complex lakeshore ecosystems. In this context, investigations of the capabilities of Sentinel-2 in regard to the spatial and spectral dimensions are needed to assess its potential and the quality of the expected output. This study presents the first simulation of the high spatial resolution (i.e., 10 m and 20 m) bands of Sentinel-2 for lakeshore mapping, based on the satellite’s Spectral Response Function and hyperspectral airborne data collected over Lake Balaton, Hungary in August 2010. A comparison of supervised classifications of the simulated products is presented and the information loss from spectral aggregation and spatial upscaling in the context of lakeshore vegetation classification is discussed. We conclude that Sentinel-2 imagery has a strong potential for monitoring fine-scale habitats, such as reed beds. PMID:26378538

a UV Spectral Library of Metal-Poor Massive Stars

NASA Astrophysics Data System (ADS)

Robert, Carmelle

1994-01-01

We propose to use the FOS to build a snapshot library of UV spectra of a sample of about 50 metal-poor massive stars located in the Magellanic Clouds. The majority of libraries already existing contains spectra of hot stars with chemical abundances close to solar. The high spectral resolution achieves with the FOS will be a major factor for the uniqueness of this new library. UV spectral libraries represent fundamental tools for the study of the massive star populations of young star-forming regions. Massive stars, which are impossible to identify directly in the optical-IR part of a composite spectrum, display on the other hand key signatures in the UV region. These signatures are mainly broad, metallicity dependent spectral features formed in the hot star winds. They require a high spectral resolution (of the order of 200-300 km/s) for an adequate study. A spectral library of metal-poor massive stars represents also a unique source of data for a stellar atmosphere analysis. Within less then 10 min we will obtain a high signal-to-noise ratio of at least 30. Finally, since short exposure times are possible, this proposal makes extremely good use of the capabilities of HST. We designed an observing strategy which yields a maximum scientific return at a minimum cost of spacecraft time.

Multipurpose spectral imager.

PubMed

Sigernes, F; Lorentzen, D A; Heia, K; Svenøe, T

2000-06-20

A small spectral imaging system is presented that images static or moving objects simultaneously as a function of wavelength. The main physical principle is outlined and demonstrated. The instrument is capable of resolving both spectral and spatial information from targets throughout the entire visible region. The spectral domain has a bandpass of 12 A. One can achieve the spatial domain by rotating the system's front mirror with a high-resolution stepper motor. The spatial resolution range from millimeters to several meters depends mainly on the front optics used and whether the target is fixed (static) or movable relative to the instrument. Different applications and examples are explored, including outdoor landscapes, industrial fish-related targets, and ground-level objects observed in the more traditional way from an airborne carrier (remote sensing). Through the examples, we found that the instrument correctly classifies whether a shrimp is peeled and whether it can disclose the spectral and spatial microcharacteristics of targets such as a fish nematode (parasite). In the macroregime, we were able to distinguish a marine vessel from the surrounding sea and sky. A study of the directional spectral albedo from clouds, mountains, snow cover, and vegetation has also been included. With the airborne experiment, the imager successfully classified snow cover, leads, and new and rafted ice, as seen from 10.000 ft (3.048 m).

Replicated Wolter-I X-ray Optics for Lightweight, High Angular Resolution, Large Collecting Area X-Ray Telescopes

NASA Technical Reports Server (NTRS)

Joy, M.; Bilbro, J.; Elsner, R.; Jones, W.; Kolodziejczak, J.; Petruzzo, J.; ODell, S.; Weisskopf, M.

1997-01-01

The next generation of orbiting x-ray observatories will require high angular resolution telescopes that have an order of magnitude greater collecting area in the 0.1-10 keV spectral region than those currently under construction, but with a much lower weight and cost per unit area. Replicated Wolter-I x-ray optics have the potential to meet this requirement. The currently demonstrated capabilities of replicated Wolter-I optics will be described, and a development plan for creating lightweight, high angular resolution, large effective area x-ray telescopes will be presented.

CMOS-TDI detector technology for reconnaissance application

NASA Astrophysics Data System (ADS)

Eckardt, Andreas; Reulke, Ralf; Jung, Melanie; Sengebusch, Karsten

2014-10-01

The Institute of Optical Sensor Systems (OS) at the Robotics and Mechatronics Center of the German Aerospace Center (DLR) has more than 30 years of experience with high-resolution imaging technology. This paper shows the institute's scientific results of the leading-edge detector design CMOS in a TDI (Time Delay and Integration) architecture. This project includes the technological design of future high or multi-spectral resolution spaceborne instruments and the possibility of higher integration. DLR OS and the Fraunhofer Institute for Microelectronic Circuits and Systems (IMS) in Duisburg were driving the technology of new detectors and the FPA design for future projects, new manufacturing accuracy and on-chip processing capability in order to keep pace with the ambitious scientific and user requirements. In combination with the engineering research, the current generation of space borne sensor systems is focusing on VIS/NIR high spectral resolution to meet the requirements on earth and planetary observation systems. The combination of large-swath and high-spectral resolution with intelligent synchronization control, fast-readout ADC (analog digital converter) chains and new focal-plane concepts opens the door to new remote-sensing and smart deep-space instruments. The paper gives an overview of the detector development status and verification program at DLR, as well as of new control possibilities for CMOS-TDI detectors in synchronization control mode.

Pathfinder in flight over Hawaii

NASA Image and Video Library

1997-08-28

Pathfinder, NASA's solar-powered, remotely-piloted aircraft is shown while it was conducting a series of science flights to highlight the aircraft's science capabilities while collecting imagery of forest and coastal zone ecosystems on Kauai, Hawaii. The flights also tested two new scientific instruments, a high spectral resolution Digital Array Scanned Interferometer (DASI) and a high spatial resolution Airborne Real-Time Imaging System (ARTIS). The remote sensor payloads were designed by NASA's Ames Research Center, Moffett Field, California, to support NASA's Mission to Planet Earth science programs.

Pathfinder over runway in Hawaii

NASA Image and Video Library

1997-08-28

Pathfinder, NASA's solar-powered, remotely-piloted aircraft is shown while it was conducting a series of science flights to highlight the aircraft's science capabilities while collecting imagery of forest and coastal zone ecosystems on Kauai, Hawaii. The flights also tested two new scientific instruments, a high-spectral-resolution Digital Array Scanned Interferometer (DASI) and a high-spatial-resolution Airborne Real-Time Imaging System (ARTIS). The remote sensor payloads were designed by NASA's Ames Research Center, Moffett Field, California, to support NASA's Mission to Planet Earth science programs.

Prospects for the design of an ultraviolet imaging Fourier transform spectrometer

NASA Astrophysics Data System (ADS)

Lemaire, Philippe

2017-11-01

Recent results from solar observations in the far and extremeultraviolet (FUV/EUV) obtained from SOHO (SOlar and Heliospheric Observatory) and TRACE (Transition Region Camera) show the extreme variability of the solar atmosphere. Within the limited resolution of the instruments (1-2 arcseconds) horizontal and vertical velocities up-to 100 to 400 km s-1 have been measured. With an horizontal velocity of 100 km s-1 an one arsecond structure crosses the one arcsecond slit width of a classical slit spectrometer in less than 10 seconds. In the future, with higher angular resolution (e.g. 0.1 arcsecond), the capability to study small structures will be greatly reduced by a classical slit spectrometer. To be able to characterize the small scale solar atmospheric structures formed in the 104 K to 106 K temperature range (which emit in the 30 to 180 nm wavelength range) a spectrometer without slit (or with wide slit) is required. At the same time to obtain an accurate measurement of the doppler velocity an high spectral resolution is needed. The two requirements, high spectral resolution and large slit, are difficult to be simultaneously fulfilled with a classical slit spectrometer within the limited volume of a space instrumentation. Also, we propose to use an Imaging Fourier Transform Spectrometer (IFTS) to provide simultaneously a bidimensionnal field and an accurate determination of line profiles and positions. The development of Fourier Transform Spectrometers (FTS), although popular in the infrared, has been very limited in the UV/FUV by the lack of very high quality beam splitter. Since 10 years, the use of diffraction gratings as beam splitters has been suggested and few intruments have been built ([Chak 94]; [Clea 92]; [File 00]). These instruments illustrate some applications in the new wavelength domain opened by using a beam splitter grating, but do not yet provide the full capabilities of an FTS. In this paper we present several optical schemes which can provide the full capabilities of a complete IFTS in the FUV/EUV spectral range.

Parallel Spectral Acquisition with an Ion Cyclotron Resonance Cell Array.

PubMed

Park, Sung-Gun; Anderson, Gordon A; Navare, Arti T; Bruce, James E

2016-01-19

Mass measurement accuracy is a critical analytical figure-of-merit in most areas of mass spectrometry application. However, the time required for acquisition of high-resolution, high mass accuracy data limits many applications and is an aspect under continual pressure for development. Current efforts target implementation of higher electrostatic and magnetic fields because ion oscillatory frequencies increase linearly with field strength. As such, the time required for spectral acquisition of a given resolving power and mass accuracy decreases linearly with increasing fields. Mass spectrometer developments to include multiple high-resolution detectors that can be operated in parallel could further decrease the acquisition time by a factor of n, the number of detectors. Efforts described here resulted in development of an instrument with a set of Fourier transform ion cyclotron resonance (ICR) cells as detectors that constitute the first MS array capable of parallel high-resolution spectral acquisition. ICR cell array systems consisting of three or five cells were constructed with printed circuit boards and installed within a single superconducting magnet and vacuum system. Independent ion populations were injected and trapped within each cell in the array. Upon filling the array, all ions in all cells were simultaneously excited and ICR signals from each cell were independently amplified and recorded in parallel. Presented here are the initial results of successful parallel spectral acquisition, parallel mass spectrometry (MS) and MS/MS measurements, and parallel high-resolution acquisition with the MS array system.

Complementarity of UV and IR differential absorption lidar for global measurements of atmospheric species

NASA Technical Reports Server (NTRS)

Megie, G.; Menzies, R. T.

1980-01-01

An analysis of the potential capabilities of a spectrally diversified DIAL technique for monitoring atmospheric species is presented assuming operation from an earth-orbiting platform. Emphasis is given to the measurement accuracies and spatial and temporal resolutions required to meet present atmospheric science objectives. The discussion points out advantages of spectral diversity to perform comprehensive studies of the atmosphere; in general it is shown that IR systems have an advantage in lower atmospheric measurements, while UV systems are superior for middle and upper atmospheric measurements.

Current and Future Applications of Multispectral (RGB) Satellite Imagery for Weather Analysis and Forecasting Applications

NASA Technical Reports Server (NTRS)

Molthan, Andrew L.; Fuell, Kevin K.; LaFontaine, Frank; McGrath, Kevin; Smith, Matt

2013-01-01

Current and future satellite sensors provide remotely sensed quantities from a variety of wavelengths ranging from the visible to the passive microwave, from both geostationary and low ]Earth orbits. The NASA Short ]term Prediction Research and Transition (SPoRT) Center has a long history of providing multispectral imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA fs Terra and Aqua satellites in support of NWS forecast office activities. Products from MODIS have recently been extended to include a broader suite of multispectral imagery similar to those developed by EUMETSAT, based upon the spectral channels available from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) aboard METEOSAT ]9. This broader suite includes products that discriminate between air mass types associated with synoptic ]scale features, assists in the identification of dust, and improves upon paired channel difference detection of fog and low cloud events. Future instruments will continue the availability of these products and also expand upon current capabilities. The Advanced Baseline Imager (ABI) on GOES ]R will improve the spectral, spatial, and temporal resolution of our current geostationary capabilities, and the recent launch of the Suomi National Polar ]Orbiting Partnership (S ]NPP) carries instruments such as the Visible Infrared Imager Radiometer Suite (VIIRS), the Cross ]track Infrared Sounder (CrIS), and the Advanced Technology Microwave Sounder (ATMS), which have unrivaled spectral and spatial resolution, as precursors to the JPSS era (i.e., the next generation of polar orbiting satellites. New applications from VIIRS extend multispectral composites available from MODIS and SEVIRI while adding new capabilities through incorporation of additional CrIS channels or information from the Near Constant Contrast or gDay ]Night Band h, which provides moonlit reflectance from clouds and detection of fires or city lights. This presentation will present a review of SPoRT, CIRA, and NRL collaborations regarding multispectral satellite imagery and recent applications within the operational forecasting environment

High-fidelity video and still-image communication based on spectral information: natural vision system and its applications

NASA Astrophysics Data System (ADS)

Yamaguchi, Masahiro; Haneishi, Hideaki; Fukuda, Hiroyuki; Kishimoto, Junko; Kanazawa, Hiroshi; Tsuchida, Masaru; Iwama, Ryo; Ohyama, Nagaaki

2006-01-01

In addition to the great advancement of high-resolution and large-screen imaging technology, the issue of color is now receiving considerable attention as another aspect than the image resolution. It is difficult to reproduce the original color of subject in conventional imaging systems, and that obstructs the applications of visual communication systems in telemedicine, electronic commerce, and digital museum. To breakthrough the limitation of conventional RGB 3-primary systems, "Natural Vision" project aims at an innovative video and still-image communication technology with high-fidelity color reproduction capability, based on spectral information. This paper summarizes the results of NV project including the development of multispectral and multiprimary imaging technologies and the experimental investigations on the applications to medicine, digital archives, electronic commerce, and computer graphics.

Spectral Reconstruction Based on Svm for Cross Calibration

NASA Astrophysics Data System (ADS)

Gao, H.; Ma, Y.; Liu, W.; He, H.

2017-05-01

Chinese HY-1C/1D satellites will use a 5nm/10nm-resolutional visible-near infrared(VNIR) hyperspectral sensor with the solar calibrator to cross-calibrate with other sensors. The hyperspectral radiance data are composed of average radiance in the sensor's passbands and bear a spectral smoothing effect, a transform from the hyperspectral radiance data to the 1-nm-resolution apparent spectral radiance by spectral reconstruction need to be implemented. In order to solve the problem of noise cumulation and deterioration after several times of iteration by the iterative algorithm, a novel regression method based on SVM is proposed, which can approach arbitrary complex non-linear relationship closely and provide with better generalization capability by learning. In the opinion of system, the relationship between the apparent radiance and equivalent radiance is nonlinear mapping introduced by spectral response function(SRF), SVM transform the low-dimensional non-linear question into high-dimensional linear question though kernel function, obtaining global optimal solution by virtue of quadratic form. The experiment is performed using 6S-simulated spectrums considering the SRF and SNR of the hyperspectral sensor, measured reflectance spectrums of water body and different atmosphere conditions. The contrastive result shows: firstly, the proposed method is with more reconstructed accuracy especially to the high-frequency signal; secondly, while the spectral resolution of the hyperspectral sensor reduces, the proposed method performs better than the iterative method; finally, the root mean square relative error(RMSRE) which is used to evaluate the difference of the reconstructed spectrum and the real spectrum over the whole spectral range is calculated, it decreses by one time at least by proposed method.

Doppler Imaging and Chemical Abundance Analysis of EK Dra: Capabilities of Small Telescopes

NASA Astrophysics Data System (ADS)

Kilicoglu, Tolgahan; Senavci, H. V.; Bahar, E.; Isik, E.; Montes, D.; Hussain, G. A. J.

2018-04-01

We investigate the chromospheric and spot activity behaviour of the young Solar-like star EK Dra via Doppler imaging and spectral synthesis methods, using mid-resolution time series spectra of the system. We also present the atmospheric parameters and detailed elemental photospheric abundances of the star. The chemical abundance pattern of EK Dra do not suggest any remarkable peculiarities except few elements. The Titanium Oxide (TiO) bandheads at 7000 - 7100 A region also give clues about the spot temperature that may be cooler than 4000 K. In addition, we also discuss the capabilities of small telescopes (40 cm in our case) and medium resolution spectrographs in terms of Doppler imaging and chemical abundance analysis.

Hyperspectral Imagers for the Study of Massive Star Nebulae

NASA Astrophysics Data System (ADS)

Drissen, L.; Alarie, A.; Martin, T.; Spiomm/Sitelle Team

2012-12-01

We present two wide-field imaging Fourier transform spectrometers built by our team to study the interstellar medium around massive stars in the Milky Way and nearby galaxies. SpIOMM, attached to the Mont Mégantic 1.6-m telescope, is capable of obtaining the visible spectrum of every source of light in a 12 arcminute field of view, with a spectral resolution ranging from R = 1 (wide-band image) to R = 25 000, resulting in about a million spectra with a spatial resolution of one arcsecond. SITELLE will be a similar instrument attached to the Canada-France-Hawaii telescope, and will be in operation in early 2013. We illustrate SpIOMM's capabilities to study the interactions between massive stars and their environment.

Imaging IR spectrometer, phase 2

NASA Technical Reports Server (NTRS)

Gradie, Jonathan; Lewis, Ralph; Lundeen, Thomas; Wang, Shu-I

1990-01-01

The development is examined of a prototype multi-channel infrared imaging spectrometer. The design, construction and preliminary performance is described. This instrument is intended for use with JPL Table Mountain telescope as well as the 88 inch UH telescope on Mauna Kea. The instrument is capable of sampling simultaneously the spectral region of 0.9 to 2.6 um at an average spectral resolution of 1 percent using a cooled (77 K) optical bench, a concave holographic grating and a special order sorting filter to allow the acquisition of the full spectral range on a 128 x 128 HgCdTe infrared detector array. The field of view of the spectrometer is 0.5 arcsec/pixel in mapping mode and designed to be 5 arcsec/pixel in spot mode. The innovative optical design has resulted in a small, transportable spectrometer, capable of remote operation. Commercial applications of this spectrometer design include remote sensing from both space and aircraft platforms as well as groundbased astronomical observations.

The Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR)

NASA Astrophysics Data System (ADS)

Peterson, Bradley M.; Fischer, Debra; LUVOIR Science and Technology Definition Team

2017-01-01

LUVOIR is one of four potential large mission concepts for which the NASA Astrophysics Division has commissioned studies by Science and Technology Definition Teams (STDTs) drawn from the astronomical community. LUVOIR will have an 8 to16-m segmented primary mirror and operate at the Sun-Earth L2 point. It will be designed to support a broad range of astrophysics and exoplanet studies. The notional initial complement of instruments will include 1) a high-performance optical/NIR coronagraph with imaging and spectroscopic capability, 2) a UV imager and spectrograph with high spectral resolution and multi-object capability, 3) a high-definition wide-field optical/NIR camera, and 4) a multi-resolution optical/NIR spectrograph. LUVOIR will be designed for extreme stability to support unprecedented spatial resolution and coronagraphy. It is intended to be a long-lifetime facility that is both serviceable and upgradable. This is the first report by the LUVOIR STDT to the community on the top-level architectures we are studying, including preliminary capabilities of a mission with those parameters. The STDT seeks feedback from the astronomical community for key science investigations that can be undertaken with the notional instrument suite and to identify desirable capabilities that will enable additional key science.

High Spatial Resolution Thermal Satellite Technologies

NASA Technical Reports Server (NTRS)

Ryan, Robert

2003-01-01

This document in the form of viewslides, reviews various low-cost alternatives to high spatial resolution thermal satellite technologies. There exists no follow-on to Landsat 7 or ASTER high spatial resolution thermal systems. This document reviews the results of the investigation in to the use of new technologies to create a low-cost useful alternative. Three suggested technologies are examined. 1. Conventional microbolometer pushbroom modes offers potential for low cost Landsat Data Continuity Mission (LDCM) thermal or ASTER capability with at least 60-120 ground sampling distance (GSD). 2. Backscanning could produce MultiSpectral Thermal Imager performance without cooled detectors. 3. Cooled detector could produce hyperspectral thermal class system or extremely high spatial resolution class instrument.

Geo-oculus: high resolution multi-spectral earth imaging mission from geostationary orbit

NASA Astrophysics Data System (ADS)

Vaillon, L.; Schull, U.; Knigge, T.; Bevillon, C.

2017-11-01

Geo-Oculus is a GEO-based Earth observation mission studied by Astrium for ESA in 2008-2009 to complement the Sentinel missions, the space component of the GMES (Global Monitoring for Environment & Security). Indeed Earth imaging from geostationary orbit offers new functionalities not covered by existing LEO observation missions, like real-time monitoring and fast revisit capability of any location within the huge area in visibility of the satellite. This high revisit capability is exploited by the Meteosat meteorogical satellites, but with a spatial resolution (500 m nadir for the third generation) far from most of GMES needs (10 to 100 m). To reach such ground resolution from GEO orbit with adequate image quality, large aperture instruments (> 1 m) and high pointing stability (<< 1 μrad) are required, which are the major challenges of such missions. To address the requirements from the GMES user community, the Geo-Oculus mission is a combination of routine observations (daily systematic coverage of European coastal waters) with "on-demand" observation for event monitoring (e.g. disasters, fires and oil slicks). The instrument is a large aperture imaging telescope (1.5 m diameter) offering a nadir spatial sampling of 10.5 m (21 m worst case over Europe, below 52.5°N) in a PAN visible channel used for disaster monitoring. The 22 multi-spectral channels have resolutions over Europe ranging from 40 m in UV/VNIR (0.3 to 1 μm) to 750 m in TIR (10-12 μm).

Real-time Full-spectral Imaging and Affinity Measurements from 50 Microfluidic Channels using Nanohole Surface Plasmon Resonance†

PubMed Central

Lee, Si Hoon; Lindquist, Nathan C.; Wittenberg, Nathan J.; Jordan, Luke R.; Oh, Sang-Hyun

2012-01-01

With recent advances in high-throughput proteomics and systems biology, there is a growing demand for new instruments that can precisely quantify a wide range of receptor-ligand binding kinetics in a high-throughput fashion. Here we demonstrate a surface plasmon resonance (SPR) imaging spectroscopy instrument capable of extracting binding kinetics and affinities from 50 parallel microfluidic channels simultaneously. The instrument utilizes large-area (~cm2) metallic nanohole arrays as SPR sensing substrates and combines a broadband light source, a high-resolution imaging spectrometer and a low-noise CCD camera to extract spectral information from every channel in real time with a refractive index resolution of 7.7 × 10−6. To demonstrate the utility of our instrument for quantifying a wide range of biomolecular interactions, each parallel microfluidic channel is coated with a biomimetic supported lipid membrane containing ganglioside (GM1) receptors. The binding kinetics of cholera toxin b (CTX-b) to GM1 are then measured in a single experiment from 50 channels. By combining the highly parallel microfluidic device with large-area periodic nanohole array chips, our SPR imaging spectrometer system enables high-throughput, label-free, real-time SPR biosensing, and its full-spectral imaging capability combined with nanohole arrays could enable integration of SPR imaging with concurrent surface-enhanced Raman spectroscopy. PMID:22895607

The AOTF-Based NO2 Camera

NASA Astrophysics Data System (ADS)

Dekemper, E.; Fussen, D.; Vanhellemont, F.; Vanhamel, J.; Pieroux, D.; Berkenbosch, S.

2017-12-01

In an urban environment, nitrogen dioxide is emitted by a multitude of static and moving point sources (cars, industry, power plants, heating systems,…). Air quality models generally rely on a limited number of monitoring stations which do not capture the whole pattern, neither allow for full validation. So far, there has been a lack of instrument capable of measuring NO2 fields with the necessary spatio-temporal resolution above major point sources (power plants), or more extended ones (cities). We have developed a new type of passive remote sensing instrument aiming at the measurement of 2-D distributions of NO2 slant column densities (SCDs) with a high spatial (meters) and temporal (minutes) resolution. The measurement principle has some similarities with the popular filter-based SO2 camera (used in volcanic and industrial sulfur emissions monitoring) as it relies on spectral images taken at wavelengths where the molecule absorption cross section is different. But contrary to the SO2 camera, the spectral selection is performed by an acousto-optical tunable filter (AOTF) capable of resolving the target molecule's spectral features. A first prototype was successfully tested with the plume of a coal-firing power plant in Romania, revealing the dynamics of the formation of NO2 in the early plume. A lighter version of the NO2 camera is now being tested on other targets, such as oil refineries and urban air masses.

Tempest: GPU-CPU computing for high-throughput database spectral matching.

PubMed

Milloy, Jeffrey A; Faherty, Brendan K; Gerber, Scott A

2012-07-06

Modern mass spectrometers are now capable of producing hundreds of thousands of tandem (MS/MS) spectra per experiment, making the translation of these fragmentation spectra into peptide matches a common bottleneck in proteomics research. When coupled with experimental designs that enrich for post-translational modifications such as phosphorylation and/or include isotopically labeled amino acids for quantification, additional burdens are placed on this computational infrastructure by shotgun sequencing. To address this issue, we have developed a new database searching program that utilizes the massively parallel compute capabilities of a graphical processing unit (GPU) to produce peptide spectral matches in a very high throughput fashion. Our program, named Tempest, combines efficient database digestion and MS/MS spectral indexing on a CPU with fast similarity scoring on a GPU. In our implementation, the entire similarity score, including the generation of full theoretical peptide candidate fragmentation spectra and its comparison to experimental spectra, is conducted on the GPU. Although Tempest uses the classical SEQUEST XCorr score as a primary metric for evaluating similarity for spectra collected at unit resolution, we have developed a new "Accelerated Score" for MS/MS spectra collected at high resolution that is based on a computationally inexpensive dot product but exhibits scoring accuracy similar to that of the classical XCorr. In our experience, Tempest provides compute-cluster level performance in an affordable desktop computer.

ACTIM: an EDA initiated study on spectral active imaging

NASA Astrophysics Data System (ADS)

Steinvall, O.; Renhorn, I.; Ahlberg, J.; Larsson, H.; Letalick, D.; Repasi, E.; Lutzmann, P.; Anstett, G.; Hamoir, D.; Hespel, L.; Boucher, Y.

2010-10-01

This paper will describe ongoing work from an EDA initiated study on Active Imaging with emphasis of using multi or broadband spectral lasers and receivers. Present laser based imaging and mapping systems are mostly based on a fixed frequency lasers. On the other hand great progress has recently occurred in passive multi- and hyperspectral imaging with applications ranging from environmental monitoring and geology to mapping, military surveillance, and reconnaissance. Data bases on spectral signatures allow the possibility to discriminate between different materials in the scene. Present multi- and hyperspectral sensors mainly operate in the visible and short wavelength region (0.4-2.5 μm) and rely on the solar radiation giving shortcoming due to shadows, clouds, illumination angles and lack of night operation. Active spectral imaging however will largely overcome these difficulties by a complete control of the illumination. Active illumination enables spectral night and low-light operation beside a robust way of obtaining polarization and high resolution 2D/3D information. Recent development of broadband lasers and advanced imaging 3D focal plane arrays has led to new opportunities for advanced spectral and polarization imaging with high range resolution. Fusing the knowledge of ladar and passive spectral imaging will result in new capabilities in the field of EO-sensing to be shown in the study. We will present an overview of technology, systems and applications for active spectral imaging and propose future activities in connection with some prioritized applications.

Virtual Sensors: Using Data Mining Techniques to Efficiently Estimate Remote Sensing Spectra

NASA Technical Reports Server (NTRS)

Srivastava, Ashok N.; Oza, Nikunj; Stroeve, Julienne

2004-01-01

Various instruments are used to create images of the Earth and other objects in the universe in a diverse set of wavelength bands with the aim of understanding natural phenomena. These instruments are sometimes built in a phased approach, with some measurement capabilities being added in later phases. In other cases, there may not be a planned increase in measurement capability, but technology may mature to the point that it offers new measurement capabilities that were not available before. In still other cases, detailed spectral measurements may be too costly to perform on a large sample. Thus, lower resolution instruments with lower associated cost may be used to take the majority of measurements. Higher resolution instruments, with a higher associated cost may be used to take only a small fraction of the measurements in a given area. Many applied science questions that are relevant to the remote sensing community need to be addressed by analyzing enormous amounts of data that were generated from instruments with disparate measurement capability. This paper addresses this problem by demonstrating methods to produce high accuracy estimates of spectra with an associated measure of uncertainty from data that is perhaps nonlinearly correlated with the spectra. In particular, we demonstrate multi-layer perceptrons (MLPs), Support Vector Machines (SVMs) with Radial Basis Function (RBF) kernels, and SVMs with Mixture Density Mercer Kernels (MDMK). We call this type of an estimator a Virtual Sensor because it predicts, with a measure of uncertainty, unmeasured spectral phenomena.

Lunar Spectral Irradiance and Radiance (LUSI): New Instrumentation to Characterize the Moon as a Space-Based Radiometric Standard

PubMed Central

Smith, Allan W.; Lorentz, Steven R.; Stone, Thomas C.; Datla, Raju V.

2012-01-01

The need to understand and monitor climate change has led to proposed radiometric accuracy requirements for space-based remote sensing instruments that are very stringent and currently outside the capabilities of many Earth orbiting instruments. A major problem is quantifying changes in sensor performance that occur from launch and during the mission. To address this problem on-orbit calibrators and monitors have been developed, but they too can suffer changes from launch and the harsh space environment. One solution is to use the Moon as a calibration reference source. Already the Moon has been used to remove post-launch drift and to cross-calibrate different instruments, but further work is needed to develop a new model with low absolute uncertainties capable of climate-quality absolute calibration of Earth observing instruments on orbit. To this end, we are proposing an Earth-based instrument suite to measure the absolute lunar spectral irradiance to an uncertainty1 of 0.5 % (k=1) over the spectral range from 320 nm to 2500 nm with a spectral resolution of approximately 0.3 %. Absolute measurements of lunar radiance will also be acquired to facilitate calibration of high spatial resolution sensors. The instruments will be deployed at high elevation astronomical observatories and flown on high-altitude balloons in order to mitigate the effects of the Earth’s atmosphere on the lunar observations. Periodic calibrations using instrumentation and techniques available from NIST will ensure traceability to the International System of Units (SI) and low absolute radiometric uncertainties. PMID:26900523

EO-1 analysis applicable to coastal characterization

NASA Astrophysics Data System (ADS)

Burke, Hsiao-hua K.; Misra, Bijoy; Hsu, Su May; Griffin, Michael K.; Upham, Carolyn; Farrar, Kris

2003-09-01

The EO-1 satellite is part of NASA's New Millennium Program (NMP). It consists of three imaging sensors: the multi-spectral Advanced Land Imager (ALI), Hyperion and Atmospheric Corrector. Hyperion provides a high-resolution hyperspectral imager capable of resolving 220 spectral bands (from 0.4 to 2.5 micron) with a 30 m resolution. The instrument images a 7.5 km by 100 km land area per image. Hyperion is currently the only space-borne HSI data source since the launch of EO-1 in late 2000. The discussion begins with the unique capability of hyperspectral sensing to coastal characterization: (1) most ocean feature algorithms are semi-empirical retrievals and HSI has all spectral bands to provide legacy with previous sensors and to explore new information, (2) coastal features are more complex than those of deep ocean that coupled effects are best resolved with HSI, and (3) with contiguous spectral coverage, atmospheric compensation can be done with more accuracy and confidence, especially since atmospheric aerosol effects are the most pronounced in the visible region where coastal feature lie. EO-1 data from Chesapeake Bay from 19 February 2002 are analyzed. In this presentation, it is first illustrated that hyperspectral data inherently provide more information for feature extraction than multispectral data despite Hyperion has lower SNR than ALI. Chlorophyll retrievals are also shown. The results compare favorably with data from other sources. The analysis illustrates the potential value of Hyperion (and HSI in general) data to coastal characterization. Future measurement requirements (air borne and space borne) are also discussed.

Lunar Spectral Irradiance and Radiance (LUSI): New Instrumentation to Characterize the Moon as a Space-Based Radiometric Standard.

PubMed

Smith, Allan W; Lorentz, Steven R; Stone, Thomas C; Datla, Raju V

2012-01-01

The need to understand and monitor climate change has led to proposed radiometric accuracy requirements for space-based remote sensing instruments that are very stringent and currently outside the capabilities of many Earth orbiting instruments. A major problem is quantifying changes in sensor performance that occur from launch and during the mission. To address this problem on-orbit calibrators and monitors have been developed, but they too can suffer changes from launch and the harsh space environment. One solution is to use the Moon as a calibration reference source. Already the Moon has been used to remove post-launch drift and to cross-calibrate different instruments, but further work is needed to develop a new model with low absolute uncertainties capable of climate-quality absolute calibration of Earth observing instruments on orbit. To this end, we are proposing an Earth-based instrument suite to measure the absolute lunar spectral irradiance to an uncertainty(1) of 0.5 % (k=1) over the spectral range from 320 nm to 2500 nm with a spectral resolution of approximately 0.3 %. Absolute measurements of lunar radiance will also be acquired to facilitate calibration of high spatial resolution sensors. The instruments will be deployed at high elevation astronomical observatories and flown on high-altitude balloons in order to mitigate the effects of the Earth's atmosphere on the lunar observations. Periodic calibrations using instrumentation and techniques available from NIST will ensure traceability to the International System of Units (SI) and low absolute radiometric uncertainties.

The Feasibility of Tropospheric and Total Ozone Determination Using a Fabry-perot Interferometer as a Satellite-based Nadir-viewing Atmospheric Sensor. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Larar, Allen Maurice

1993-01-01

Monitoring of the global distribution of tropospheric ozone (O3) is desirable for enhanced scientific understanding as well as to potentially lessen the ill-health impacts associated with exposure to elevated concentrations in the lower atmosphere. Such a capability can be achieved using a satellite-based device making high spectral resolution measurements with high signal-to-noise ratios; this would enable observation in the pressure-broadened wings of strong O3 lines while minimizing the impact of undesirable signal contributions associated with, for example, the terrestrial surface, interfering species, and clouds. The Fabry-Perot Interferometer (FPI) provides high spectral resolution and high throughput capabilities that are essential for this measurement task. Through proper selection of channel spectral regions, the FPI optimized for tropospheric O3 measurements can simultaneously observe a stratospheric component and thus the total O3 column abundance. Decreasing stratospheric O3 concentrations may lead to an increase in biologically harmful solar ultraviolet radiation reaching the earth's surface, which is detrimental to health. In this research, a conceptual instrument design to achieve the desired measurement has been formulated. This involves a double-etalon fixed-gap series configuration FPI along with an ultra-narrow bandpass filter to achieve single-order operation with an overall spectral resolution of approximately .068 cm(exp -1). A spectral region of about 1 cm(exp -1) wide centered at 1054.73 cm(exp -1) within the strong 9.6 micron ozone infrared band is sampled with 24 spectral channels. Other design characteristics include operation from a nadir-viewing satellite configuration utilizing a 9 inch (diameter) telescope and achieving horizontal spatial resolution with a 50 km nadir footprint. A retrieval technique has been implemented and is demonstrated for a tropical atmosphere possessing enhanced tropospheric ozone amounts. An error analysis assessing the impact on retrieved O3 amounts of the most significant uncertainties associated with this particular measurement has been performed for several different types of atmospheres. Results show the proposed instrumentation to enable a good measurement of absolute ozone amounts and an even better determination of relative changes, with a range of accuracy to within 7.55 to 20.6 percent for integrated tropospheric amounts (and 1.99 to 4.02 percent for total O3 column abundance) and a corresponding range in precision to within 7.73 to 10.4 percent (and 3.30 to 3.95 percent for total O3 column abundance), for the atmospheric conditions considered.

Current Usage and Future Prospects of Multispectral (RGB) Satellite Imagery in Support of NWS Forecast Offices and National Centers

NASA Technical Reports Server (NTRS)

Molthan, Andrew L.; Fuell, Kevin K.; Knaff, John; Lee, Thomas

2012-01-01

Current and future satellite sensors provide remotely sensed quantities from a variety of wavelengths ranging from the visible to the passive microwave, from both geostationary and low-Earth orbits. The NASA Short-term Prediction Research and Transition (SPoRT) Center has a long history of providing multispectral imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA s Terra and Aqua satellites in support of NWS forecast office activities. Products from MODIS have recently been extended to include a broader suite of multispectral imagery similar to those developed by EUMETSAT, based upon the spectral channel s available from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) aboard METEOSAT-9. This broader suite includes products that discriminate between air mass types associated with synoptic-scale features, assists in the identification of dust, and improves upon paired channel difference detection of fog and low cloud events. Similarly, researchers at NOAA/NESDIS and CIRA have developed air mass discrimination capabilities using channels available from the current GOES Sounders. Other applications of multispectral composites include combinations of high and low frequency, horizontal and vertically polarized passive microwave brightness temperatures to discriminate tropical cyclone structures and other synoptic-scale features. Many of these capabilities have been transitioned for evaluation and operational use at NWS Weather Forecast Offices and National Centers through collaborations with SPoRT and CIRA. Future instruments will continue the availability of these products and also expand upon current capabilities. The Advanced Baseline Imager (ABI) on GOES-R will improve the spectral, spatial, and temporal resolution of our current geostationary capabilities, and the recent launch of the Suomi National Polar-Orbiting Partnership (S-NPP) carries instruments such as the Visible Infrared Imager Radiometer Suite (VIIRS), the Cross-track Infrared Sounder (CrIS), and the Advanced Technology Microwave Sounder (ATMS), which have unrivaled spectral and spatial resolution, as precursors to the JPSS era (i.e., the next generation of polar orbiting satellites). At the same time, new image manipulation and display capabilities are available within AWIPS II, the next generation of the NWS forecaster decision support system. This presentation will present a review of SPoRT, CIRA, and NRL collaborations regarding multispectral satellite imagery and articulate an integrated and collaborative path forward with Raytheon AWIPS II development staff for integrating current and future capabilities that support new satellite instrumentation and the AWIPS II decision support system.

Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS): Imaging and Tracking Capability

NASA Technical Reports Server (NTRS)

Zhou, D. K.; Larar, A. M.; Liu, Xu; Reisse, R. A.; Smith, W. L.; Revercomb, H. E.; Bingham, G. E.; Zollinger, L. J.; Tansock, J. J.; Huppi, Ronald J.

2007-01-01

The geosynchronous-imaging Fourier transform spectrometer (GIFTS) engineering demonstration unit (EDU) is an imaging infrared spectrometer designed for atmospheric soundings. It measures the infrared spectrum in two spectral bands (14.6 to 8.8 microns, 6.0 to 4.4 microns) using two 128 128 detector arrays with a spectral resolution of 0.57/cm with a scan duration of approx. 11 seconds. From a geosynchronous orbit, the instrument will have the capability of taking successive measurements of such data to scan desired regions of the globe, from which atmospheric status, cloud parameters, wind field profiles, and other derived products can be retrieved. The GIFTS EDU provides a flexible and accurate testbed for the new challenges of the emerging hyperspectral era. The EDU ground-based measurement experiment, held in Logan, Utah during September 2006, demonstrated its extensive capabilities and potential for geosynchronous and other applications (e.g., Earth observing environmental measurements). This paper addresses the experiment objectives and overall performance of the sensor system with a focus on the GIFTS EDU imaging capability and proof of the GIFTS measurement concept.

CRISM/HiRISE Correlative Spectroscopy

NASA Astrophysics Data System (ADS)

Seelos, F. P.; Murchie, S. L.; McGovern, A.; Milazzo, M. P.; Herkenhoff, K. E.

2011-12-01

The Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and High Resolution Imaging Science Experiment (HiRISE) are complementary investigations with high spectral resolution and broad wavelength coverage (CRISM ~20 m/pxl; ~400 - 4000 nm, 6.55 nm sampling) and high spatial resolution with broadband color capability (HiRISE ~25 cm/pxl; ~500, 700, 900 nm band centers, ~200-300 nm FWHM). Over the course of the MRO mission it has become apparent that spectral variations in the IR detected by CRISM (~1000 nm - 4000 nm) sometimes correlate spatially with visible and near infrared 3-band color variations observed by HiRISE. We have developed a data processing procedure that establishes a numerical mapping between HiRISE color and CRISM VNIR and IR spectral data and provides a statistical evaluation of the uncertainty in the mapping, with the objective of extrapolating CRISM-inferred mineralogy to the HiRISE spatial scale. The MRO mission profile, spacecraft capabilities, and science planning process emphasize coordinated observations - the simultaneous observation of a common target by multiple instruments. The commonalities of CRISM/HiRISE coordinated observations present a unique opportunity for tandem data analysis. Recent advances in the systematic processing of CRISM hyperspectral targeted observations account for gimbal-induced photometric variations and transform the data to a synthetic nadir acquisition geometry. The CRISM VNIR (~400 nm - 1000 nm) data can then be convolved to the HiRISE Infrared, Red, and Blue/Green (IRB) response functions to generate a compatible CRISM IRB product. Statistical evaluation of the CRISM/HiRISE spatial overlap region establishes a quantitative link between the data sets. IRB spectral similarity mapping for each HiRISE color spatial pixel with respect to the CRISM IRB product allows a given HiRISE pixel to be populated with information derived from the coordinated CRISM observation, including correlative VNIR or IR spectral data, spectral summary parameters, or browse products. To properly characterize the quality and fidelity of the IRB correlation, a series of ancillary information bands that record the numerical behavior of the procedure are also generated. Prototype CRISM/HiRISE correlative data products have been generated for a small number of coordinated observation pairs. The resulting products have the potential to support integrated spectral and morphological mapping at sub-meter spatial scales. Such data products would be invaluable for strategic and tactical science operations on landed missions, and would allow observations from a landed platform to be evaluated in a CRISM-based spectral and mineralogical context.

Optical design of the PEPSI high-resolution spectrograph at LBT

NASA Astrophysics Data System (ADS)

Andersen, Michael I.; Spano, Paolo; Woche, Manfred; Strassmeier, Klaus G.; Beckert, Erik

2004-09-01

PEPSI is a high-resolution, fiber fed echelle spectrograph with polarimetric capabilities for the LBT. In order to reach a maximum resolution R=120.000 in polarimetric mode and 300.000 in integral light mode with high efficiency in the spectral range 390-1050~nm, we designed a white-pupil configuration with Maksutov collimators. Light is dispersed by an R4 31.6 lines/mm monolithic echelle grating mosaic and split into two arms through dichroics. The two arms, optimized for the spectral range 390-550~nm and 550-1050~nm, respectively, consist of Maksutov transfer collimators, VPH-grism cross dispersers, optimized dioptric cameras and 7.5K x 7.5K 8~μ CCDs. Fibers of different core sizes coupled to different image-slicers allow a high throughput, comparable to that of direct feed instruments. The optical configuration with only spherical and cylindrical surfaces, except for one aspherical surface in each camera, reduces costs and guarantees high optical quality. PEPSI is under construction at AIP with first light expected in 2006.

PEPSI: the Potsdam Echelle Polarimetric and Spectroscopic Instrument for the LBT

NASA Astrophysics Data System (ADS)

Strassmeier, K. G.; Woche, M.; Ilyin, I.; Popow, E.; Bauer, S.-M.; Dionies, F.; Fechner, T.; Weber, M.; Hofmann, A.; Storm, J.; Materne, R.; Bittner, W.; Bartus, J.; Granzer, T.; Denker, C.; Carroll, T.; Kopf, M.; DiVarano, I.; Beckert, E.; Lesser, M.

2008-07-01

We present the status of PEPSI, the bench-mounted fibre-fed and stabilized "Potsdam Echelle Polarimetric and Spectroscopic Instrument" for the 2×8.4m Large Binocular Telescope in southern Arizona. PEPSI is under construction at AIP and is scheduled for first light in 2009/10. Its ultra-high-resolution mode will deliver an unprecedented spectral resolution of approximately R=310,000 at high efficiency throughout the entire optical/red wavelength range 390-1050nm without the need for adaptive optics. Besides its polarimetric Stokes IQUV mode, the capability to cover the entire optical range in three exposures at resolutions of 40,000, 130,000 and 310,000 will surpass all existing facilities in terms of light-gathering-power times spectral-coverage product. A solar feed will make use of the spectrograph also during day time. As such, we hope that PEPSI will be the most powerful spectrometer of its kind for the years to come.

Ultrahigh resolution photographic films for X-ray/EUV/FUV astronomy

NASA Technical Reports Server (NTRS)

Hoover, Richard B.; Walker, Arthur B. C., Jr.; Deforest, Craig E.; Watts, Richard; Tarrio, Charles

1993-01-01

The quest for ultrahigh resolution full-disk images of the sun at soft X-ray/EUV/FUV wavelengths has increased the demand for photographic films with broad spectral sensitivity, high spatial resolution, and wide dynamic range. These requirements were made more stringent by the recent development of multilayer telescopes and coronagraphs capable of operating at normal incidence at soft X-ray/EUV wavelengths. Photographic films are the only detectors now available with the information storage capacity and dynamic range such as is required for recording images of the solar disk and corona simultaneously with sub arc second spatial resolution. During the Stanford/MSFC/LLNL Rocket X-Ray Spectroheliograph and Multi-Spectral Solar Telescope Array (MSSTA) programs, we utilized photographic films to obtain high resolution full-disk images of the sun at selected soft X-ray/EUV/FUV wavelengths. In order to calibrate our instrumentation for quantitative analysis of our solar data and to select the best emulsions and processing conditions for the MSSTA reflight, we recently tested several photographic films. These studies were carried out at the NIST SURF II synchrotron and the Stanford Synchrotron Radiation Laboratory. In this paper, we provide the results of those investigations.

Spectral band passes for a high precision satellite sounder

NASA Technical Reports Server (NTRS)

Kaplan, L. D.; Chahine, M. T.; Susskind, J.; Searl, J. E.

1977-01-01

Atmospheric temperature soundings with significantly improved vertical resolution can be obtained from carefully chosen narrow band-pass measurements in the 4.3-micron band of CO2 by taking advantage of the variation of the absorption coefficients, and thereby the weighting functions, with pressure and temperature. A set of channels has been found in the 4.2-micron region that is capable of yielding about 2-km vertical resolution in the troposphere. The concept of a complete system is presented for obtaining high resolution retrievals of temperature and water vapor distribution, as well as surface and cloud top temperatures, even in the presence of broken clouds.

Resolution Enhancement of Hyperion Hyperspectral Data using Ikonos Multispectral Data

DTIC Science & Technology

2007-09-01

spatial - resolution hyperspectral image to produce a sharpened product. The result is a product that has the spectral properties of the ...multispectral sensors. In this work, we examine the benefits of combining data from high- spatial - resolution , low- spectral - resolution spectral imaging...sensors with data obtained from high- spectral - resolution , low- spatial - resolution spectral imaging sensors.

Miniature high-resolution guided-wave spectrometer for atmospheric remote sensing

NASA Astrophysics Data System (ADS)

Sloan, James; Kruzelecky, Roman; Wong, Brian; Zou, Jing; Jamroz, Wes; Haddad, Emile; Poirier, Michel

This paper describes the design and application of an innovative spectrometer in which a guided-wave integrated optical spectrometer (IOSPEC) has been coupled with a Fabry-Perot (FP) interferometer. This miniature spectrometer has a net mass under 3 kg, but is capable of broadband operation at spectral resolutions below 0.03 nm full width half maximum (FWHM). The tuneable FP filter provides very high spectral resolution combined with a large input aper-ture. The solid state guided-wave spectrometer is currently configured for a 512-channel array detector, which provides sub-nm coarse resolution. The ultimate resolution is determined by the FP filter, which is tuned across the desired spectral bands, thereby providing a signal-to-noise ratio (SNR) advantage over scanned spectrometer systems of the square root of the number of detector channels. The guided-wave optics provides robust, long-term optical alignment, while minimising the mechanical complexity. The miniaturisation of the FP-IOSPEC spectrometer allows multiple spectrometers to be accommodated on a single MicroSat. Each of these can be optimised for selected measurement tasks and views, thereby enabling more flexible data acquisition strategies with enhanced information content, while minimizing the mission cost. The application of this innovative technology in the proposed Miniature Earth Observation Satellite (MEOS) mission will also be discussed. The MEOS mission, which is designed for the investigation of the carbon and water cycles, relies on multiple IO-SPEC instruments for the simultaneous measurement of a range of atmospheric and surface properties important to climate change.

A solar radio dynamic spectrograph with flexible temporal-spectral resolution

NASA Astrophysics Data System (ADS)

Du, Qing-Fu; Chen, Lei; Zhao, Yue-Chang; Li, Xin; Zhou, Yan; Zhang, Jun-Rui; Yan, Fa-Bao; Feng, Shi-Wei; Li, Chuan-Yang; Chen, Yao

2017-09-01

Observation and research on solar radio emission have unique scientific values in solar and space physics and related space weather forecasting applications, since the observed spectral structures may carry important information about energetic electrons and underlying physical mechanisms. In this study, we present the design of a novel dynamic spectrograph that has been installed at the Chashan Solar Radio Observatory operated by the Laboratory for Radio Technologies, Institute of Space Sciences at Shandong University. The spectrograph is characterized by real-time storage of digitized radio intensity data in the time domain and its capability to perform off-line spectral analysis of the radio spectra. The analog signals received via antennas and amplified with a low-noise amplifier are converted into digital data at a speed reaching up to 32 k data points per millisecond. The digital data are then saved into a high-speed electronic disk for further off-line spectral analysis. Using different word lengths (1-32 k) and time cadences (5 ms-10 s) for off-line fast Fourier transform analysis, we can obtain the dynamic spectrum of a radio burst with different (user-defined) temporal (5 ms-10 s) and spectral (3 kHz˜320 kHz) resolutions. This enables great flexibility and convenience in data analysis of solar radio bursts, especially when some specific fine spectral structures are under study.

Calibration of the ROSAT HRI Spectral Response

NASA Technical Reports Server (NTRS)

Prestwich, Andrea H.; Silverman, John; McDowell, Jonathan; Callanan, Paul; Snowden, Steve

2000-01-01

The ROSAT High Resolution Imager has a limited (2-band) spectral response. This spectral capability can give X-ray hardness ratios on spatial scales of 5 arcseconds. The spectral response of the center of the detector was calibrated before the launch of ROSAT, but the gain decreases with time and also is a function of position on the detector. To complicate matters further, the satellite is 'wobbled', possibly moving a source across several spatial gain states. These difficulties have prevented the spectral response of the ROSAT High Resolution Imager (HRI) from being used for scientific measurements. We have used Bright Earth data and in-flight calibration sources to map the spatial and temporal gain changes, and written software which will allow ROSAT users to generate a calibrated XSPEC (an x ray spectral fitting package) response matrix and hence determine a calibrated hardness ratio. In this report, we describe the calibration procedure and show how to obtain a response matrix. In Section 2 we give an overview of the calibration procedure, in Section 3 we give a summary of HRI spatial and temporal gain variations. Section 4 describes the routines used to determine the gain distribution of a source. In Sections 5 and 6, we describe in detail how, the Bright Earth database and calibration sources are used to derive a corrected response matrix for a given observation. Finally, Section 7 describes how to use the software.

High-resolution hyperspectral ground mapping for robotic vision

NASA Astrophysics Data System (ADS)

Neuhaus, Frank; Fuchs, Christian; Paulus, Dietrich

2018-04-01

Recently released hyperspectral cameras use large, mosaiced filter patterns to capture different ranges of the light's spectrum in each of the camera's pixels. Spectral information is sparse, as it is not fully available in each location. We propose an online method that avoids explicit demosaicing of camera images by fusing raw, unprocessed, hyperspectral camera frames inside an ego-centric ground surface map. It is represented as a multilayer heightmap data structure, whose geometry is estimated by combining a visual odometry system with either dense 3D reconstruction or 3D laser data. We use a publicly available dataset to show that our approach is capable of constructing an accurate hyperspectral representation of the surface surrounding the vehicle. We show that in many cases our approach increases spatial resolution over a demosaicing approach, while providing the same amount of spectral information.

Spectral Properties and Dynamics of Gold Nanorods Revealed by EMCCD Based Spectral-Phasor Method

PubMed Central

Chen, Hongtao; Digman, Michelle A.

2015-01-01

Gold nanorods (NRs) with tunable plasmon-resonant absorption in the near-infrared region have considerable advantages over organic fluorophores as imaging agents. However, the luminescence spectral properties of NRs have not been fully explored at the single particle level in bulk due to lack of proper analytic tools. Here we present a global spectral phasor analysis method which allows investigations of NRs' spectra at single particle level with their statistic behavior and spatial information during imaging. The wide phasor distribution obtained by the spectral phasor analysis indicates spectra of NRs are different from particle to particle. NRs with different spectra can be identified graphically in corresponding spatial images with high spectral resolution. Furthermore, spectral behaviors of NRs under different imaging conditions, e.g. different excitation powers and wavelengths, were carefully examined by our laser-scanning multiphoton microscope with spectral imaging capability. Our results prove that the spectral phasor method is an easy and efficient tool in hyper-spectral imaging analysis to unravel subtle changes of the emission spectrum. Moreover, we applied this method to study the spectral dynamics of NRs during direct optical trapping and by optothermal trapping. Interestingly, spectral shifts were observed in both trapping phenomena. PMID:25684346

Experimental benchmark for an improved simulation of absolute soft-x-ray emission from polystyrene targets irradiated with the Nike laser.

PubMed

Weaver, J L; Busquet, M; Colombant, D G; Mostovych, A N; Feldman, U; Klapisch, M; Seely, J F; Brown, C; Holland, G

2005-02-04

Absolutely calibrated, time-resolved spectral intensity measurements of soft-x-ray emission (hnu approximately 0.1-1.0 keV) from laser-irradiated polystyrene targets are compared to radiation-hydrodynamic simulations that include our new postprocessor, Virtual Spectro. This new capability allows a unified, detailed treatment of atomic physics and radiative transfer in nonlocal thermodynamic equilibrium conditions for simple spectra from low-Z materials as well as complex spectra from high-Z materials. The excellent agreement (within a factor of approximately 1.5) demonstrates the powerful predictive capability of the codes for the complex conditions in the ablating plasma. A comparison to data with high spectral resolution (E/deltaE approximately 1000) emphasizes the importance of including radiation coupling in the quantitative simulation of emission spectra.

Constraining hot Jupiter’s atmospheric structure and dynamics through Doppler shifted emission spectra

NASA Astrophysics Data System (ADS)

Zhang, Jisheng; Kempton, Eliza; Rauscher, Emily

2017-01-01

In recent years, astronomers have begun successfully observing the atmospheres of extrasolar planets using ground-based telescopes equipped with spectrographs capable of observing at high spectral resolution (R~105). Such studies are capable of diagnosing the atmospheric structure, composition, and dynamics (winds and rotation) of both transiting and non-transiting exoplanets. However, few studies have examined how the 3-D atmospheric dynamics could alter the emitted light of hot Jupiters at such high spectral resolution. Here, we present a model to explore such influence on the hot Jupiters’ thermal emission spectra. Our aim is to investigate the extent to which the effects of 3-D atmospheric dynamics are imprinted on planet-averaged thermal emission spectra. We couple together a 3-D general circulation model of hot Jupiter atmospheric dynamics (Rauscher & Menou, 2012) with a radiative transfer solver to predict the planet’s disk-integrated emission spectrum as a function of its orbital phase. For the first time, we self-consistently include the effects of the line-of-sight atmospheric motions (resulting from winds and rotation) in the calculation to produce Doppler-shifted spectral line profiles that result from the atmospheric dynamics. We focus our study on three benchmark hot Jupiters, HD 189733b, HD 209458b, and WASP-43b which have been the focus of previous detailed observational studies. We find that the high-resolution Doppler shifted thermal emission spectra can be used to diagnose key properties of the dynamical atmosphere - the planet’s longitudinal temperature and wind structure, and its rotation rate.

Infrared atmospheric sounding interferometer correlation interferometry for the retrieval of atmospheric gases: the case of H2O and CO2.

PubMed

Grieco, Giuseppe; Masiello, Guido; Serio, Carmine; Jones, Roderic L; Mead, Mohammed I

2011-08-01

Correlation interferometry is a particular application of Fourier transform spectroscopy with partially scanned interferograms. Basically, it is a technique to obtain the difference between the spectra of atmospheric radiance at two diverse spectral resolutions. Although the technique could be exploited to design an appropriate correlation interferometer, in this paper we are concerned with the analytical aspects of the method and its application to high-spectral-resolution infrared observations in order to separate the emission of a given atmospheric gas from a spectral signal dominated by surface emission, such as in the case of satellite spectrometers operated in the nadir looking mode. The tool will be used to address some basic questions concerning the vertical spatial resolution of H2O and to develop an algorithm to retrieve the columnar amount of CO2. An application to complete interferograms from the Infrared Atmospheric Sounding Interferometer will be presented and discussed. For H2O, we have concluded that the vertical spatial resolution in the lower troposphere mostly depends on broad features associated with the spectrum, whereas for CO2, we have derived a technique capable of retrieving a CO2 columnar amount with accuracy of ≈±7 parts per million by volume at the level of each single field of view.

Performance Assessment of Different Pulse Reconstruction Algorithms for the ATHENA X-Ray Integral Field Unit

NASA Technical Reports Server (NTRS)

Peille, Phillip; Ceballos, Maria Teresa; Cobo, Beatriz; Wilms, Joern; Bandler, Simon; Smith, Stephen J.; Dauser, Thomas; Brand, Thorsten; Den Haretog, Roland; de Plaa, Jelle;

Model-independent Exoplanet Transit Spectroscopy

NASA Astrophysics Data System (ADS)

Aronson, Erik; Piskunov, Nikolai

2018-05-01

We propose a new data analysis method for obtaining transmission spectra of exoplanet atmospheres and brightness variation across the stellar disk from transit observations. The new method is capable of recovering exoplanet atmosphere absorption spectra and stellar specific intensities without relying on theoretical models of stars and planets. We simultaneously fit both stellar specific intensity and planetary radius directly to transit light curves. This allows stellar models to be removed from the data analysis. Furthermore, we use a data quality weighted filtering technique to achieve an optimal trade-off between spectral resolution and reconstruction fidelity homogenizing the signal-to-noise ratio across the wavelength range. Such an approach is more efficient than conventional data binning onto a low-resolution wavelength grid. We demonstrate that our analysis is capable of reproducing results achieved by using an explicit quadratic limb-darkening equation and that the filtering technique helps eliminate spurious spectral features in regions with strong telluric absorption. The method is applied to the VLT FORS2 observations of the exoplanets GJ 1214 b and WASP-49 b, and our results are in agreement with previous studies. Comparisons between obtained stellar specific intensity and numerical models indicates that the method is capable of accurately reconstructing the specific intensity. The proposed method enables more robust characterization of exoplanetary atmospheres by separating derivation of planetary transmission and stellar specific intensity spectra (that is model-independent) from chemical and physical interpretation.

Topochemical Analysis of Cell Wall Components by TOF-SIMS.

PubMed

Aoki, Dan; Fukushima, Kazuhiko

2017-01-01

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a recently developing analytical tool and a type of imaging mass spectrometry. TOF-SIMS provides mass spectral information with a lateral resolution on the order of submicrons, with widespread applicability. Sometimes, it is described as a surface analysis method without the requirement for sample pretreatment; however, several points need to be taken into account for the complete utilization of the capabilities of TOF-SIMS. In this chapter, we introduce methods for TOF-SIMS sample treatments, as well as basic knowledge of wood samples TOF-SIMS spectral and image data analysis.

Optimal attributes for the object based detection of giant reed in riparian habitats: A comparative study between Airborne High Spatial Resolution and WorldView-2 imagery

NASA Astrophysics Data System (ADS)

Fernandes, Maria Rosário; Aguiar, Francisca C.; Silva, João M. N.; Ferreira, Maria Teresa; Pereira, José M. C.

2014-10-01

Giant reed is an aggressive invasive plant of riparian ecosystems in many sub-tropical and warm-temperate regions, including Mediterranean Europe. In this study we tested a set of geometric, spectral and textural attributes in an object based image analysis (OBIA) approach to map giant reed invasions in riparian habitats. Bagging Classification and Regression Tree were used to select the optimal attributes and to build the classification rules sets. Mapping accuracy was performed using landscape metrics and the Kappa coefficient to compare the topographical and geometric similarity between the giant reed patches obtained with the OBIA map and with a validation map derived from on-screen digitizing. The methodology was applied in two high spatial resolution images: an airborne multispectral imagery and the newly WorldView-2 imagery. A temporal coverage of the airborne multispectral images was radiometrically calibrated with the IR-Mad transformation and used to assess the influence of the phenological variability of the invader. We found that optimal attributes for giant reed OBIA detection are a combination of spectral, geometric and textural information, with different scoring selection depending on the spectral and spatial characteristics of the imagery. WorldView-2 showed higher mapping accuracy (Kappa coefficient of 77%) and spectral attributes, including the newly yellow band, were preferentially selected, although a tendency to overestimate the total invaded area, due to the low spatial resolution (2 m of pixel size vs. 50 cm) was observed. When airborne images were used, geometric attributes were primarily selected and a higher spatial detail of the invasive patches was obtained, due to the higher spatial resolution. However, in highly heterogeneous landscapes, the low spectral resolution of the airborne images (4 bands instead of the 8 of WorldView-2) reduces the capability to detect giant reed patches. Giant reed displays peculiar spectral and geometric traits, at leaf, canopy and stand level, which makes the OBIA approach a very suitable technique for management purposes.

Probing the Invisible Universe: The Case for Far-IR/Submillimeter Interferometry

NASA Technical Reports Server (NTRS)

Leisawitz, D.; Armstrong, T.; Benford, D. J.; Blain, A.; Borne, K.; Danchi, W.; Evans, N.; Gardner, J.; Gezari, D.; Harwit, M.

2004-01-01

The question "How did we get here and what will the future bring?"captures the human imagination and the attention of the National Academy of Science's Astronomy and Astrophysics Survey Committee (AASC). Fulfillment of this fundamental goal requires astronomers to have sensitive, high angular and spectral resolution observations in the far-infrared/submillimeter (far- IR/sub-mm) spectral region. With half the luminosity of the universe and vital information about galaxy, star and planet formation, observations in this spectral region require capabilities similar to those currently available or planned at shorter wavelengths. In this paper we summarize the scientific motivation, some mission concepts and technology requirements for far-IR/sub-mm space interferometers that can be developed in the 2010-2020 timeframe.

Probing The Invisible Universe: The Case for Far-IR/Submillimeter Interferometry

NASA Technical Reports Server (NTRS)

Leisawitz, D.; Armstrong, T; Benford, D.; Blain, A.; Borne, K.; Danchi, W.; Evans, N.; Gardner, J.; Gezari, D.; Harwit, M.

2003-01-01

The question "How did we get here and what will the future bring? captures the human imagination and the attention of the National Academy of Science s Astronomy and Astrophysics Survey Committee (AASC). Fulfillment of this fundamental goal requires astronomers to have sensitive, high angular and spectral resolution observations in the far-infrared submillimeter (far-IR-sub-mm) spectral region. With half the luminosity of the universe and vital information about galaxy, star and planet formation, observations in this spectral region require capabilities similar to those currently available or planned at shorter wavelengths. The scientific motivation, some mission concepts and technology requirements for far-IR-sub-mm space interferometers that can be developed in the 2010-2020 timeframe are summarized.

Upgrade of goniospectrophtometer GEFE for near-field scattering and fluorescence radiance measurements

NASA Astrophysics Data System (ADS)

Bernad, Berta; Ferrero, Alejandro; Pons, Alicia; Hernanz, M. L.; Campos, Joaquín.

2015-03-01

The goniospectrophotometer GEFE, designed and developed at IO-CSIC (Instituto de Optica, Agencia Estatal Consejo Superior de Investigaciones Cientificas), was conceived to measure the spectral Bidirectional Reflectance Distribution Function (BRDF) at any pair of irradiation and detection directions. Although the potential of this instrument has largely been proved, it still required to be upgraded to deal with some important scattering features for the assessment of the appearance. Since it was not provided with a detector with spatial resolution, it simply could not measure spectrophotometric quantities to characterize texture through the Bidirectional Texture Function (BTF) or translucency through the more complex Bidirectional Scattering-Surface Reflectance Distribution Function (BSSRDF). Another requirement in the GEFE upgrading was to provide it with the capability of measuring fluorescence at different geometries, since some of the new pigments used in industry are fluorescent, which can have a non-negligible impact in the color of the product. Then, spectral resolution at irradiation and detection had to be available in GEFE. This paper describes the upgrading of the goniospectrophotometer GEFE, and its new capabilities through the presentation of sparkle and goniofluorescence measurements. In addition, the potential of the instrument to evaluate translucency by the measurement of the BSSRDF is briefly discussed.

Spectrally-encoded color imaging

PubMed Central

Kang, DongKyun; Yelin, Dvir; Bouma, Brett E.; Tearney, Guillermo J.

2010-01-01

Spectrally-encoded endoscopy (SEE) is a technique for ultraminiature endoscopy that encodes each spatial location on the sample with a different wavelength. One limitation of previous incarnations of SEE is that it inherently creates monochromatic images, since the spectral bandwidth is expended in the spatial encoding process. Here we present a spectrally-encoded imaging system that has color imaging capability. The new imaging system utilizes three distinct red, green, and blue spectral bands that are configured to illuminate the grating at different incident angles. By careful selection of the incident angles, the three spectral bands can be made to overlap on the sample. To demonstrate the method, a bench-top system was built, comprising a 2400-lpmm grating illuminated by three 525-μm-diameter beams with three different spectral bands. Each spectral band had a bandwidth of 75 nm, producing 189 resolvable points. A resolution target, color phantoms, and excised swine small intestine were imaged to validate the system's performance. The color SEE system showed qualitatively and quantitatively similar color imaging performance to that of a conventional digital camera. PMID:19688002

First Keck Interferometer measurements in self-phase referencing mode: spatially resolving circum-stellar line emission of 48 Lib

NASA Astrophysics Data System (ADS)

Pott, J.-U.; Woillez, J.; Ragland, S.; Wizinowich, P. L.; Eisner, J. A.; Monnier, J. D.; Akeson, R. L.; Ghez, A. M.; Graham, J. R.; Hillenbrand, L. A.; Millan-Gabet, R.; Appleby, E.; Berkey, B.; Colavita, M. M.; Cooper, A.; Felizardo, C.; Herstein, J.; Hrynevych, M.; Medeiros, D.; Morrison, D.; Panteleeva, T.; Smith, B.; Summers, K.; Tsubota, K.; Tyau, C.; Wetherell, E.

2010-07-01

Recently, the Keck interferometer was upgraded to do self-phase-referencing (SPR) assisted K-band spectroscopy at R ~ 2000. This means, combining a spectral resolution of 150 km/s with an angular resolution of 2.7 mas, while maintaining high sensitiviy. This SPR mode operates two fringe trackers in parallel, and explores several infrastructural requirements for off-axis phase-referencing, as currently being implemented as the KI-ASTRA project. The technology of self-phasereferencing opens the way to reach very high spectral resolution in near-infrared interferometry. We present the scientific capabilities of the KI-SPR mode in detail, at the example of observations of the Be-star 48 Lib. Several spectral lines of the cirumstellar disk are resolved. We describe the first detection of Pfund-lines in an interferometric spectrum of a Be star, in addition to Br γ. The differential phase signal can be used to (i) distinguish circum-stellar line emission from the star, (ii) to directly measure line asymmetries tracing an asymetric gas density distribution, (iii) to reach a differential, astrometric precision beyond single-telescope limits sufficient for studying the radial disk structure. Our data support the existence of a radius-dependent disk density perturbation, typically used to explain slow variations of Be-disk hydrogen line profiles.

SIMBIO-SYS for BepiColombo: status and issues.

NASA Astrophysics Data System (ADS)

Flamini, E.; Capaccioni, F.; Cremonese, G.; Palumbo, P.; Formaro, R.; Mugnuolo, R.; Debei, S.; Ficai Veltroni, I.; Dami, M.; Tommasi, L.; SIMBIO-SYS Team

The SIMBIO-SYS (Spectrometer and Imaging for MPO BepiColombo Integrated Observatory SYStem) is a complex instrument suite part of the scientific payload of the Mercury Planetary Orbiter for the BepiColombo mission, the last of the cornerstone missions of the European Space Agency (ESA) Horizon+ science program. The BepiColombo mission is compose by two scientific satellites on, Mercury Magnetic Orbiter-MMO, realized by the Japanese Space Agency JAXA, devoted to the study of the planet environment and the other, the Mercury Planetary Orbiter realized by ESA, devoted to the detailed study of the Hermean surface and interior. The SIMBIOSYS instrument will provide all the science imaging capability of the Bepicolombo MPO spacecraft. It consists of three channels: the STereo imaging Channel (STC), with broad spectral band in the 400-950 nm range and medium spatial resolution (up to 50 m/px), that will provide Digital Terrain Model of the entire surface of the planet with an accuracy better than 80 m; the High Resolution Imaging Channel HRIC), with broad spectral bands in the 400-900 nm range and high spatial resolution (up to 5 m/px), that will provide high resolution images of about 20% of the surface, and the Visible and near-Infrared Hyperspectral Imaging channel (VIHI), with high spectral resolution (up to 6 nm) in the 400-2000 nm range and spatial resolution up to 100 m/px, it will provide the global covergae at 400 m/px with the spectral information. SIMBIO-SYS will provide unprecedented high-resolution images, the Digital Terrain Model of the entire surface, and the surface composition in wide spectral range, at resolutions and coverage higher than the MESSENGER mission with a full co-alignememt of the three channels. The main scientific objectives can be summarized as follows: Definition of the impact flux in the inner Solar System: based on the impact crater population records Understanding of the accretional model of an end member of the Solar System: based on the type and distribution of mineral species Reconstruction of the surface geology and stratigraphic history: based on the combination of stereo and high- resolution imaging along with compositional information coming from the spectrometer Relative surface age by impact craters population density and distribution: based on the global imaging including the high-resolution mode Surface degradation processes and global resurfacing: derived from the erosional status of the impact crater and ejecta Identification of volcanic landforms and style: using the morphological and compositional information Crustal dynamics and mechanical properties of the lithosphere: based on the identification and classification of tectonic structures from visible images and detailed DTM Surface composition and crustal differentiation: based on the identification and distribution of mineral species as seen by the NIR hyperspectral imager Soil maturity and alteration processes: based on the measure of the spectral slope derived by the hyperspectral imager and the colour capabilities of the stereo camera Determination of moment of inertia of the planet: the high-resolution imaging channel as landmark pairs of surface features that can be observed on the periside as support for the libration experiment Surface-Atmosphere interaction processes and origin of the exosphere: knowledge of the surface composition is also crucial to unambiguously identify the source minerals for each of the constituents of the Mercury.s exosphere The instrument has been realized by Selex-ES under the contract and management of the Italian Space Agency (ASI) that have signed an MoU with CNES for the development of VIHI Proximity Electronics, the Main Electronics, and the instrument final calibration . All the realization and calibration has been carried on under the scientific supervision of the SIMBIO-SYS science team SIMBIOSYS has been delivered to ESA on April 2015 for the final integration on the BepiColombo MPO spacecraft.

Rigorous quantitative elemental microanalysis by scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS) with spectrum processing by NIST DTSA-II

NASA Astrophysics Data System (ADS)

Newbury, Dale E.; Ritchie, Nicholas W. M.

2014-09-01

Quantitative electron-excited x-ray microanalysis by scanning electron microscopy/silicon drift detector energy dispersive x-ray spectrometry (SEM/SDD-EDS) is capable of achieving high accuracy and high precision equivalent to that of the high spectral resolution wavelength dispersive x-ray spectrometer even when severe peak interference occurs. The throughput of the SDD-EDS enables high count spectra to be measured that are stable in calibration and resolution (peak shape) across the full deadtime range. With this high spectral stability, multiple linear least squares peak fitting is successful for separating overlapping peaks and spectral background. Careful specimen preparation is necessary to remove topography on unknowns and standards. The standards-based matrix correction procedure embedded in the NIST DTSA-II software engine returns quantitative results supported by a complete error budget, including estimates of the uncertainties from measurement statistics and from the physical basis of the matrix corrections. NIST DTSA-II is available free for Java-platforms at: http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html).

Spectral behavior of hydrated sulfate salts: implications for Europa mission spectrometer design

NASA Technical Reports Server (NTRS)

Dalton, James Bradley 3rd

2003-01-01

Remote sensing of the surface of Europa with near-infrared instruments has suggested the presence of hydrated materials, including sulfate salts. Attention has been focused on these salts for the information they might yield regarding the evolution of a putative interior ocean, and the evaluation of its astrobiological potential. These materials exhibit distinct infrared absorption features due to bound water. The interactions of this water with the host molecules lead to fine structure that can be used to discriminate among these materials on the basis of their spectral behavior. This fine structure is even more pronounced at the low temperatures prevalent on icy satellites. Examination of hydrated sulfate salt spectra measured under cryogenic temperature conditions provides realistic constraints for future remote-sensing missions to Europa. In particular, it suggests that a spectrometer system capable of 2-5 nm spectral resolution or better, with a spatial resolution approaching 100 m, would be able to differentiate among proposed hydrated surface materials, if present, and constrain their distributions across the surface. Such information would provide valuable insights into the evolutionary history of Europa.

Spectral behavior of hydrated sulfate salts: implications for Europa mission spectrometer design.

PubMed

Dalton, James Bradley

2003-01-01

Remote sensing of the surface of Europa with near-infrared instruments has suggested the presence of hydrated materials, including sulfate salts. Attention has been focused on these salts for the information they might yield regarding the evolution of a putative interior ocean, and the evaluation of its astrobiological potential. These materials exhibit distinct infrared absorption features due to bound water. The interactions of this water with the host molecules lead to fine structure that can be used to discriminate among these materials on the basis of their spectral behavior. This fine structure is even more pronounced at the low temperatures prevalent on icy satellites. Examination of hydrated sulfate salt spectra measured under cryogenic temperature conditions provides realistic constraints for future remote-sensing missions to Europa. In particular, it suggests that a spectrometer system capable of 2-5 nm spectral resolution or better, with a spatial resolution approaching 100 m, would be able to differentiate among proposed hydrated surface materials, if present, and constrain their distributions across the surface. Such information would provide valuable insights into the evolutionary history of Europa.

WorldView-2 and the evolution of the DigitalGlobe remote sensing satellite constellation: introductory paper for the special session on WorldView-2

NASA Astrophysics Data System (ADS)

Anderson, Neal T.; Marchisio, Giovanni B.

2012-06-01

Over the last decade DigitalGlobe (DG) has built and launched a series of remote sensing satellites with steadily increasing capabilities: QuickBird, WorldView-1 (WV-1), and WorldView-2 (WV-2). Today, this constellation acquires over 2.5 million km2 of imagery on a daily basis. This paper presents the configuration and performance capabilities of each of these satellites, with emphasis on the unique spatial and spectral capabilities of WV-2. WV-2 employs high-precision star tracker and inertial measurement units to achieve a geolocation accuracy of 5 m Circular Error, 90% confidence (CE90). The native resolution of WV-2 is 0.5 m GSD in the panchromatic band and 2 m GSD in 8 multispectral bands. Four of the multispectral bands match those of the Landsat series of satellites; four new bands enable novel and expanded applications. We are rapidly establishing and refreshing a global database of very high resolution (VHR) 8-band multispectral imagery. Control moment gyroscopes (CMGs) on both WV-1 and WV-2 improve collection capacity and provide the agility to capture multi-angle sequences in rapid succession. These capabilities result in a rich combination of image features that can be exploited to develop enhanced monitoring solutions. Algorithms for interpretation and analysis can leverage: 1) broader and more continuous spectral coverage at 2 m resolution; 2) textural and morphological information from the 0.5 m panchromatic band; 3) ancillary information from stereo and multi-angle collects, including high precision digital elevation models; 4) frequent revisits and time-series collects; and 5) the global reference image archives. We introduce the topic of creative fusion of image attributes, as this provides a unifying theme for many of the papers in this WV-2 Special Session.

Optical Technologies for UV Remote Sensing Instruments

NASA Technical Reports Server (NTRS)

Keski-Kuha, R. A. M.; Osantowski, J. F.; Leviton, D. B.; Saha, T. T.; Content, D. A.; Boucarut, R. A.; Gum, J. S.; Wright, G. A.; Fleetwood, C. M.; Madison, T. J.

1993-01-01

Over the last decade significant advances in technology have made possible development of instruments with substantially improved efficiency in the UV spectral region. In the area of optical coatings and materials, the importance of recent developments in chemical vapor deposited (CVD) silicon carbide (SiC) mirrors, SiC films, and multilayer coatings in the context of ultraviolet instrumentation design are discussed. For example, the development of chemically vapor deposited (CVD) silicon carbide (SiC) mirrors, with high ultraviolet (UV) reflectance and low scatter surfaces, provides the opportunity to extend higher spectral/spatial resolution capability into the 50-nm region. Optical coatings for normal incidence diffraction gratings are particularly important for the evolution of efficient extreme ultraviolet (EUV) spectrographs. SiC films are important for optimizing the spectrograph performance in the 90 nm spectral region. The performance evaluation of the flight optical components for the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument, a spectroscopic instrument to fly aboard the Solar and Heliospheric Observatory (SOHO) mission, designed to study dynamic processes, temperatures, and densities in the plasma of the upper atmosphere of the Sun in the wavelength range from 50 nm to 160 nm, is discussed. The optical components were evaluated for imaging and scatter in the UV. The performance evaluation of SOHO/CDS (Coronal Diagnostic Spectrometer) flight gratings tested for spectral resolution and scatter in the DGEF is reviewed and preliminary results on resolution and scatter testing of Space Telescope Imaging Spectrograph (STIS) technology development diffraction gratings are presented.

The STROBE-X Science Case: An Overview

NASA Astrophysics Data System (ADS)

Maccarone, Thomas J.; STROBE-X consortium

2018-01-01

STROBE-X is a proposed NASA Probe class mission aimed at the extremes of high throughput X-ray astronomy, making use of an 8 m^2 total collecting area, CCD-quality spectral resolution, and a state-of-the art wide field monitor with both very large instantaneous sky coverage (ideal for follow-up of LIGO events) and good intrinsic spectral and time resolution. The core goals are time domain astrophysics and high count spectroscopy. Its capabilities span a broad range of topics, including those traditional to X-ray timing missions, like understanding the equation of states of neutron stars, and the spin distributions and masses of neutron stars and stellar mass and supermassive black holes, and the rates, and detailed properties, of a variety of classes of X-ray transients; and also topics not traditionally studied by such missions such as the spectra of supernova remnants, comets and of clusters and groups of galaxies.

Report of the x ray and gamma ray sensors panel

NASA Technical Reports Server (NTRS)

Szymkowiak, Andrew; Collins, S.; Kurfess, J.; Mahoney, W.; Mccammon, D.; Pehl, R.; Ricker, G.

1991-01-01

Overall five major areas of technology are recommended for development in order to meet the science requirements of the Astrotech 21 mission set. These are: detectors for high resolution gamma ray spectroscopy, cryogenic detectors for improved x ray spectral and spatial resolution, advanced x ray charge coupled devices (CCDs) for higher energy resolution and larger format, extension to higher energies, liquid and solid position sensitive detectors for improving stopping power in the energy range 5 to 500 keV and 0.2 to 2 MeV. Development plans designed to achieve the desired capabilities on the time scales required by the technology freeze dates have been recommended in each of these areas.

Evaluation of LANDSAT MSS vs TM simulated data for distinguishing hydrothermal alteration

NASA Technical Reports Server (NTRS)

Abrams, M. J.; Kahle, A. B.; Madura, D. P.; Soha, J. M.

1978-01-01

The LANDSAT Follow-On (LFO) data was simulated to demonstrate the mineral exploration capability of this system for segregating different types of hydrothermal alteration and to compare this capability with that of the existing LANDSAT system. Multispectral data were acquired for several test sites with the Bendix 24-channel MSDS scanner. Contrast enhancements, band ratioing, and principal component transformations were used to process the simulated LFO data for analysis. For Red Mountain, Arizona, the LFO data allowed identification of silicified areas, not identifiable with LANDSAT 1 and 2 data. The improved LFO resolution allowed detection of small silicic outcrops and of a narrow silicified dike. For Cuprite - Ralston, Nevada, the LFO spectral bands allowed discrimination of argillic and opalized altered areas; these could not be spectrally discriminated using LANDSAT 1 and 2 data. Addition of data from the 1.3- and 2.2- micrometer regions allowed better discriminations of hydrothermal alteration types.

Measuring full-field displacement spectral components using photographs taken with a DSLR camera via an analogue Fourier integral

NASA Astrophysics Data System (ADS)

Javh, Jaka; Slavič, Janko; Boltežar, Miha

2018-02-01

Instantaneous full-field displacement fields can be measured using cameras. In fact, using high-speed cameras full-field spectral information up to a couple of kHz can be measured. The trouble is that high-speed cameras capable of measuring high-resolution fields-of-view at high frame rates prove to be very expensive (from tens to hundreds of thousands of euro per camera). This paper introduces a measurement set-up capable of measuring high-frequency vibrations using slow cameras such as DSLR, mirrorless and others. The high-frequency displacements are measured by harmonically blinking the lights at specified frequencies. This harmonic blinking of the lights modulates the intensity changes of the filmed scene and the camera-image acquisition makes the integration over time, thereby producing full-field Fourier coefficients of the filmed structure's displacements.

Combined spectral-domain optical coherence tomography and hyperspectral imaging applied for tissue analysis: Preliminary results

NASA Astrophysics Data System (ADS)

Dontu, S.; Miclos, S.; Savastru, D.; Tautan, M.

2017-09-01

In recent years many optoelectronic techniques have been developed for improvement and the development of devices for tissue analysis. Spectral-Domain Optical Coherence Tomography (SD-OCT) is a new medical interferometric imaging modality that provides depth resolved tissue structure information with resolution in the μm range. However, SD-OCT has its own limitations and cannot offer the biochemical information of the tissue. These data can be obtained with hyperspectral imaging, a non-invasive, sensitive and real time technique. In the present study we have combined Spectral-Domain Optical Coherence Tomography (SD-OCT) with Hyperspectral imaging (HSI) for tissue analysis. The Spectral-Domain Optical Coherence Tomography (SD-OCT) and Hyperspectral imaging (HSI) are two methods that have demonstrated significant potential in this context. Preliminary results using different tissue have highlighted the capabilities of this technique of combinations.

Improving spatial and spectral resolution of TCV Thomson scattering

NASA Astrophysics Data System (ADS)

Hawke, J.; Andrebe, Y.; Bertizzolo, R.; Blanchard, P.; Chavan, R.; Decker, J.; Duval, B.; Lavanchy, P.; Llobet, X.; Marlétaz, B.; Marmillod, P.; Pochon, G.; Toussaint, M.

2017-12-01

The recently completed MST2 upgrade to the Thomson scattering (TS) system on TCV (Tokamak à Configuration Variable) at the Swiss Plasma Center aims to provide an enhanced spatial and spectral resolution while maintaining the high level of diagnostic flexibility for the study of TCV plasmas. The MST2 (Medium Sized Tokamak) is a work program within the Eurofusion ITER physics department, aimed at exploiting Europe's medium sized tokamak programs for a better understanding of ITER physics. This upgrade to the TCV Thomson scattering system involved the installation of 40 new compact 5-channel spectrometers and modifications to the diagnostics fiber optic design. The complete redesign of the fiber optic backplane incorporates fewer larger diameter fibers, allowing for a higher resolution in both the core and edge of TCV plasmas along the laser line, with a slight decrease in the signal to noise ratio of Thomson measurements. The 40 new spectrometers added to the system are designed to cover the full range of temperatures expected in TCV, able to measure electron temperatures (Te) with high precision between (6 eV and 20 keV) . The design of these compact spectrometers stems originally from the design utilized in the MAST (Mega Amp Spherical Tokamak) TS system located in Oxfordshire, United Kingdom. This design was implemented on TCV with an overall layout of optical fibers and spectrometers to achieve an overall increase in the spatial resolution, specifically a resolution of approximately 1% of the minor radius within the plasma pedestal region. These spectrometers also enhance the diagnostic spectral resolution, especially within the plasma edge, due to the low Te measurement capabilities. These additional spectrometers allow for a much greater diagnostic flexibility, allowing for quality full Thomson profiles in 75% of TCV plasma configurations.

National Centers for Environmental Prediction

Science.gov Websites

resolution at T574 becomes ~ 23 km T382 Spectral truncation equivalent to horizontal resolution ~37 km T254 Spectral truncation equivalent to horizontal resolution ~50-55 km T190 Spectral truncation equivalent to horizontal resolution ~70 km T126 Spectral truncation equivalent to horizontal resolution ~100 km UM Unified

Performance, results, and prospects of the visible spectrograph VEGA on CHARA

NASA Astrophysics Data System (ADS)

Mourard, Denis; Challouf, Mounir; Ligi, Roxanne; Bério, Philippe; Clausse, Jean-Michel; Gerakis, Jérôme; Bourges, Laurent; Nardetto, Nicolas; Perraut, Karine; Tallon-Bosc, Isabelle; McAlister, H.; ten Brummelaar, T.; Ridgway, S.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

2012-07-01

In this paper, we review the current performance of the VEGA/CHARA visible spectrograph and make a review of the most recent astrophysical results. The science programs take benefit of the exceptional angular resolution, the unique spectral resolution and one of the main features of CHARA: Infrared and Visible parallel operation. We also discuss recent developments concerning the tools for the preparation of observations and important features of the data reduction software. A short discussion of the future developments will complete the presentation, directed towards new detectors and possible new beam combination scheme for improved sensitivity and imaging capabilities.

Static FBG strain sensor with high resolution and large dynamic range by dual-comb spectroscopy.

PubMed

Kuse, Naoya; Ozawa, Akira; Kobayashi, Yohei

2013-05-06

We demonstrate a fiber Bragg grating (FBG) strain sensor with optical frequency combs. To precisely characterize the optical response of the FBG when strain is applied, dual-comb spectroscopy is used. Highly sensitive dual-comb spectroscopy of the FBG enabled strain measurements with a resolution of 34 nε. The optical spectral bandwidth of the measurement exceeds 1 THz. Compared with conventional FBG strain sensor using a continuous-wave laser that requires rather slow frequency scanning with a limited range, the dynamic range and multiplexing capability are significantly improved by using broadband dual-comb spectroscopy.

The Expected Performance from the NASA OCO-2 Mission

NASA Astrophysics Data System (ADS)

Crisp, D.; Eldering, A.; Gunson, M. R.; Pollock, H.

2013-12-01

The NASA Orbiting Carbon Observatory-2 (OCO-2) will be launched from Vandenberg Air Force Base on a Delta-II 7320 launch vehicle as early as 1 July 2014. Once deployed in the 705-km Afternoon Constellation (A-Train), it will collect the measurements needed to estimate the column-averaged, atmospheric carbon dioxide (CO2) dry air mole fraction (XCO2) with improved precision, resolution, and coverage. The OCO-2 spacecraft carries and points a 3-channel, imaging, grating spectrometer that collects high resolution spectra of reflected sunlight in the 765 nm O2 A-band and in the CO2 bands centered near 1610 and 2060 nm. These spectral ranges overlap those used by the Japanese Greenhouse gases Observing SATellite (GOSAT) TANSO-FTS, the current standard in space-based XCO2 measurements. The OCO-2 instrument performance was extensively characterized during pre-launch testing, facilitating comparisons with the TANSO-FTS. OCO-2 has slightly lower spectral resolution, but the far wings of its instrument line shape functions decay more rapidly, such that it yields similar spectral contrast within O2 and CO2 bands. The instruments have similar continuum signal to noise ratios (SNR) for bright scenes, but the OCO-2 instrument has higher SNR at low light levels associated with absorption lines or dark surfaces. The OCO-2 spectrometers will collect 24 soundings per second, yielding up to a million soundings per day over the sunlit hemisphere. For routine operations, the OCO-2 instrument boresight will be pointed at the local nadir or at the 'glint spot,' where sunlight is specularly reflected from the surface. Nadir observations provide the best spatial resolution and are expected to yield more cloud-free soundings. Glint observations will have much better SNR over dark, ocean surfaces. The nominal plan is to alternate between glint and nadir observations on successive 16-day ground-track repeat cycles, so that the entire sunlit hemisphere is sampled in both modes at 32-day intervals. The instrument's rapid sampling, small (< 3 km2) sounding footprint, and high SNR, combined with the spacecraft's ability to point the instrument's aperture toward the glint spot over the entire sunlit hemisphere, are expected to provide more complete coverage of the ocean, cloudy regions, and high latitude continents. While the OCO-2 measurement capabilities provide opportunities to improve the XCO2 precision, resolution, and coverage, they also pose some formidable challenges for calibration, retrieval, and validation. To fully exploit this instrument's capabilities, the 24,000 spectral/spatial channels must be cross-calibrated to within a fraction of 1%. Substantial increases in algorithm speed and more efficient data screening techniques are needed to fully utilize the much larger data volume. Finally, a comprehensive validation program will be needed to ensure the accuracy of the retrieved XCO2 estimates. This presentation will summarize the OCO-2 measurement capabilities and observation strategies, and the methods adopted to address these challenges.

Multispectral Resource Sampler Workshop

NASA Technical Reports Server (NTRS)

1979-01-01

The utility of the multispectral resource sampler (MRS) was examined by users in the following disciplines: agriculture, atmospheric studies, engineering, forestry, geology, hydrology/oceanography, land use, and rangelands/soils. Modifications to the sensor design were recommended and the desired types of products and number of scenes required per month were indicated. The history, design, capabilities, and limitations of the MRS are discussed as well as the multilinear spectral array technology which it uses. Designed for small area inventory, the MRS can provide increased temporal, spectral, and spatial resolution, facilitate polarization measurement and atmospheric correction, and test onboard data compression techniques. The advantages of using it along with the thematic mapper are considered.

Design and evaluation of a filter spectrometer concept for facsimile cameras

NASA Technical Reports Server (NTRS)

Kelly, W. L., IV; Jobson, D. J.; Rowland, C. W.

1974-01-01

The facsimile camera is an optical-mechanical scanning device which was selected as the imaging system for the Viking '75 lander missions to Mars. A concept which uses an interference filter-photosensor array to integrate a spectrometric capability with the basic imagery function of this camera was proposed for possible application to future missions. This paper is concerned with the design and evaluation of critical electronic circuits and components that are required to implement this concept. The feasibility of obtaining spectroradiometric data is demonstrated, and the performance of a laboratory model is described in terms of spectral range, angular and spectral resolution, and noise-equivalent radiance.

Implications of information from LANDSAT-4 for private industry

NASA Technical Reports Server (NTRS)

Everett, J. R.; Dykstra, J. D. (Principal Investigator)

1983-01-01

The broader spectral coverage and higher resolution of LANDSAT-4 Thematic Mapper (TM) data open the door for identification from space of spectral phenomena associated with mineralization and microseepage of hydrocarbon. Digitally enhanced image products generated from TM data allow the mapping of many major and minor structural features that mark or influence emplacement of mineralization and accumulation of hydrocarbons. These improvements in capabilities over multispectral scanner data should accelerate the acceptance and integration of satellite data as a routinely used exploration tool that allows rapid examination of large areas in considerable detail. Imagery of Southern Ontario, Canada as well as of Cement, Oklahoma and Death Valley, California is discussed.

Multiplane and Spectrally-Resolved Single Molecule Localization Microscopy with Industrial Grade CMOS cameras.

PubMed

Babcock, Hazen P

2018-01-29

This work explores the use of industrial grade CMOS cameras for single molecule localization microscopy (SMLM). We show that industrial grade CMOS cameras approach the performance of scientific grade CMOS cameras at a fraction of the cost. This makes it more economically feasible to construct high-performance imaging systems with multiple cameras that are capable of a diversity of applications. In particular we demonstrate the use of industrial CMOS cameras for biplane, multiplane and spectrally resolved SMLM. We also provide open-source software for simultaneous control of multiple CMOS cameras and for the reduction of the movies that are acquired to super-resolution images.

Applying aerial digital photography as a spectral remote sensing technique for macrophytic cover assessment in small rural streams

NASA Astrophysics Data System (ADS)

Anker, Y.; Hershkovitz, Y.; Gasith, A.; Ben-Dor, E.

2011-12-01

Although remote sensing of fluvial ecosystems is well developed, the tradeoff between spectral and spatial resolutions prevents its application in small streams (<3m width). In the current study, a remote sensing approach for monitoring and research of small ecosystem was developed. The method is based on differentiation between two indicative vegetation species out of the ecosystem flora. Since when studied, the channel was covered mostly by a filamentous green alga (Cladophora glomerata) and watercress (Nasturtium officinale), these species were chosen as indicative; nonetheless, common reed (Phragmites australis) was also classified in order to exclude it from the stream ROI. The procedure included: A. For both section and habitat scales classifications, acquisition of aerial digital RGB datasets. B. For section scale classification, hyperspectral (HSR) dataset acquisition. C. For calibration, HSR reflectance measurements of specific ground targets, in close proximity to each dataset acquisition swath. D. For habitat scale classification, manual, in-stream flora grid transects classification. The digital RGB datasets were converted to reflectance units by spectral calibration against colored reference plates. These red, green, blue, white, and black EVA foam reference plates were measured by an ASD field spectrometer and each was given a spectral value. Each spectral value was later applied to the spectral calibration and radiometric correction of spectral RGB (SRGB) cube. Spectral calibration of the HSR dataset was done using the empirical line method, based on reference values of progressive grey scale targets. Differentiation between the vegetation species was done by supervised classification both for the HSR and for the SRGB datasets. This procedure was done using the Spectral Angle Mapper function with the spectral pattern of each vegetation species as a spectral end member. Comparison between the two remote sensing techniques and between the SRGB classification and the in-situ transects indicates that: A. Stream vegetation classification resolution is about 4 cm by the SRGB method compared to about 1 m by HSR. Moreover, this resolution is also higher than of the manual grid transect classification. B. The SRGB method is by far the most cost-efficient. The combination of spectral information (rather than the cognitive color) and high spatial resolution of aerial photography provides noise filtration and better sub-water detection capabilities than the HSR technique. C. Only the SRGB method applies for habitat and section scales; hence, its application together with in-situ grid transects for validation, may be optimal for use in similar scenarios.
The HSR dataset was first degraded to 17 bands with the same spectral range as the RGB dataset and also to a dataset with 3 equivalent bands

EEG resolutions in detecting and decoding finger movements from spectral analysis

PubMed Central

Xiao, Ran; Ding, Lei

2015-01-01

Mu/beta rhythms are well-studied brain activities that originate from sensorimotor cortices. These rhythms reveal spectral changes in alpha and beta bands induced by movements of different body parts, e.g., hands and limbs, in electroencephalography (EEG) signals. However, less can be revealed in them about movements of different fine body parts that activate adjacent brain regions, such as individual fingers from one hand. Several studies have reported spatial and temporal couplings of rhythmic activities at different frequency bands, suggesting the existence of well-defined spectral structures across multiple frequency bands. In the present study, spectral principal component analysis (PCA) was applied on EEG data, obtained from a finger movement task, to identify cross-frequency spectral structures. Features from identified spectral structures were examined in their spatial patterns, cross-condition pattern changes, detection capability of finger movements from resting, and decoding performance of individual finger movements in comparison to classic mu/beta rhythms. These new features reveal some similar, but more different spatial and spectral patterns as compared with classic mu/beta rhythms. Decoding results further indicate that these new features (91%) can detect finger movements much better than classic mu/beta rhythms (75.6%). More importantly, these new features reveal discriminative information about movements of different fingers (fine body-part movements), which is not available in classic mu/beta rhythms. The capability in decoding fingers (and hand gestures in the future) from EEG will contribute significantly to the development of non-invasive BCI and neuroprosthesis with intuitive and flexible controls. PMID:26388720

Broadband mid-infrared and THz chemical detection with quantum cascade laser multi-heterodyne spectrometers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Westberg, Jonas; Sterczewski, Lukasz A.; Patrick, Link; Wysocki, Gerard

2017-05-01

Majority of chemical species of interest in security and safety applications (e.g. explosives) have complex molecular structures that produce unresolved rotational-vibrational spectroscopic signatures in the mid-infrared. This requires spectroscopic techniques that can provide broadband coverage in the mid-IR region to target broadband absorbers and high resolution to address small molecules that exhibit well-resolved spectral lines. On the other hand, many broadband mid-IR absorbers exhibit well-resolved rotational components in the THz spectral region. Thus, development of spectroscopic sensing technologies that can address both spectral regions is of great importance. Here we demonstrate recent progress towards broadband high-resolution spectroscopic sensing applications with Fabry-Perot quantum cascade lasers (QCLs) and frequency combs using multi-heterodyne spectroscopy (MHS) techniques. In this paper, we will present spectroscopic sensing of large and small molecules in the mid-IR region using QCLs operating at 8.5µm. An example high-resolution, broadband MHS of ammonia (small molecule) and isobutane (broadband absorber) at atmospheric pressure in the 1165-1190 cm^-1 range will be discussed. We have developed a balanced MHS system for mitigation of the laser intensity fluctuations. Absorption spectroscopy as well as dispersion spectroscopy with minimum fractional absorption down to 10^-4/Hz1/2 and fast spectral acquisition capabilities down to 10 µs/spectrum range will be demonstrated. In order to mitigate the shortcomings of the limited chemical selectivity in the mid-IR, THz QCL based spectrometer is currently under development to provide spectral de-congestion and thus significantly improve chemical identification. Preliminary characterization of the performance of THZ QCL combs for the THz QCL-MHS will be presented.

The X-ray Integral Field Unit (X-IFU) for Athena

NASA Technical Reports Server (NTRS)

Ravera, Laurent; Barret, Didier; Willem den Herder, Jan; Piro, Luigi; Cledassou, Rodolphe; Pointecouteau, Etienne; Peille, Philippe; Pajot, Francois; Arnaud, Monique; Pigot, Claude;

Compact characterization of liquid absorption and emission spectra using linear variable filters integrated with a CMOS imaging camera.

PubMed

Wan, Yuhang; Carlson, John A; Kesler, Benjamin A; Peng, Wang; Su, Patrick; Al-Mulla, Saoud A; Lim, Sung Jun; Smith, Andrew M; Dallesasse, John M; Cunningham, Brian T

2016-07-08

A compact analysis platform for detecting liquid absorption and emission spectra using a set of optical linear variable filters atop a CMOS image sensor is presented. The working spectral range of the analysis platform can be extended without a reduction in spectral resolution by utilizing multiple linear variable filters with different wavelength ranges on the same CMOS sensor. With optical setup reconfiguration, its capability to measure both absorption and fluorescence emission is demonstrated. Quantitative detection of fluorescence emission down to 0.28 nM for quantum dot dispersions and 32 ng/mL for near-infrared dyes has been demonstrated on a single platform over a wide spectral range, as well as an absorption-based water quality test, showing the versatility of the system across liquid solutions for different emission and absorption bands. Comparison with a commercially available portable spectrometer and an optical spectrum analyzer shows our system has an improved signal-to-noise ratio and acceptable spectral resolution for discrimination of emission spectra, and characterization of colored liquid's absorption characteristics generated by common biomolecular assays. This simple, compact, and versatile analysis platform demonstrates a path towards an integrated optical device that can be utilized for a wide variety of applications in point-of-use testing and point-of-care diagnostics.

Contrast-enhanced optical coherence tomography with picomolar sensitivity for functional in vivo imaging

NASA Astrophysics Data System (ADS)

Liba, Orly; Sorelle, Elliott D.; Sen, Debasish; de La Zerda, Adam

2016-03-01

Optical Coherence Tomography (OCT) enables real-time imaging of living tissues at cell-scale resolution over millimeters in three dimensions. Despite these advantages, functional biological studies with OCT have been limited by a lack of exogenous contrast agents that can be distinguished from tissue. Here we report an approach to functional OCT imaging that implements custom algorithms to spectrally identify unique contrast agents: large gold nanorods (LGNRs). LGNRs exhibit 110-fold greater spectral signal per particle than conventional GNRs, which enables detection of individual LGNRs in water and concentrations as low as 250 pM in the circulation of living mice. This translates to ~40 particles per imaging voxel in vivo. Unlike previous implementations of OCT spectral detection, the methods described herein adaptively compensate for depth and processing artifacts on a per sample basis. Collectively, these methods enable high-quality noninvasive contrast-enhanced imaging of OCT in living subjects, including detection of tumor microvasculature at twice the depth achievable with conventional OCT. Additionally, multiplexed detection of spectrally-distinct LGNRs was demonstrated to observe discrete patterns of lymphatic drainage and identify individual lymphangions and lymphatic valve functional states. These capabilities provide a powerful platform for molecular imaging and characterization of tissue noninvasively at cellular resolution, called MOZART.

Ground-Based Measurement Experiment and First Results with Geosynchronous-Imaging Fourier Transform Spectrometer Engineering Demonstration Unit

NASA Technical Reports Server (NTRS)

Zhou, Daniel K.; Smith, William L.; Bingham, Gail E.; Huppi, Ronald J.; Revercomb, Henry E.; Zollinger, Lori J.; Larar, Allen M.; Liu, Xu; Tansock, Joseph J.; Reisse, Robert A.;

Calibration Efforts and Unique Capabilities of the HST Space Telescope Imaging Spectrograph

NASA Astrophysics Data System (ADS)

Monroe, TalaWanda R.; Proffitt, Charles R.; Welty, Daniel; Branton, Doug; Carlberg, Joleen K.; debes, John Henry; Lockwood, Sean; Riley, Allyssa; Sohn, Sangmo Tony; Sonnentrucker, Paule G.; Walborn, Nolan R.; Jedrzejewski, Robert I.

2018-01-01

The Space Telescope Imaging Spectrograph (STIS) continues to offer the astronomy community the ability to carry out innovative UV and optical spectroscopic and imaging studies, two decades after its deployment on the Hubble Space Telescope (HST). Most notably, STIS provides spectroscopy in the FUV and NUV, including high spectral resolution echelle modes, imaging in the FUV, optical spectroscopy, and coronagraphic capabilities. Additionally, spatial scanning on the CCD with the long-slits is now possible to enable very high S/N spectroscopic observations without saturation while mitigating telluric and fringing concerns in the far red and near-IR. This new mode may especially benefit the diffuse interstellar bands and exoplanet transiting communities. We present recent calibration efforts for the instrument, including work to optimize the calibration of the echelle spectroscopic modes by improving the flux agreement of overlapping spectral orders affected by changes in the grating blaze function since HST Servicing Mission 4. We also discuss considerations to maintain the wavelength precision of the spectroscopic modes, and the current capabilities of CCD spectroscopic spatial trails.

The FALCON Concept: Multi-Object Spectroscopy Combined with MCAO in Near-IR

NASA Astrophysics Data System (ADS)

Hammer, François; Sayède, Frédéric; Gendron, Eric; Fusco, Thierry; Burgarella, Denis; Cayatte, Véronique; Conan, Jean-Marc; Courbin, Frédéric; Flores, Hector; Guinouard, Isabelle; Jocou, Laurent; Lançon, Ariane; Monnet, Guy; Mouhcine, Mustapha; Rigaud, François; Rouan, Daniel; Rousset, Gérard; Buat, Véronique; Zamkotsian, Frédéric

A large fraction of the present-day stellar mass was formed between z=0.5 and z˜ 3 and our understanding of the formation mechanisms at work at these epochs requires both high spatial and high spectral resolution: one shall simultaneously obtain images of objects with typical sizes as small as 1-2 kpc (˜ 0".1), while achieving 20-50 km/s (R≥ 5000) spectral resolution. In addition, the redshift range to be considered implies that most important spectral features are redshifted in the near-infrared. The obvious instrumental solution to adopt in order to tackle the science goal is therefore a combination of multi-object 3D spectrograph with multi-conjugate adaptive optics in large fields. A very promising way to achieve such a technically challenging goal is to relax the conditions of the traditional full adaptive optics correction. A partial, but still competitive correction shall be prefered, over a much wider field of view. This can be done by estimating the turbulent volume from sets of natural guide stars, by optimizing the correction to several and discrete small areas of few arcsec 2 selected in a large field (Nasmyth field of 25 arcmin) and by correcting up to the 6th, and eventually, up to the 60 th Zernike modes. Simulations on real extragalactic fields, show that for most sources (> 80%), the recovered resolution could reach 0".15-0".25 in the J and H bands. Detection of point-like objects is improved by factors from 3 to ≥10, when compared with an instrument without adaptive correction. The proposed instrument concept, FALCON, is equipped with deployable mini-integral field units (IFUs), achieving spectral resolutions between R=5000 and 20000. Its multiplex capability, combined with high spatial and spectral resolution characteristics, is a natural ground based complement to the next generation of space telescopes. Galaxy formation in the early Universe is certainly a main science driver. We describe here how FALCON shall allow to answer puzzling questions in this area, although the science cases naturally accessible to the instrument concept makes it of interest for most areas of astrophysics.

Spectral Band Characterization for Hyperspectral Monitoring of Water Quality

NASA Technical Reports Server (NTRS)

Vermillion, Stephanie C.; Raqueno, Rolando; Simmons, Rulon

2001-01-01

A method for selecting the set of spectral characteristics that provides the smallest increase in prediction error is of interest to those using hyperspectral imaging (HSI) to monitor water quality. The spectral characteristics of interest to these applications are spectral bandwidth and location. Three water quality constituents of interest that are detectable via remote sensing are chlorophyll (CHL), total suspended solids (TSS), and colored dissolved organic matter (CDOM). Hyperspectral data provides a rich source of information regarding the content and composition of these materials, but often provides more data than an analyst can manage. This study addresses the spectral characteristics need for water quality monitoring for two reasons. First, determination of the greatest contribution of these spectral characteristics would greatly improve computational ease and efficiency. Second, understanding the spectral capabilities of different spectral resolutions and specific regions is an essential part of future system development and characterization. As new systems are developed and tested, water quality managers will be asked to determine sensor specifications that provide the most accurate and efficient water quality measurements. We address these issues using data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and a set of models to predict constituent concentrations.

CAM-SE: A scalable spectral element dynamical core for the Community Atmosphere Model.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dennis, John; Edwards, Jim; Evans, Kate J

2012-01-01

The Community Atmosphere Model (CAM) version 5 includes a spectral element dynamical core option from NCAR's High-Order Method Modeling Environment. It is a continuous Galerkin spectral finite element method designed for fully unstructured quadrilateral meshes. The current configurations in CAM are based on the cubed-sphere grid. The main motivation for including a spectral element dynamical core is to improve the scalability of CAM by allowing quasi-uniform grids for the sphere that do not require polar filters. In addition, the approach provides other state-of-the-art capabilities such as improved conservation properties. Spectral elements are used for the horizontal discretization, while most othermore » aspects of the dynamical core are a hybrid of well tested techniques from CAM's finite volume and global spectral dynamical core options. Here we first give a overview of the spectral element dynamical core as used in CAM. We then give scalability and performance results from CAM running with three different dynamical core options within the Community Earth System Model, using a pre-industrial time-slice configuration. We focus on high resolution simulations of 1/4 degree, 1/8 degree, and T340 spectral truncation.« less

The development of a modified spectral ripple test.

PubMed

Aronoff, Justin M; Landsberger, David M

2013-08-01

Poor spectral resolution can be a limiting factor for hearing impaired listeners, particularly for complex listening tasks such as speech understanding in noise. Spectral ripple tests are commonly used to measure spectral resolution, but these tests contain a number of potential confounds that can make interpretation of the results difficult. To measure spectral resolution while avoiding those confounds, a modified spectral ripple test with dynamically changing ripples was created, referred to as the spectral-temporally modulated ripple test (SMRT). This paper describes the SMRT and provides evidence that it is sensitive to changes in spectral resolution.

AOTF-based near-infrared imaging spectrometer for rapid identification of camouflaged target

NASA Astrophysics Data System (ADS)

Gao, Zhifan; Zeng, Libo; Wu, Qiongshui

2014-11-01

Acousto-optic tunable filter (AOTF) is a novel device for spectrometer. The electronic tunability qualifies it with the most compelling advantages of higher wavelength scan rate over the conventional spectrometers that are mechanically tuned, and the feature of large angular aperture makes the AOTF particularly suitable in imaging applications. In this research, an AOTF-based near-infrared imaging spectrometer was developed. The spectrometer consists of a TeO2 AOTF module, a near-infrared imaging lens assembly, an AOTF controller, an InGaAs array detector, an image acquisition card, and a PC. A precisely designed optical wedge is placed at the emergent surface of the AOTF to deal with the inherent dispersion of the TeO2 that may degrade the spatial resolution. The direct digital synthesizer (DDS) techniques and the phase locked loop (PLL) techniques are combined for radio frequency (RF) signal synthesis. The PLL is driven by the DDS to take advantage of both their merits of high frequency resolution, high frequency scan rate and strong spurious signals resistance capability. All the functions relating to wavelength scan, image acquisition, processing, storge and display are controlled by the PC. Calibration results indicate that the spectral range is 898~1670 nm, the spectral resolution is 6.8 nm(@1064 nm), the wavelength separation between frames in the spectral image assembly is 1.0 nm, and the processing time of a single image is less than 1 ms if a TV camera with 640×512 detector is incorporated. A prototype device was assembled to test the capability of differentiating samples with similar appearances, and satisfactory results were achieved. By this device, the chemical compositions and the distribution information can be obtained simultaneously. This system has the most advantages of no moving parts, fast wavelength scan and strong vibration resistance. The proposed imaging spectrometer has a significant application prospect in the area of identification of camouflaged target from complex backgrounds. In addition, only the objective lens and its accessories are required to be replaced for its use in microscopic spectral imaging system, which may be popularized to a large number of other possible applications.

Compositional Mapping of the Transantarctic Mountains Using Orbital Reflectance Data

NASA Astrophysics Data System (ADS)

Salvatore, M. R.; Niebuhr, S.; Morin, P. J.; Cox, S.

2014-12-01

We report on our progress of remotely mapping compositional variations throughout the Transantarctic Mountains (TAM) using orbital spectroscopic data. These techniques were originally proven effective in Antarctica using moderate spatial resolution (30 m/pixel) Advanced Land Imager (ALI) data, and showed great successes in identifying even minor variations in composition throughout the McMurdo Dry Valleys (MDV) [Salvatore et al., 2013]. However, due to the orbital inclination of the Earth Observing-1 spacecraft, ALI is unable to image the central and southern TAM, making comparable studies at comparable resolutions impossible on a continental scale. Fortunately, the WorldView-2 satellite (DigitalGlobe, Inc.) boasts high-resolution (2 m/pixel) multispectral capabilities, with 8 spectral bands located between 427 nm and 908 nm, and is able to image the entirety of the TAM through off-nadir pointing capabilities. This provides the ability to continue our remote spectral mapping campaign throughout the TAM to identify compositional variations in support of past and future field operations. We present an updated map of relative spectral variability (RSV) in the vicinity of Shackleton Glacier. This mapping product consists of 91 individual WorldView-2 images, each corrected to top-of-atmosphere radiance and parameterized to highlight known compositional properties. The mapped area covers approximately 17,850 square kilometers of ice-covered and exposed terrain. Compositional variations are easily mapped, and small-scale variations in iron-bearing mineralogy are particularly well resolved. We also describe our updated atmospheric correction algorithm for the WorldView-2 dataset, which utilizes in-scene techniques to derive surface reflectance and does not necessitate the use of radiative transfer modeling. Our technique is validated using laboratory reflectance measurements. In conjunction with the Polar Rock Repository at the Ohio State University, we have measured hundreds of individual samples in an effort to verify and "ground-truth" this atmospheric removal algorithm. Using these methodologies and revised techniques, our objective is to make a fully calibrated and atmospherically corrected spectral map of the central TAM available to the scientific community.

Software algorithm and hardware design for real-time implementation of new spectral estimator

PubMed Central

2014-01-01

Background Real-time spectral analyzers can be difficult to implement for PC computer-based systems because of the potential for high computational cost, and algorithm complexity. In this work a new spectral estimator (NSE) is developed for real-time analysis, and compared with the discrete Fourier transform (DFT). Method Clinical data in the form of 216 fractionated atrial electrogram sequences were used as inputs. The sample rate for acquisition was 977 Hz, or approximately 1 millisecond between digital samples. Real-time NSE power spectra were generated for 16,384 consecutive data points. The same data sequences were used for spectral calculation using a radix-2 implementation of the DFT. The NSE algorithm was also developed for implementation as a real-time spectral analyzer electronic circuit board. Results The average interval for a single real-time spectral calculation in software was 3.29 μs for NSE versus 504.5 μs for DFT. Thus for real-time spectral analysis, the NSE algorithm is approximately 150× faster than the DFT. Over a 1 millisecond sampling period, the NSE algorithm had the capability to spectrally analyze a maximum of 303 data channels, while the DFT algorithm could only analyze a single channel. Moreover, for the 8 second sequences, the NSE spectral resolution in the 3-12 Hz range was 0.037 Hz while the DFT spectral resolution was only 0.122 Hz. The NSE was also found to be implementable as a standalone spectral analyzer board using approximately 26 integrated circuits at a cost of approximately $500. The software files used for analysis are included as a supplement, please see the Additional files 1 and 2. Conclusions The NSE real-time algorithm has low computational cost and complexity, and is implementable in both software and hardware for 1 millisecond updates of multichannel spectra. The algorithm may be helpful to guide radiofrequency catheter ablation in real time. PMID:24886214

UWB Tracking System Design for Free-Flyers

NASA Technical Reports Server (NTRS)

Ni, Jianjun; Arndt, Dickey; Phan, Chan; Ngo, Phong; Gross, Julia; Dusl, John

2004-01-01

This paper discusses an ultra-wideband (UWB) tracking system design effort for Mini-AERCam (Autonomous Extra-vehicular Robotic Camera), a free-flying video camera system under development at NASA Johnson Space Center for aid in surveillance around the International Space Station (ISS). UWB technology is exploited to implement the tracking system due to its properties, such as high data rate, fine time resolution, and low power spectral density. A system design using commercially available UWB products is proposed. A tracking algorithm TDOA (Time Difference of Arrival) that operates cooperatively with the UWB system is developed in this research effort. Matlab simulations show that the tracking algorithm can achieve fine tracking resolution with low noise TDOA data. Lab experiments demonstrate the UWB tracking capability with fine resolution.

Imaging Optical Frequencies with 100  μHz Precision and 1.1  μm Resolution.

PubMed

Marti, G Edward; Hutson, Ross B; Goban, Akihisa; Campbell, Sara L; Poli, Nicola; Ye, Jun

2018-03-09

We implement imaging spectroscopy of the optical clock transition of lattice-trapped degenerate fermionic Sr in the Mott-insulating regime, combining micron spatial resolution with submillihertz spectral precision. We use these tools to demonstrate atomic coherence for up to 15 s on the clock transition and reach a record frequency precision of 2.5×10^{-19}. We perform the most rapid evaluation of trapping light shifts and record a 150 mHz linewidth, the narrowest Rabi line shape observed on a coherent optical transition. The important emerging capability of combining high-resolution imaging and spectroscopy will improve the clock precision, and provide a path towards measuring many-body interactions and testing fundamental physics.

Picometer-resolution dual-comb spectroscopy with a free-running fiber laser.

PubMed

Zhao, Xin; Hu, Guoqing; Zhao, Bofeng; Li, Cui; Pan, Yingling; Liu, Ya; Yasui, Takeshi; Zheng, Zheng

2016-09-19

Dual-comb spectroscopy holds the promise as real-time, high-resolution spectroscopy tools. However, in its conventional schemes, the stringent requirement on the coherence between two lasers requires sophisticated control systems. By replacing control electronics with an all-optical dual-comb lasing scheme, a simplified dual-comb spectroscopy scheme is demonstrated using one dual-wavelength, passively mode-locked fiber laser. Pulses with a intracavity-dispersion-determined repetition-frequency difference are shown to have good mutual coherence and stability. Capability to resolve the comb teeth and a picometer-wide optical spectral resolution are demonstrated using a simple data acquisition system. Energy-efficient, free-running fiber lasers with a small comb-tooth-spacing could enable low-cost dual-comb systems.

Pristine Survey : High-Resolution Spectral Analyses of New Metal-poor Stars

NASA Astrophysics Data System (ADS)

Venn, Kim; Starkenburg, Else; Martin, Nicolas; Kielty, Collin; Youakim, Kris; Arnetsen, Anke

2018-06-01

The Pristine survey (Starkenburg et al. 2017) is a new and very successful metal-poor star survey. Combining high-quality narrow-band CaHK CFHT/MegaCam photometry with existing broadband photometry from SDSS, then very metal-poor stars have been found as confirmed from low-resolution spectroscopy (Youakim et al. 2017). Furthermore, we have extended this survey towards the Galactic bulge in a pilot program to test the capabilities in the highly crowded and (inhomogeneously) extincted bulge (Arentsen et al. 2018). High resolution spectral follow-up analyses have been initiated at the CFHT with Espadons (V<15) and the Gemini/GRACES long optical fibre that also feeds the Espadons spectrograph (15

Mapping plastic greenhouse with medium spatial resolution satellite data: Development of a new spectral index

NASA Astrophysics Data System (ADS)

Yang, Dedi; Chen, Jin; Zhou, Yuan; Chen, Xiang; Chen, Xuehong; Cao, Xin

2017-06-01

Plastic greenhouses (PGs) are an important agriculture development technique to protect and control the growing environment for food crops. The extensive use of PGs can change the agriculture landscape and affects the local environment. Accurately mapping and estimating the coverage of PGs is a necessity to the strategic planning of modern agriculture. Unfortunately, PG mapping over large areas is methodologically challenging, as the medium spatial resolution satellite imagery (such as Landsat data) used for analysis lacks spatial details and spectral variations. To fill the gap, the paper proposes a new plastic greenhouse index (PGI) based on the spectral, sensitivity, and separability analysis of PGs using medium spatial resolution images. In the context of the Landsat Enhanced Thematic Mapper Plus (ETM+) imagery, the paper examines the effectiveness and capability of the proposed PGI. The results indicate that PGs in Landsat ETM+ image can be successfully detected by the PGI if the PG fraction is greater than 12% in a mixed pixel. A kappa coefficient of 0.83 and overall accuracy of 91.2% were achieved when applying the proposed PGI in the case of Weifang District, Shandong, China. These results show that the proposed index can be applied to identifying transparent PGs in atmospheric corrected Landsat image and has the potential for the digital mapping of plastic greenhouse coverage over a large area.

Concept Study Report: Extreme-Ultraviolet Imaging Spectrometer Solar-B

NASA Technical Reports Server (NTRS)

Doschek, George, A.; Brown, Charles M.; Davila, Joseph M.; Dere, Kenneth P.; Korendyke, Clarence M.; Mariska, John T.; Seely, John F.

1999-01-01

We propose a next generation Extreme-ultraviolet Imaging Spectrometer (EIS) that for the first time combines high spectral, spatial, and temporal resolution in a single solar spectroscopic instrument. The instrument consists of a multilayer-coated off-axis telescope mirror and a multilayer-coated grating spectrometer. The telescope mirror forms solar images on the spectrometer entrance slit assembly. The spectrometer forms stigmatic spectra of the solar region located at the slit. This region is selected by the articulated telescope mirror. Monochromatic images are obtained either by rastering the solar region across a narrow entrance slit, or by using a very wide slit (called a slot) in place of the slit. Monochromatic images of the region centered on the slot are obtained in a single exposure. Half of each optic is coated to maximize reflectance at 195 Angstroms; the other half to maximize reflectance at 270 Angstroms. The two Extreme Ultraviolet (EUV) wavelength bands have been selected to maximize spectral and dynamical and plasma diagnostic capabilities. Spectral lines are observed that are formed over a temperature range from about 0.1 MK to about 20 MK. The main EIS instrument characteristics are: wavelength bands - 180 to 204 Angstroms; 250 to 290 Angstroms; spectral resolution - 0.0223 Angstroms/pixel (34.3km/s at 195 Angstroms and 23.6 km/s at 284 Angstroms); slit dimensions - 4 slits, two currently specified dimensions are 1" x 1024" and 50" x 1024" (the slot); largest spatial field of view in a single exposure - 50" x 1024"; highest time resolution for active region velocity studies - 4.4 s.

Mercury exosphere. III: Energetic characterization of its sodium component

NASA Astrophysics Data System (ADS)

Leblanc, Francois; Chaufray, Jean-Yves; Doressoundiram, Alain; Berthelier, Jean-Jacques; Mangano, Valeria; López-Ariste, Arturo; Borin, Patrizia

2013-04-01

Mercury's sodium exosphere has been observed only few times with high spectral resolution from ground based observatories enabling the analysis of the emission spectra. These observations highlighted the energetic state of the sodium exospheric atoms relative to the surface temperature. More recently, the Doppler shift of the exospheric Na atoms was measured and interpreted as consistent with an exosphere moving outwards from the subsolar point (Potter, A.E., Morgan, T.H., Killen, R.E. [2009]. Icarus 204, 355-367). Using THEMIS solar telescope, we observed Mercury's sodium exosphere with very high spectral resolution at two opposite positions of its orbit. Using this very high spectral resolution and the scanning capabilities of THEMIS, we were able to reconstruct the 2D spatial distributions of the Doppler shifts and widths of the sodium atomic Na D2 and D1 lines. These observations revealed surprisingly large Doppler shift as well as spectral width consistent with previous observations. Starting from our 3D model of Mercury Na exosphere (Mercury Exosphere Global Circulation Model, Leblanc, F., Johnson, R.E. [2010]. Icarus 209, 280-300), we coupled this model with a 3D radiative transfer model described in a companion paper (Chaufray, J.Y., Leblanc, F. [2013]. Icarus, submitted for publication) which allows us to properly treat the non-maxwellian state of the simulated sodium exospheric population. Comparisons between THEMIS observations and simulations suggest that the previously observed energetic state of the Na exosphere might be essentially explained by a state of the Na exospheric atoms far from thermal equilibrium along with the Doppler shift dispersion of the Na atoms induced by the solar radiation pressure. However, the Doppler shift of the spectral lines cannot be explained by our modelling, suggesting either an exosphere spatially structured very differently than in our model or the inaccuracy of the spectral calibration when deriving the Doppler shift.

New tools: potential medical applications of data from new and old environmental satellites.

PubMed

Huh, O K; Malone, J B

2001-04-27

The last 40 years, beginning with the first TIROS (television infrared observational satellite) launched on 1 April 1960, has seen an explosion of earth environmental satellite systems and their capabilities. They can provide measurements in globe encircling arrays or small select areas, with increasing resolutions, and new capabilities. Concurrently there are expanding numbers of existing and emerging infectious diseases, many distributed according to areal patterns of physical conditions at the earth's surface. For these reasons, the medical and remote sensing communities can beneficially collaborate with the objective of making needed progress in public health activities by exploiting the advances of the national and international space programs. Major improvements in applicability of remotely sensed data are becoming possible with increases in the four kinds of resolution: spatial, temporal, radiometric and spectral, scheduled over the next few years. Much collaborative research will be necessary before data from these systems are fully exploited by the medical community.

Superharmonic imaging with chirp coded excitation: filtering spectrally overlapped harmonics.

PubMed

Harput, Sevan; McLaughlan, James; Cowell, David M J; Freear, Steven

2014-11-01

Superharmonic imaging improves the spatial resolution by using the higher order harmonics generated in tissue. The superharmonic component is formed by combining the third, fourth, and fifth harmonics, which have low energy content and therefore poor SNR. This study uses coded excitation to increase the excitation energy. The SNR improvement is achieved on the receiver side by performing pulse compression with harmonic matched filters. The use of coded signals also introduces new filtering capabilities that are not possible with pulsed excitation. This is especially important when using wideband signals. For narrowband signals, the spectral boundaries of the harmonics are clearly separated and thus easy to filter; however, the available imaging bandwidth is underused. Wideband excitation is preferable for harmonic imaging applications to preserve axial resolution, but it generates spectrally overlapping harmonics that are not possible to filter in time and frequency domains. After pulse compression, this overlap increases the range side lobes, which appear as imaging artifacts and reduce the Bmode image quality. In this study, the isolation of higher order harmonics was achieved in another domain by using the fan chirp transform (FChT). To show the effect of excitation bandwidth in superharmonic imaging, measurements were performed by using linear frequency modulated chirp excitation with varying bandwidths of 10% to 50%. Superharmonic imaging was performed on a wire phantom using a wideband chirp excitation. Results were presented with and without applying the FChT filtering technique by comparing the spatial resolution and side lobe levels. Wideband excitation signals achieved a better resolution as expected, however range side lobes as high as -23 dB were observed for the superharmonic component of chirp excitation with 50% fractional bandwidth. The proposed filtering technique achieved >50 dB range side lobe suppression and improved the image quality without affecting the axial resolution.

The AOTF-based NO2 camera

NASA Astrophysics Data System (ADS)

Dekemper, Emmanuel; Vanhamel, Jurgen; Van Opstal, Bert; Fussen, Didier

2016-12-01

The abundance of NO2 in the boundary layer relates to air quality and pollution source monitoring. Observing the spatiotemporal distribution of NO2 above well-delimited (flue gas stacks, volcanoes, ships) or more extended sources (cities) allows for applications such as monitoring emission fluxes or studying the plume dynamic chemistry and its transport. So far, most attempts to map the NO2 field from the ground have been made with visible-light scanning grating spectrometers. Benefiting from a high retrieval accuracy, they only achieve a relatively low spatiotemporal resolution that hampers the detection of dynamic features. We present a new type of passive remote sensing instrument aiming at the measurement of the 2-D distributions of NO2 slant column densities (SCDs) with a high spatiotemporal resolution. The measurement principle has strong similarities with the popular filter-based SO2 camera as it relies on spectral images taken at wavelengths where the molecule absorption cross section is different. Contrary to the SO2 camera, the spectral selection is performed by an acousto-optical tunable filter (AOTF) capable of resolving the target molecule's spectral features. The NO2 camera capabilities are demonstrated by imaging the NO2 abundance in the plume of a coal-fired power plant. During this experiment, the 2-D distribution of the NO2 SCD was retrieved with a temporal resolution of 3 min and a spatial sampling of 50 cm (over a 250 × 250 m2 area). The detection limit was close to 5 × 1016 molecules cm-2, with a maximum detected SCD of 4 × 1017 molecules cm-2. Illustrating the added value of the NO2 camera measurements, the data reveal the dynamics of the NO to NO2 conversion in the early plume with an unprecedent resolution: from its release in the air, and for 100 m upwards, the observed NO2 plume concentration increased at a rate of 0.75-1.25 g s-1. In joint campaigns with SO2 cameras, the NO2 camera could also help in removing the bias introduced by the NO2 interference with the SO2 spectrum.

A distributed microcomputer-controlled system for data acquisition and power spectral analysis of EEG.

PubMed

Vo, T D; Dwyer, G; Szeto, H H

1986-04-01

A relatively powerful and inexpensive microcomputer-based system for the spectral analysis of the EEG is presented. High resolution and speed is achieved with the use of recently available large-scale integrated circuit technology with enhanced functionality (INTEL Math co-processors 8087) which can perform transcendental functions rapidly. The versatility of the system is achieved with a hardware organization that has distributed data acquisition capability performed by the use of a microprocessor-based analog to digital converter with large resident memory (Cyborg ISAAC-2000). Compiled BASIC programs and assembly language subroutines perform on-line or off-line the fast Fourier transform and spectral analysis of the EEG which is stored as soft as well as hard copy. Some results obtained from test application of the entire system in animal studies are presented.

Estimation of Cardiopulmonary Parameters From Ultra Wideband Radar Measurements Using the State Space Method.

PubMed

Naishadham, Krishna; Piou, Jean E; Ren, Lingyun; Fathy, Aly E

2016-12-01

Ultra wideband (UWB) Doppler radar has many biomedical applications, including remote diagnosis of cardiovascular disease, triage and real-time personnel tracking in rescue missions. It uses narrow pulses to probe the human body and detect tiny cardiopulmonary movements by spectral analysis of the backscattered electromagnetic (EM) field. With the help of super-resolution spectral algorithms, UWB radar is capable of increased accuracy for estimating vital signs such as heart and respiration rates in adverse signal-to-noise conditions. A major challenge for biomedical radar systems is detecting the heartbeat of a subject with high accuracy, because of minute thorax motion (less than 0.5 mm) caused by the heartbeat. The problem becomes compounded by EM clutter and noise in the environment. In this paper, we introduce a new algorithm based on the state space method (SSM) for the extraction of cardiac and respiration rates from UWB radar measurements. SSM produces range-dependent system poles that can be classified parametrically with spectral peaks at the cardiac and respiratory frequencies. It is shown that SSM produces accurate estimates of the vital signs without producing harmonics and inter-modulation products that plague signal resolution in widely used FFT spectrograms.

Absolute high spectral resolution measurements of surface solar radiation for detection of water vapour continuum absorption.

PubMed

Gardiner, T D; Coleman, M; Browning, H; Tallis, L; Ptashnik, I V; Shine, K P

2012-06-13

Solar-pointing Fourier transform infrared (FTIR) spectroscopy offers the capability to measure both the fine scale and broadband spectral structure of atmospheric transmission simultaneously across wide spectral regions. It is therefore suited to the study of both water vapour monomer and continuum absorption behaviours. However, in order to properly address this issue, it is necessary to radiatively calibrate the FTIR instrument response. A solar-pointing high-resolution FTIR spectrometer was deployed as part of the 'Continuum Absorption by Visible and Infrared radiation and its Atmospheric Relevance' (CAVIAR) consortium project. This paper describes the radiative calibration process using an ultra-high-temperature blackbody and the consideration of the related influence factors. The result is a radiatively calibrated measurement of the solar irradiation at the ground across the IR region from 2000 to 10 000 cm(-1) with an uncertainty of between 3.3 and 5.9 per cent. This measurement is shown to be in good general agreement with a radiative-transfer model. The results from the CAVIAR field measurements are being used in ongoing studies of atmospheric absorbers, in particular the water vapour continuum.

Validation of Spectral Unmixing Results from Informed Non-Negative Matrix Factorization (INMF) of Hyperspectral Imagery

NASA Astrophysics Data System (ADS)

Wright, L.; Coddington, O.; Pilewskie, P.

2017-12-01

Hyperspectral instruments are a growing class of Earth observing sensors designed to improve remote sensing capabilities beyond discrete multi-band sensors by providing tens to hundreds of continuous spectral channels. Improved spectral resolution, range and radiometric accuracy allow the collection of large amounts of spectral data, facilitating thorough characterization of both atmospheric and surface properties. We describe the development of an Informed Non-Negative Matrix Factorization (INMF) spectral unmixing method to exploit this spectral information and separate atmospheric and surface signals based on their physical sources. INMF offers marked benefits over other commonly employed techniques including non-negativity, which avoids physically impossible results; and adaptability, which tailors the method to hyperspectral source separation. The INMF algorithm is adapted to separate contributions from physically distinct sources using constraints on spectral and spatial variability, and library spectra to improve the initial guess. Using this INMF algorithm we decompose hyperspectral imagery from the NASA Hyperspectral Imager for the Coastal Ocean (HICO), with a focus on separating surface and atmospheric signal contributions. HICO's coastal ocean focus provides a dataset with a wide range of atmospheric and surface conditions. These include atmospheres with varying aerosol optical thicknesses and cloud cover. HICO images also provide a range of surface conditions including deep ocean regions, with only minor contributions from the ocean surfaces; and more complex shallow coastal regions with contributions from the seafloor or suspended sediments. We provide extensive comparison of INMF decomposition results against independent measurements of physical properties. These include comparison against traditional model-based retrievals of water-leaving, aerosol, and molecular scattering radiances and other satellite products, such as aerosol optical thickness from the Moderate Resolution Imaging Spectroradiometer (MODIS).

Multimodal Broadband Vibrational Sum Frequency Generation (MM-BB-V-SFG) Spectrometer and Microscope.

PubMed

Lee, Christopher M; Kafle, Kabindra; Huang, Shixin; Kim, Seong H

2016-01-14

A broadband sum frequency generation (BB-SFG) spectrometer with multimodal (MM) capabilities was constructed, which could be routinely reconfigured for tabletop experiments in reflection, transmission, and total internal reflection (TIR) geometries, as well as microscopic imaging. The system was constructed using a Ti:sapphire amplifier (800 nm, pulse width = 85 fs, repetition rate = 2 kHz), an optical parameter amplification (OPA) system for production of broadband IR pulses tunable between 1000 and 4000 cm(-1), and two Fabry-Pérot etalons arranged in series for production of narrowband 800 nm pulses. The key feature allowing the MM operation was the nearly collinear alignment of the visible (fixed, 800 nm) and infrared (tunable, 1000-4000 cm(-1)) pulses which were spatially separated. Physical insights discussed in this paper include the comparison of spectral bandwidth produced with 40 and 85 fs pump beams, the improvement of spectral resolution using etalons, the SFG probe volume in bulk analysis, the normalization of SFG signals, the stitching of multiple spectral segments, and the operation in different modes for air/liquid and adsorbate/solid interfaces, bulk samples, as well as spectral imaging combined with principle component analysis (PCA). The SFG spectral features obtained with the MM-BB-SFG system were compared with those obtained with picosecond-scanning-SFG system and high-resolution BB-SFG system (HR-BB-SFG) for dimethyl sulfoxide, α-pinene, and various samples containing cellulose (purified commercial products, Cladophora cell wall, cotton and flax fibers, and onion epidermis cell wall).

Rare-earth-doped materials with application to optical signal processing, quantum information science, and medical imaging technology

NASA Astrophysics Data System (ADS)

Cone, R. L.; Thiel, C. W.; Sun, Y.; Böttger, Thomas; Macfarlane, R. M.

2012-02-01

Unique spectroscopic properties of isolated rare earth ions in solids offer optical linewidths rivaling those of trapped single atoms and enable a variety of recent applications. We design rare-earth-doped crystals, ceramics, and fibers with persistent or transient "spectral hole" recording properties for applications including high-bandwidth optical signal processing where light and our solids replace the high-bandwidth portion of the electronics; quantum cryptography and information science including the goal of storage and recall of single photons; and medical imaging technology for the 700-900 nm therapeutic window. Ease of optically manipulating rare-earth ions in solids enables capturing complex spectral information in 105 to 108 frequency bins. Combining spatial holography and spectral hole burning provides a capability for processing high-bandwidth RF and optical signals with sub-MHz spectral resolution and bandwidths of tens to hundreds of GHz for applications including range-Doppler radar and high bandwidth RF spectral analysis. Simply stated, one can think of these crystals as holographic recording media capable of distinguishing up to 108 different colors. Ultra-narrow spectral holes also serve as a vibration-insensitive sub-kHz frequency reference for laser frequency stabilization to a part in 1013 over tens of milliseconds. The unusual properties and applications of spectral hole burning of rare earth ions in optical materials are reviewed. Experimental results on the promising Tm3+:LiNbO3 material system are presented and discussed for medical imaging applications. Finally, a new application of these materials as dynamic optical filters for laser noise suppression is discussed along with experimental demonstrations and theoretical modeling of the process.

High-Resolution Spectroscopy with the Chandra X-ray Observatory

ScienceCinema

Canizares, Claude R. [MIT, Cambridge, Massachusetts, United States

2017-12-09

The capabilities of the Chandra X-ray Observatory and XMM-Newton for high-resolution spectroscopy have brought tradition plasma diagnostic techniques to the study of cosmic plasma. Observations have probed nearly every class of astronomical object, from young proto-starts through massive O starts and black hole binaries, supernova remnants, active galactic nuclei, and the intergalactic medium. Many of these sources show remarkable rich spectra that reveal new physical information, such as emission measure distributions, elemental abundances, accretion disk and wind signatures, and time variability. This talk will present an overview of the Chandra instrumentaton and selected examples of spectral observations of astrophysical and cosmological importance.

Soft X-ray microscope with nanometer spatial resolution and its applications

NASA Astrophysics Data System (ADS)

Wachulak, P. W.; Torrisi, A.; Bartnik, A.; Wegrzynski, L.; Fok, T.; Patron, Z.; Fiedorowicz, H.

2016-12-01

A compact size microscope based on nitrogen double stream gas puff target soft X-ray source, which emits radiation in water-window spectral range at the wavelength of λ = 2.88 nm is presented. The microscope employs ellipsoidal grazing incidence condenser mirror for sample illumination and silicon nitride Fresnel zone plate objective for object magnification and imaging. The microscope is capable of capturing water-window images of objects with 60 nm spatial resolution and exposure time as low as a few seconds. Details about the microscopy system as well as some examples of different applications from various fields of science, are presented and discussed.

Geology team

NASA Technical Reports Server (NTRS)

1982-01-01

Evaluating of the combined utility of narrowband and multispectral imaging in both the infrared and visible for the lithologic identification of geologic materials, and of the combined utility of multispectral imaging in the visible and infrared for lithologic mapping on a global bases are near term recommendations for future imaging capabilities. Long term recommendations include laboratory research into methods of field sampling and theoretical models of microscale mixing. The utility of improved spatial and spectral resolutions and radiometric sensitivity is also suggested for the long term. Geobotanical remote sensing research should be conducted to (1) separate geological and botanical spectral signatures in individual picture elements; (2) study geobotanical correlations that more fully simulate natural conditions; and use test sites designed to test specific geobotanical hypotheses.

The 1991 AVIRIS/POLDER experiment in Camargue, France

NASA Technical Reports Server (NTRS)

Baret, F.; Leprieur, C.; Jacquemoud, S.; Carrere, V.; Gu, X. F.; Steven, M.; Vanderbilt, V.; Hanocq, J. F.; Ustin, Susan L.; Rondeaux, G.

1992-01-01

Airborne campaigns during the eighties provided high spectral resolution data, collected with imaging instruments such as AIS, AVIRIS, FLI, CAESI, and ISM, in order to investigate the relationship with canopy biophysical characteristics. The statistical approaches used to analyze these data do not allow investigation of the causality and the applicability of the observed correlations. Further, statistical studies demonstrated the high degree of redundancy of the spectral information amongst many others. And for retrieving vegetation biophysical characteristics, few results demonstrate the real information gain attributable to the high spectral resolution capability as compared to the use of a few wide wavelength bands. With several new imaging spectrophotometers scheduled for launch during the next 10 years (MERIS, MODIS, HIRIS), progress in the description and understanding of the mechanisms that drive the spectral variation of canopy reflectance is required. Most of these new sensor systems will also have the capability to observe the target under differing view directions. The problem of the combination and the use of the synergy between both the spectral and the directional sources of canopy reflectance variations has to be addressed. Apart from the atmospheric effects, the spectral variation of the light reflected by canopies originates from the leaves, the soil or the other vegetation elements such as branches and fruits. At leaf level, both diffuse reflectance and transmittance may be simulated by simple models, although no accurate information exists on the absorption features of the biochemicals (except water) in the 900-2500nm wavelength range. Many models mimic the directional variability of canopy reflectance at a given wavelength. Combining a leaf spectral model with a canopy directional model provides a powerful tool to analyze this problem. Some of us have initiated such a study, but our approach and theory remain to be tested using canopy data with their complexity, associated experimental error, and atmospheric effects. The main objective of the 1990 POLDER/AVIRIS experiment in Camargue was to provide a consistent data set over various canopies in order to test the applicability of the theory. The experiment, part of the 1991 MAC Europe experiment, involved simultaneous data collection using two sensors: AVIRIS and POLDER which measures the bidirectional and polarization properties of the targets at 670 and 880nm wavebands.

Remote sensing of environmental impact of land use activities

NASA Technical Reports Server (NTRS)

Paul, C. K.

1977-01-01

The capability to monitor land cover, associated in the past with aerial film cameras and radar systems, was discussed in regard to aircraft and spacecraft multispectral scanning sensors. A proposed thematic mapper with greater spectral and spatial resolutions for the fourth LANDSAT is expected to usher in new environmental monitoring capability. In addition, continuing improvements in image classification by supervised and unsupervised computer techniques are being operationally verified for discriminating environmental impacts of human activities on the land. The benefits of employing remote sensing for this discrimination was shown to far outweigh the incremental costs of converting to an aircraft-satellite multistage system.

High-resolution Observations of Hα Spectra with a Subtractive Double Pass

NASA Astrophysics Data System (ADS)

Beck, C.; Rezaei, R.; Choudhary, D. P.; Gosain, S.; Tritschler, A.; Louis, R. E.

2018-02-01

High-resolution imaging spectroscopy in solar physics has relied on Fabry-Pérot interferometers (FPIs) in recent years. FPI systems, however, become technically challenging and expensive for telescopes larger than the 1 m class. A conventional slit spectrograph with a diffraction-limited performance over a large field of view (FOV) can be built at much lower cost and effort. It can be converted into an imaging spectro(polari)meter using the concept of a subtractive double pass (SDP). We demonstrate that an SDP system can reach a similar performance as FPI-based systems with a high spatial and moderate spectral resolution across a FOV of 100^'' ×100^' ' with a spectral coverage of 1 nm. We use Hα spectra taken with an SDP system at the Dunn Solar Telescope and complementary full-disc data to infer the properties of small-scale superpenumbral filaments. We find that the majority of all filaments end in patches of opposite-polarity fields. The internal fine-structure in the line-core intensity of Hα at spatial scales of about 0.5'' exceeds that in other parameters such as the line width, indicating small-scale opacity effects in a larger-scale structure with common properties. We conclude that SDP systems in combination with (multi-conjugate) adaptive optics are a valid alternative to FPI systems when high spatial resolution and a large FOV are required. They can also reach a cadence that is comparable to that of FPI systems, while providing a much larger spectral range and a simultaneous multi-line capability.

Science Objectives of EOS-Aura's Ozone Monitoring Instrument (OMI)

NASA Technical Reports Server (NTRS)

Levelt, P. F.; Veefkind, J. P.; Stammes, P.; Hilsenrath, E.; Bhartia, P. K.; Chance, K. V.; Leppelmeier, G. W.; Maelkki, A.; Bhartia, Pawan (Technical Monitor)

2002-01-01

OMI is a UV/VIS nadir solar backscatter spectrograph, which provides near global coverage in one day with a spatial resolution of 13 x 24 sq km. OMI is a new instrument, with a heritage from the European satellite instruments GOME, GOMOS and SCIAMACHY. OMI's unique capabilities for measuring important trace gases with a small footprint and daily global coverage, in conjunction with the other Aura instruments, will make a major contribution to our understanding of stratospheric and tropospheric chemistry and climate change. OMI will measure solar irradiance and Earth radiances in the wavelength range of 270 to 500 nm with spectral resolution of about 0.5 nm and a spectral sampling of about 2-3 per FWHM. From these observations, total columns of O3, NO2, BrO and SO2 will be derived from the back-scattered solar radiance using differential absorption spectroscopy (DOAS). The TOMS total ozone record will also be continued by employing the well established TOMS algorithm. Because of the high accuracy and spatial resolution of the measurements, a good estimate of tropospheric amounts of ozone and NO2 are expected. Ozone profiles will be derived using the optimal estimation method. The spectral aerosol optical depth will be determined from measurements between 340 and 500 nm. This will provide information on aerosol concentration, aerosol size distribution and aerosol type. This wavelength range makes it possible to retrieve aerosol information over both land and sea. OMI observations will also allow retrievals of cloud coverage and cloud heights. From these products, the UV-B flux at the surface can then be derived with high spatial resolution.

Analysis on the optical aberration effect on spectral resolution of coded aperture spectroscopy

NASA Astrophysics Data System (ADS)

Hao, Peng; Chi, Mingbo; Wu, Yihui

2017-10-01

The coded aperture spectrometer can achieve high throughput and high spectral resolution by replacing the traditional single slit with two-dimensional array slits manufactured by MEMS technology. However, the sampling accuracy of coding spectrum image will be distorted due to the existence of system aberrations, machining error, fixing errors and so on, resulting in the declined spectral resolution. The influence factor of the spectral resolution come from the decode error, the spectral resolution of each column, and the column spectrum offset correction. For the Czerny-Turner spectrometer, the spectral resolution of each column most depend on the astigmatism, in this coded aperture spectroscopy, the uncorrected astigmatism does result in degraded performance. Some methods must be used to reduce or remove the limiting astigmatism. The curvature of field and the spectral curvature can be result in the spectrum revision errors.

Windprofiler optimization using digital deconvolution procedures

NASA Astrophysics Data System (ADS)

Hocking, W. K.; Hocking, A.; Hocking, D. G.; Garbanzo-Salas, M.

2014-10-01

Digital improvements to data acquisition procedures used for windprofiler radars have the potential for improving the height coverage at optimum resolution, and permit improved height resolution. A few newer systems already use this capability. Real-time deconvolution procedures offer even further optimization, and this has not been effectively employed in recent years. In this paper we demonstrate the advantages of combining these features, with particular emphasis on the advantages of real-time deconvolution. Using several multi-core CPUs, we have been able to achieve speeds of up to 40 GHz from a standard commercial motherboard, allowing data to be digitized and processed without the need for any type of hardware except for a transmitter (and associated drivers), a receiver and a digitizer. No Digital Signal Processor chips are needed, allowing great flexibility with analysis algorithms. By using deconvolution procedures, we have then been able to not only optimize height resolution, but also have been able to make advances in dealing with spectral contaminants like ground echoes and other near-zero-Hz spectral contamination. Our results also demonstrate the ability to produce fine-resolution measurements, revealing small-scale structures within the backscattered echoes that were previously not possible to see. Resolutions of 30 m are possible for VHF radars. Furthermore, our deconvolution technique allows the removal of range-aliasing effects in real time, a major bonus in many instances. Results are shown using new radars in Canada and Costa Rica.

Validation of Atmospheric InfraRed Sounder (AIRS) spectral radiances with the Scanning High-resolution Interferometer Sounder (S-HIS) aircraft instrument

NASA Astrophysics Data System (ADS)

Tobin, David C.; Revercomb, Henry E.; Moeller, Chris C.; Knuteson, Robert O.; Best, Fred A.; Smith, William L.; van Delst, Paul; LaPorte, Daniel D.; Ellington, Scott D.; Werner, Mark D.; Dedecker, Ralph G.; Garcia, Raymond K.; Ciganovich, Nick N.; Howell, Hugh B.; Dutcher, Steven B.; Taylor, Joe K.

2004-11-01

The ability to accurately validate high spectral resolution infrared radiance measurements from space using comparisons with aircraft spectrometer observations has been successfully demonstrated. The demonstration is based on an under-flight of the Atmospheric Infrared Sounder (AIRS) on the NASA Aqua spacecraft by the Scanning High resolution Interferometer Sounder (S-HIS) on the NASA ER-2 high altitude aircraft on 21 November 2002 and resulted in brightness temperature differences approaching 0.1K for most of the spectrum. This paper presents the details of this AIRS/S-HIS validation case and also presents comparisons of Aqua AIRS and Moderate Resolution Imaging Spectroradiometer (MODIS) radiance observations. Aircraft comparisons of this type provide a mechanism for periodically testing the absolute calibration of spacecraft instruments with instrumentation for which the calibration can be carefully maintained on the ground. This capability is especially valuable for assuring the long-term consistency and accuracy of climate observations. It is expected that aircraft flights of the S-HIS and its close cousin the National Polar Orbiting Environmental Satellite System (NPOESS) Atmospheric Sounder Testbed (NAST) will be used to check the long-term stability of the NASA EOS spacecrafts (Terra, Aqua and Aura) and the follow-on complement of operational instruments, including the Cross-track Infrared Sounder (CrIS).

Dust Science with SPICA/MCS

NASA Astrophysics Data System (ADS)

Sakon, I.; Onaka, T.; Kataza, H.; Wada, T.; Sarugaku, Y.; Matsuhara, H.; Nakagawa, T.; Kobayashi, N.; Kemper, C.; Ohyama, Y.; Matsumoto, T.; Seok, J. Y.

Mid-Infrared Camera and Spectrometers (MCS) is one of the Focal-Plane Instruments proposed for the SPICA mission in the pre-project phase. SPICA MCS is equipped with two spectrometers with different spectral resolution powers (R=λ /δ λ ); medium-resolution spectrometer (MRS) which covers 12-38µ m with R≃1100-3000, and high-resolution spectrometer (HRS) which covers either 12-18µ m with R≃30000. MCS is also equipped with Wide Field Camera (WFC), which is capable of performing multi-objects grism spectroscopy in addition to the imaging observation. A small slit aperture for low-resolution slit spectroscopy is planned to be placed just next to the field of view (FOV) aperture for imaging and slit-less spectroscopic observation. MCS covers an important part of the core spectral range of SPICA and, complementary with SAFARI (SpicA FAR-infrared Instrument), can do crucial observations for a number of key science cases to revolutionize our understanding of the lifecycle of dust in the universe. In this article, the latest design specification and the expected performance of the SPICA/MCS are introduced. Key science cases that should be targetted by SPICA/MCS have been discussed by the MCS science working group. Among such science cases, some of those related to dust science are briefly introduced.

Using speech sounds to test functional spectral resolution in listeners with cochlear implants

PubMed Central

Winn, Matthew B.; Litovsky, Ruth Y.

2015-01-01

In this study, spectral properties of speech sounds were used to test functional spectral resolution in people who use cochlear implants (CIs). Specifically, perception of the /ba/-/da/ contrast was tested using two spectral cues: Formant transitions (a fine-resolution cue) and spectral tilt (a coarse-resolution cue). Higher weighting of the formant cues was used as an index of better spectral cue perception. Participants included 19 CI listeners and 10 listeners with normal hearing (NH), for whom spectral resolution was explicitly controlled using a noise vocoder with variable carrier filter widths to simulate electrical current spread. Perceptual weighting of the two cues was modeled with mixed-effects logistic regression, and was found to systematically vary with spectral resolution. The use of formant cues was greatest for NH listeners for unprocessed speech, and declined in the two vocoded conditions. Compared to NH listeners, CI listeners relied less on formant transitions, and more on spectral tilt. Cue-weighting results showed moderately good correspondence with word recognition scores. The current approach to testing functional spectral resolution uses auditory cues that are known to be important for speech categorization, and can thus potentially serve as the basis upon which CI processing strategies and innovations are tested. PMID:25786954

Fabry-Perot interferometer development for rocket engine plume spectroscopy

NASA Astrophysics Data System (ADS)

Bickford, R. L.; Madzsar, G.

1990-07-01

This paper describes a new rugged high-resolution Fabry-Perot interferometer (FPI) designed for rocket engine plume spectroscopy, which is capable of detecting spectral signatures of eroding engine components during rocket engine tests and/or flight operations. The FPI system will make it possible to predict and to respond to the incipient rocket engine failures and to indicate the presence of rocket components degradation. The design diagram of the FPI spectrometer is presented.

Fabry-Perot interferometer development for rocket engine plume spectroscopy

NASA Technical Reports Server (NTRS)

Bickford, R. L.; Madzsar, G.

1990-01-01

This paper describes a new rugged high-resolution Fabry-Perot interferometer (FPI) designed for rocket engine plume spectroscopy, which is capable of detecting spectral signatures of eroding engine components during rocket engine tests and/or flight operations. The FPI system will make it possible to predict and to respond to the incipient rocket engine failures and to indicate the presence of rocket components degradation. The design diagram of the FPI spectrometer is presented.

Processing and analysis of commercial satellite image data of the nuclear accident near Chernobyl, U.S.S.R.

USGS Publications Warehouse

Sadowski, Franklin G.; Covington, Steven J.

1987-01-01

Advanced digital processing techniques were applied to Landsat-5 Thematic Mapper (TM) data and SPOT highresolution visible (HRV) panchromatic data to maximize the utility of images of a nuclear powerplant emergency at Chernobyl in the Soviet Ukraine. The images demonstrate the unique interpretive capabilities provided by the numerous spectral bands of the Thematic Mapper and the high spatial resolution of the SPOT HRV sensor.

MISTiC Winds, a Micro-Satellite Constellation Approach to High Resolution Observations of the Atmosphere using Infrared Sounding and 3D Winds Measurements

NASA Astrophysics Data System (ADS)

Maschhoff, K. R.; Polizotti, J. J.; Aumann, H. H.; Susskind, J.

2017-12-01

MISTiCTM Winds is an approach to improve short-term weather forecasting based on a miniature high resolution, wide field, thermal emission spectrometry instrument that will provide global tropospheric vertical profiles of atmospheric temperature and humidity at high (3-4 km) horizontal and vertical ( 1 km) spatial resolution. MISTiC's extraordinarily small size, payload mass of less than 15 kg, and minimal cooling requirements can be accommodated aboard a ESPA-Class (50 kg) micro-satellite. Low fabrication and launch costs enable a LEO sun-synchronous sounding constellation that would provide frequent IR vertical profiles and vertically resolved atmospheric motion vector wind observations in the troposphere. These observations are highly complementary to present and emerging environmental observing systems, and would provide a combination of high vertical and horizontal resolution not provided by any other environmental observing system currently in operation. The spectral measurements that would be provided by MISTiC Winds are similar to those of NASA's Atmospheric Infrared Sounder. These new observations, when assimilated into high resolution numerical weather models, would revolutionize short-term and severe weather forecasting, save lives, and support key economic decisions in the energy, air transport, and agriculture arenas-at much lower cost than providing these observations from geostationary orbit. In addition, this observation capability would be a critical tool for the study of transport processes for water vapor, clouds, pollution, and aerosols. In this third year of a NASA Instrument incubator program, the compact infrared spectrometer has been integrated into an airborne version of the instrument for high-altitude flights on a NASA ER2. The purpose of these airborne tests is to examine the potential for improved capabilities for tracking atmospheric motion-vector wind tracer features, and determining their height using hyper-spectral sounding and imaging methods.

Single-frequency 3D synthetic aperture imaging with dynamic metasurface antennas.

PubMed

Boyarsky, Michael; Sleasman, Timothy; Pulido-Mancera, Laura; Diebold, Aaron V; Imani, Mohammadreza F; Smith, David R

2018-05-20

Through aperture synthesis, an electrically small antenna can be used to form a high-resolution imaging system capable of reconstructing three-dimensional (3D) scenes. However, the large spectral bandwidth typically required in synthetic aperture radar systems to resolve objects in range often requires costly and complex RF components. We present here an alternative approach based on a hybrid imaging system that combines a dynamically reconfigurable aperture with synthetic aperture techniques, demonstrating the capability to resolve objects in three dimensions (3D), with measurements taken at a single frequency. At the core of our imaging system are two metasurface apertures, both of which consist of a linear array of metamaterial irises that couple to a common waveguide feed. Each metamaterial iris has integrated within it a diode that can be biased so as to switch the element on (radiating) or off (non-radiating), such that the metasurface antenna can produce distinct radiation profiles corresponding to different on/off patterns of the metamaterial element array. The electrically large size of the metasurface apertures enables resolution in range and one cross-range dimension, while aperture synthesis provides resolution in the other cross-range dimension. The demonstrated imaging capabilities of this system represent a step forward in the development of low-cost, high-performance 3D microwave imaging systems.

Results and Lessons from a Decade of Terra MODIS On-Orbit Spectral Characterization

NASA Technical Reports Server (NTRS)

Xiong, X.; Choi, T.; Che, N.; Wang, Z.; Dodd, J.

2010-01-01

Since its launch in December 1999, the NASA EOS Terra MODIS has successfully operated for more than a decade. MODIS makes observations in 36 spectral bands from visible (VIS) to longwave infrared (LWIR) and at three nadir spatial resolutions: 250m (2 bands), 500m (5 bands), and 1km (29 bands). In addition to its on-board calibrators designed for the radiometric calibration, MODIS was built with a unique device, called the spectro-radiometric calibration assembly (SRCA). It can be configured in three different modes: radiometric, spatial, and spectral. When it is operated in the spectral modes, the SRCA can monitor changes in Sensor spectral performance for the VIS and near-infrared (NIR) spectral bands. For more than 10 years, the SRCA operation has continued to provide valuable information for MODIS on-orbit spectral performance. This paper briefly describes SRCA on-orbit operation and calibration activities; it presents decade-long spectral characterization results for Terra MODIS VIS and NIR spectral bands in terms of chances in their center wavelengths (CW) and bandwidths (BW). It is shown that the SRCA on-orbit wavelength calibration capability remains satisfactory. For most spectral bands, the changes in CW and BW are less than 0.5 and 1 nm, respectively. Results and lessons from Terra MODIS on-orbit spectral characterization have and will continue to benefit its successor, Aqua MODIS, and other future missions.

Magnetic field sensing with nitrogen-vacancy color centers in diamond

NASA Astrophysics Data System (ADS)

Pham, Linh My

In recent years, the nitrogen-vacancy (NV) center has emerged as a promising magnetic sensor capable of measuring magnetic fields with high sensitivity and spatial resolution under ambient conditions. This combination of characteristics allows NV magnetometers to probe magnetic structures and systems that were previously inaccessible with alternative magnetic sensing technologies This dissertation presents and discusses a number of the initial efforts to demonstrate and improve NV magnetometry. In particular, a wide-field CCD based NV magnetic field imager capable of micron-scale spatial resolution is demonstrated; and magnetic field alignment, preferential NV orientation, and multipulse dynamical decoupling techniques are explored for enhancing magnetic sensitivity. The further application of dynamical decoupling control sequences as a spectral probe to extract information about the dynamics of the NV spin environment is also discussed; such information may be useful for determining optimal diamond sample parameters for different applications. Finally, several proposed and recently demonstrated applications which take advantage of NV magnetometers' sensitivity and spatial resolution at room temperature are presented, with particular focus on bio-magnetic field imaging.

SEEDS Moving Groups and CHARIS Status Updates

NASA Technical Reports Server (NTRS)

McElwain, Michael

2012-01-01

We present the status update for the SEEDS Moving Groups category. To date, we have observed 59 targets and currently have more than 20 candidates. We also present the expected scientific capabilities of CHARIS, the Coronagraphic High Angular Resolution Imaging Spectrograph, which is being built for the Subaru 8.2 m telescope of the National Astronomical Observatory of Japan. CHARIS will be implemented behind the new extreme adaptive optics system at Subaru, SCExAO, and the existing 188-actuator system AO188. CHARIS will offer three observing modes over nearinfrared wavelengths from 0.9 to 2.4 microns (the y-, J-, H-, and K-bands), including a low-spectral-resolution mode covering this entire wavelength range and a high-resolution mode within a single band. With these capabilities, CHARIS will offer exceptional sensitivity for discovering giant exoplanets, and will enable detailed characterization of their atmospheres, CHARIS, the only planned high-contrast integral field spectrograph on an 8m-class telescope in the Northern Hemisphere, will complement the similar instruments such as Project 1640 at Palomar, and GPI and SPHERE in Chile.

HARDI: A high angular resolution deployable interferometer for space

NASA Technical Reports Server (NTRS)

Bely, Pierre Y.; Burrows, Christopher; Roddier, Francois; Weigelt, Gerd

1992-01-01

We describe here a proposed orbiting interferometer covering the UV, visible, and near-IR spectral ranges. With a 6-m baseline and a collecting area equivalent to about a 1.4 m diameter full aperture, this instrument will offer significant improvements in resolution over the Hubble Space Telescope, and complement the new generation of ground-based interferometers with much better limiting magnitude and spectral coverage. On the other hand, it has been designed as a considerably less ambitious project (one launch) than other current proposals. We believe that this concept is feasible given current technological capabilities, yet would serve to prove the concepts necessary for the much larger systems that must eventually be flown. The interferometer is of the Fizeau type. It therefore has a much larger field (for guiding) better UV throughout (only 4 surfaces) than phased arrays. Optimize aperture configurations and ideas for the cophasing and coalignment system are presented. The interferometer would be placed in a geosynchronous or sunsynchronous orbit to minimize thermal and mechanical disturbances and to maximize observing efficiency.

Techniques for the measurements of the line of sight velocity of high altitude Barium clouds

NASA Technical Reports Server (NTRS)

Mende, S. B.

1981-01-01

It is demonstrated that for maximizing the scientific output of future ion cloud release experiments a new type of instrument is required which will measure the line of sight velocity of the ion cloud by the Doppler Technique. A simple instrument was constructed using a 5 cm diameter solid Fabry-Perot etalon coupled to a low light level integrating television camera. It was demonstrated that the system has both the sensitivity and spectral resolution for the detection of ion clouds and the measurement of their line of sight Doppler velocity. The tests consisted of (1) a field experiment using a rocket barium cloud release to check the sensitivity, (2) laboratory experiments to show the spectral resolving capabilities of the system. The instrument was found to be operational if the source was brighter than about 1 kilorayleigh and it had a wavelength resolution much better than .2A which corresponds to about 12 km/sec or an acceleration potential of 100 volts.

Spectrum Analyzers Incorporating Tunable WGM Resonators

NASA Technical Reports Server (NTRS)

Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry; Maleki, Lute

2009-01-01

A photonic instrument is proposed to boost the resolution for ultraviolet/ optical/infrared spectral analysis and spectral imaging allowing the detection of narrow (0.00007-to-0.07-picometer wavelength resolution range) optical spectral signatures of chemical elements in space and planetary atmospheres. The idea underlying the proposal is to exploit the advantageous spectral characteristics of whispering-gallery-mode (WGM) resonators to obtain spectral resolutions at least three orders of magnitude greater than those of optical spectrum analyzers now in use. Such high resolutions would enable measurement of spectral features that could not be resolved by prior instruments.

Interplanetary Magnetic Field Power Spectrum Variations: A VHO Enabled Study

NASA Astrophysics Data System (ADS)

Szabo, A.; Koval, A.; Merka, J.; Narock, T. W.

2010-12-01

The newly reprocessed high time resolution (11/22 vectors/sec) Wind mission interplanetary magnetic field data and the solar wind key parameter search capability of the Virtual Heliospheric Observatory (VHO) affords an opportunity to study magnetic field power spectral density variations as a function of solar wind conditions. In the reprocessed Wind Magnetic Field Investigation (MFI) data, the spin tone and its harmonics are greatly reduced that allows the meaningful fitting of power spectra to the ~2 Hz limit above which digitization noise becomes apparent. The power spectral density is computed and the spectral index is fitted for the MHD and ion inertial regime separately along with the break point between the two for various solar wind conditions . The time periods of fixed solar wind conditions are obtained from VHO searches that greatly simplify the process. The functional dependence of the ion inertial spectral index and break point on solar wind plasma and magnetic field conditions will be discussed.

Interpreting forest and grassland biome productivity utilizing nested scales of image resolution and biogeographical analysis

NASA Technical Reports Server (NTRS)

Iverson, L. R.; Olson, J. S.; Risser, P. G.; Treworgy, C.; Frank, T.; Cook, E.; Ke, Y.

1986-01-01

Data acquisition, initial site characterization, image and geographic information methods available, and brief evaluations of first-year for NASA's Thematic Mapper (TM) working group are presented. The TM and other spectral data are examined in order to relate local, intensive ecosystem research findings to estimates of carbon cycling rates over wide geographic regions. The effort is to span environments ranging from dry to moist climates and from good to poor site quality using the TM capability, with and without the inclusion of geographic information system (GIS) data, and thus to interpret the local spatial pattern of factors conditioning biomass or productivity. Twenty-eight TM data sets were acquired, archived, and evaluated. The ERDAS image processing and GIS system were installed on the microcomputer (PC-AT) and its capabilities are being investigated. The TM coverage of seven study areas were exported via ELAS software on the Prime to the ERDAS system. Statistical analysis procedures to be used on the spectral data are being identified.

Compact characterization of liquid absorption and emission spectra using linear variable filters integrated with a CMOS imaging camera

PubMed Central

Wan, Yuhang; Carlson, John A.; Kesler, Benjamin A.; Peng, Wang; Su, Patrick; Al-Mulla, Saoud A.; Lim, Sung Jun; Smith, Andrew M.; Dallesasse, John M.; Cunningham, Brian T.

2016-01-01

A compact analysis platform for detecting liquid absorption and emission spectra using a set of optical linear variable filters atop a CMOS image sensor is presented. The working spectral range of the analysis platform can be extended without a reduction in spectral resolution by utilizing multiple linear variable filters with different wavelength ranges on the same CMOS sensor. With optical setup reconfiguration, its capability to measure both absorption and fluorescence emission is demonstrated. Quantitative detection of fluorescence emission down to 0.28 nM for quantum dot dispersions and 32 ng/mL for near-infrared dyes has been demonstrated on a single platform over a wide spectral range, as well as an absorption-based water quality test, showing the versatility of the system across liquid solutions for different emission and absorption bands. Comparison with a commercially available portable spectrometer and an optical spectrum analyzer shows our system has an improved signal-to-noise ratio and acceptable spectral resolution for discrimination of emission spectra, and characterization of colored liquid’s absorption characteristics generated by common biomolecular assays. This simple, compact, and versatile analysis platform demonstrates a path towards an integrated optical device that can be utilized for a wide variety of applications in point-of-use testing and point-of-care diagnostics. PMID:27389070

Compact characterization of liquid absorption and emission spectra using linear variable filters integrated with a CMOS imaging camera

NASA Astrophysics Data System (ADS)

Wan, Yuhang; Carlson, John A.; Kesler, Benjamin A.; Peng, Wang; Su, Patrick; Al-Mulla, Saoud A.; Lim, Sung Jun; Smith, Andrew M.; Dallesasse, John M.; Cunningham, Brian T.

2016-07-01

A compact analysis platform for detecting liquid absorption and emission spectra using a set of optical linear variable filters atop a CMOS image sensor is presented. The working spectral range of the analysis platform can be extended without a reduction in spectral resolution by utilizing multiple linear variable filters with different wavelength ranges on the same CMOS sensor. With optical setup reconfiguration, its capability to measure both absorption and fluorescence emission is demonstrated. Quantitative detection of fluorescence emission down to 0.28 nM for quantum dot dispersions and 32 ng/mL for near-infrared dyes has been demonstrated on a single platform over a wide spectral range, as well as an absorption-based water quality test, showing the versatility of the system across liquid solutions for different emission and absorption bands. Comparison with a commercially available portable spectrometer and an optical spectrum analyzer shows our system has an improved signal-to-noise ratio and acceptable spectral resolution for discrimination of emission spectra, and characterization of colored liquid’s absorption characteristics generated by common biomolecular assays. This simple, compact, and versatile analysis platform demonstrates a path towards an integrated optical device that can be utilized for a wide variety of applications in point-of-use testing and point-of-care diagnostics.

True resolution enhancement for optical spectroscopy

NASA Astrophysics Data System (ADS)

Cooper, Justin T.; Oleske, Jeffrey B.

2018-02-01

Resolving spectrally adjacent peaks is important for techniques, such as tracking small shifts in Raman or fluorescence spectra, quantifying pharmaceutical polymorph ratios, or molecular orientation studies. Thus, suitable spectral resolution is a vital consideration when designing most spectroscopic systems. Most parameters that influence spectral resolution are fixed for a given system (spectrometer length, grating groove density, excitation source, CCD pixel size, etc.). Inflexible systems are non-problematic if the spectrometer is dedicated for a single purpose; however, these specifications cannot be optimized for different applications with wider range resolution requirements. Data processing techniques, including peak fitting, partial least squares, or principal component analysis, are typically used to achieve sub-optical resolution information. These techniques can be plagued by spectral artifacts introduced by post-processing as well as the subjective implementation of statistical parameters. TruRes™, from Andor Technology, uses an innovative optical means to greatly improve and expand the range of spectral resolutions accessible on a single setup. True spectral resolution enhancement of >30% is achieved without mathematical spectral alteration, dataprocessing, or spectrometer component changes. Discreet characteristic spectral lines from Laser-Induced Breakdown Spectroscopy (LIBS) and atomic calibration sources are now fully resolved from spectrally-adjacent peaks under otherwise identical configuration. TruRes™ has added advantage of increasing the spectral resolution without sacrificing bandpass. Using TruRes™ the Kymera 328i resolution can approach that of a 500 mm focal spectrometer. Furthermore, the bandpass of a 500 mm spectrograph with would be 50% narrower than the Kymera 328i with all other spectrometer components constant. However, the Kymera 328i with TruRes™ is able to preserve a 50% wider bandpass.

Ocean Color Measurements from Landsat-8 OLI using SeaDAS

NASA Technical Reports Server (NTRS)

Franz, Bryan Alden; Bailey, Sean W.; Kuring, Norman; Werdell, P. Jeremy

2014-01-01

The Operational Land Imager (OLI) is a multi-spectral radiometer hosted on the recently launched Landsat-8 satellite. OLI includes a suite of relatively narrow spectral bands at 30-meter spatial resolution in the visible to shortwave infrared that make it a potential tool for ocean color radiometry: measurement of the reflected spectral radiance upwelling from beneath the ocean surface that carries information on the biogeochemical constituents of the upper ocean euphotic zone. To evaluate the potential of OLI to measure ocean color, processing support was implemented in SeaDAS, which is an open-source software package distributed by NASA for processing, analysis, and display of ocean remote sensing measurements from a variety of satellite-based multi-spectral radiometers. Here we describe the implementation of OLI processing capabilities within SeaDAS, including support for various methods of atmospheric correction to remove the effects of atmospheric scattering and absorption and retrieve the spectral remote-sensing reflectance (Rrs; sr exp 1). The quality of the retrieved Rrs imagery will be assessed, as will the derived water column constituents such as the concentration of the phytoplankton pigment chlorophyll a.

Wavelength-Scanning SPR Imaging Sensors Based on an Acousto-Optic Tunable Filter and a White Light Laser

PubMed Central

Zeng, Youjun; Wang, Lei; Wu, Shu-Yuen; He, Jianan; Qu, Junle; Li, Xuejin; Ho, Ho-Pui; Gu, Dayong; Gao, Bruce Zhi; Shao, Yonghong

2017-01-01

A fast surface plasmon resonance (SPR) imaging biosensor system based on wavelength interrogation using an acousto-optic tunable filter (AOTF) and a white light laser is presented. The system combines the merits of a wide-dynamic detection range and high sensitivity offered by the spectral approach with multiplexed high-throughput data collection and a two-dimensional (2D) biosensor array. The key feature is the use of AOTF to realize wavelength scan from a white laser source and thus to achieve fast tracking of the SPR dip movement caused by target molecules binding to the sensor surface. Experimental results show that the system is capable of completing a SPR dip measurement within 0.35 s. To the best of our knowledge, this is the fastest time ever reported in the literature for imaging spectral interrogation. Based on a spectral window with a width of approximately 100 nm, a dynamic detection range and resolution of 4.63 × 10−2 refractive index unit (RIU) and 1.27 × 10−6 RIU achieved in a 2D-array sensor is reported here. The spectral SPR imaging sensor scheme has the capability of performing fast high-throughput detection of biomolecular interactions from 2D sensor arrays. The design has no mechanical moving parts, thus making the scheme completely solid-state. PMID:28067766

HMM for hyperspectral spectrum representation and classification with endmember entropy vectors

NASA Astrophysics Data System (ADS)

Arabi, Samir Y. W.; Fernandes, David; Pizarro, Marco A.

2015-10-01

The Hyperspectral images due to its good spectral resolution are extensively used for classification, but its high number of bands requires a higher bandwidth in the transmission data, a higher data storage capability and a higher computational capability in processing systems. This work presents a new methodology for hyperspectral data classification that can work with a reduced number of spectral bands and achieve good results, comparable with processing methods that require all hyperspectral bands. The proposed method for hyperspectral spectra classification is based on the Hidden Markov Model (HMM) associated to each Endmember (EM) of a scene and the conditional probabilities of each EM belongs to each other EM. The EM conditional probability is transformed in EM vector entropy and those vectors are used as reference vectors for the classes in the scene. The conditional probability of a spectrum that will be classified is also transformed in a spectrum entropy vector, which is classified in a given class by the minimum ED (Euclidian Distance) among it and the EM entropy vectors. The methodology was tested with good results using AVIRIS spectra of a scene with 13 EM considering the full 209 bands and the reduced spectral bands of 128, 64 and 32. For the test area its show that can be used only 32 spectral bands instead of the original 209 bands, without significant loss in the classification process.

A compact "water-window" microscope with 60-nm spatial resolution based on a double stream gas-puff target and Fresnel zone plate optics

NASA Astrophysics Data System (ADS)

Wachulak, Przemyslaw; Torrisi, Alfio; Nawaz, Muhammad F.; Adjei, Daniel; Bartnik, Andrzej; Kostecki, Jerzy; Wegrzynski, Łukasz; Vondrová, Šárka; Turňová, Jana; Fok, Tomasz; Jančarek, Alexandr; Fiedorowicz, Henryk

2015-05-01

Radiation with shorter illumination wavelength allows for extension of the diffraction limit towards nanometer scale, which is a straightforward way to significantly improve a spatial resolution in photon based microscopes. Soft X-ray (SXR) radiation, from the so called "water window" spectral range, λ=2.3-4.4 nm, which is particularly suitable for biological imaging due to natural optical contrast, providing much better spatial resolution than one obtained with visible light microscopes. The high contrast is obtained because of selective absorption of radiation by carbon and water, being constituents of the biological samples. We present a desk-top system, capable of resolving 60 nm features in few seconds exposure time. We exploit the advantages of a compact, laser-plasma SXR source, based on a double stream nitrogen gas puff target, developed at the Institute of Optoelectronics, Military University of Technology. The source, emitting quasi-monochromatic, incoherent radiation, in the "water widow" spectral range at λ = 2.88 nm, is coupled with ellipsoidal, grazing incidence condenser and Fresnel zone plate objective. The construction of the microscope with some recent images of test and real samples will be presented and discussed.

BiI 3 Crystals for High Energy Resolution Gamma-Ray Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nino, Juan C.; Baciak, James; Johns, Paul

2017-04-12

BiI 3 had been investigated for its unique properties as a layered compound semiconductor for many decades. However, despite the exceptional atomic, physical, and electronic properties of this material, good resolution gamma ray spectra had never been reported for BiI 3. The shortcomings that previously prevented BiI 3 from reaching success as a gamma ray sensor were, through this project, identified and suppressed to unlock the performance of this promising compound. Included in this work were studies on a number of methods which have, for the first time, enabled BiI 3 to exhibit spectral performance rivaling many other candidate semiconductorsmore » for room temperature gamma ray sensors. New approaches to crystal growth were explored that allow BiI 3 spectrometers to be fabricated with up to 2.2% spectral resolution at 662 keV. Fundamental studies on trap states, dopant incorporation, and polarization were performed to enhance performance of this compound. Additionally, advanced detection techniques were applied to display the capabilities of high quality BiI 3 spectrometers. Overall, through this work, BiI 3 has been revealed as a potentially transformative material for nuclear security and radiation detection sciences.« less

Simultaneous measurement of stratospheric O3, H2O, CH4, and N2O profiles from infrared limb thermal emissions

NASA Technical Reports Server (NTRS)

Abbas, M. M.; Glenn, M. J.; Kunde, V. G.; Brasunas, J.; Conrath, B. J.; Maguire, W. C.; Herman, J. R.

1987-01-01

Thermal emission measurements of the earth's stratospheric limb were made with a cryogenically cooled high-resolution Michelson interferometer on a balloon flight launched from Palestine, TX, on Nov. 6, 1984. Infrared spectra for complete limb sequences were obtained over portions of the 700-1940/cm range with an unapodized spectral resolution of 0.03/cm for tangent heights varying from 13 to 39 km. The observed data from 1125 to 1425/cm have been analyzed for simultaneous measurement of O3, H2O, CH4, and N2O profiles. The analysis employs line-by-line and layer-by-layer radiative-transfer calculations, including curvature and refraction effects. The optimum use of geometric and spectral effects is made to obtain sharply peaked weighting functions. Contributions from stratospheric aerosol are included by measuring the light extinction within the window regions of the observed spectra. The retrieved constituent profiles are compared with measurements made with a variety of techniques by other groups. The comparison shows good agreement with the published data for all gases, indicating the capability of retrieving trace gas profiles from high-resolution thermal emission limb measurements.

Endoscopic optical coherence tomography with a focus-adjustable probe.

PubMed

Liao, Wenchao; Chen, Tianyuan; Wang, Chengming; Zhang, Wenxin; Peng, Zhangkai; Zhang, Xiao; Ai, Shengnan; Fu, Deyong; Zhou, Tieying; Xue, Ping

2017-10-15

We present a focus-adjustable endoscopic probe for optical coherence tomography (OCT), which is able to acquire images with different focal planes and overcome depth-of-focus limitations by image fusing. The use of a two-way shape-memory-alloy spring enables the probe to adjust working distance over 1.5 mm, providing a large scanning range with high resolution and no sensitivity loss. Equipped with a homemade hollow-core ultrasonic motor, the probe is capable of performing an unobstructed 360 deg field-of-view distal scanning. Both the axial resolution and the best lateral resolution are ∼4  μm, with a sensitivity of 100.3 dB. Spectral-domain OCT imaging of phantom and biological tissues with the probe is also demonstrated.

Tip-enhanced ablation and ionization mass spectrometry for nanoscale chemical analysis

PubMed Central

Liang, Zhisen; Zhang, Shudi; Li, Xiaoping; Wang, Tongtong; Huang, Yaping; Hang, Wei; Yang, Zhilin; Li, Jianfeng; Tian, Zhongqun

2017-01-01

Spectroscopic methods with nanoscale lateral resolution are becoming essential in the fields of physics, chemistry, geology, biology, and materials science. However, the lateral resolution of laser-based mass spectrometry imaging (MSI) techniques has so far been limited to the microscale. This report presents the development of tip-enhanced ablation and ionization time-of-flight mass spectrometry (TEAI-TOFMS), using a shell-isolated apertureless silver tip. The TEAI-TOFMS results indicate the capability and reproducibility of the system for generating nanosized craters and for acquiring the corresponding mass spectral signals. Multi-elemental analysis of nine inorganic salt residues and MSI of a potassium salt residue pattern at a 50-nm lateral resolution were achieved. These results demonstrate the opportunity for the distribution of chemical compositions at the nanoscale to be visualized. PMID:29226250

Space telescope scientific instruments

NASA Technical Reports Server (NTRS)

Leckrone, D. S.

1979-01-01

The paper describes the Space Telescope (ST) observatory, the design concepts of the five scientific instruments which will conduct the initial observatory observations, and summarizes their astronomical capabilities. The instruments are the wide-field and planetary camera (WFPC) which will receive the highest quality images, the faint-object camera (FOC) which will penetrate to the faintest limiting magnitudes and achieve the finest angular resolution possible, and the faint-object spectrograph (FOS), which will perform photon noise-limited spectroscopy and spectropolarimetry on objects substantially fainter than those accessible to ground-based spectrographs. In addition, the high resolution spectrograph (HRS) will provide higher spectral resolution with greater photometric accuracy than previously possible in ultraviolet astronomical spectroscopy, and the high-speed photometer will achieve precise time-resolved photometric observations of rapidly varying astronomical sources on short time scales.

Airborne measurements in the infrared using FTIR-based imaging hyperspectral sensors

NASA Astrophysics Data System (ADS)

Puckrin, E.; Turcotte, C. S.; Lahaie, P.; Dubé, D.; Lagueux, P.; Farley, V.; Marcotte, F.; Chamberland, M.

2009-09-01

Hyperspectral ground mapping is being used in an ever-increasing extent for numerous applications in the military, geology and environmental fields. The different regions of the electromagnetic spectrum help produce information of differing nature. The visible, near-infrared and short-wave infrared radiation (400 nm to 2.5 μm) has been mostly used to analyze reflected solar light, while the mid-wave (3 to 5 μm) and long-wave (8 to 12 μm or thermal) infrared senses the self-emission of molecules directly, enabling the acquisition of data during night time. Push-broom dispersive sensors have been typically used for airborne hyperspectral mapping. However, extending the spectral range towards the mid-wave and long-wave infrared brings performance limitations due to the self emission of the sensor itself. The Fourier-transform spectrometer technology has been extensively used in the infrared spectral range due to its high transmittance as well as throughput and multiplex advantages, thereby reducing the sensor self-emission problem. Telops has developed the Hyper-Cam, a rugged and compact infrared hyperspectral imager. The Hyper-Cam is based on the Fourier-transform technology yielding high spectral resolution and enabling high accuracy radiometric calibration. It provides passive signature measurement capability, with up to 320x256 pixels at spectral resolutions of up to 0.25 cm-1. The Hyper-Cam has been used on the ground in several field campaigns, including the demonstration of standoff chemical agent detection. More recently, the Hyper-Cam has been integrated into an airplane to provide airborne measurement capabilities. A special pointing module was designed to compensate for airplane attitude and forward motion. To our knowledge, the Hyper-Cam is the first commercial airborne hyperspectral imaging sensor based on Fourier-transform infrared technology. The first airborne measurements and some preliminary performance criteria for the Hyper-Cam are presented in this paper.

Airborne measurements in the infrared using FTIR-based imaging hyperspectral sensors

NASA Astrophysics Data System (ADS)

Puckrin, E.; Turcotte, C. S.; Lahaie, P.; Dubé, D.; Farley, V.; Lagueux, P.; Marcotte, F.; Chamberland, M.

2009-05-01

Hyperspectral ground mapping is being used in an ever-increasing extent for numerous applications in the military, geology and environmental fields. The different regions of the electromagnetic spectrum help produce information of differing nature. The visible, near-infrared and short-wave infrared radiation (400 nm to 2.5 μm) has been mostly used to analyze reflected solar light, while the mid-wave (3 to 5 μm) and long-wave (8 to 12 μm or thermal) infrared senses the self-emission of molecules directly, enabling the acquisition of data during night time. Push-broom dispersive sensors have been typically used for airborne hyperspectral mapping. However, extending the spectral range towards the mid-wave and long-wave infrared brings performance limitations due to the self emission of the sensor itself. The Fourier-transform spectrometer technology has been extensively used in the infrared spectral range due to its high transmittance as well as throughput and multiplex advantages, thereby reducing the sensor self-emission problem. Telops has developed the Hyper-Cam, a rugged and compact infrared hyperspectral imager. The Hyper-Cam is based on the Fourier-transform technology yielding high spectral resolution and enabling high accuracy radiometric calibration. It provides passive signature measurement capability, with up to 320x256 pixels at spectral resolutions of up to 0.25 cm-1. The Hyper-Cam has been used on the ground in several field campaigns, including the demonstration of standoff chemical agent detection. More recently, the Hyper-Cam has been integrated into an airplane to provide airborne measurement capabilities. A special pointing module was designed to compensate for airplane attitude and forward motion. To our knowledge, the Hyper-Cam is the first commercial airborne hyperspectral imaging sensor based on Fourier-transform infrared technology. The first airborne measurements and some preliminary performance criteria for the Hyper-Cam are presented in this paper.

A study of aerosol absorption and height retrievals with a hyperspectral (UV to NIR) passive sensor

NASA Astrophysics Data System (ADS)

Gasso, S.

2017-12-01

With the deployment of the first sensor (TOMS, in 1978) with capabilities to detect aerosol absorption (AA) from space, there has been a continuous evolution in hardware and algorithms used to measured this property. Although with TOMS and its more advanced successors (such as OMI) made significant progress in globally characterizing AA , there is room for improvement especially by taking advantage of sensors with extended spectral coverage (UV to NIR) and high spatial resolution (<1 km). While such unique sensor does not exist yet, the collocation of observations from different platforms that jointly fulfill those characteristics (e.g. A-Train, S-NPP) confirm that it is possible to fully retrieve all AA parameters that modulate absorption in the upwelling radiance (AOD, SSA and aerosol layer height). However, such combined approaches still have some drawbacks such as the difficulty to account for cloud contamination. The upcoming deployment of satellite detectors with the desired features all in one sensor (PACE, TropOMI, GEMS) prompt a revision of the AA retrieval technique used in past approaches. In particular,the TropOMI mission, a hyperspectral UV-to-NIR sensor with moderate ( 5km nadir pixel) spatial resolution to be launched in Fall 2017. In addition , the sensor will include sensing capabilities for the wavelength range of the Oxygen bands A and B at very high wavelength resolution. This study will be centered on the aerosol detection capabilities of TropOMI. Because the spectral range covered, it is theoretically possible to simultaneously retrieve the aerosol optical depth, the single scattering albedo and aerosol mean height without assuming any of them as it was the case with previous retrieval approaches. Specifically, we intend to present a theoretical study based on simulated radiances at selected UV, VIS and near-IR bands (including the Oxygen bands) and evaluate the sensitivity of this sensor to different levels of aerosol concentration, height and absorption properties (imaginary index) along with particle size distribution.

Comparing different approaches for an effective monitoring of forest fires based on MSG/SEVIRI images

NASA Astrophysics Data System (ADS)

Laneve, Giovanni

2010-05-01

The remote sensing sensors on board of geostationary satellite, as consequence of the high frequency of the observations, allow, in principle, the monitoring of these phenomena characterized by a fast dynamics. The only condition for is that the events to be monitored should be enough strong to be recognizable notwithstanding the low spatial resolution of the present geostationary systems (MSG/SEVIRI, GOES Imager, MTSAT). Apart from meteorological phenomena other events, like those associated with forest fires and/or volcanic eruption, are characterized by a very fast dynamics. These events are also associated with a very strong signal that make them observable by geostationary satellite in a quasi-continuous way. However, in order to make possible the detection of small fires by using the low resolution multi-spectral imagery provided by geostationary sensor like SEVIRI (3x3 km2 at the equator) new algorithms, capable to exploit it high observation frequency, has been developed. This paper is devoted to show the results obtained by comparing some of these algorithms trying to highlight their advantages and limits. The algorithms herein considered are these developed by CRPSM (SFIDE®), UNIBAS/CNR (RST-FIRES) and ESA-ESRIN (MDIFRM). In general, the new approaches proposed by each one of them are capable to promptly detect small fires making possible an operational utilization of the satellite based fire detection system in the fire fighting phases. In fact, these algorithms are quite different from these introduced in the past and specifically devoted to fire detection using low resolution multi-spectral imagery on LEO (Low Earth Orbit) satellite. Thanks to these differences they are capable of detecting sub-hectare (0.2 ha) forest fires providing an useful instrument for monitoring quasi-continuously forest fires, estimating the FRP (Fire Radiative Power), evaluating the burned biomass, retrieving the emission in the atmosphere.

Handling of huge multispectral image data volumes from a spectral hole burning device (SHBD)

NASA Astrophysics Data System (ADS)

Graff, Werner; Rosselet, Armel C.; Wild, Urs P.; Gschwind, Rudolf; Keller, Christoph U.

1995-06-01

We use chlorin-doped polymer films at low temperatures as the primary imaging detector. Based on the principles of persistent spectral hole burning, this system is capable of storing spatial and spectral information simultaneously in one exposure with extremely high resolution. The sun as an extended light source has been imaged onto the film. The information recorded amounts to tens of GBytes. This data volume is read out by scanning the frequency of a tunable dye laser and reading the images with a digital CCD camera. For acquisition, archival, processing, and visualization, we use MUSIC (MUlti processor System with Intelligent Communication), a single instruction multiple data parallel processor system equipped with the necessary I/O facilities. The huge amount of data requires the developemnt of sophisticated algorithms to efficiently calibrate the data and to extract useful and new information for solar physics.

The rationale and suggested approaches for research geosynchronous satellite measurements for severe storm and mesoscale investigations

NASA Technical Reports Server (NTRS)

Shenk, W. E.; Adler, R. F.; Chesters, D.; Susskind, J.; Uccellini, L.

1984-01-01

The measurements from current and planned geosynchronous satellites provide quantitative estimates of temperature and moisture profiles, surface temperature, wind, cloud properties, and precipitation. A number of significant observation characteristics remain, they include: (1) temperature and moisture profiles in cloudy areas; (2) high vertical profile resolution; (3) definitive precipitation area mapping and precipitation rate estimates on the convective cloud scale; (4) winds from low level cloud motions at night; (5) the determination of convective cloud structure; and (6) high resolution surface temperature determination. Four major new observing capabilities are proposed to overcome these deficiencies: a microwave sounder/imager, a high resolution visible and infrared imager, a high spectral resolution infrared sounder, and a total ozone mapper. It is suggested that the four sensors are flown together and used to support major mesoscale and short range forecasting field experiments.

UWB Tracking System Design with TDOA Algorithm

NASA Technical Reports Server (NTRS)

Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Phan, Chau; Gross, Julia; Dusl, John; Schwing, Alan

2006-01-01

This presentation discusses an ultra-wideband (UWB) tracking system design effort using a tracking algorithm TDOA (Time Difference of Arrival). UWB technology is exploited to implement the tracking system due to its properties, such as high data rate, fine time resolution, and low power spectral density. A system design using commercially available UWB products is proposed. A two-stage weighted least square method is chosen to solve the TDOA non-linear equations. Matlab simulations in both two-dimensional space and three-dimensional space show that the tracking algorithm can achieve fine tracking resolution with low noise TDOA data. The error analysis reveals various ways to improve the tracking resolution. Lab experiments demonstrate the UWBTDOA tracking capability with fine resolution. This research effort is motivated by a prototype development project Mini-AERCam (Autonomous Extra-vehicular Robotic Camera), a free-flying video camera system under development at NASA Johnson Space Center for aid in surveillance around the International Space Station (ISS).

MODTRAN3: Suitability as a flux-divergence code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, G.P.; Chetwynd, J.H.; Wang, J.

1995-04-01

The Moderate Resolution Atmospheric Radiance and Transmittance Model (MODTRAN3) is the developmental version of MODTRAN and MODTRAN2. The Geophysics Directorate, Phillips Laboratory, released a beta version of this model in October 1994. It encompasses all the capabilities of LOWTRAN7, the historic 20 cm{sup -1} resolution (full width at half maximum, FWHM) radiance code, but incorporates a much more sensitive molecular band model with 2 cm{sup -1} resolution. The band model is based directly upon the HITRAN spectral parameters, including both temperature and pressure (line shape) dependencies. Validation against full Voigt line-by-line calculations (e.g., FASCODE) has shown excellent agreement. In addition,more » simple timing runs demonstrate potential improvement of more than a factor of 100 for a typical 500 cm{sup -1} spectral interval and comparable vertical layering. Not only is MODTRAN an excellent band model for {open_quotes}full path{close_quotes} calculations (that is, radiance and/or transmittance from point A to point B), but it replicates layer-specific quantities to a very high degree of accuracy. Such layer quantities, derived from ratios and differences of longer path MODTRAN calculations from point A to adjacent layer boundaries, can be used to provide inversion algorithm weighting functions or similarly formulated quantities. One of the most exciting new applications is the rapid calculation of reliable IR cooling rates, including species, altitude, and spectral distinctions, as well as the standard spectrally integrated quantities. Comparisons with prior line-by-line cooling rate calculations are excellent, and the techniques can be extended to incorporate global climatologies of both standard and trace atmospheric species.« less

sCMOS detector for imaging VNIR spectrometry

NASA Astrophysics Data System (ADS)

Eckardt, Andreas; Reulke, Ralf; Schwarzer, Horst; Venus, Holger; Neumann, Christian

2013-09-01

The facility Optical Information Systems (OS) at the Robotics and Mechatronics Center of the German Aerospace Center (DLR) has more than 30 years of experience with high-resolution imaging technology. This paper shows the scientific results of the institute of leading edge instruments and focal plane designs for EnMAP VIS/NIR spectrograph. EnMAP (Environmental Mapping and Analysis Program) is one of the selected proposals for the national German Space Program. The EnMAP project includes the technological design of the hyper spectral space borne instrument and the algorithms development of the classification. The EnMAP project is a joint response of German Earth observation research institutions, value-added resellers and the German space industry like Kayser-Threde GmbH (KT) and others to the increasing demand on information about the status of our environment. The Geo Forschungs Zentrum (GFZ) Potsdam is the Principal Investigator of EnMAP. DLR OS and KT were driving the technology of new detectors and the FPA design for this project, new manufacturing accuracy and on-chip processing capability in order to keep pace with the ambitious scientific and user requirements. In combination with the engineering research, the current generations of space borne sensor systems are focusing on VIS/NIR high spectral resolution to meet the requirements on earth and planetary observation systems. The combination of large swath and high spectral resolution with intelligent synchronization control, fast-readout ADC chains and new focal-plane concepts open the door to new remote-sensing and smart deep space instruments. The paper gives an overview over the detector verification program at DLR on FPA level, new control possibilities for sCMOS detectors in global shutter mode and key parameters like PRNU, DSNU, MTF, SNR, Linearity, Spectral Response, Quantum Efficiency, Flatness and Radiation Tolerance will be discussed in detail.

Satellite image fusion based on principal component analysis and high-pass filtering.

PubMed

Metwalli, Mohamed R; Nasr, Ayman H; Allah, Osama S Farag; El-Rabaie, S; Abd El-Samie, Fathi E

2010-06-01

This paper presents an integrated method for the fusion of satellite images. Several commercial earth observation satellites carry dual-resolution sensors, which provide high spatial resolution or simply high-resolution (HR) panchromatic (pan) images and low-resolution (LR) multi-spectral (MS) images. Image fusion methods are therefore required to integrate a high-spectral-resolution MS image with a high-spatial-resolution pan image to produce a pan-sharpened image with high spectral and spatial resolutions. Some image fusion methods such as the intensity, hue, and saturation (IHS) method, the principal component analysis (PCA) method, and the Brovey transform (BT) method provide HR MS images, but with low spectral quality. Another family of image fusion methods, such as the high-pass-filtering (HPF) method, operates on the basis of the injection of high frequency components from the HR pan image into the MS image. This family of methods provides less spectral distortion. In this paper, we propose the integration of the PCA method and the HPF method to provide a pan-sharpened MS image with superior spatial resolution and less spectral distortion. The experimental results show that the proposed fusion method retains the spectral characteristics of the MS image and, at the same time, improves the spatial resolution of the pan-sharpened image.

Solar Confocal Interferometers for Sub-Picometer-Resolution Spectral Filters

NASA Technical Reports Server (NTRS)

Gary, G. Allen; Pietraszewski, Chris; West, Edward A.; Dines, Terence C.

2006-01-01

The confocal Fabry-Perot interferometer allows sub-picometer spectral resolution of Fraunhofer line profiles. Such high spectral resolution is needed to keep pace with the higher spatial resolution of the new set of large-aperture solar telescopes. The line-of-sight spatial resolution derived for line profile inversions would then track the improvements of the transverse spatial scale provided by the larger apertures. The confocal interferometer's unique properties allow a simultaneous increase in both etendue and spectral power. Methods: We have constructed and tested two confocal interferometers. Conclusions: In this paper we compare the confocal interferometer with other spectral imaging filters, provide initial design parameters, show construction details for two designs, and report on the laboratory test results for these interferometers, and propose a multiple etalon system for future testing of these units and to obtain sub-picometer spectral resolution information on the photosphere in both the visible and near-infrared.

Atmospheric Transmission and Particle Size Measurements, Proceedings of Workshop: 23-25 October 1979, Dayton Ohio

DTIC Science & Technology

1980-05-01

102 17. A Feasibility Study: Application of Lidar Transmission Measurement in the Slant Visual Range Problem - Ronald H. Kohl 108 18. Multiwavelength ...discrete filters gives greater spectral resolution over the whole band. The success of the Model 14-703 System led to the development of a more advanced...REQUIREMENTS Success in a wide range of atmospheric transmission measurement applications has led to the reqi,-st for more advanced capabilities which are listed

An Advanced SAGE III Instrument on the International Space Station

NASA Astrophysics Data System (ADS)

McCormick, M. P.; Zawodny, J. M.

2016-12-01

An improved and more capable SAGE III instrument is scheduled to be launched in November 2016 to the International Space Station. It will combine the experience and capabilities of its successful predecessor satellite instruments SAM II, SAGE, SAGE II, and SAGE III-Meteor to measure aerosol, cloud, O3, H2O, and NO2 profiles from the upper troposphere through the stratosphere. In addition to solar and lunar occultation with vertical resolutions of about 1.0 km, SAGE III-ISS will make limb scattering measurements on the solar side of each orbit greatly expanding the measurement coverage per spacecraft orbit, and tying in the very high resolution and precise solar occultation measurements with the limb scattering measurements. The new design incorporates an array detector that enhances its measurement capability and should allow for experimental data products like BrO, and IO, and along with a single photodiode detector the measurement of larger aerosols. The wavelengths covered by SAGE III-ISS range from 280 to 1040 nm with 1 to 2 mm spectral resolution using a grating spectrometer. The single photodiode extends measurements to 1550 nm. This talk will describe the measurement capabilities of SAGE III, its additional modes and increased geographical coverage, its calibration and characterization, and data archival and validation approach. In addition, examples of past data products important to climate, and ozone recovery, will be discussed as will the expanded contributions from SAGE III-ISS.

Infrared Astrophysics in the SOFIA Era - An Overview

NASA Astrophysics Data System (ADS)

Yorke, Harold W.

2018-06-01

The Stratospheric Observatory for Infrared Astronomy (SOFIA) provides the international astronomical community access to a broad range of instrumentation that covers wavelengths spanning the near to far infrared. The high spectral resolution of many of these instruments in several wavelength bands is unmatched by any existing or near future planned facility. The far infrared polarization capabilities of one of its instruments, HAWC+, is also unique. Moreover, SOFIA allows for additional instrument augmentations, as new state-of-the-art photometric, spectrometric, and polarimetric capabilities have been added and are being further improved. The fact that SOFIA provides ample mass, power, computing capabilities as well as 4K cooling eases the constraints on future instrument design, technical readiness, and the instrument build to an extent not possible for space-borne missions. We will review SOFIA's current and future planned capabilities and highlight specific science areas for which the stratospheric observatory will be able to significantly advance Origins science topics.

Distribution of H2O and CO2 in the inner coma of 67P/CG as observed by VIRTIS-M onboard Rosetta

NASA Astrophysics Data System (ADS)

Capaccioni, F.

2015-10-01

VIRTIS (Visible, Infrared and Thermal Imaging Spectrometers) is a dual channel spectrometer; VIRTIS-M (M for Mapper) is a hyper-spectral imager covering a wide spectral range with two detectors: a CCD (VIS) ranging from 0.25 through 1.0 μm and an HgCdTe detector (IR) covering the 1.0 through 5.1 μm region. VIRTIS-M uses a slit and a scan mirror to generate images with spatial resolution of 250 μrad over a FOV of 64 mrad. The second channel is VIRTIS-H (H for High resolution), a point spectrometer with high spectral resolution (λ/Δλ=3000@3 μm) in the range 2-5 μm [1].The VIRTIS instrument has been used to investigate the molecular composition of the coma of 67P/CG by observing resonant fluorescent excitation in the 2 to 5 μm spectral region. The spectrum consists of emission bands superimposed on a background continuum. The strongest features are the bands of H2O at 2.7 μm and the CO2 band at 4.27 μm [1]. The high spectral resolution of VIRTIS-H obtains a detailed description of the fluorescent bands, while the mapping capability of VIRTIS-M extends the coverage in the spatial dimension to map and monitor the abundance of water and carbon dioxide in space and time. We have already reported [2,3,4] some preliminary observations by VIRTIS of H2O and CO2 in the coma. In the present work we perform a systematic mapping of the distribution and variability of these molecules using VIRTIS-M measurements of their band areas. All the spectra were carefully selected to avoid contamination due to nucleus radiance. A median filter is applied on the spatial dimensions of each data cube to minimise the pixel-to-pixel residual variability. This is at the expense of some reduction in the spatial resolution, which is still in the order of few tens of metres and thus adequate for the study of the spatial distribution of the volatiles. Typical spectra are shown in Figure 1

Spectral and temporal resolutions of information-bearing acoustic changes for understanding vocoded sentencesa)

PubMed Central

Stilp, Christian E.; Goupell, Matthew J.

2015-01-01

Short-time spectral changes in the speech signal are important for understanding noise-vocoded sentences. These information-bearing acoustic changes, measured using cochlea-scaled entropy in cochlear implant simulations [CSECI; Stilp et al. (2013). J. Acoust. Soc. Am. 133(2), EL136–EL141; Stilp (2014). J. Acoust. Soc. Am. 135(3), 1518–1529], may offer better understanding of speech perception by cochlear implant (CI) users. However, perceptual importance of CSECI for normal-hearing listeners was tested at only one spectral resolution and one temporal resolution, limiting generalizability of results to CI users. Here, experiments investigated the importance of these informational changes for understanding noise-vocoded sentences at different spectral resolutions (4–24 spectral channels; Experiment 1), temporal resolutions (4–64 Hz cutoff for low-pass filters that extracted amplitude envelopes; Experiment 2), or when both parameters varied (6–12 channels, 8–32 Hz; Experiment 3). Sentence intelligibility was reduced more by replacing high-CSECI intervals with noise than replacing low-CSECI intervals, but only when sentences had sufficient spectral and/or temporal resolution. High-CSECI intervals were more important for speech understanding as spectral resolution worsened and temporal resolution improved. Trade-offs between CSECI and intermediate spectral and temporal resolutions were minimal. These results suggest that signal processing strategies that emphasize information-bearing acoustic changes in speech may improve speech perception for CI users. PMID:25698018

A New Satellite Aerosol Retrieval Using High Spectral Resolution Oxygen A-Band Measurements

NASA Astrophysics Data System (ADS)

Winker, D. M.; Zhai, P.

2014-12-01

Efforts to advance current satellite aerosol retrieval capabilities have mostly focused on polarimetric techniques. While there has been much interest in recent decades in the use of the oxygen A-band for retrievals of cloud height or surface pressure, these techniques are mostly based on A-band measurements with relatively low spectral resolution. We report here on a new aerosol retrieval technique based on high-resolution A-band spectra. Our goal is the development of a technique to retrieve aerosol absorption, one of the critical parameters affecting the global radiation budget and one which is currently poorly constrained by satellite measurements. Our approach relies on two key factors: 1) the use of high spectral resolution measurements which resolve the A-band line structure, and 2) the use of co-located lidar profile measurements to constrain the vertical distribution of scatterers. The OCO-2 satellite, launched in July this year and now flying in formation with the CALIPSO satellite, carries an oxygen A-band spectrometer with a spectral resolution of 21,000:1. This is sufficient to resolve the A-band line structure, which contains information on atmospheric photon path lengths. Combining channels with oxygen absorption ranging from weak to strong allows the separation of atmospheric and surface scattering. An optimal estimation algorithm for simultaneous retrieval of aerosol optical depth, aerosol absorption, and surface albedo has been developed. Lidar profile data is used for scene identification and to provide constraints on the vertical distribution of scatterers. As calibrated OCO-2 data is not expected until the end of this year, the algorithm has been developed and tested using simulated OCO-2 spectra. The simulations show that AOD and surface albedo can be retrieved with high accuracy. Retrievals of aerosol single scatter albedo are encouraging, showing good performance when AOD is larger than about 0.15. Retrieval performance improves as the albedo of the underlying surface increases. Thus, the technique shows great promise for retrieving the absorption optical depth of aerosols located above clouds. This presentation will discuss the basis of the approach and results of the A-band/lidar retrievals based on simulated data.

High resolution Fouier transform spectrometer Serial No. 091002: Instruction manual

NASA Technical Reports Server (NTRS)

1971-01-01

A description of the spectrometer and procedures for its operation, maintenance, alignments, adjustments, and control functions are presented. The interferometer spectrometer is a modified Model 296 capable of 0.5/cm resolution over the spectral region of 5 to 15 microns configured for operation with the optical head at a temperature of approximately 80 K. Details are given on the optical system and the electronic circuits. The detector used with the optical head is mercury doped germanium kept at a temperature of about 4 K by means of liquid helium. Electronic schematics, and instruction manuals for handling the liquid helium dewars, tape recorder for analog outputs, and playback console are included.

Remote sensing of tropospheric constituents by OMI on the EOS Aura satellite

NASA Technical Reports Server (NTRS)

Bhartia, Pawan K.

2006-01-01

The Ozone Monitoring Instrument (OMI) was launched on NASA's EOS Aura satellite in July 2004. This instrument was built in the Netherlands with collaboration with Finland. The science data products are being developed jointly by scientists from the three countries. OMI is the first instrument to combine the high spatial resolution daily global mapping capability of TOMS with high spectral resolution measurements necessary for retrieving a number of trace gases of relevance to atmospheric chemistry, using techniques pioneered by GOME. In this talk I will show what our planet looks like at UV wavelengths and what these data can tell us about the effects of human activities on global air quality and climate.

Sub-Nanosecond Cinematography In Laser Fusion Research: Current Techniques And Applications At The Lawrence Livermore National Laboratory*

NASA Astrophysics Data System (ADS)

Coleman, Lamar W...

1985-02-01

Progress in laser fusion research has increased the need for detail and precision in the diagnosis of experiments. This has spawned the development and use of sophisticated sub-nanosecond resolution diavostic systems. These systems typically use ultrafast x-ray or optical streak caAleras in combination. with spatially imaging or spectrally dispersing elements. These instruments provide high resolution data essential for understanding the processes occurrilltg in the interaction. of high. intensity laser light with targets. Several of these types of instruments and their capabilities will be discussed. The utilization of these kinds of diagnostics systems on the nearly completed 100 kJ Nova laser facility will be described.

Sub-nanosecond cinematography in laser fusion research: Current techniques and applications at the Lawrence Livermore Laboratory

NASA Astrophysics Data System (ADS)

Coleman, L. W.

1985-01-01

Progress in laser fusion research has increased the need for detail and precision in the diagnosis of experiments. This has spawned the development and use of sophisticated sub-nanosecond resolution diagnostic systems. These systems typically use ultrafast X-ray or optical streak cameras in combination with spatially imaging or spectrally dispersing elements. These instruments provide high resolution data essential for understanding the processes occurring in the interaction of high intensity laser light with targets. Several of these types of instruments and their capabilities will be discussed. The utilization of these kinds of diagnostics systems on the nearly completed 100 kJ Nova laser facility will be described.

Fusion of Modis and Palsar Principal Component Images Through Curvelet Transform for Land Cover Classification

NASA Astrophysics Data System (ADS)

Singh, Dharmendra; Kumar, Harish

Earth observation satellites provide data that covers different portions of the electromagnetic spectrum at different spatial and spectral resolutions. The increasing availability of information products generated from satellite images are extending the ability to understand the patterns and dynamics of the earth resource systems at all scales of inquiry. In which one of the most important application is the generation of land cover classification from satellite images for understanding the actual status of various land cover classes. The prospect for the use of satel-lite images in land cover classification is an extremely promising one. The quality of satellite images available for land-use mapping is improving rapidly by development of advanced sensor technology. Particularly noteworthy in this regard is the improved spatial and spectral reso-lution of the images captured by new satellite sensors like MODIS, ASTER, Landsat 7, and SPOT 5. For the full exploitation of increasingly sophisticated multisource data, fusion tech-niques are being developed. Fused images may enhance the interpretation capabilities. The images used for fusion have different temporal, and spatial resolution. Therefore, the fused image provides a more complete view of the observed objects. It is one of the main aim of image fusion to integrate different data in order to obtain more information that can be de-rived from each of the single sensor data alone. A good example of this is the fusion of images acquired by different sensors having a different spatial resolution and of different spectral res-olution. Researchers are applying the fusion technique since from three decades and propose various useful methods and techniques. The importance of high-quality synthesis of spectral information is well suited and implemented for land cover classification. More recently, an underlying multiresolution analysis employing the discrete wavelet transform has been used in image fusion. It was found that multisensor image fusion is a tradeoff between the spectral information from a low resolution multi-spectral images and the spatial information from a high resolution multi-spectral images. With the wavelet transform based fusion method, it is easy to control this tradeoff. A new transform, the curvelet transform was used in recent years by Starck. A ridgelet transform is applied to square blocks of detail frames of undecimated wavelet decomposition, consequently the curvelet transform is obtained. Since the ridgelet transform possesses basis functions matching directional straight lines therefore, the curvelet transform is capable of representing piecewise linear contours on multiple scales through few significant coefficients. This property leads to a better separation between geometric details and background noise, which may be easily reduced by thresholding curvelet coefficients before they are used for fusion. The Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) instrument provides high radiometric sensitivity (12 bit) in 36 spectral bands ranging in wavelength from 0.4 m to 14.4 m and also it is freely available. Two bands are imaged at a nominal resolution of 250 m at nadir, with five bands at 500 m, and the remaining 29 bands at 1 km. In this paper, the band 1 of spatial resolution 250 m and bandwidth 620-670 nm, and band 2, of spatial resolution of 250m and bandwidth 842-876 nm is considered as these bands has special features to identify the agriculture and other land covers. In January 2006, the Advanced Land Observing Satellite (ALOS) was successfully launched by the Japan Aerospace Exploration Agency (JAXA). The Phased Arraytype L-band SAR (PALSAR) sensor onboard the satellite acquires SAR imagery at a wavelength of 23.5 cm (frequency 1.27 GHz) with capabilities of multimode and multipolarization observation. PALSAR can operate in several modes: the fine-beam single (FBS) polarization mode (HH), fine-beam dual (FBD) polariza-tion mode (HH/HV or VV/VH), polarimetric (PLR) mode (HH/HV/VH/VV), and ScanSAR (WB) mode (HH/VV) [15]. These makes PALSAR imagery very attractive for spatially and temporally consistent monitoring system. The Overview of Principal Component Analysis is that the most of the information within all the bands can be compressed into a much smaller number of bands with little loss of information. It allows us to extract the low-dimensional subspaces that capture the main linear correlation among the high-dimensional image data. This facilitates viewing the explained variance or signal in the available imagery, allowing both gross and more subtle features in the imagery to be seen. In this paper we have explored the fusion technique for enhancing the land cover classification of low resolution satellite data espe-cially freely available satellite data. For this purpose, we have considered to fuse the PALSAR principal component data with MODIS principal component data. Initially, the MODIS band 1 and band 2 is considered, its principal component is computed. Similarly the PALSAR HH, HV and VV polarized data are considered, and there principal component is also computed. con-sequently, the PALSAR principal component image is fused with MODIS principal component image. The aim of this paper is to analyze the effect of classification accuracy on major type of land cover types like agriculture, water and urban bodies with fusion of PALSAR data to MODIS data. Curvelet transformation has been applied for fusion of these two satellite images and Minimum Distance classification technique has been applied for the resultant fused image. It is qualitatively and visually observed that the overall classification accuracy of MODIS image after fusion is enhanced. This type of fusion technique may be quite helpful in near future to use freely available satellite data to develop monitoring system for different land cover classes on the earth.

Low-Temperature Single Carbon Nanotube Spectroscopy of sp 3 Quantum Defects

DOE PAGES

He, Xiaowei; Gifford, Brendan J.; Hartmann, Nicolai F.; ...

2017-09-28

Aiming to unravel the relationship between chemical configuration and electronic structure of sp3 defects of aryl-functionalized (6,5) single-walled carbon nanotubes (SWCNTs), we perform low-temperature single nanotube photoluminescence (PL) spectroscopy studies and correlate our observations with quantum chemistry simulations. Here, we observe sharp emission peaks from individual defect sites that are spread over an extremely broad, 1000-1350 nm, spectral range. Our simulations allow us to attribute this spectral diversity to the occurrence of six chemically and energetically distinct defect states resulting from topological variation in the chemical binding configuration of the monovalent aryl groups. Both PL emission efficiency and spectral linemore » width of the defect states are strongly influenced by the local dielectric environment. Wrapping the SWCNT with a polyfluorene polymer provides the best isolation from the environment and yields the brightest emission with near-resolution limited spectral line width of 270 ueV, as well as spectrally resolved emission wings associated with localized acoustic phonons. Pump-dependent studies further revealed that the defect states are capable of emitting single, sharp, isolated PL peaks over 3 orders of magnitude increase in pump power, a key characteristic of two-level systems and an important prerequisite for single-photon emission with high purity. Our findings point to the tremendous potential of sp3 defects in development of room temperature quantum light sources capable of operating at telecommunication wavelengths as the emission of the defect states can readily be extended to this range via use of larger diameter SWCNTs.« less

Low-Temperature Single Carbon Nanotube Spectroscopy of sp 3 Quantum Defects

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Xiaowei; Gifford, Brendan J.; Hartmann, Nicolai F.

Aiming to unravel the relationship between chemical configuration and electronic structure of sp3 defects of aryl-functionalized (6,5) single-walled carbon nanotubes (SWCNTs), we perform low-temperature single nanotube photoluminescence (PL) spectroscopy studies and correlate our observations with quantum chemistry simulations. Here, we observe sharp emission peaks from individual defect sites that are spread over an extremely broad, 1000-1350 nm, spectral range. Our simulations allow us to attribute this spectral diversity to the occurrence of six chemically and energetically distinct defect states resulting from topological variation in the chemical binding configuration of the monovalent aryl groups. Both PL emission efficiency and spectral linemore » width of the defect states are strongly influenced by the local dielectric environment. Wrapping the SWCNT with a polyfluorene polymer provides the best isolation from the environment and yields the brightest emission with near-resolution limited spectral line width of 270 ueV, as well as spectrally resolved emission wings associated with localized acoustic phonons. Pump-dependent studies further revealed that the defect states are capable of emitting single, sharp, isolated PL peaks over 3 orders of magnitude increase in pump power, a key characteristic of two-level systems and an important prerequisite for single-photon emission with high purity. Our findings point to the tremendous potential of sp3 defects in development of room temperature quantum light sources capable of operating at telecommunication wavelengths as the emission of the defect states can readily be extended to this range via use of larger diameter SWCNTs.« less

Remote sensing of Earth's atmosphere and surface using a digital array scanned interferometer: A new type of imaging spectrometer

NASA Technical Reports Server (NTRS)

Hammer, Philip D.; Valero, Francisco P. J.; Peterson, David L.; Smith, William Hayden

1991-01-01

The capabilities of the digital array scanned interferometer (DASI) class of instruments for measuring terrestrial radiation fields over the visible to mid-infrared are evaluated. DASI's are capable of high throughput, sensitivity and spectral resolution and have the potential for field-of-view spatial discrimination (an imaging spectrometer). The simplicity of design and operation of DASI's make them particularly suitable for field and airborne platform based remote sensing. The long term objective is to produce a versatile field instrument which may be applied toward a variety of atmospheric and surface studies. The operation of DASI and its advantages over other spectrometers are discussed.

A Satellite-Based Imaging Instrumentation Concept for Hyperspectral Thermal Remote Sensing.

PubMed

Udelhoven, Thomas; Schlerf, Martin; Segl, Karl; Mallick, Kaniska; Bossung, Christian; Retzlaff, Rebecca; Rock, Gilles; Fischer, Peter; Müller, Andreas; Storch, Tobias; Eisele, Andreas; Weise, Dennis; Hupfer, Werner; Knigge, Thiemo

2017-07-01

This paper describes the concept of the hyperspectral Earth-observing thermal infrared (TIR) satellite mission HiTeSEM (High-resolution Temperature and Spectral Emissivity Mapping). The scientific goal is to measure specific key variables from the biosphere, hydrosphere, pedosphere, and geosphere related to two global problems of significant societal relevance: food security and human health. The key variables comprise land and sea surface radiation temperature and emissivity, surface moisture, thermal inertia, evapotranspiration, soil minerals and grain size components, soil organic carbon, plant physiological variables, and heat fluxes. The retrieval of this information requires a TIR imaging system with adequate spatial and spectral resolutions and with day-night following observation capability. Another challenge is the monitoring of temporally high dynamic features like energy fluxes, which require adequate revisit time. The suggested solution is a sensor pointing concept to allow high revisit times for selected target regions (1-5 days at off-nadir). At the same time, global observations in the nadir direction are guaranteed with a lower temporal repeat cycle (>1 month). To account for the demand of a high spatial resolution for complex targets, it is suggested to combine in one optic (1) a hyperspectral TIR system with ~75 bands at 7.2-12.5 µm (instrument NEDT 0.05 K-0.1 K) and a ground sampling distance (GSD) of 60 m, and (2) a panchromatic high-resolution TIR-imager with two channels (8.0-10.25 µm and 10.25-12.5 µm) and a GSD of 20 m. The identified science case requires a good correlation of the instrument orbit with Sentinel-2 (maximum delay of 1-3 days) to combine data from the visible and near infrared (VNIR), the shortwave infrared (SWIR) and TIR spectral regions and to refine parameter retrieval.

Absolute Calibration of Optical Satellite Sensors Using Libya 4 Pseudo Invariant Calibration Site

NASA Technical Reports Server (NTRS)

Mishra, Nischal; Helder, Dennis; Angal, Amit; Choi, Jason; Xiong, Xiaoxiong

2014-01-01

The objective of this paper is to report the improvements in an empirical absolute calibration model developed at South Dakota State University using Libya 4 (+28.55 deg, +23.39 deg) pseudo invariant calibration site (PICS). The approach was based on use of the Terra MODIS as the radiometer to develop an absolute calibration model for the spectral channels covered by this instrument from visible to shortwave infrared. Earth Observing One (EO-1) Hyperion, with a spectral resolution of 10 nm, was used to extend the model to cover visible and near-infrared regions. A simple Bidirectional Reflectance Distribution function (BRDF) model was generated using Terra Moderate Resolution Imaging Spectroradiometer (MODIS) observations over Libya 4 and the resulting model was validated with nadir data acquired from satellite sensors such as Aqua MODIS and Landsat 7 (L7) Enhanced Thematic Mapper (ETM+). The improvements in the absolute calibration model to account for the BRDF due to off-nadir measurements and annual variations in the atmosphere are summarized. BRDF models due to off-nadir viewing angles have been derived using the measurements from EO-1 Hyperion. In addition to L7 ETM+, measurements from other sensors such as Aqua MODIS, UK-2 Disaster Monitoring Constellation (DMC), ENVISAT Medium Resolution Imaging Spectrometer (MERIS) and Operational Land Imager (OLI) onboard Landsat 8 (L8), which was launched in February 2013, were employed to validate the model. These satellite sensors differ in terms of the width of their spectral bandpasses, overpass time, off-nadir-viewing capabilities, spatial resolution and temporal revisit time, etc. The results demonstrate that the proposed empirical calibration model has accuracy of the order of 3% with an uncertainty of about 2% for the sensors used in the study.

Time-resolved High Spectral Resolution Observation of 2MASSW J0746425+200032AB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ji; Mawet, Dimitri; Prato, Lisa, E-mail: ji.wang@caltech.edu

Many brown dwarfs (BDs) exhibit photometric variability at levels from tenths to tens of percents. The photometric variability is related to magnetic activity or patchy cloud coverage, characteristic of BDs near the L–T transition. Time-resolved spectral monitoring of BDs provides diagnostics of cloud distribution and condensate properties. However, current time-resolved spectral studies of BDs are limited to low spectral resolution ( R ∼ 100) with the exception of the study of Luhman 16 AB at a resolution of 100,000 using the VLT+CRIRES. This work yielded the first map of BD surface inhomogeneity, highlighting the importance and unique contribution of highmore » spectral resolution observations. Here, we report on the time-resolved high spectral resolution observations of a nearby BD binary, 2MASSW J0746425+200032AB. We find no coherent spectral variability that is modulated with rotation. Based on simulations, we conclude that the coverage of a single spot on 2MASSW J0746425+200032AB is smaller than 1% or 6.25% if spot contrast is 50% or 80% of its surrounding flux, respectively. Future high spectral resolution observations aided by adaptive optics systems can put tighter constraints on the spectral variability of 2MASSW J0746425+200032AB and other nearby BDs.« less

Ultraspectral imaging for propulsion test monitoring

NASA Astrophysics Data System (ADS)

Otten, Leonard John, III; Jones, Bernard A.; Prinzing, Philip; Swantner, William H.; Rafert, Bruce

2002-02-01

Under a NASA Stennis Space Center (SSC) SBIR, technologies required for an imaging spectral radiometer with wavenumber spectral resolution and milliradian spatial resolution that operates over the 8 micrometers to 12 micrometers (LWIR), and 3 micrometers to 5 micrometers (MWIR) bands, for use in a non-intrusive monitoring static rocket firing application are being investigated. The research is based on a spatially modulated Fourier transform spectral imager to take advantage of the inherent benefits in these devices in the MWIR and LWIR. The research verified optical techniques that could be merged with a Sagnac interferometer to create conceptual designs for an LWIR imaging spectrometer that has a 0.4 cm-1 spectral resolution using an available HgCdTe detector. These same techniques produce an MWIR imaging spectrometer with 1.5 cm-1 spectral resolution based on a commercial InSb array. Initial laboratory measurements indicate that the modeled spectral resolution is being met. Applications to environmental measurement applications under standard temperatures can be undertaken by taking advantage of several unique features of the Sagnac interferometer in being able to decouple the limiting aperature from the spectral resolution.

Assessing the Tundra-taiga Boundary with Multi-Sensor Satellite Data

NASA Technical Reports Server (NTRS)

Ranson, K. J.; Sun, G.; Kharuk, V. I.; Kovacs, K.

2004-01-01

Monitoring the dynamics of the circumpolar boreal forest (taiga) and Arctic tundra boundary is important for understanding the causes and consequences of changes observed in these areas. This ecotone, the world's largest, stretches for over 13,400 km and marks the transition between the northern limits of forests and the southern margin of the tundra. Because of the inaccessibility and large extent of this zone, remote sensing data can play an important role for mapping the characteristics and monitoring the dynamics. Basic understanding of the capabilities of existing space borne instruments for these purposes is required. In this study we examined the use of several remote sensing techniques for identifying the existing tundra- taiga ecotone. These include Landsat-7, MISR, MODIS and RADARSAT data. Historical cover maps, recent forest stand measurements and high-resolution IKONOS images were used for local ground truth. It was found that a tundra-taiga transitional area can be characterized using multi- spectral Landsat ETM+ summer images, multi-angle MISR red band reflectance images, RADARSAT images with larger incidence angle, or multi-temporal and multi-spectral MODIS data. Because of different resolutions and spectral regions covered, the transition zone maps derived from different data types were not identical, but the general patterns were consistent.

New opportunities with spectro-interferometry and spectro-astrometry

NASA Astrophysics Data System (ADS)

Kraus, Stefan

2012-07-01

Latest-generation spectro-interferometric instruments combine a milliarcsecond angular resolution with spectral capabilities, resulting in an immensely increased information content. Here, I present methodological work and results that illustrate the fundamentally new scientific insights provided by spectro-interferometry with very high spectral dispersion or in multiple line transitions (Brackett and Pfund lines). In addition, I discuss some pitfalls in the interpretation of spectro-interferometric data. In the context of our recent studies on the classical Be stars β CMi and ζ Tau, I present the first position-velocity diagram obtained with optical interferometry and provide a physical interpretation for a phase inversion, which has in the meantime been observed for several classical Be-stars. In the course of our study on the Herbig B[e] star V921 Sco, we combined, for the first time, spectro-interferometry and spectro-astrometry, providing a powerful and resource-efficient way to constrain the spatial distribution as well as the kinematics of the circumstellar gas with an unprecedented velocity resolution up to R = λ/Δλ = 100,000. Finally, I discuss our phase sign calibration procedure, which has allowed us to calibrate AMBER differential phases and closure phases for all spectral modes, and derive from the gained experience science-driven requirements for future instrumentation projects.

Evaluating an image-fusion algorithm with synthetic-image-generation tools

NASA Astrophysics Data System (ADS)

Gross, Harry N.; Schott, John R.

1996-06-01

An algorithm that combines spectral mixing and nonlinear optimization is used to fuse multiresolution images. Image fusion merges images of different spatial and spectral resolutions to create a high spatial resolution multispectral combination. High spectral resolution allows identification of materials in the scene, while high spatial resolution locates those materials. In this algorithm, conventional spectral mixing estimates the percentage of each material (called endmembers) within each low resolution pixel. Three spectral mixing models are compared; unconstrained, partially constrained, and fully constrained. In the partially constrained application, the endmember fractions are required to sum to one. In the fully constrained application, all fractions are additionally required to lie between zero and one. While negative fractions seem inappropriate, they can arise from random spectral realizations of the materials. In the second part of the algorithm, the low resolution fractions are used as inputs to a constrained nonlinear optimization that calculates the endmember fractions for the high resolution pixels. The constraints mirror the low resolution constraints and maintain consistency with the low resolution fraction results. The algorithm can use one or more higher resolution sharpening images to locate the endmembers to high spatial accuracy. The algorithm was evaluated with synthetic image generation (SIG) tools. A SIG developed image can be used to control the various error sources that are likely to impair the algorithm performance. These error sources include atmospheric effects, mismodeled spectral endmembers, and variability in topography and illumination. By controlling the introduction of these errors, the robustness of the algorithm can be studied and improved upon. The motivation for this research is to take advantage of the next generation of multi/hyperspectral sensors. Although the hyperspectral images will be of modest to low resolution, fusing them with high resolution sharpening images will produce a higher spatial resolution land cover or material map.

The use of Sentinel-2 imagery for seagrass mapping: Kalloni Gulf (Lesvos Island, Greece) case study

NASA Astrophysics Data System (ADS)

Topouzelis, Konstantinos; Charalampis Spondylidis, Spyridon; Papakonstantinou, Apostolos; Soulakellis, Nikolaos

2016-08-01

Seagrass meadows play a significant role in ecosystems by stabilizing sediment and improving water clarity, which enhances seagrass growing conditions. It is high on the priority of EU legislation to map and protect them. The traditional use of medium spatial resolution satellite imagery e.g. Landsat-8 (30m) is very useful for mapping seagrass meadows on a regional scale. However, the availability of Sentinel-2 data, the recent ESA's satellite with its payload Multi-Spectral Instrument (MSI) is expected to improve the mapping accuracy. MSI designed to improve coastline studies due to its enhanced spatial and spectral capabilities e.g. optical bands with 10m spatial resolution. The present work examines the quality of Sentinel-2 images for seagrass mapping, the ability of each band in detection and discrimination of different habitats and estimates the accuracy of seagrass mapping. After pre-processing steps, e.g. radiometric calibration and atmospheric correction, image classified into four classes. Classification classes included sub-bottom composition e.g. seagrass, soft bottom, and hard bottom. Concrete vectors describing the areas covered by seagrass extracted from the high-resolution satellite image and used as in situ measurements. The developed methodology applied in the Gulf of Kalloni, (Lesvos Island - Greece). Results showed that Sentinel-2 images can be robustly used for seagrass mapping due to their spatial resolution, band availability and radiometric accuracy.

Trade-off studies of a hyperspectral infrared sounder on a geostationary satellite.

PubMed

Wang, Fang; Li, Jun; Schmit, Timothy J; Ackerman, Steven A

2007-01-10

Trade-off studies on spectral coverage, signal-to-noise ratio (SNR), and spectral resolution for a hyperspectral infrared (IR) sounder on a geostationary satellite are summarized. The data density method is applied for the vertical resolution analysis, and the rms error between true and retrieved profiles is used to represent the retrieval accuracy. The effects of spectral coverage, SNR, and spectral resolution on vertical resolution and retrieval accuracy are investigated. The advantages of IR and microwave sounder synergy are also demonstrated. When focusing on instrument performance and data processing, the results from this study show that the preferred spectral coverage combines long-wave infrared (LWIR) with the shorter middle-wave IR (SMidW). Using the appropriate spectral coverage, a hyperspectral IR sounder with appropriate SNR can achieve the required science performance (1 km vertical resolution, 1 K temperature, and 10% relative humidity retrieval accuracy). The synergy of microwave and IR sounders can improve the vertical resolution and retrieval accuracy compared to either instrument alone.

High-resolution time-frequency representation of EEG data using multi-scale wavelets

NASA Astrophysics Data System (ADS)

Li, Yang; Cui, Wei-Gang; Luo, Mei-Lin; Li, Ke; Wang, Lina

2017-09-01

An efficient time-varying autoregressive (TVAR) modelling scheme that expands the time-varying parameters onto the multi-scale wavelet basis functions is presented for modelling nonstationary signals and with applications to time-frequency analysis (TFA) of electroencephalogram (EEG) signals. In the new parametric modelling framework, the time-dependent parameters of the TVAR model are locally represented by using a novel multi-scale wavelet decomposition scheme, which can allow the capability to capture the smooth trends as well as track the abrupt changes of time-varying parameters simultaneously. A forward orthogonal least square (FOLS) algorithm aided by mutual information criteria are then applied for sparse model term selection and parameter estimation. Two simulation examples illustrate that the performance of the proposed multi-scale wavelet basis functions outperforms the only single-scale wavelet basis functions or Kalman filter algorithm for many nonstationary processes. Furthermore, an application of the proposed method to a real EEG signal demonstrates the new approach can provide highly time-dependent spectral resolution capability.

High dynamic range bio-molecular ion microscopy with the Timepix detector.

PubMed

Jungmann, Julia H; MacAleese, Luke; Visser, Jan; Vrakking, Marc J J; Heeren, Ron M A

2011-10-15

Highly parallel, active pixel detectors enable novel detection capabilities for large biomolecules in time-of-flight (TOF) based mass spectrometry imaging (MSI). In this work, a 512 × 512 pixel, bare Timepix assembly combined with chevron microchannel plates (MCP) captures time-resolved images of several m/z species in a single measurement. Mass-resolved ion images from Timepix measurements of peptide and protein standards demonstrate the capability to return both mass-spectral and localization information of biologically relevant analytes from matrix-assisted laser desorption ionization (MALDI) on a commercial ion microscope. The use of a MCP-Timepix assembly delivers an increased dynamic range of several orders of magnitude. The Timepix returns defined mass spectra already at subsaturation MCP gains, which prolongs the MCP lifetime and allows the gain to be optimized for image quality. The Timepix peak resolution is only limited by the resolution of the in-pixel measurement clock. Oligomers of the protein ubiquitin were measured up to 78 kDa. © 2011 American Chemical Society

Doppler lidar for measurement of atmospheric wind fields

NASA Technical Reports Server (NTRS)

Menzies, Robert T.

1991-01-01

Measurements of wind fields in the earth's troposphere with daily global coverage is widely considered as a significant advance for forecasting and transport studies. For optimal use by NWP (Numerical Weather Prediction) models the horizontal and vertical resolutions should be approximately 100 km and 1 km, respectively. For boundary layer studies vertical resolution of a few hundred meters seems essential. Earth-orbiting Doppler lidar has a unique capability to measure global winds in the troposphere with the high vertical resolution required. The lidar approach depends on transmission of pulses with high spectral purity and backscattering from the atmospheric aerosol particles or layered clouds to provide a return signal. Recent field measurement campaigns using NASA research aircraft have resulted in collection of aerosol and cloud data which can be used to optimize the Doppler lidar instrument design and measurement strategy.

Harmonizing Landsat and Sentinel-2 Reflectances for Better Land Monitoring

NASA Technical Reports Server (NTRS)

Masek, Jeffrey; Vermote, Eric; Franch, Belen; Roger, Jean-Claude; Skakun, Sergii; Claverie, Martin; Dungan, Jennifer

2016-01-01

When combined, Landsat and ESA Sentinel-2 observations can provide 2-4 day coverage for the global land area. A collaboration among NASA GSFC (Goddard Space Flight Center), University of Maryland, and NASA Ames has developed a processing chain to create seamless, "harmonized" reflectance products using standardized atmospheric correction, BRDF (Bidirectional Reflectance Distribution Function) adjustment, spectral bandpass adjustment, and gridding algorithms. These products point the way to a "30-m MODIS (Moderate Resolution Imaging Spectroradiometer)" capability for agricultural and ecosystem monitoring by leveraging international sensors.

Processing and analysis of commercial satellite image data of the nuclear accident near Chernobyl, U. S. S. R

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadowski, F.G.; Covington, S.J.

1987-01-01

Advanced digital processing techniques were applied to Landsat-5 Thematic Mapper (TM) data and SPOT high-resolution visible (HRV) panchromatic data to maximize the utility of images of a nuclear power plant emergency at Chernobyl in the Soviet Ukraine. The results of the data processing and analysis illustrate the spectral and spatial capabilities of the two sensor systems and provide information about the severity and duration of the events occurring at the power plant site.

Influence of spectral resolution, spectral range and signal-to-noise ratio of Fourier transform infra-red spectra on identification of high explosive substances

NASA Astrophysics Data System (ADS)

Banas, Krzysztof; Banas, Agnieszka M.; Heussler, Sascha P.; Breese, Mark B. H.

2018-01-01

In the contemporary spectroscopy there is a trend to record spectra with the highest possible spectral resolution. This is clearly justified if the spectral features in the spectrum are very narrow (for example infra-red spectra of gas samples). However there is a plethora of samples (in the liquid and especially in the solid form) where there is a natural spectral peak broadening due to collisions and proximity predominately. Additionally there is a number of portable devices (spectrometers) with inherently restricted spectral resolution, spectral range or both, which are extremely useful in some field applications (archaeology, agriculture, food industry, cultural heritage, forensic science). In this paper the investigation of the influence of spectral resolution, spectral range and signal-to-noise ratio on the identification of high explosive substances by applying multivariate statistical methods on the Fourier transform infra-red spectral data sets is studied. All mathematical procedures on spectral data for dimension reduction, clustering and validation were implemented within R open source environment.

Satellite Observations of Coastal Processes from a Geostationary Orbit: Application to estuarine, coastal, and ocean resource management

NASA Astrophysics Data System (ADS)

Tzortziou, M.; Mannino, A.; Schaeffer, B. A.

2016-02-01

Coastal areas are among the most vulnerable yet economically valuable ecosystems on Earth. Estuaries and coastal oceans are critically important as essential habitat for marine life, as highly productive ecosystems and a rich source of food for human consumption, as a strong economic driver for coastal communities, and as a highly dynamic interface between land and ocean carbon and nutrient cycles. Still, our present capabilities to remotely observe coastal ocean processes from space are limited in their temporal, spatial, and spectral resolution. These limitations, in turn, constrain our ability to observe and understand biogeochemical processes in highly dynamic coastal ecosystems, or predict their response and resilience to current and future pressures including sea level rise, coastal urbanization, and anthropogenic pollution.On a geostationary orbit, and with high spatial resolution and hyper-spectral capabilities, NASA's Decadal Survey mission GEO-CAPE (GEO-stationary for Coastal and Air Pollution Events) will provide, for the first time, a satellite view of the short-term changes and evolution of processes along the economically invaluable but, simultaneously, particularly vulnerable near-shore waters of the United States. GEO-CAPE will observe U.S. lakes, estuaries, and coastal regions at sufficient temporal and spatial scales to resolve near-shore processes, tides, coastal fronts, and eddies, track sediments and pollutants, capture diurnal biogeochemical processes and rates of transformation, monitor harmful algal blooms and large oil spills, observe episodic events and coastal hazards. Here we discuss the GEO-CAPE applications program and the new capabilities afforded by this future satellite mission, to identify potential user communities, incorporate end-user needs into future mission planning, and allow integration of science and management at the coastal interface.

Satellite Observations of Coastal Processes from a Geostationary Orbit: Application to estuarine, coastal, and ocean resource management

NASA Astrophysics Data System (ADS)

Tzortziou, M.; Mannino, A.; Schaeffer, B. A.

2016-12-01

Coastal areas are among the most vulnerable yet economically valuable ecosystems on Earth. Estuaries and coastal oceans are critically important as essential habitat for marine life, as highly productive ecosystems and a rich source of food for human consumption, as a strong economic driver for coastal communities, and as a highly dynamic interface between land and ocean carbon and nutrient cycles. Still, our present capabilities to remotely observe coastal ocean processes from space are limited in their temporal, spatial, and spectral resolution. These limitations, in turn, constrain our ability to observe and understand biogeochemical processes in highly dynamic coastal ecosystems, or predict their response and resilience to current and future pressures including sea level rise, coastal urbanization, and anthropogenic pollution.On a geostationary orbit, and with high spatial resolution and hyper-spectral capabilities, NASA's Decadal Survey mission GEO-CAPE (GEO-stationary for Coastal and Air Pollution Events) will provide, for the first time, a satellite view of the short-term changes and evolution of processes along the economically invaluable but, simultaneously, particularly vulnerable near-shore waters of the United States. GEO-CAPE will observe U.S. lakes, estuaries, and coastal regions at sufficient temporal and spatial scales to resolve near-shore processes, tides, coastal fronts, and eddies, track sediments and pollutants, capture diurnal biogeochemical processes and rates of transformation, monitor harmful algal blooms and large oil spills, observe episodic events and coastal hazards. Here we discuss the GEO-CAPE applications program and the new capabilities afforded by this future satellite mission, to identify potential user communities, incorporate end-user needs into future mission planning, and allow integration of science and management at the coastal interface.

In-operando synchronous time-multiplexed O K-edge x-ray absorption spectromicroscopy of functioning tantalum oxide memristors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Suhas; Department of Electrical Engineering, Stanford University, Stanford, California 94305; Graves, Catherine E.

2015-07-21

Memristors are receiving keen interest because of their potential varied applications and promising large-scale information storage capabilities. Tantalum oxide is a memristive material that has shown promise for high-performance nonvolatile computer memory. The microphysics has been elusive because of the small scale and subtle physical changes that accompany conductance switching. In this study, we probed the atomic composition, local chemistry, and electronic structure of functioning tantalum oxide memristors through spatially mapped O K-edge x-ray absorption. We developed a time-multiplexed spectromicroscopy technique to enhance the weak and possibly localized oxide modifications with spatial and spectral resolutions of <30 nm and 70 meV, respectively.more » During the initial stages of conductance switching of a micrometer sized crosspoint device, the spectral changes were uniform within the spatial resolution of our technique. When the device was further driven with millions of high voltage-pulse cycles, we observed lateral motion and separation of ∼100 nm-scale agglomerates of both oxygen interstitials and vacancies. We also demonstrate a unique capability of this technique by identifying the relaxation behavior in the material during electrical stimuli by identifying electric field driven changes with varying pulse widths. In addition, we show that changes to the material can be localized to a spatial region by modifying its topography or uniformity, as against spatially uniform changes observed here during memristive switching. The goal of this report is to introduce the capability of time-multiplexed x-ray spectromicroscopy in studying weak-signal transitions in inhomogeneous media through the example of the operation and temporal evolution of a memristor.« less

ISSM-SESAW v1.0: mesh-based computation of gravitationally consistent sea-level and geodetic signatures caused by cryosphere and climate driven mass change

NASA Astrophysics Data System (ADS)

Adhikari, Surendra; Ivins, Erik R.; Larour, Eric

2016-03-01

A classical Green's function approach for computing gravitationally consistent sea-level variations associated with mass redistribution on the earth's surface employed in contemporary sea-level models naturally suits the spectral methods for numerical evaluation. The capability of these methods to resolve high wave number features such as small glaciers is limited by the need for large numbers of pixels and high-degree (associated Legendre) series truncation. Incorporating a spectral model into (components of) earth system models that generally operate on a mesh system also requires repetitive forward and inverse transforms. In order to overcome these limitations, we present a method that functions efficiently on an unstructured mesh, thus capturing the physics operating at kilometer scale yet capable of simulating geophysical observables that are inherently of global scale with minimal computational cost. The goal of the current version of this model is to provide high-resolution solid-earth, gravitational, sea-level and rotational responses for earth system models operating in the domain of the earth's outer fluid envelope on timescales less than about 1 century when viscous effects can largely be ignored over most of the globe. The model has numerous important geophysical applications. For example, we compute time-varying computations of global geodetic and sea-level signatures associated with recent ice-sheet changes that are derived from space gravimetry observations. We also demonstrate the capability of our model to simultaneously resolve kilometer-scale sources of the earth's time-varying surface mass transport, derived from high-resolution modeling of polar ice sheets, and predict the corresponding local and global geodetic signatures.

The Interaction of Temporal and Spectral Acoustic Information with Word Predictability on Speech Intelligibility

NASA Astrophysics Data System (ADS)

Shahsavarani, Somayeh Bahar

High-level, top-down information such as linguistic knowledge is a salient cortical resource that influences speech perception under most listening conditions. But, are all listeners able to exploit these resources for speech facilitation to the same extent? It was found that children with cochlear implants showed different patterns of benefit from contextual information in speech perception compared with their normal-haring peers. Previous studies have discussed the role of non-acoustic factors such as linguistic and cognitive capabilities to account for this discrepancy. Given the fact that the amount of acoustic information encoded and processed by auditory nerves of listeners with cochlear implants differs from normal-hearing listeners and even varies across individuals with cochlear implants, it is important to study the interaction of specific acoustic properties of the speech signal with contextual cues. This relationship has been mostly neglected in previous research. In this dissertation, we aimed to explore how different acoustic dimensions interact to affect listeners' abilities to combine top-down information with bottom-up information in speech perception beyond the known effects of linguistic and cognitive capacities shown previously. Specifically, the present study investigated whether there were any distinct context effects based on the resolution of spectral versus slowly-varying temporal information in perception of spectrally impoverished speech. To that end, two experiments were conducted. In both experiments, a noise-vocoded technique was adopted to generate spectrally-degraded speech to approximate acoustic cues delivered to listeners with cochlear implants. The frequency resolution was manipulated by varying the number of frequency channels. The temporal resolution was manipulated by low-pass filtering of amplitude envelope with varying low-pass cutoff frequencies. The stimuli were presented to normal-hearing native speakers of American English. Our results revealed a significant interaction effect between spectral, temporal, and contextual information in the perception of spectrally-degraded speech. This suggests that specific types and degradation of bottom-up information combine differently to utilize contextual resources. These findings emphasize the importance of taking the listener's specific auditory abilities into consideration while studying context effects. These results also introduce a novel perspective for designing interventions for listeners with cochlear implants or other auditory prostheses.

Exponential convergence rate (the spectral convergence) of the fast Padé transform for exact quantification in magnetic resonance spectroscopy.

PubMed

Belkić, Dzevad

2006-12-21

This study deals with the most challenging numerical aspect for solving the quantification problem in magnetic resonance spectroscopy (MRS). The primary goal is to investigate whether it could be feasible to carry out a rigorous computation within finite arithmetics to reconstruct exactly all the machine accurate input spectral parameters of every resonance from a synthesized noiseless time signal. We also consider simulated time signals embedded in random Gaussian distributed noise of the level comparable to the weakest resonances in the corresponding spectrum. The present choice for this high-resolution task in MRS is the fast Padé transform (FPT). All the sought spectral parameters (complex frequencies and amplitudes) can unequivocally be reconstructed from a given input time signal by using the FPT. Moreover, the present computations demonstrate that the FPT can achieve the spectral convergence, which represents the exponential convergence rate as a function of the signal length for a fixed bandwidth. Such an extraordinary feature equips the FPT with the exemplary high-resolution capabilities that are, in fact, theoretically unlimited. This is illustrated in the present study by the exact reconstruction (within machine accuracy) of all the spectral parameters from an input time signal comprised of 25 harmonics, i.e. complex damped exponentials, including those for tightly overlapped and nearly degenerate resonances whose chemical shifts differ by an exceedingly small fraction of only 10(-11) ppm. Moreover, without exhausting even a quarter of the full signal length, the FPT is shown to retrieve exactly all the input spectral parameters defined with 12 digits of accuracy. Specifically, we demonstrate that when the FPT is close to the convergence region, an unprecedented phase transition occurs, since literally a few additional signal points are sufficient to reach the full 12 digit accuracy with the exponentially fast rate of convergence. This is the critical proof-of-principle for the high-resolution power of the FPT for machine accurate input data. Furthermore, it is proven that the FPT is also a highly reliable method for quantifying noise-corrupted time signals reminiscent of those encoded via MRS in clinical neuro-diagnostics.

Hyperspectral Fluorescence and Reflectance Imaging Instrument

NASA Technical Reports Server (NTRS)

Ryan, Robert E.; O'Neal, S. Duane; Lanoue, Mark; Russell, Jeffrey

2008-01-01

The system is a single hyperspectral imaging instrument that has the unique capability to acquire both fluorescence and reflectance high-spatial-resolution data that is inherently spatially and spectrally registered. Potential uses of this instrument include plant stress monitoring, counterfeit document detection, biomedical imaging, forensic imaging, and general materials identification. Until now, reflectance and fluorescence spectral imaging have been performed by separate instruments. Neither a reflectance spectral image nor a fluorescence spectral image alone yields as much information about a target surface as does a combination of the two modalities. Before this system was developed, to benefit from this combination, analysts needed to perform time-consuming post-processing efforts to co-register the reflective and fluorescence information. With this instrument, the inherent spatial and spectral registration of the reflectance and fluorescence images minimizes the need for this post-processing step. The main challenge for this technology is to detect the fluorescence signal in the presence of a much stronger reflectance signal. To meet this challenge, the instrument modulates artificial light sources from ultraviolet through the visible to the near-infrared part of the spectrum; in this way, both the reflective and fluorescence signals can be measured through differencing processes to optimize fluorescence and reflectance spectra as needed. The main functional components of the instrument are a hyperspectral imager, an illumination system, and an image-plane scanner. The hyperspectral imager is a one-dimensional (line) imaging spectrometer that includes a spectrally dispersive element and a two-dimensional focal plane detector array. The spectral range of the current imaging spectrometer is between 400 to 1,000 nm, and the wavelength resolution is approximately 3 nm. The illumination system consists of narrowband blue, ultraviolet, and other discrete wavelength light-emitting-diode (LED) sources and white-light LED sources designed to produce consistently spatially stable light. White LEDs provide illumination for the measurement of reflectance spectra, while narrowband blue and UV LEDs are used to excite fluorescence. Each spectral type of LED can be turned on or off depending on the specific remote-sensing process being performed. Uniformity of illumination is achieved by using an array of LEDs and/or an integrating sphere or other diffusing surface. The image plane scanner uses a fore optic with a field of view large enough to provide an entire scan line on the image plane. It builds up a two-dimensional image in pushbroom fashion as the target is scanned across the image plane either by moving the object or moving the fore optic. For fluorescence detection, spectral filtering of a narrowband light illumination source is sometimes necessary to minimize the interference of the source spectrum wings with the fluorescence signal. Spectral filtering is achieved with optical interference filters and absorption glasses. This dual spectral imaging capability will enable the optimization of reflective, fluorescence, and fused datasets as well as a cost-effective design for multispectral imaging solutions. This system has been used in plant stress detection studies and in currency analysis.

Advances in Low-Temperature Tungsten Spectroscopy Capability to Quantify DIII-D Divertor Erosion

DOE PAGES

Abrams, Tyler; Thomas, Daniel M.; Unterberg, Ezekial A.; ...

2018-01-05

Recent emphasis of tungsten (W) plasma-materialsinteractions (PMI) experiments on DIII-D has made it essential to enhance the W I and W II measurement capabilities of its spectroscopy diagnostic suite to acquire W sourcing measurements with high temporal, spatial, and wavelength resolution. To this end, four new viewing chords for the Multichordal Divertor Spectrometer (MDS) and diverter filterscope systems were installed, leading to a 7x increase in blue light sensitivity. W I and low-Z impurity line identifications were performed in the 3995-4030 Å region, placing wavelengths within 0.1 Å of the NIST values. A novel method was also developed for themore » DIII-D high temporal resolution filterscopes to distinguish between W I light and background contamination, important due to the relatively weak intensity of this line, using two different bandpass filters width different widths but the same center wavelength. Lastly, fast imaging of the W I 4008.75 Å spectral line with a PCO Pixelfly VGA 200/205 camera allowed for discrimination between ELMy and intra-ELM W I emission profiles with very high (~1 mm) spatial resolution.« less

Imaging multi-scale dynamics in vivo with spiral volumetric optoacoustic tomography

NASA Astrophysics Data System (ADS)

Deán-Ben, X. Luís.; Fehm, Thomas F.; Ford, Steven J.; Gottschalk, Sven; Razansky, Daniel

2017-03-01

Imaging dynamics in living organisms is essential for the understanding of biological complexity. While multiple imaging modalities are often required to cover both microscopic and macroscopic spatial scales, dynamic phenomena may also extend over different temporal scales, necessitating the use of different imaging technologies based on the trade-off between temporal resolution and effective field of view. Optoacoustic (photoacoustic) imaging has been shown to offer the exclusive capability to link multiple spatial scales ranging from organelles to entire organs of small animals. Yet, efficient visualization of multi-scale dynamics remained difficult with state-of-the-art systems due to inefficient trade-offs between image acquisition and effective field of view. Herein, we introduce a spiral volumetric optoacoustic tomography (SVOT) technique that provides spectrally-enriched high-resolution optical absorption contrast across multiple spatio-temporal scales. We demonstrate that SVOT can be used to monitor various in vivo dynamics, from video-rate volumetric visualization of cardiac-associated motion in whole organs to high-resolution imaging of pharmacokinetics in larger regions. The multi-scale dynamic imaging capability thus emerges as a powerful and unique feature of the optoacoustic technology that adds to the multiple advantages of this technology for structural, functional and molecular imaging.

The LUVOIR Large Mission Concept

NASA Astrophysics Data System (ADS)

O'Meara, John; LUVOIR Science and Technology Definition Team

2018-01-01

LUVOIR is one of four large mission concepts for which the NASA Astrophysics Division has commissioned studies by Science and Technology Definition Teams (STDTs) drawn from the astronomical community. We are currently developing two architectures: Architecture A with a 15.1 meter segmented primary mirror, and Architecture B with a 9.2 meter segmented primary mirror. Our focus in this presentation is the Architecture A LUVOIR. LUVOIR will operate at the Sun-Earth L2 point. It will be designed to support a broad range of astrophysics and exoplanet studies. The initial instruments developed for LUVOIR Architecture A include 1) a high-performance optical/NIR coronagraph with imaging and spectroscopic capability, 2) a UV imager and spectrograph with high spectral resolution and multi-object capability, 3) a high-definition wide-field optical/NIR camera, and 4) a high resolution UV/optical spectropolarimeter. LUVOIR will be designed for extreme stability to support unprecedented spatial resolution and coronagraphy. It is intended to be a long-lifetime facility that is both serviceable, upgradable, and primarily driven by guest observer science programs. In this presentation, we will describe the observatory, its instruments, and survey the transformative science LUVOIR can accomplish.

Advances in Low-Temperature Tungsten Spectroscopy Capability to Quantify DIII-D Divertor Erosion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abrams, Tyler; Thomas, Daniel M.; Unterberg, Ezekial A.

Recent emphasis of tungsten (W) plasma-materialsinteractions (PMI) experiments on DIII-D has made it essential to enhance the W I and W II measurement capabilities of its spectroscopy diagnostic suite to acquire W sourcing measurements with high temporal, spatial, and wavelength resolution. To this end, four new viewing chords for the Multichordal Divertor Spectrometer (MDS) and diverter filterscope systems were installed, leading to a 7x increase in blue light sensitivity. W I and low-Z impurity line identifications were performed in the 3995-4030 Å region, placing wavelengths within 0.1 Å of the NIST values. A novel method was also developed for themore » DIII-D high temporal resolution filterscopes to distinguish between W I light and background contamination, important due to the relatively weak intensity of this line, using two different bandpass filters width different widths but the same center wavelength. Lastly, fast imaging of the W I 4008.75 Å spectral line with a PCO Pixelfly VGA 200/205 camera allowed for discrimination between ELMy and intra-ELM W I emission profiles with very high (~1 mm) spatial resolution.« less

StarNet: An application of deep learning in the analysis of stellar spectra

NASA Astrophysics Data System (ADS)

Kielty, Collin; Bialek, Spencer; Fabbro, Sebastien; Venn, Kim; O'Briain, Teaghan; Jahandar, Farbod; Monty, Stephanie

2018-06-01

In an era when spectroscopic surveys are capable of collecting spectra for hundreds of thousands of stars, fast and efficient analysis methods are required to maximize scientific impact. These surveys provide a homogeneous database of stellar spectra that are ideal for machine learning applications. In this poster, we present StarNet: a convolutional neural network model applied to the analysis of both SDSS-III APOGEE DR13 and synthetic stellar spectra. When trained on synthetic spectra alone, the calculated stellar parameters (temperature, surface gravity, and metallicity) are of excellent precision and accuracy for both APOGEE data and synthetic data, over a wide range of signal-to-noise ratios. While StarNet was developed using the APOGEE observed spectra and corresponding ASSeT synthetic grid, we suggest that this technique is applicable to other spectral resolutions, spectral surveys, and wavelength regimes. As a demonstration of this, we present a StarNet model trained on lower resolution, R=6000, IR synthetic spectra, describing the spectra delivered by Gemini/NIFS and the forthcoming Gemini/GIRMOS instrument (PI Sivanandam, UToronto). Preliminary results suggest that the stellar parameters determined from this low resolution StarNet model are comparable in precision to the high-resolution APOGEE results. The success of StarNet at lower resolution can be attributed to (1) a large training set of synthetic spectra (N ~200,000) with a priori stellar labels, and (2) the use of the entire spectrum in the solution rather than a few weighted windows, which are common methods in other spectral analysis tools (e.g. FERRE or The Cannon). Remaining challenges in our StarNet applications include rectification, continuum normalization, and wavelength coverage. Solutions to these problems could be used to guide decisions made in the development of future spectrographs, spectroscopic surveys, and data reduction pipelines, such as for the future MSE.

Coded aperture coherent scatter spectral imaging for assessment of breast cancers: an ex-vivo demonstration

NASA Astrophysics Data System (ADS)

Spencer, James R.; Carter, Joshua E.; Leung, Crystal K.; McCall, Shannon J.; Greenberg, Joel A.; Kapadia, Anuj J.

2017-03-01

A Coded Aperture Coherent Scatter Spectral Imaging (CACSSI) system was developed in our group to differentiate cancer and healthy tissue in the breast. The utility of the experimental system was previously demonstrated using anthropomorphic breast phantoms and breast biopsy specimens. Here we demonstrate CACSSI utility in identifying tumor margins in real time using breast lumpectomy specimens. Fresh lumpectomy specimens were obtained from Surgical Pathology with the suspected cancerous area designated on the specimen. The specimens were scanned using CACSSI to obtain spectral scatter signatures at multiple locations within the tumor and surrounding tissue. The spectral reconstructions were matched with literature form-factors to classify the tissue as cancerous or non-cancerous. The findings were then compared against pathology reports to confirm the presence and location of the tumor. The system was found to be capable of consistently differentiating cancerous and healthy regions in the breast with spatial resolution of 5 mm. Tissue classification results from the scanned specimens could be correlated with pathology results. We now aim to develop CACSSI as a clinical imaging tool to aid breast cancer assessment and other diagnostic purposes.

Design and development of the Sentinel-2 Multi Spectral Instrument and satellite system

NASA Astrophysics Data System (ADS)

Chorvalli, Vincent; Cazaubiel, Vincent; Bursch, Stefan; Welsch, Mario; Sontag, Heinz; Martimort, Philippe; Del Bello, Umberto; Sy, Omar; Laberinti, Paolo; Spoto, François

2010-10-01

2A and Sentinel-2B satellites currently under development will ensure systematic global acquisition of all land and coastal waters in the visible and short-wave infrared spectral domain with a 5 day revisit time at the equator. The Multi Spectral Instrument is a push-broom imager providing imagery in 13 spectral channels with spatial resolutions ranging from 10 m to 60 m and a swath width of 290 Km, larger than SPOT and Landsat. The instrument features a full field of view calibration device, a silicon carbide Three Mirror Anastigmat telescope with mirror dimensions up to 600 mm, specific filter stripe assemblies, newly developed Si-CMOS and HgCDTe detectors and a low noise wavelet compression video electronics. The 1.4 Tbits/s raw image date rate is reduced down to 490 Mbits/s at the output of the instrument to cope with the overall system transmission capability. The Sentinel-2 program has entered in the CD phase in 2009. Launch of Sentinel-2A satellite is scheduled for 2013.

Mid-IR Spectral Investigation of Normal and Malignant Breast and Cervical Tissue Samples Using a Quantum Cascade Laser-Based Microscope

NASA Astrophysics Data System (ADS)

Haugen, Paul

Mid-infrared (MIR) spectroscopy has been a tool used to identify specific features of normal and malignant tissue samples by utilizing MIR characteristics, specifically in the "fingerprint" region. The fingerprint region is a biologically significant spectral region typically identified between 1500 and 500 cm-1. MIR spectroscopy can be used to study molecular changes and variations occurring in samples, which can then be used to fingerprint specific spectral characteristics and biomarkers in order to categorize the specimens. The most common instruments currently used in this analysis are Fourier transform infrared (FTIR) spectrometers, although properties inherent in these instruments, such as slow data collection time and an inability to specify sample location for the spectral data collection, have placed a ceiling on the clinical practicality of their use for specimen classification and identification. In this thesis, we use a prototype of an infrared hyperspectral imaging microscopy platform based around tunable quantum cascade laser (QCL) technology that has a spectral coverage from 1800-900 cm-1. The quantum cascade lasers are coupled with a series of MIR refractive objectives and an uncooled microbolometer camera. The speed of spectral imaging improves to 30 frames per second, and the high magnification objective has a 1.34 microm pixel resolution with a 0.70 numerical aperture and 4.3 microm spatial resolution. We are able to specify data collection at specific discrete wavelengths as opposed to the full spectrum, which improves the data collection time and de-clutters the data for analysis expediency. Finally, we perform spectral imaging real-time, which aides in selecting precise regions of interest on the target sample. This thesis demonstrates the advantages of exploiting the capabilities of the QCL microscope to advance MIR spectroscopy in the identification of distinguishing traits of normal and malignant breast and cervical tissue samples.

ComPAQS: a compact concentric UV/visible spectrometer, providing a new tool for air quality monitoring from space

NASA Astrophysics Data System (ADS)

Leigh, Roland J.; Whyte, C.; Cutter, M. A.; Lobb, D. R.; Monks, P. S.

2017-11-01

Under the first phase of the Centre for Earth Observation Instrumentation (CEOI), a breadboard demonstrator of a novel UV/VIS spectrometer has been developed. Using designs from Surrey Satellite Technology Ltd (SSTL) the demonstrator has been constructed and tested at the University of Leicester's Space Research Centre. This spectrometer provides an exceptionally compact instrument for differential optical absorption spectroscopy (DOAS) applications from LEO, GEO, HAP or ground-based platforms. Measurement of atmo spheric compounds with climate change or air quality implications is a key driver for the ground and space-based Earth Observation communities. Techniques using UV/VIS spectroscopy such as DOAS provide measurements of ozone profiles, aerosol optical depth, certain Volatile Organic Compounds, halogenated species, and key air quality parameters including tropospheric nitrogen dioxide. Compact instruments providing the necessary optical performance and spectral resolution are therefore a key enabling technology. The Compact Air Quality Spectrometer (CompAQS) features a concentric arrangement of a spherical meniscus lens, a concave spherical mirror and a suitable curved diffraction grating. This compact design provides efficiency and performance benefits over traditional concepts, improving the precision and spatial resolution available from space borne instruments with limited weight and size budgets. The breadboard spectrometer currently operating at the University of Leicester offers high throughput with a spectral range from 310 to 450 nm at 0.5nm(UV) to 1.0nm (visible) resolution, suitable for DOAS applications. The concentric design is capable of handling high relative apertures, owing to spherical aberration and coma being near zero at all surfaces. The design also provides correction for transverse chromatic aberration and distortion, in addition to correcting for the distortion called `smile' - the curvature of the slit image formed at each wavelength. These properties render this design capable of superior spectral and spatial performance with size and weight budgets significantly lower than standard configurations. In this presentation, the design of the spectrometer is detailed, with results from instrument characterisations undertaken at the University of Leicester, including demonstrations of DOAS fits for key air quality species.

High-resolution Bent-crystal Spectrometer for the Ultra-soft X-ray Region

DOE R&D Accomplishments Database

Beiersdorfer, P.; von Goeler, S.; Bitter, M.; Hill, K. W.; Hulse, R. A.; Walling, R. S.

1988-10-01

A multichannel vacuum Brag-crystal spectrometer has been developed for high-resolution measurements of the line emission from tokamak plasmas in the wavelength region between 4 and 25 angstrom. The spectrometer employs a bent crystal in Johann geometry and a microchannel-plate intensified photodiode array. The instrument is capable of measuring high-resolution spectra (lambda/..delta..lambda approx. 3000) with fast time resolution (4 msec per spectrum) and good spatial resolution (3 cm). The spectral bandwidth is ..delta..lambda/lambda{sub 0} = 8 angstrom. A simple tilt mechanism allows access to different wavelength intervals. In order to illustrate the utility of the new spectrometer, time- and space-resolved measurements of the n = 3 to n = 2 spectrum of selenium from the Princeton Large Torus tokamak plasmas are presented. The data are used to determine the plasma transport parameters and to infer the radial distribution of fluorinelike, neonlike, and sodiumlike ions of selenium in the plasma. The new ultra-soft x-ray spectrometer has thus enabled us to demonstrate the utility of high-resolution L-shell spectroscopy of neonlike ions as a fusion diagnostic.

Towards 10 meV resolution: The design of an ultrahigh resolution soft X-ray RIXS spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dvorak, Joseph; Jarrige, Ignace; Bisogni, Valentina

Here we present the optical design of the Centurion soft X-ray resonant inelastic X-ray scattering (RIXS) spectrometer to be located on the SIX beamline at NSLS-II. The spectrometer is designed to reach a resolving power of 100 000 at 1000 eV at its best resolution. It is also designed to have continuously variable 2θ motion over a range of 112° using a custom triple rotating flange. We have analyzed several possible spectrometer designs capable of reaching the target resolution. After careful analysis, we have adopted a Hettrick-Underwood spectrometer design, with an additional plane mirror to maintain a fixed direction formore » the outgoing beam. The spectrometer can cancel defocus and coma aberrations at all energies, has an erect focal plane, and minimizes mechanical motions of the detector. When the beamline resolution is accounted for, the net spectral resolution will be 14 meV at 1000 eV. Lastly, this will open up many low energy excitations to study and will expand greatly the power of soft X-ray RIXS.« less

Towards 10 meV resolution: The design of an ultrahigh resolution soft X-ray RIXS spectrometer

DOE PAGES

Dvorak, Joseph; Jarrige, Ignace; Bisogni, Valentina; ...

2016-11-10

Here we present the optical design of the Centurion soft X-ray resonant inelastic X-ray scattering (RIXS) spectrometer to be located on the SIX beamline at NSLS-II. The spectrometer is designed to reach a resolving power of 100 000 at 1000 eV at its best resolution. It is also designed to have continuously variable 2θ motion over a range of 112° using a custom triple rotating flange. We have analyzed several possible spectrometer designs capable of reaching the target resolution. After careful analysis, we have adopted a Hettrick-Underwood spectrometer design, with an additional plane mirror to maintain a fixed direction formore » the outgoing beam. The spectrometer can cancel defocus and coma aberrations at all energies, has an erect focal plane, and minimizes mechanical motions of the detector. When the beamline resolution is accounted for, the net spectral resolution will be 14 meV at 1000 eV. Lastly, this will open up many low energy excitations to study and will expand greatly the power of soft X-ray RIXS.« less

The Infrared-Optical Telescope (IRT) of the Exist Observatory

NASA Technical Reports Server (NTRS)

Kutyrev, Alexander; Bloom, Joshua; Gehrels, Neil; Golisano, Craig; Gong, Quan; Grindlay, Jonathan; Moseley, Samuel; Woodgate, Bruce

2010-01-01

The IRT is a 1.1m visible and infrared passively cooled telescope, which can locate, identify and obtain spectra of GRB afterglows at redshifts up to z 20. It will also acquire optical-IR, imaging and spectroscopy of AGN and transients discovered by the EXIST (The Energetic X-ray Imaging Survey Telescope). The IRT imaging and spectroscopic capabilities cover a broad spectral range from 0.32.2m in four bands. The identical fields of view in the four instrument bands are each split in three subfields: imaging, objective prism slitless for the field and objective prism single object slit low resolution spectroscopy, and high resolution long slit on single object. This allows the instrument, to do simultaneous broadband photometry or spectroscopy of the same object over the full spectral range, thus greatly improving the efficiency of the observatory and its detection limits. A prompt follow up (within three minutes) of the transient discovered by the EXIST makes IRT a unique tool for detection and study of these events, which is particularly valuable at wavelengths unavailable to the ground based observatories.

The 27-28 October 1986 FIRE IFO cirrus case study - Cloud optical properties determined by High Spectral Resolution Lidar

NASA Technical Reports Server (NTRS)

Grund, C. J.; Eloranta, E. W.

1990-01-01

The High Spectral Resolution Lidar (HSRL) was operated from a roof-top site in Madison, Wisconsin. The transmitter configuration used to acquire the case study data produces about 50 mW of ouput power and achieved eye-safe, direct optical depth, and backscatter cross section measurements with 10 min averaging times. A new continuously pumped, injection seeded, frequency doubled Nd:YAG laser transmitter reduces time-averaging constraints by a factor of about 10, while improving the aerosol-molecular signal separation capabilities and wavelength stability of the instrument. The cirrus cloud backscatter-phase functions have been determined for the October 27-28, 1986 segment of the HSRL FIRE dataset. Features exhibiting backscatter cross sections ranging over four orders of magnitude have been observed within this 33 h period. During this period, cirrus clouds were observed with optical thickness ranging from 0.01 to 1.4. The altitude relationship between cloud top and bottom boundaries and the optical center of the cloud is influenced by the type of formation observed.

Simulation studies of improved sounding systems

NASA Technical Reports Server (NTRS)

Yates, H.; Wark, D.; Aumann, H.; Evans, N.; Phillips, N.; Susskind, J.; Mcmillin, L.; Goldman, A.; Chahine, M.; Crone, L.

1989-01-01

Two instrument designs for indirect satellite sounding of the atmosphere in the infrared are represented by the High Resolution Infra-Red Sounder, Model 2 (HIRS-2) and by the Advanced Meteorological Temperature Sounder (AMTS). The relative capabilities of the two instruments were tested by simulating satellite measurements from a group of temperature soundings, allowing the two participants to retrieve the temperature profiles from the simulated data, and comparing the results with the original temperature profiles. Four data sets were produced from radiosondes data extrapolated to a suitable altitude, representing continents and oceans, between 30S and 30N. From the information available, temperature profiles were retrieved by two different methods, statistical regression and inversion of the radiative transfer equation. Results show the consequence of greater spectral purity, concomitant increase in the number of spectral intervals, and the better spatial resolution in partly clouded areas. At the same time, the limitation of the HIRS-2 without its companion instrument leads to some results which should be ignored in comparing the two instruments. A clear superiority of AMTS results is shown.

An integrated hyperspectral and SAR satellite constellation for environment monitoring

NASA Astrophysics Data System (ADS)

Wang, Jinnian; Ren, Fuhu; Xie, Chou; An, Jun; Tong, Zhanbo

2017-09-01

A fully-integrated, Hyperspectral optical and SAR (Synthetic Aperture Radar) constellation of small earth observation satellites will be deployed over multiple launches from last December to next five years. The Constellation is expected to comprise a minimum of 16 satellites (8 SAR and 8 optical ) flying in two orbital planes, with each plane consisting of four satellite pairs, equally-spaced around the orbit plane. Each pair of satellites will consist of a hyperspectral/mutispectral optical satellite and a high-resolution SAR satellite (X-band) flying in tandem. The constellation is expected to offer a number of innovative capabilities for environment monitoring. As a pre-launch experiment, two hyperspectral earth observation minisatellites, Spark 01 and 02 were launched as secondary payloads together with Tansat in December 2016 on a CZ-2D rocket. The satellites feature a wide-range hyperspectral imager. The ground resolution is 50 m, covering spectral range from visible to near infrared (420 nm - 1000 nm) and a swath width of 100km. The imager has an average spectral resolution of 5 nm with 148 channels, and a single satellite could obtain hyperspectral imagery with 2.5 million km2 per day, for global coverage every 16 days. This paper describes the potential applications of constellation image in environment monitoring.

Improving the spectral resolution and spectral fitting of (1) H MRSI data from human calf muscle by the SPREAD technique.

PubMed

Dong, Zhengchao; Zhang, Yudong; Liu, Feng; Duan, Yunsuo; Kangarlu, Alayar; Peterson, Bradley S

2014-11-01

Proton magnetic resonance spectroscopic imaging ((1) H MRSI) has been used for the in vivo measurement of intramyocellular lipids (IMCLs) in human calf muscle for almost two decades, but the low spectral resolution between extramyocellular lipids (EMCLs) and IMCLs, partially caused by the magnetic field inhomogeneity, has hindered the accuracy of spectral fitting. The purpose of this paper was to enhance the spectral resolution of (1) H MRSI data from human calf muscle using the SPREAD (spectral resolution amelioration by deconvolution) technique and to assess the influence of improved spectral resolution on the accuracy of spectral fitting and on in vivo measurement of IMCLs. We acquired MRI and (1) H MRSI data from calf muscles of three healthy volunteers. We reconstructed spectral lineshapes of the (1) H MRSI data based on field maps and used the lineshapes to deconvolve the measured MRS spectra, thereby eliminating the line broadening caused by field inhomogeneities and improving the spectral resolution of the (1) H MRSI data. We employed Monte Carlo (MC) simulations with 200 noise realizations to measure the variations of spectral fitting parameters and used an F-test to evaluate the significance of the differences of the variations between the spectra before SPREAD and after SPREAD. We also used Cramer-Rao lower bounds (CRLBs) to assess the improvements of spectral fitting after SPREAD. The use of SPREAD enhanced the separation between EMCL and IMCL peaks in (1) H MRSI spectra from human calf muscle. MC simulations and F-tests showed that the use of SPREAD significantly reduced the standard deviations of the estimated IMCL peak areas (p < 10(-8) ), and the CRLBs were strongly reduced (by ~37%). Copyright © 2014 John Wiley & Sons, Ltd.

Current Research in Lidar Technology Used for the Remote Sensing of Atmospheric Aerosols

PubMed Central

Comerón, Adolfo; Muñoz-Porcar, Constantino; Rocadenbosch, Francesc; Rodríguez-Gómez, Alejandro; Sicard, Michaël

2017-01-01

Lidars are active optical remote sensing instruments with unique capabilities for atmospheric sounding. A manifold of atmospheric variables can be profiled using different types of lidar: concentration of species, wind speed, temperature, etc. Among them, measurement of the properties of aerosol particles, whose influence in many atmospheric processes is important but is still poorly stated, stands as one of the main fields of application of current lidar systems. This paper presents a review on fundamentals, technology, methodologies and state-of-the art of the lidar systems used to obtain aerosol information. Retrieval of structural (aerosol layers profiling), optical (backscatter and extinction coefficients) and microphysical (size, shape and type) properties requires however different levels of instrumental complexity; this general outlook is structured following a classification that attends these criteria. Thus, elastic systems (detection only of emitted frequencies), Raman systems (detection also of Raman frequency-shifted spectral lines), high spectral resolution lidars, systems with depolarization measurement capabilities and multi-wavelength instruments are described, and the fundamentals in which the retrieval of aerosol parameters is based is in each case detailed. PMID:28632170

Fitting and Modeling in the ASC Data Analysis Environment

NASA Astrophysics Data System (ADS)

Doe, S.; Siemiginowska, A.; Joye, W.; McDowell, J.

As part of the AXAF Science Center (ASC) Data Analysis Environment, we will provide to the astronomical community a Fitting Application. We present a design of the application in this paper. Our design goal is to give the user the flexibility to use a variety of optimization techniques (Levenberg-Marquardt, maximum entropy, Monte Carlo, Powell, downhill simplex, CERN-Minuit, and simulated annealing) and fit statistics (chi (2) , Cash, variance, and maximum likelihood); our modular design allows the user easily to add their own optimization techniques and/or fit statistics. We also present a comparison of the optimization techniques to be provided by the Application. The high spatial and spectral resolutions that will be obtained with AXAF instruments require a sophisticated data modeling capability. We will provide not only a suite of astronomical spatial and spectral source models, but also the capability of combining these models into source models of up to four data dimensions (i.e., into source functions f(E,x,y,t)). We will also provide tools to create instrument response models appropriate for each observation.

Solar Confocal interferometers for Sub-Picometer-Resolution Spectral Filters

NASA Technical Reports Server (NTRS)

Gary, G. Allen; Pietraszewski, Chris; West, Edward A.; Dines. Terence C.

2007-01-01

The confocal Fabry-Perot interferometer allows sub-picometer spectral resolution of Fraunhofer line profiles. Such high spectral resolution is needed to keep pace with the higher spatial resolution of the new set of large-aperture solar telescopes. The line-of-sight spatial resolution derived for line profile inversions would then track the improvements of the transverse spatial scale provided by the larger apertures. In particular, profile inversion allows improved velocity and magnetic field gradients to be determined independent of multiple line analysis using different energy levels and ions. The confocal interferometer's unique properties allow a simultaneous increase in both etendue and spectral power. The higher throughput for the interferometer provides significant decrease in the aperture, which is important in spaceflight considerations. We have constructed and tested two confocal interferometers. A slow-response thermal-controlled interferometer provides a stable system for laboratory investigation, while a piezoelectric interferometer provides a rapid response for solar observations. In this paper we provide design parameters, show construction details, and report on the laboratory test for these interferometers. The field of view versus aperture for confocal interferometers is compared with other types of spectral imaging filters. We propose a multiple etalon system for observing with these units using existing planar interferometers as pre-filters. The radiometry for these tests established that high spectral resolution profiles can be obtained with imaging confocal interferometers. These sub-picometer spectral data of the photosphere in both the visible and near-infrared can provide important height variation information. However, at the diffraction-limited spatial resolution of the telescope, the spectral data is photon starved due to the decreased spectral passband.

X-Ray and near-infrared imaging: similarities, differences and combinations

NASA Astrophysics Data System (ADS)

Pogue, Brian W.

2010-02-01

The integration of x-ray imaging with optical imaging is becoming routine at the pre-clinical level, as both projection and tomography systems are now commercially integrated as packaged systems. Yet, the differences between their capabilities are wide, and there is still perhaps a lack of appreciation about how difference pre-clinical x-ray systems are from clinical x-ray systems. In this survey, the key advantages of each approach, x-ray and optical, are described, and the potential synergies and deficiencies are discussed. In simple terms, the major benefit of optical imaging is in the spectroscopic capabilities, which allow the potential for imaging fluorescent agents in vivo, and the future potential for imaging multiple species at a time with spectral discrimination or spectral fitting of the data. In comparison, multienergy x-ray systems are being realized in clinical use, or automated discrimination of soft versus hard tissues, and the combination of optical imaging with this type of dual-energy x-ray imaging will significantly enhance the capabilities of the hybrid systems. Unfortunately, the power of dual energy imaging is not as possible at the pre-clinical stage, because of the limitations of contrast-resolution and x-ray dose. This is discussed and future human systems outlined.

Investigating SWOT's capabilities to detect meso and submesoscale eddies in the western Mediterranean

NASA Astrophysics Data System (ADS)

Gomez-Navarro, Laura; Pascual, Ananda; Fablet, Ronan; Mason, Evan

2017-04-01

The primary oceanographic objective of the future Surface Water Ocean Topography (SWOT) altimetric satellite is to characterize the mesoscale and submesoscale ocean circulation. The aim of this study is to assess the capabilities of SWOT to resolve the meso and submesoscale in the western Mediterranean. With ROMS model data as inputs for the SWOT simulator, pseudo-SWOT data were generated. These data were compared with the original ROMS model data and ADT data from present day altimetric satellites to assess the temporal and spatial resolution of SWOT in the western Mediterranean. We then addressed the removal of the satellite's noise in the pseudo-SWOT data using a Laplacian diffusion. We investigated different parameters of the filter by looking at their impact on the spatial spectra and RMSEs calculated from the simulator outputs. To further assess the satellites capabilities, we derived absolute geostrophic velocities and relative vorticity. Our numerical experiments show that the noise patterns affect the spectral content of the pseudo-SWOT fields below 30 km. The Laplacian diffusion improves the recovery of the spectral signature of the altimetric field, especially down to 20 km. With the help of this filter, we manage to observe small scale oceanic features in pseudo-SWOT data, and in its derived variables.

Combining Direct Broadcast Polar Hyper-spectral Soundings with Geostationary Multi-spectral Imagery for Producing Low Latency Sounding Products

NASA Astrophysics Data System (ADS)

Smith, W.; Weisz, E.; McNabb, J. M. C.

2017-12-01

A technique is described which enables the combination of high vertical resolution (1 to 2-km) JPSS hyper-spectral soundings (i.e., from AIRS, CrIS, and IASI) with high horizontal (2-km) and temporal (15-min) resolution GOES multi-spectral imagery (i.e., provided by ABI) to produce low latency sounding products with the highest possible spatial and temporal resolution afforded by the instruments.

Demonstration of Airborne Wide Area Assessment Technologies at Pueblo Precision Bombing Ranges, Colorado. Hyperspectral Imaging, Version 2.0

DTIC Science & Technology

2007-09-27

the spatial and spectral resolution ...variety of geological and vegetation mapping efforts, the Hymap sensor offered the best available combination of spectral and spatial resolution , signal... The limitations of the technology currently relate to spatial and spectral resolution and geo- correction accuracy. Secondly, HSI datasets

Phase Grating Design for a Dual-Band Snapshot Imaging Spectrometer

NASA Astrophysics Data System (ADS)

Scholl, James F.; Dereniak, Eustace L.; Descour, Michael R.; Tebow, Christopher P.; Volin, Curtis E.

2003-01-01

Infrared spectral features have proved useful in the identification of threat objects. Dual-band focal-plane arrays (FPAs) have been developed in which each pixel consists of superimposed midwave and long-wave photodetectors [Dyer and Tidrow, Conference on Infrared Detectors and Focal Plane Arrays (SPIE, Bellingham, Wash., 1999), pp. 434 -440 . Combining dual-band FPAs with imaging spectrometers capable of interband hyperspectral resolution greatly improves spatial target discrimination. The computed-tomography imaging spectrometer (CTIS) ] [Descour and Dereniak, Appl. Opt. 34, 4817 -4826 (1995) has proved effective in producing hyperspectral images in a single spectral region. Coupling the CTIS with a dual-band detector can produce two hyperspectral data cubes simultaneously. We describe the design of two-dimensional, surface-relief, computer-generated hologram dispersers that permit image information in these two bands simultaneously.

Herschel Shines Light on the Episodic Evolutionary Sequence of Protostars

NASA Astrophysics Data System (ADS)

Green, Joel D.; DIGIT; FOOSH; COPS Teams

2014-01-01

New far-infrared and submillimeter spectroscopic capabilities, along with moderate spatial and spectral resolution, provide the opportunity to study the diversity of shocks, accretion processes, and compositions of the envelopes of developing protostellar objects in nearby molecular clouds. We present the "COPS" (CO in Protostars) sample; a statistical analysis of the full sample of 30 Class 0/I protostars from the "DIGIT" Key project using Herschel-PACS/SPIRE 50-700 micron spectroscopy. We consider the sample as a whole in characteristic spectral lines, using a standardized data reduction procedure for all targets, and analyze the differences in the continuum and gas over the full sample, presenting an overview of trends. We compare the sources in evolutionary state, envelope mass, and gas properties to more evolved sources from the"FOOSH'' (FUor) samples.

Voice gender identification by cochlear implant users: The role of spectral and temporal resolution

NASA Astrophysics Data System (ADS)

Fu, Qian-Jie; Chinchilla, Sherol; Nogaki, Geraldine; Galvin, John J.

2005-09-01

The present study explored the relative contributions of spectral and temporal information to voice gender identification by cochlear implant users and normal-hearing subjects. Cochlear implant listeners were tested using their everyday speech processors, while normal-hearing subjects were tested under speech processing conditions that simulated various degrees of spectral resolution, temporal resolution, and spectral mismatch. Voice gender identification was tested for two talker sets. In Talker Set 1, the mean fundamental frequency values of the male and female talkers differed by 100 Hz while in Talker Set 2, the mean values differed by 10 Hz. Cochlear implant listeners achieved higher levels of performance with Talker Set 1, while performance was significantly reduced for Talker Set 2. For normal-hearing listeners, performance was significantly affected by the spectral resolution, for both Talker Sets. With matched speech, temporal cues contributed to voice gender identification only for Talker Set 1 while spectral mismatch significantly reduced performance for both Talker Sets. The performance of cochlear implant listeners was similar to that of normal-hearing subjects listening to 4-8 spectral channels. The results suggest that, because of the reduced spectral resolution, cochlear implant patients may attend strongly to periodicity cues to distinguish voice gender.

Improvements and Extensions for Joint Polar Satellite System Algorithms

NASA Astrophysics Data System (ADS)

Grant, K. D.

2016-12-01

The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation civilian weather satellite system: the Joint Polar Satellite System (JPSS). JPSS replaced the afternoon orbit component and ground processing of the old POES system managed by NOAA. JPSS satellites carry sensors designed to collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The ground processing system for JPSS is the Common Ground System (CGS), and provides command, control, and communications (C3), data processing and product delivery. CGS's data processing capability provides environmental data products (Sensor Data Records (SDRs) and Environmental Data Records (EDRs)) to the NOAA Satellite Operations Facility. The first satellite in the JPSS constellation, S-NPP, was launched in October 2011. The second satellite, JPSS-1, is scheduled for launch in January 2017. During a satellite's calibration and validation (Cal/Val) campaign, numerous algorithm updates occur. Changes identified during Cal/Val become available for implementation into the operational system for both S-NPP and JPSS-1. In addition, new capabilities, such as higher spectral and spatial resolution, will be exercised on JPSS-1. This paper will describe changes to current algorithms and products as a result of S-NPP Cal/Val and related initiatives for improved capabilities. Improvements include Cross Track Infrared Sounder high spectral processing, extended spectral and spatial ranges for Ozone Mapping and Profiler Suite ozone Total Column and Nadir Profiles, and updates to Vegetation Index, Snow Cover, Active Fires, Suspended Matter, and Ocean Color. Updates will include Sea Surface Temperature, Cloud Mask, Cloud Properties, and other improvements.

Principle, system, and applications of tip-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Zhang, MingQian; Wang, Rui; Wu, XiaoBin; Wang, Jia

2012-08-01

Raman spectroscopy is a powerful technique in chemical information characterization. However, this spectral method is subject to two obstacles in nano-material detection. One is diffraction limited spatial resolution, and the other is its inherent small Raman cross section and weak signaling. To resolve these problems, a new approach has been developed, denoted as tip-enhanced Raman spectroscopy (TERS). TERS is capable of high-resolution and high-sensitivity detection and demonstrated to be a promising spectroscopic and micro-topographic method to characterize nano-materials and nanostructures. In this paper, the principle and experimental system of TERS are discussed. The latest application of TERS in molecule detection, biological specimen identification, nanao-material characterization, and semi-conductor material determination with some specific experimental examples are presented.

Etalon Array Reconstructive Spectrometry

NASA Astrophysics Data System (ADS)

Huang, Eric; Ma, Qian; Liu, Zhaowei

2017-01-01

Compact spectrometers are crucial in areas where size and weight may need to be minimized. These types of spectrometers often contain no moving parts, which makes for an instrument that can be highly durable. With the recent proliferation in low-cost and high-resolution cameras, camera-based spectrometry methods have the potential to make portable spectrometers small, ubiquitous, and cheap. Here, we demonstrate a novel method for compact spectrometry that uses an array of etalons to perform spectral encoding, and uses a reconstruction algorithm to recover the incident spectrum. This spectrometer has the unique capability for both high resolution and a large working bandwidth without sacrificing sensitivity, and we anticipate that its simplicity makes it an excellent candidate whenever a compact, robust, and flexible spectrometry solution is needed.

VizieR Online Data Catalog: Spectroscopy of the foreground population in Orion A (Fang+, 2017)

NASA Astrophysics Data System (ADS)

Fang, M.; Kim, J. S.; Pascucci, I.; Apai, D.; Zhang, L.; Sicilia-Aguilar, A.; Alonso-Martinez, M.; Eiroa, C.; Wang, H.

2018-05-01

We performed a low-resolution spectroscopic survey of the stellar population in NGC 1980 with the Hectospec multi-object spectrograph, capable of taking a maximum of 300 spectra simultaneously. We used the 270 groove/mm grating and obtained spectra in the 3700-9000Å range with a spectral resolution of ~5Å. The data were taken in 2016 February. In Table 4, we list the young stars with X-Shooter spectra. These sources are mainly from the {eta} Cha cluster, the TW Hydra Association, the Lupus star-forming region, the σ Ori cluster, and the Cha I star-forming region. We extract the spectra of these sources from the X-Shooter phase III data archive. (3 data files).

High resolution energy-angle correlation measurement of hard x rays from laser-Thomson backscattering.

PubMed

Jochmann, A; Irman, A; Bussmann, M; Couperus, J P; Cowan, T E; Debus, A D; Kuntzsch, M; Ledingham, K W D; Lehnert, U; Sauerbrey, R; Schlenvoigt, H P; Seipt, D; Stöhlker, Th; Thorn, D B; Trotsenko, S; Wagner, A; Schramm, U

2013-09-13

Thomson backscattering of intense laser pulses from relativistic electrons not only allows for the generation of bright x-ray pulses but also for the investigation of the complex particle dynamics at the interaction point. For this purpose a complete spectral characterization of a Thomson source powered by a compact linear electron accelerator is performed with unprecedented angular and energy resolution. A rigorous statistical analysis comparing experimental data to 3D simulations enables, e.g., the extraction of the angular distribution of electrons with 1.5% accuracy and, in total, provides predictive capability for the future high brightness hard x-ray source PHOENIX (photon electron collider for narrow bandwidth intense x rays) and potential gamma-ray sources.

Temporal Coding of Volumetric Imagery

NASA Astrophysics Data System (ADS)

Llull, Patrick Ryan

'Image volumes' refer to realizations of images in other dimensions such as time, spectrum, and focus. Recent advances in scientific, medical, and consumer applications demand improvements in image volume capture. Though image volume acquisition continues to advance, it maintains the same sampling mechanisms that have been used for decades; every voxel must be scanned and is presumed independent of its neighbors. Under these conditions, improving performance comes at the cost of increased system complexity, data rates, and power consumption. This dissertation explores systems and methods capable of efficiently improving sensitivity and performance for image volume cameras, and specifically proposes several sampling strategies that utilize temporal coding to improve imaging system performance and enhance our awareness for a variety of dynamic applications. Video cameras and camcorders sample the video volume (x,y,t) at fixed intervals to gain understanding of the volume's temporal evolution. Conventionally, one must reduce the spatial resolution to increase the framerate of such cameras. Using temporal coding via physical translation of an optical element known as a coded aperture, the compressive temporal imaging (CACTI) camera emonstrates a method which which to embed the temporal dimension of the video volume into spatial (x,y) measurements, thereby greatly improving temporal resolution with minimal loss of spatial resolution. This technique, which is among a family of compressive sampling strategies developed at Duke University, temporally codes the exposure readout functions at the pixel level. Since video cameras nominally integrate the remaining image volume dimensions (e.g. spectrum and focus) at capture time, spectral (x,y,t,lambda) and focal (x,y,t,z) image volumes are traditionally captured via sequential changes to the spectral and focal state of the system, respectively. The CACTI camera's ability to embed video volumes into images leads to exploration of other information within that video; namely, focal and spectral information. The next part of the thesis demonstrates derivative works of CACTI: compressive extended depth of field and compressive spectral-temporal imaging. These works successfully show the technique's extension of temporal coding to improve sensing performance in these other dimensions. Geometrical optics-related tradeoffs, such as the classic challenges of wide-field-of-view and high resolution photography, have motivated the development of mulitscale camera arrays. The advent of such designs less than a decade ago heralds a new era of research- and engineering-related challenges. One significant challenge is that of managing the focal volume (x,y,z ) over wide fields of view and resolutions. The fourth chapter shows advances on focus and image quality assessment for a class of multiscale gigapixel cameras developed at Duke. Along the same line of work, we have explored methods for dynamic and adaptive addressing of focus via point spread function engineering. We demonstrate another form of temporal coding in the form of physical translation of the image plane from its nominal focal position. We demonstrate this technique's capability to generate arbitrary point spread functions.

Laser interference fringe tomography: a novel 3D imaging technique for pathology

NASA Astrophysics Data System (ADS)

Kazemzadeh, Farnoud; Haylock, Thomas M.; Chifman, Lev M.; Hajian, Arsen R.; Behr, Bradford B.; Cenko, Andrew T.; Meade, Jeff T.; Hendrikse, Jan

2011-03-01

Laser interference fringe tomography (LIFT) is within the class of optical imaging devices designed for in vivo and ex vivo medical imaging applications. LIFT is a very simple and cost-effective three-dimensional imaging device with performance rivaling some of the leading three-dimensional imaging devices used for histology. Like optical coherence tomography (OCT), it measures the reflectivity as a function of depth within a sample and is capable of producing three-dimensional images from optically scattering media. LIFT has the potential capability to produce high spectral resolution, full-color images. The optical design of LIFT along with the planned iterations for improvements and miniaturization are presented and discussed in addition to the theoretical concepts and preliminary imaging results of the device.

Field Geology/Processes

NASA Technical Reports Server (NTRS)

Allen, Carlton; Jakes, Petr; Jaumann, Ralf; Marshall, John; Moses, Stewart; Ryder, Graham; Saunders, Stephen; Singer, Robert

1996-01-01

The field geology/process group examined the basic operations of a terrestrial field geologist and the manner in which these operations could be transferred to a planetary lander. Four basic requirements for robotic field geology were determined: geologic content; surface vision; mobility; and manipulation. Geologic content requires a combination of orbital and descent imaging. Surface vision requirements include range, resolution, stereo, and multispectral imaging. The minimum mobility for useful field geology depends on the scale of orbital imagery. Manipulation requirements include exposing unweathered surfaces, screening samples, and bringing samples in contact with analytical instruments. To support these requirements, several advanced capabilities for future development are recommended. Capabilities include near-infrared reflectance spectroscopy, hyper-spectral imaging, multispectral microscopy, artificial intelligence in support of imaging, x ray diffraction, x ray fluorescence, and rock chipping.

Algal Accessory Pigment Detection Using AVIRIS Image-Derived Spectral Radiance Data

NASA Technical Reports Server (NTRS)

Richardson, Laurie L.; Ambrosia, Vincent G.

1996-01-01

Visual and derivative analyses of AVIRIS spectral data can be used to detect algal accessory pigments in aquatic communities. This capability extends the use of remote sensing for the study of aquatic ecosystems by allowing detection of taxonomically significant pigment signatures which yield information about the type of algae present. Such information allows remote sensing-based assessment of aquatic ecosystem health, as in the detection of nuisance blooms of cyanobacteria or toxic blooms of dinoflagellates. Remote sensing of aquatic systems has traditionally focused on quantification of chlorophyll a, a photoreactive (and light-harvesting) pigment which is common to all algae as well as cyanobacteria (bluegreen algae). Due to the ubiquitousness of this pigment within algae, chl a is routinely measured to estimate algal biomass both during ground-truthing and using various airborne or satellite based sensors, including AVIRIS. Within the remote sensing and aquatic sciences communities, ongoing research has been performed to detect algal accessory pigments for assessment of algal population composition. This research is based on the fact that many algal accessory pigments are taxonomically significant, and all are spectrally unique. Aquatic scientists have been refining pigment analysis techniques, primarily high performance liquid chromatography, or HPLC, to detect specific pigments as a time-saving alternative to individual algal cell identifications and counts. Remote sensing scientists are investigating the use of pigment signatures to construct pigment libraries analogous to mineral spectral libraries used in geological remote sensing applications. The accessory pigment approach has been used successfully in remote sensing using data from the Thematic Mapper, low-altitude, multiple channel scanners, field spectroradiometers and the AVIRIS hyperspectral scanner. Due to spectral and spatial resolution capabilities, AVIRIS is the sensor of choice for such studies. We present here our results on detection of algal accessory pigments using AVIRIS data.

Cochlear implant users' spectral ripple resolution.

PubMed

Jeon, Eun Kyung; Turner, Christopher W; Karsten, Sue A; Henry, Belinda A; Gantz, Bruce J

2015-10-01

This study revisits the issue of the spectral ripple resolution abilities of cochlear implant (CI) users. The spectral ripple resolution of recently implanted CI recipients (implanted during the last 10 years) were compared to those of CI recipients implanted 15 to 20 years ago, as well as those of normal-hearing and hearing-impaired listeners from previously published data from Henry, Turner, and Behrens [J. Acoust. Soc. Am. 118, 1111-1121 (2005)]. More recently, implanted CI recipients showed significantly better spectral ripple resolution. There is no significant difference in spectral ripple resolution for these recently implanted subjects compared to hearing-impaired (acoustic) listeners. The more recently implanted CI users had significantly better pre-operative speech perception than previously reported CI users. These better pre-operative speech perception scores in CI users from the current study may be related to better performance on the spectral ripple discrimination task; however, other possible factors such as improvements in internal and external devices cannot be excluded.

Cochlear implant users' spectral ripple resolution

PubMed Central

Jeon, Eun Kyung; Turner, Christopher W.; Karsten, Sue A.; Henry, Belinda A.; Gantz, Bruce J.

2015-01-01

This study revisits the issue of the spectral ripple resolution abilities of cochlear implant (CI) users. The spectral ripple resolution of recently implanted CI recipients (implanted during the last 10 years) were compared to those of CI recipients implanted 15 to 20 years ago, as well as those of normal-hearing and hearing-impaired listeners from previously published data from Henry, Turner, and Behrens [J. Acoust. Soc. Am. 118, 1111–1121 (2005)]. More recently, implanted CI recipients showed significantly better spectral ripple resolution. There is no significant difference in spectral ripple resolution for these recently implanted subjects compared to hearing-impaired (acoustic) listeners. The more recently implanted CI users had significantly better pre-operative speech perception than previously reported CI users. These better pre-operative speech perception scores in CI users from the current study may be related to better performance on the spectral ripple discrimination task; however, other possible factors such as improvements in internal and external devices cannot be excluded. PMID:26520316

Characterization of spatial and spectral resolution of a rotating prism chromotomographic hyperspectral imager

NASA Astrophysics Data System (ADS)

Bostick, Randall L.; Perram, Glen P.; Tuttle, Ronald

2009-05-01

The Air Force Institute of Technology (AFIT) has built a rotating prism chromotomographic hyperspectral imager (CTI) with the goal of extending the technology to exploit spatially extended sources with quickly varying (> 10 Hz) phenomenology, such as bomb detonations and muzzle flashes. This technology collects successive frames of 2-D data dispersed at different angles multiplexing spatial and spectral information which can then be used to reconstruct any arbitrary spectral plane(s). In this paper, the design of the AFIT instrument is described and then tested against a spectral target with near point source spatial characteristics to measure spectral and spatial resolution. It will be shown that, in theory, the spectral and spatial resolution in the 3-D spectral image cube is the nearly the same as a simple prism spectrograph with the same design. However, error in the knowledge of the prism linear dispersion at the detector array as a function of wavelength and projection angle will degrade resolution without further corrections. With minimal correction for error and use of a simple shift-and-add reconstruction algorithm, the CTI is able to produce a spatial resolution of about 2 mm in the object plane (234 μrad IFOV) and is limited by chromatic aberration. A spectral resolution of less than 1nm at shorter wavelengths is shown, limited primarily by prism dispersion.

Objective Assessment of Spectral Ripple Discrimination in Cochlear Implant Listeners Using Cortical Evoked Responses to an Oddball Paradigm

PubMed Central

Lopez Valdes, Alejandro; Mc Laughlin, Myles; Viani, Laura; Walshe, Peter; Smith, Jaclyn; Zeng, Fan-Gang; Reilly, Richard B.

2014-01-01

Cochlear implants (CIs) can partially restore functional hearing in deaf individuals. However, multiple factors affect CI listener's speech perception, resulting in large performance differences. Non-speech based tests, such as spectral ripple discrimination, measure acoustic processing capabilities that are highly correlated with speech perception. Currently spectral ripple discrimination is measured using standard psychoacoustic methods, which require attentive listening and active response that can be difficult or even impossible in special patient populations. Here, a completely objective cortical evoked potential based method is developed and validated to assess spectral ripple discrimination in CI listeners. In 19 CI listeners, using an oddball paradigm, cortical evoked potential responses to standard and inverted spectrally rippled stimuli were measured. In the same subjects, psychoacoustic spectral ripple discrimination thresholds were also measured. A neural discrimination threshold was determined by systematically increasing the number of ripples per octave and determining the point at which there was no longer a significant difference between the evoked potential response to the standard and inverted stimuli. A correlation was found between the neural and the psychoacoustic discrimination thresholds (R2 = 0.60, p<0.01). This method can objectively assess CI spectral resolution performance, providing a potential tool for the evaluation and follow-up of CI listeners who have difficulty performing psychoacoustic tests, such as pediatric or new users. PMID:24599314

Objective assessment of spectral ripple discrimination in cochlear implant listeners using cortical evoked responses to an oddball paradigm.

PubMed

Lopez Valdes, Alejandro; Mc Laughlin, Myles; Viani, Laura; Walshe, Peter; Smith, Jaclyn; Zeng, Fan-Gang; Reilly, Richard B

2014-01-01

Cochlear implants (CIs) can partially restore functional hearing in deaf individuals. However, multiple factors affect CI listener's speech perception, resulting in large performance differences. Non-speech based tests, such as spectral ripple discrimination, measure acoustic processing capabilities that are highly correlated with speech perception. Currently spectral ripple discrimination is measured using standard psychoacoustic methods, which require attentive listening and active response that can be difficult or even impossible in special patient populations. Here, a completely objective cortical evoked potential based method is developed and validated to assess spectral ripple discrimination in CI listeners. In 19 CI listeners, using an oddball paradigm, cortical evoked potential responses to standard and inverted spectrally rippled stimuli were measured. In the same subjects, psychoacoustic spectral ripple discrimination thresholds were also measured. A neural discrimination threshold was determined by systematically increasing the number of ripples per octave and determining the point at which there was no longer a significant difference between the evoked potential response to the standard and inverted stimuli. A correlation was found between the neural and the psychoacoustic discrimination thresholds (R2=0.60, p<0.01). This method can objectively assess CI spectral resolution performance, providing a potential tool for the evaluation and follow-up of CI listeners who have difficulty performing psychoacoustic tests, such as pediatric or new users.

A two-dimensional intensified photodiode array for imaging spectroscopy

NASA Technical Reports Server (NTRS)

Tennyson, P. D.; Dymond, K.; Moos, H. W.; Feldman, P. D.; Mackey, E. F.

1986-01-01

The Johns Hopkins University is currently developing an instrument to fly aboard NASA's Space Shuttle as a Spartan payload in the late 1980s. This Spartan free flyer will obtain spatially resolved spectra of faint extended emission line objects in the wavelength range 750-1150 A at about 2-A resolution. The use of two-dimensional photon counting detectors will give simultaneous coverage of the 400 A spectral range and the 9 arc-minute spatial resolution along the spectrometer slit. The progress towards the flight detector is reported here with preliminary results from a laboratory breadboard detector, and a comparison with the one-dimensional detector developed for the Hopkins Ultraviolet Telescope. A hardware digital centroiding algorithm has been successfully implemented. The system is ultimately capable of 15-micron resolution in two dimensions at the image plane and can handle continuous counting rates of up to 8000 counts/s.

ANS hard X-ray experiment development program. [emission from X-ray sources

NASA Technical Reports Server (NTRS)

Parsignault, D.; Gursky, H.; Frank, R.; Kubierschky, K.; Austin, G.; Paganetti, R.; Bawdekar, V.

1974-01-01

The hard X-ray (HXX) experiment is one of three experiments included in the Dutch Astronomical Netherlands Satellite, which was launched into orbit on 30 August 1974. The overall objective of the HXX experiment is the detailed study of the emission from known X-ray sources over the energy range 1.5-30keV. The instrument is capable of the following measurements: (1) spectral content over the full energy range with an energy resolution of approximately 20% and time resolution down to 4 seconds; (2) source time variability down to 4 milliseconds; (3) silicon emission lines at 1.86 and 2.00keV; (4) source location to a limit of one arc minute in ecliptic latitude; and (5) spatial structure with angular resolution of the arc minutes. Scientific aspects of experiment, engineering design and implementation of the experiment, and program history are included.

Theoretical Noise Analysis on a Position-sensitive Metallic Magnetic Calorimeter

NASA Technical Reports Server (NTRS)

Smith, Stephen J.

2007-01-01

We report on the theoretical noise analysis for a position-sensitive Metallic Magnetic Calorimeter (MMC), consisting of MMC read-out at both ends of a large X-ray absorber. Such devices are under consideration as alternatives to other cryogenic technologies for future X-ray astronomy missions. We use a finite-element model (FEM) to numerically calculate the signal and noise response at the detector outputs and investigate the correlations between the noise measured at each MMC coupled by the absorber. We then calculate, using the optimal filter concept, the theoretical energy and position resolution across the detector and discuss the trade-offs involved in optimizing the detector design for energy resolution, position resolution and count rate. The results show, theoretically, the position-sensitive MMC concept offers impressive spectral and spatial resolving capabilities compared to pixel arrays and similar position-sensitive cryogenic technologies using Transition Edge Sensor (TES) read-out.

Compressive hyperspectral time-resolved wide-field fluorescence lifetime imaging

NASA Astrophysics Data System (ADS)

Pian, Qi; Yao, Ruoyang; Sinsuebphon, Nattawut; Intes, Xavier

2017-07-01

Spectrally resolved fluorescence lifetime imaging and spatial multiplexing have offered information content and collection-efficiency boosts in microscopy, but efficient implementations for macroscopic applications are still lacking. An imaging platform based on time-resolved structured light and hyperspectral single-pixel detection has been developed to perform quantitative macroscopic fluorescence lifetime imaging (MFLI) over a large field of view (FOV) and multiple spectral bands simultaneously. The system makes use of three digital micromirror device (DMD)-based spatial light modulators (SLMs) to generate spatial optical bases and reconstruct N by N images over 16 spectral channels with a time-resolved capability (∼40 ps temporal resolution) using fewer than N2 optical measurements. We demonstrate the potential of this new imaging platform by quantitatively imaging near-infrared (NIR) Förster resonance energy transfer (FRET) both in vitro and in vivo. The technique is well suited for quantitative hyperspectral lifetime imaging with a high sensitivity and paves the way for many important biomedical applications.

Focused Study of Thermonuclear Bursts on Neutron Stars

NASA Astrophysics Data System (ADS)

Chenevez, Jérôme

2009-05-01

X-ray bursters form a class of Low Mass X-Ray Binaries where accreted material from a donor star undergoes rapid thermonuclear burning in the surface layers of a neutron star. The flux released can temporarily exceed the Eddington limit and drive the photosphere to large radii. Such photospheric radius expansion bursts likely eject nuclear burning ashes into the interstellar medium, and may make possible the detection of photoionization edges. Indeed, theoretical models predict that absorption edges from 58Fe at 9.2 keV, 60Zn and 62Zn at 12.2 keV should be detectable by the future missions Simbol-X and NuSTAR. A positive detection would thus probe the nuclear burning as well as the gravitational redshift from the neutron star. Moreover, likely observations of atomic X-ray spectral components reflected from the inner accretion disk have been reported. The high spectral resolution capabilities of the focusing X-ray telescopes may therefore make possible to differentiate between the potential interpretations of the X-ray bursts spectral features.

The high resolution stereo camera (HRSC): acquisition of multi-spectral 3D-data and photogrammetric processing

NASA Astrophysics Data System (ADS)

Neukum, Gerhard; Jaumann, Ralf; Scholten, Frank; Gwinner, Klaus

2017-11-01

At the Institute of Space Sensor Technology and Planetary Exploration of the German Aerospace Center (DLR) the High Resolution Stereo Camera (HRSC) has been designed for international missions to planet Mars. For more than three years an airborne version of this camera, the HRSC-A, has been successfully applied in many flight campaigns and in a variety of different applications. It combines 3D-capabilities and high resolution with multispectral data acquisition. Variable resolutions depending on the camera control settings can be generated. A high-end GPS/INS system in combination with the multi-angle image information yields precise and high-frequent orientation data for the acquired image lines. In order to handle these data a completely automated photogrammetric processing system has been developed, and allows to generate multispectral 3D-image products for large areas and with accuracies for planimetry and height in the decimeter range. This accuracy has been confirmed by detailed investigations.

High resolution ultrasonic spectroscopy system for nondestructive evaluation

NASA Technical Reports Server (NTRS)

Chen, C. H.

1991-01-01

With increased demand for high resolution ultrasonic evaluation, computer based systems or work stations become essential. The ultrasonic spectroscopy method of nondestructive evaluation (NDE) was used to develop a high resolution ultrasonic inspection system supported by modern signal processing, pattern recognition, and neural network technologies. The basic system which was completed consists of a 386/20 MHz PC (IBM AT compatible), a pulser/receiver, a digital oscilloscope with serial and parallel communications to the computer, an immersion tank with motor control of X-Y axis movement, and the supporting software package, IUNDE, for interactive ultrasonic evaluation. Although the hardware components are commercially available, the software development is entirely original. By integrating signal processing, pattern recognition, maximum entropy spectral analysis, and artificial neural network functions into the system, many NDE tasks can be performed. The high resolution graphics capability provides visualization of complex NDE problems. The phase 3 efforts involve intensive marketing of the software package and collaborative work with industrial sectors.

High-resolution Interferometer Sounder (HIS), phase 2

NASA Technical Reports Server (NTRS)

1988-01-01

The High-resolution Interferometer Sounder (HIS) was successfully built, tested, and flight proven on the NASA U-2/ER-2 high altitude aircraft. The HIS demonstration has shown that, by using the technology of Fourier Transform Spectroscopy (FTS), it is possible to measure the spectrum of upwelling infrared radiance needed for temperature and humidity sounding with high spectral resolution and high radiometric precision. By resolving individual carbon dioxide lines, the retrieved temperature profiles have vertical resolutions of 1 to 2 km and RMS errors less than 1 C, about 2 to 4 times better than possible with current sounders. Implementing this capability on satellite sounders will greatly enhance the dynamical information content of temperature measurements from space. The aircraft model HIS is now a resource which should be used to support field experiments in mesoscale meteorology, to monitor trace gas concentrations and to better understand their effects on climate, to monitor the surface radiation budget and the radiative effects of clouds, and to collect data for research into retrieval techniques, especially under partially cloudy conditions.

Imaging Exoplanets with the Exo-S Starshade Mission: Baseline Design

NASA Astrophysics Data System (ADS)

Cady, Eric; Lisman, Doug; Martin, Stefan; Scharf, Daniel; Shaklan, Stuart; Trabert, Rachel; Webb, David; Exo-S Science; Technology Definition Team, Exoplanet Program Probe Study Design Team

2015-01-01

Starshades suppress on-axis starlight to enable the direct imaging of exoplanets with non-specialized space telescopes of variable size. Even relatively small, commercially available telescopes are capable of imaging Earth-like planets in the habitable zone, and larger telescopes provide the capability to characterize planet atmospheres with increasing spectral resolution. We detail two options developed by the STDT for probe-class starshade missions (Exo-S): a co-launch of a starshade with a dedicated 1.1m telescope, and a standalone starshade to augment an existing large telescope such as WFIRST-AFTA. For these concepts, we describe the optical and mechanical design, the formation flying system, and the augmentations required to make a telescope 'starshade-ready'. We also lay out typical design reference missions for each and their scientific yield, and show both concepts have the capability to image terrestrial exoplanets orbiting nearby stars.

Evaluating the utility of the medium-spatial resolution Landsat 8 multispectral sensor in quantifying aboveground biomass in uMgeni catchment, South Africa

NASA Astrophysics Data System (ADS)

Dube, Timothy; Mutanga, Onisimo

2015-03-01

Aboveground biomass estimation is critical in understanding forest contribution to regional carbon cycles. Despite the successful application of high spatial and spectral resolution sensors in aboveground biomass (AGB) estimation, there are challenges related to high acquisition costs, small area coverage, multicollinearity and limited availability. These challenges hamper the successful regional scale AGB quantification. The aim of this study was to assess the utility of the newly-launched medium-resolution multispectral Landsat 8 Operational Land Imager (OLI) dataset with a large swath width, in quantifying AGB in a forest plantation. We applied different sets of spectral analysis (test I: spectral bands; test II: spectral vegetation indices and test III: spectral bands + spectral vegetation indices) in testing the utility of Landsat 8 OLI using two non-parametric algorithms: stochastic gradient boosting and the random forest ensembles. The results of the study show that the medium-resolution multispectral Landsat 8 OLI dataset provides better AGB estimates for Eucalyptus dunii, Eucalyptus grandis and Pinus taeda especially when using the extracted spectral information together with the derived spectral vegetation indices. We also noted that incorporating the optimal subset of the most important selected medium-resolution multispectral Landsat 8 OLI bands improved AGB accuracies. We compared medium-resolution multispectral Landsat 8 OLI AGB estimates with Landsat 7 ETM + estimates and the latter yielded lower estimation accuracies. Overall, this study demonstrates the invaluable potential and strength of applying the relatively affordable and readily available newly-launched medium-resolution Landsat 8 OLI dataset, with a large swath width (185-km) in precisely estimating AGB. This strength of the Landsat OLI dataset is crucial especially in sub-Saharan Africa where high-resolution remote sensing data availability remains a challenge.

Analytical SuperSTEM for extraterrestrial materials research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bradley, J P; Dai, Z R

2009-09-08

Electron-beam studies of extraterrestrial materials with significantly improved spatial resolution, energy resolution and sensitivity are enabled using a 300 keV SuperSTEM scanning transmission electron microscope with a monochromator and two spherical aberration correctors. The improved technical capabilities enable analyses previously not possible. Mineral structures can be directly imaged and analyzed with single-atomic-column resolution, liquids and implanted gases can be detected, and UV-VIS optical properties can be measured. Detection limits for minor/trace elements in thin (<100 nm thick) specimens are improved such that quantitative measurements of some extend to the sub-500 ppm level. Electron energy-loss spectroscopy (EELS) can be carried outmore » with 0.10-0.20 eV energy resolution and atomic-scale spatial resolution such that variations in oxidation state from one atomic column to another can be detected. Petrographic mapping is extended down to the atomic scale using energy-dispersive x-ray spectroscopy (EDS) and energy-filtered transmission electron microscopy (EFTEM) imaging. Technical capabilities and examples of the applications of SuperSTEM to extraterrestrial materials are presented, including the UV spectral properties and organic carbon K-edge fine structure of carbonaceous matter in interplanetary dust particles (IDPs), x-ray elemental maps showing the nanometer-scale distribution of carbon within GEMS (glass with embedded metal and sulfides), the first detection and quantification of trace Ti in GEMS using EDS, and detection of molecular H{sub 2}O in vesicles and implanted H{sub 2} and He in irradiated mineral and glass grains.« less

The Impact of Varying the Physics Grid Resolution Relative to the Dynamical Core Resolution in CAM-SE-CSLAM

NASA Astrophysics Data System (ADS)

Herrington, A. R.; Lauritzen, P. H.; Reed, K. A.

2017-12-01

The spectral element dynamical core of the Community Atmosphere Model (CAM) has recently been coupled to an approximately isotropic, finite-volume grid per implementation of the conservative semi-Lagrangian multi-tracer transport scheme (CAM-SE-CSLAM; Lauritzen et al. 2017). In this framework, the semi-Lagrangian transport of tracers are computed on the finite-volume grid, while the adiabatic dynamics are solved using the spectral element grid. The physical parameterizations are evaluated on the finite-volume grid, as opposed to the unevenly spaced Gauss-Lobatto-Legendre nodes of the spectral element grid. Computing the physics on the finite-volume grid reduces numerical artifacts such as grid imprinting, possibly because the forcing terms are no longer computed at element boundaries where the resolved dynamics are least smooth. The separation of the physics grid and the dynamics grid allows for a unique opportunity to understand the resolution sensitivity in CAM-SE-CSLAM. The observed large sensitivity of CAM to horizontal resolution is a poorly understood impediment to improved simulations of regional climate using global, variable resolution grids. Here, a series of idealized moist simulations are presented in which the finite-volume grid resolution is varied relative to the spectral element grid resolution in CAM-SE-CSLAM. The simulations are carried out at multiple spectral element grid resolutions, in part to provide a companion set of simulations, in which the spectral element grid resolution is varied relative to the finite-volume grid resolution, but more generally to understand if the sensitivity to the finite-volume grid resolution is consistent across a wider spectrum of resolved scales. Results are interpreted in the context of prior ideas regarding resolution sensitivity of global atmospheric models.

New in situ Aerosol Spectral Optical Measurements over 300-700 nm, Extinction and Total Absorption, Paired with Absorption from Water- and Methanol-soluble Aerosol Extracts

NASA Astrophysics Data System (ADS)

Jordan, C. E.; Stauffer, R. M.; Lamb, B.; Novak, M. G.; Mannino, A.; Hudgins, C.; Thornhill, K. L., II; Crosbie, E.; Winstead, E.; Anderson, B.; Martin, R.; Shook, M.; Ziemba, L. D.; Beyersdorf, A. J.; Corr, C.

2017-12-01

A new in situ spectral aerosol extinction instrument (custom built, SpEx) built to cover the 300-700 nm range at 1 nm spectral resolution and temporal resolution of 4 minutes was deployed on the top deck ( 10 m above the water surface) of the R/V Onnuri during the KORUS-OC research cruise around South Korea in spring 2016. This new instrument was one component of a suite of in situ aerosol optical measurements that included 3-visible-wavelength scattering (Airphoton IN101 Nephelometer, at 450, 532, & 632 nm) and absorption (Brechtel Tricolor Absorption Photometer Model 2901, at 467, 528, & 652 nm) with sub-minute temporal resolution; two sets of filters (Teflon and glass fiber, both collected over 3 hour daytime and 12 hour overnight intervals) to provide aerosol absorption spectra over the same wavelength range as SpEx. The glass fiber filters were placed in the center of an integrating sphere (Labsphere DRA-CA-30) attached to a dual beam spectrophotometer (Cary 100 Bio UV-Visible Spectrophotometer) to measure total aerosol absorption spectra via an established method used by the ocean color community to obtain absorption spectra from particles suspended in sea water. Adapting this methodology for atmospheric aerosol measurements provides a new avenue to obtain spectral total aerosol absorption, particularly useful for expanding in situ measurement capabilities into the UV range. The Teflon filters were cut in half with one half extracted in deionized water and the other half extracted in methanol. The solutions were filtered and injected into a liquid waveguide capillary cell (World Precision Instruments LWCC-3100, 100 cm pathlength) to measure the absorption spectra for each solution. In addition, the water extracts were measured via ion chromatography (Dionex ICS-3000 Ion Chromatography System) to obtain water-soluble inorganic ion concentrations, as well as via aerosol mass spectrometry (Aerodyne Research, Inc. HR-ToF High Resolution Aerosol Mass Spectrometer) to obtain organic aerosol concentrations. Results from the KORUS-OC data set will be discussed. In particular, the relationships between the optical information and chemical information will be examined.

Kelvin waves: a comparison study between SABER and normal mode analysis of ECMWF data

NASA Astrophysics Data System (ADS)

Blaauw, Marten; Garcia, Rolando; Zagar, Nedjeljka; Tribbia, Joe

2014-05-01

Equatorial Kelvin waves spectra are sensitive to the multi-scale variability of their source of tropical convective forcing. Moreover, Kelvin wave spectra are modified upward by changes in the background winds and stability. Recent high resolution data from observations as well as analyses are capable of resolving the slower Kelvin waves with shorter vertical wavelength near the tropical tropopause. In this presentation, results from a quantitive comparison study of stratospheric Kelvin waves in satellite data (SABER) and analysis data from the ECMWF operational archive will be shown. Temperature data from SABER is extracted over a six year period (2007-2012) with an effective vertical resolution of 2 km. Spectral power of stratospheric Kelvin waves in SABER data is isolated by selecting symmetric and eastward spectral components in the 8-20 days range. Global data from ECMWF operational analysis is extracted for the same six years on 91 model levels (top level at 0.01 hPa) and 25 km horizontal resolution. Using three-dimensional orthogonal normal-mode expansions, the input mass and wind data from ECMWF is projected onto balanced rotational modes and unbalanced inertia-gravity modes, including spectral data for pure Kelvin waves. The results show good agreement between Kelvin waves in SABER and ECMWF analyses data for: (i) the frequency shift of Kelvin wave variance with height and (ii) vertical wavelengths. Variability with respect to QBO will also be discussed. In a previous study, discrepancies in the upper stratosphere were found to be 60% and are found here to be 10% (8-20 day averaged value), which can be explained by the better stratosphere representation in the 91 model level version of the ECMWF operational model. New discrepancies in Kelvin wave variance are found in the lower stratosphere at 20 km. Averaged spectral power over the 8-20 day range is found to be 35% higher in ECMWF compared to SABER data. We compared results at 20 km with additional satellite data from HIRDLS (1 km eff. resolution) and conclude preliminary that SABER data does not represent the shortest 20 day Kelvin waves as well as HIRDLS and ECMWF operational analysis.

Integration of airborne optical and thermal imagery for archaeological subsurface structures detection: the Arpi case study (Italy)

NASA Astrophysics Data System (ADS)

Bassani, C.; Cavalli, R. M.; Fasulli, L.; Palombo, A.; Pascucci, S.; Santini, F.; Pignatti, S.

2009-04-01

The application of Remote Sensing data for detecting subsurface structures is becoming a remarkable tool for the archaeological observations to be combined with the near surface geophysics [1, 2]. As matter of fact, different satellite and airborne sensors have been used for archaeological applications, such as the identification of spectral anomalies (i.e. marks) related to the buried remnants within archaeological sites, and the management and protection of archaeological sites [3, 5]. The dominant factors that affect the spectral detectability of marks related to manmade archaeological structures are: (1) the spectral contrast between the target and background materials, (2) the proportion of the target on the surface (relative to the background), (3) the imaging system characteristics being used (i.e. bands, instrument noise and pixel size), and (4) the conditions under which the surface is being imaged (i.e. illumination and atmospheric conditions) [4]. In this context, just few airborne hyperspectral sensors were applied for cultural heritage studies, among them the AVIRIS (Airborne Visible/Infrared Imaging Spectrometer), the CASI (Compact Airborne Spectrographic Imager), the HyMAP (Hyperspectral MAPping) and the MIVIS (Multispectral Infrared and Visible Imaging Spectrometer). Therefore, the application of high spatial/spectral resolution imagery arise the question on which is the trade off between high spectral and spatial resolution imagery for archaeological applications and which spectral region is optimal for the detection of subsurface structures. This paper points out the most suitable spectral information useful to evaluate the image capability in terms of spectral anomaly detection of subsurface archaeological structures in different land cover contexts. In this study, we assess the capability of MIVIS and CASI reflectances and of ATM and MIVIS emissivities (Table 1) for subsurface archaeological prospection in different sites of the Arpi archaeological area (southern Italy). We identify, for the selected sites, three main land cover overlying the buried structures: (a) photosynthetic (i.e. green low vegetation), (b) non-photosynthetic vegetation (i.e. yellow, dry low vegetation), and (c) dry bare soil. Afterwards, we analyse the spectral regions showing an inherent potential for the archaeological detection as a function of the land cover characteristics. The classified land cover units have been used in a spectral mixture analysis to assess the land cover fractional abundance surfacing the buried structures (i.e. mark-background system). The classification and unmixing results for the CASI, MIVIS and ATM remote sensing data processing showed a good accordance both in the land cover units and in the subsurface structures identification. The integrated analysis of the unmixing results for the three sensors allowed us to establish that for the land cover characterized by green and dry vegetation (occurrence higher than 75%), the visible and near infrared (VNIR) spectral regions better enhance the buried man-made structures. In particular, if the structures are covered by more than 75% of vegetation the two most promising wavelengths for their detection are the chlorophyll peak at 0.56 m (Visible region) and the red edge region (0.67 to 0.72 m; NIR region). This result confirms that the variation induced by the subsurface structures (e.g., stone walls, tile concentrations, pavements near the surface, road networks) to the natural vegetation growth and/or colour (i.e., for different stress factors) is primarily detectable by the chlorophyll peak and the red edge region applied for the vegetation stress detection. Whereas, if dry soils cover the structures (occurrence higher than 75%), both the VNIR and thermal infrared (TIR) regions are suitable to detect the subsurface structures. This work demonstrates that airborne reflectances and emissivities data, even though at different spatial/spectral resolutions and acquisition time represent an effective and rapid tool to detect subsurface structures within different land cover contexts. As concluding results, this study reveals that the airborne multi/hyperspectral image processing can be an effective and cost-efficient tool to perform a preliminary analysis of those areas where large cultural heritage assets prioritising and localizing the sites where to apply near surface geophysics surveys. Spectral Region Spectral Resolution ( m )Spectral Range ( m) Spatial Resolution (m)IFOV (deg) ATM VIS-NIR SWIR-TIR (tot 12 ch) variable from 24 to 3100 0.42 - 1150 2 0.143 CASI VNIR (48 ch.) 0.01 0.40-0.94 2 0.115 MIVIS VNIR (28ch.) 0.02 (VIS) 0.05 (NIR) 0.43-0.83 (VIS) 1.15-1.55 (NIR) 6 - 7 0.115 SWIR (64ch.) 0.09 1.983-2.478 TIR (10ch.) 0.34-0.54 8.180-12.700 Table 1. Characteristics of airborne sensors used for the Arpi test area. 1 References 2 [1] Beck, A., Philip, G., Abdulkarim, M. and Donoghue, D., 2007. Evaluation of Corona and Ikonos high resolution satellite imagery for archaeological prospection in western Syria. Antiquity, 81: 161-175. 3 [2] Altaweel, M., 2005. The Use of ASTER Satellite Imagery in Archaeological Contexts. Archaeological Prospection, 12: 151- 166. 4 [3] Cavalli, R.M.; Colosi, F.; Palombo, A.; Pignatti, S.; Poscolieri, M. Remote hyperspectral imagery as a support to archaeological prospection. J. of Cultural Heritage 2007, 8, 272-283. 5 [4] Kucukkaya, A.G. Photogrammetry and remote sensing in archaeology. J. Quant. Spectrosc. Radiat. Transfer 2004, 97(1-3), 83-97. [5] Rowlands, A.; Sarris, A. Detection of exposed and subsurface archaeological remains using multi-sensor remote sensing. J. of Archaeological Science 2007, 34, 795-803.

Cluster secondary ion mass spectrometry microscope mode mass spectrometry imaging.

PubMed

Kiss, András; Smith, Donald F; Jungmann, Julia H; Heeren, Ron M A

2013-12-30

Microscope mode imaging for secondary ion mass spectrometry is a technique with the promise of simultaneous high spatial resolution and high-speed imaging of biomolecules from complex surfaces. Technological developments such as new position-sensitive detectors, in combination with polyatomic primary ion sources, are required to exploit the full potential of microscope mode mass spectrometry imaging, i.e. to efficiently push the limits of ultra-high spatial resolution, sample throughput and sensitivity. In this work, a C60 primary source was combined with a commercial mass microscope for microscope mode secondary ion mass spectrometry imaging. The detector setup is a pixelated detector from the Medipix/Timepix family with high-voltage post-acceleration capabilities. The system's mass spectral and imaging performance is tested with various benchmark samples and thin tissue sections. The high secondary ion yield (with respect to 'traditional' monatomic primary ion sources) of the C60 primary ion source and the increased sensitivity of the high voltage detector setup improve microscope mode secondary ion mass spectrometry imaging. The analysis time and the signal-to-noise ratio are improved compared with other microscope mode imaging systems, all at high spatial resolution. We have demonstrated the unique capabilities of a C60 ion microscope with a Timepix detector for high spatial resolution microscope mode secondary ion mass spectrometry imaging. Copyright © 2013 John Wiley & Sons, Ltd.

A Comparison of Spatial and Spectral Image Resolution for Mapping Invasive Plants in Coastal California

NASA Astrophysics Data System (ADS)

Underwood, Emma C.; Ustin, Susan L.; Ramirez, Carlos M.

2007-01-01

We explored the potential of detecting three target invasive species: iceplant ( Carpobrotus edulis), jubata grass ( Cortaderia jubata), and blue gum ( Eucalyptus globulus) at Vandenberg Air Force Base, California. We compared the accuracy of mapping six communities (intact coastal scrub, iceplant invaded coastal scrub, iceplant invaded chaparral, jubata grass invaded chaparral, blue gum invaded chaparral, and intact chaparral) using four images with different combinations of spatial and spectral resolution: hyperspectral AVIRIS imagery (174 wavebands, 4 m spatial resolution), spatially degraded AVIRIS (174 bands, 30 m), spectrally degraded AVIRIS (6 bands, 4 m), and both spatially and spectrally degraded AVIRIS (6 bands, 30 m, i.e., simulated Landsat ETM data). Overall success rates for classifying the six classes was 75% (kappa 0.7) using full resolution AVIRIS, 58% (kappa 0.5) for the spatially degraded AVIRIS, 42% (kappa 0.3) for the spectrally degraded AVIRIS, and 37% (kappa 0.3) for the spatially and spectrally degraded AVIRIS. A true Landsat ETM image was also classified to illustrate that the results from the simulated ETM data were representative, which provided an accuracy of 50% (kappa 0.4). Mapping accuracies using different resolution images are evaluated in the context of community heterogeneity (species richness, diversity, and percent species cover). Findings illustrate that higher mapping accuracies are achieved with images possessing high spectral resolution, thus capturing information across the visible and reflected infrared solar spectrum. Understanding the tradeoffs in spectral and spatial resolution can assist land managers in deciding the most appropriate imagery with respect to target invasives and community characteristics.

Scaling dimensions in spectroscopy of soil and vegetation

NASA Astrophysics Data System (ADS)

Malenovský, Zbyněk; Bartholomeus, Harm M.; Acerbi-Junior, Fausto W.; Schopfer, Jürg T.; Painter, Thomas H.; Epema, Gerrit F.; Bregt, Arnold K.

2007-05-01

The paper revises and clarifies definitions of the term scale and scaling conversions for imaging spectroscopy of soil and vegetation. We demonstrate a new four-dimensional scale concept that includes not only spatial but also the spectral, directional and temporal components. Three scaling remote sensing techniques are reviewed: (1) radiative transfer, (2) spectral (un)mixing, and (3) data fusion. Relevant case studies are given in the context of their up- and/or down-scaling abilities over the soil/vegetation surfaces and a multi-source approach is proposed for their integration. Radiative transfer (RT) models are described to show their capacity for spatial, spectral up-scaling, and directional down-scaling within a heterogeneous environment. Spectral information and spectral derivatives, like vegetation indices (e.g. TCARI/OSAVI), can be scaled and even tested by their means. Radiative transfer of an experimental Norway spruce ( Picea abies (L.) Karst.) research plot in the Czech Republic was simulated by the Discrete Anisotropic Radiative Transfer (DART) model to prove relevance of the correct object optical properties scaled up to image data at two different spatial resolutions. Interconnection of the successive modelling levels in vegetation is shown. A future development in measurement and simulation of the leaf directional spectral properties is discussed. We describe linear and/or non-linear spectral mixing techniques and unmixing methods that demonstrate spatial down-scaling. Relevance of proper selection or acquisition of the spectral endmembers using spectral libraries, field measurements, and pure pixels of the hyperspectral image is highlighted. An extensive list of advanced unmixing techniques, a particular example of unmixing a reflective optics system imaging spectrometer (ROSIS) image from Spain, and examples of other mixture applications give insight into the present status of scaling capabilities. Simultaneous spatial and temporal down-scaling by means of a data fusion technique is described. A demonstrative example is given for the moderate resolution imaging spectroradiometer (MODIS) and LANDSAT Thematic Mapper (TM) data from Brazil. Corresponding spectral bands of both sensors were fused via a pyramidal wavelet transform in Fourier space. New spectral and temporal information of the resultant image can be used for thematic classification or qualitative mapping. All three described scaling techniques can be integrated as the relevant methodological steps within a complex multi-source approach. We present this concept of combining numerous optical remote sensing data and methods to generate inputs for ecosystem process models.

Landsat 8 Multispectral and Pansharpened Imagery Processing on the Study of Civil Engineering Issues

NASA Astrophysics Data System (ADS)

Lazaridou, M. A.; Karagianni, A. Ch.

2016-06-01

Scientific and professional interests of civil engineering mainly include structures, hydraulics, geotechnical engineering, environment, and transportation issues. Topics included in the context of the above may concern urban environment issues, urban planning, hydrological modelling, study of hazards and road construction. Land cover information contributes significantly on the study of the above subjects. Land cover information can be acquired effectively by visual image interpretation of satellite imagery or after applying enhancement routines and also by imagery classification. The Landsat Data Continuity Mission (LDCM - Landsat 8) is the latest satellite in Landsat series, launched in February 2013. Landsat 8 medium spatial resolution multispectral imagery presents particular interest in extracting land cover, because of the fine spectral resolution, the radiometric quantization of 12bits, the capability of merging the high resolution panchromatic band of 15 meters with multispectral imagery of 30 meters as well as the policy of free data. In this paper, Landsat 8 multispectral and panchromatic imageries are being used, concerning surroundings of a lake in north-western Greece. Land cover information is extracted, using suitable digital image processing software. The rich spectral context of the multispectral image is combined with the high spatial resolution of the panchromatic image, applying image fusion - pansharpening, facilitating in this way visual image interpretation to delineate land cover. Further processing concerns supervised image classification. The classification of pansharpened image preceded multispectral image classification. Corresponding comparative considerations are also presented.

OH/H2O Detection Capability Evaluation on Chang'e-5 Lunar Mineralogical Spectrometer (LMS)

NASA Astrophysics Data System (ADS)

Liu, Bin; Ren, Xin; Liu, Jianjun; Li, Chunlai; Mu, Lingli; Deng, Liyan

2016-10-01

The Chang'e-5 (CE-5) lunar sample return mission is scheduled to launch in 2017 to bring back lunar regolith and drill samples. The Chang'e-5 Lunar Mineralogical Spectrometer (LMS), as one of the three sets of scientific payload installed on the lander, is used to collect in-situ spectrum and analyze the mineralogical composition of the samplingsite. It can also help to select the sampling site, and to compare the measured laboratory spectrum of returned sample with in-situ data. LMS employs acousto-optic tunable filters (AOTFs) and is composed of a VIS/NIR module (0.48μm-1.45μm) and an IR module (1.4μm -3.2μm). It has spectral resolution ranging from 3 to 25 nm, with a field of view (FOV) of 4.24°×4.24°. Unlike Chang'e-3 VIS/NIR Imaging Spectrometer (VNIS), the spectral coverage of LMS is extended from 2.4μm to 3.2μm, which has capability to identify H2O/OH absorption features around 2.7μm. An aluminum plate and an Infragold plate are fixed in the dust cover, being used as calibration targets in the VIS/NIR and IR spectral range respectively when the dust cover is open. Before launch, a ground verification test of LMS needs to be conducted in order to: 1) test and verify the detection capability of LMS through evaluation on the quality of image and spectral data collected for the simulated lunar samples; and 2) evaluate the accuracy of data processing methods by the simulation of instrument working on the moon. The ground verification test will be conducted both in the lab and field. The spectra of simulated lunar regolith/mineral samples will be collected simultaneously by the LMS and two calibrated spectrometers: a FTIR spectrometer (Model 102F) and an ASD FieldSpec 4 Hi-Res spectrometer. In this study, the results of the LMS ground verification test will be reported, and OH/H2O Detection Capability will be evaluated especially.

Living Matter Observations with a Novel Hyperspectral Supercontinuum Confocal Microscope for VIS to Near-IR Reflectance Spectroscopy

PubMed Central

Bertani, Francesca R.; Ferrari, Luisa; Mussi, Valentina; Botti, Elisabetta; Costanzo, Antonio; Selci, Stefano

2013-01-01

A broad range hyper-spectroscopic microscope fed by a supercontinuum laser source and equipped with an almost achromatic optical layout is illustrated with detailed explanations of the design, implementation and data. The real novelty of this instrument, a confocal spectroscopic microscope capable of recording high resolution reflectance data in the VIS-IR spectral range from about 500 nm to 2.5 μm wavelengths, is the possibility of acquiring spectral data at every physical point as defined by lateral coordinates, X and Y, as well as at a depth coordinate, Z, as obtained by the confocal optical sectioning advantage. With this apparatus we collect each single scanning point as a whole spectrum by combining two linear spectral detector arrays, one CCD for the visible range, and one InGaAs infrared array, simultaneously available at the sensor output channel of the home made instrument. This microscope has been developed for biomedical analysis of human skin and other similar applications. Results are shown illustrating the technical performances of the instrument and the capability in extracting information about the composition and the structure of different parts or compartments in biological samples as well as in solid statematter. A complete spectroscopic fingerprinting of samples at microscopic level is shown possible by using statistical analysis on raw data or analytical reflectance models based on Abelés matrix transfer methods. PMID:24233077

Terrain Extraction by Integrating Terrestrial Laser Scanner Data and Spectral Information

NASA Astrophysics Data System (ADS)

Lau, C. L.; Halim, S.; Zulkepli, M.; Azwan, A. M.; Tang, W. L.; Chong, A. K.

2015-10-01

The extraction of true terrain points from unstructured laser point cloud data is an important process in order to produce an accurate digital terrain model (DTM). However, most of these spatial filtering methods just utilizing the geometrical data to discriminate the terrain points from nonterrain points. The point cloud filtering method also can be improved by using the spectral information available with some scanners. Therefore, the objective of this study is to investigate the effectiveness of using the three-channel (red, green and blue) of the colour image captured from built-in digital camera which is available in some Terrestrial Laser Scanner (TLS) for terrain extraction. In this study, the data acquisition was conducted at a mini replica landscape in Universiti Teknologi Malaysia (UTM), Skudai campus using Leica ScanStation C10. The spectral information of the coloured point clouds from selected sample classes are extracted for spectral analysis. The coloured point clouds which within the corresponding preset spectral threshold are identified as that specific feature point from the dataset. This process of terrain extraction is done through using developed Matlab coding. Result demonstrates that a higher spectral resolution passive image is required in order to improve the output. This is because low quality of the colour images captured by the sensor contributes to the low separability in spectral reflectance. In conclusion, this study shows that, spectral information is capable to be used as a parameter for terrain extraction.

Vacuum compatible sample positioning device for matrix assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aizikov, Konstantin; Lin, Tzu-Yung; Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215

The high mass accuracy and resolving power of Fourier transform ion cyclotron resonance mass spectrometers (FT-ICR MS) make them ideal mass detectors for mass spectrometry imaging (MSI), promising to provide unmatched molecular resolution capabilities. The intrinsic low tolerance of FT-ICR MS to RF interference, however, along with typically vertical positioning of the sample, and MSI acquisition speed requirements present numerous engineering challenges in creating robotics capable of achieving the spatial resolution to match. This work discusses a two-dimensional positioning stage designed to address these issues. The stage is capable of operating in {approx}1 x 10{sup -8} mbar vacuum. The rangemore » of motion is set to 100 mm x 100 mm to accommodate large samples, while the positioning accuracy is demonstrated to be less than 0.4 micron in both directions under vertical load over the entire range. This device was integrated into three different matrix assisted laser desorption/ionization (MALDI) FT-ICR instruments and showed no detectable RF noise. The ''oversampling'' MALDI-MSI experiments, under which the sample is completely ablated at each position, followed by the target movement of the distance smaller than the laser beam, conducted on the custom-built 7T FT-ICR MS demonstrate the stability and positional accuracy of the stage robotics which delivers high spatial resolution mass spectral images at a fraction of the laser spot diameter.« less

Landsat-8: Science and product vision for terrestrial global change research

USGS Publications Warehouse

Roy, David P.; Wulder, M.A.; Loveland, Thomas R.; Woodcock, C.E.; Allen, R. G.; Anderson, M. C.; Helder, D.; Irons, J.R.; Johnson, D.M.; Kennedy, R.; Scambos, T.A.; Schaaf, Crystal B.; Schott, J.R.; Sheng, Y.; Vermote, E. F.; Belward, A.S.; Bindschadler, R.; Cohen, W.B.; Gao, F.; Hipple, J. D.; Hostert, Patrick; Huntington, J.; Justice, C.O.; Kilic, A.; Kovalskyy, Valeriy; Lee, Z. P.; Lymburner, Leo; Masek, J.G.; McCorkel, J.; Shuai, Y.; Trezza, R.; Vogelmann, James; Wynne, R.H.; Zhu, Z.

2014-01-01

Landsat 8, a NASA and USGS collaboration, acquires global moderate-resolution measurements of the Earth's terrestrial and polar regions in the visible, near-infrared, short wave, and thermal infrared. Landsat 8 extends the remarkable 40 year Landsat record and has enhanced capabilities including new spectral bands in the blue and cirrus cloud-detection portion of the spectrum, two thermal bands, improved sensor signal-to-noise performance and associated improvements in radiometric resolution, and an improved duty cycle that allows collection of a significantly greater number of images per day. This paper introduces the current (2012–2017) Landsat Science Team's efforts to establish an initial understanding of Landsat 8 capabilities and the steps ahead in support of priorities identified by the team. Preliminary evaluation of Landsat 8 capabilities and identification of new science and applications opportunities are described with respect to calibration and radiometric characterization; surface reflectance; surface albedo; surface temperature, evapotranspiration and drought; agriculture; land cover, condition, disturbance and change; fresh and coastal water; and snow and ice. Insights into the development of derived ‘higher-level’ Landsat products are provided in recognition of the growing need for consistently processed, moderate spatial resolution, large area, long-term terrestrial data records for resource management and for climate and global change studies. The paper concludes with future prospects, emphasizing the opportunities for land imaging constellations by combining Landsat data with data collected from other international sensing systems, and consideration of successor Landsat mission requirements.

SAGE III on the International Space Station

NASA Astrophysics Data System (ADS)

McCormick, M. P.; Damadeo, R. P.; Hill, C. A.

2017-12-01

A much-improved Stratospheric Aerosol and Gas Experiment (SAGE III) instrument was launched on February 19, 2017 from NASA's Kennedy Space Center aboard the SpaceX CRS-10 Dragon Spacecraft. It subsequently docked with the International Space Station (ISS), completed commissioning on July 1, 2017, and is now in its Mission Operations phase. SAGE III-ISS will combine the experience and capabilities of its successful predecessor satellite instruments SAM II, SAGE, SAGE II, and SAGE III-Meteor-3M to measure aerosol, cloud, O3, H2O, and NO2 profiles from the upper troposphere through the stratosphere. In addition to solar and lunar occultation with vertical resolutions of about 1.0 km, SAGE III-ISS will make limb scattering measurements on the solar side of each orbit greatly expanding the measurement coverage per spacecraft orbit, and tie the very high resolution and precise solar occultation measurements with the limb scattering measurements. The programmable readout array detector enhances its measurement capability and should allow for experimental data products like BrO, and IO, and along with a single photodiode detector, the measurement of larger aerosols. The wavelengths covered by SAGE III-ISS range from 280 to 1050 nm with 1 to 2 nm spectral resolution using a grating spectrometer. The single photodiode extends measurements to 1550 nm. This talk will describe the measurement capabilities of SAGE III, and include early data and validation examples, its additional modes and increased geographical coverage, its calibration and characterization, and data archival and validation approach.

Improving the spectral resolution of flat-field concave grating miniature spectrometers by dividing a wide spectral band into two narrow ones.

PubMed

Zhou, Qian; Pang, Jinchao; Li, Xinghui; Ni, Kai; Tian, Rui

2015-11-10

In this study, a new flat-field concave grating miniature spectrometer is proposed with improved resolution across a wide spectral band. A mirror is added to a conventional concave grating spectrometer and placed near the existing detector array, allowing a wide spectral band to be divided into two adjacent subspectral bands. One of these bands is directly detected by the detector, and the other is indirectly analyzed by the same detector after being reflected by the mirror. These two subspectral bands share the same entrance slit, concave grating, and detector, which allows for a compact size, while maintaining an improved spectral resolution across the entire spectral band. The positions of the mirror and other parameters of the spectrometer are designed by a computer procedure and the optical design software ZEMAX. Simulation results show that the resolution of this kind of flat-field concave grating miniature spectrometer is better than 1.6 nm across a spectral band of 700 nm. Experiments based on three laser sources reveal that the measured resolutions are comparable to the simulated ones, with a maximum relative error between them of less than 19%.

The Anomalous Influence of Spectral Resolution on Pulsed THz Time Domain Spectroscopy under Real Conditions

PubMed Central

Trofimov, Vyacheslav A.; Varentsova, Svetlana A.

2017-01-01

We have studied the spectral resolution influence on the accuracy of the substance detection and identification at using a broadband THz pulse measured under real conditions (at a distance of more than 3 m from a THz emitter in ambient air with a relative humidity of about 50%). We show that increasing spectral resolution leads to manifestation of small-scale perturbations (random fluctuations) in the signal spectrum caused by the influence of the environment or the sample structure. Decreasing the spectral resolution allows us to exclude from consideration this small-scale modulation of the signal as well as to detect the water vapor absorption frequencies. This fact is important in practice because it allows us to increase the signal processing rate. In order to increase the detection reliability, it is advisable to decrease the spectral resolution up to values of not more than 40% of the corresponding spectral line bandwidth. The method of spectral dynamics analysis together with the integral correlation criteria is used for the substance detection and identification. Neutral substances such as chocolate and cookies are used as the samples in the physical experiment. PMID:29231895

Hyperspectral and multispectral data fusion based on linear-quadratic nonnegative matrix factorization

NASA Astrophysics Data System (ADS)

Benhalouche, Fatima Zohra; Karoui, Moussa Sofiane; Deville, Yannick; Ouamri, Abdelaziz

2017-04-01

This paper proposes three multisharpening approaches to enhance the spatial resolution of urban hyperspectral remote sensing images. These approaches, related to linear-quadratic spectral unmixing techniques, use a linear-quadratic nonnegative matrix factorization (NMF) multiplicative algorithm. These methods begin by unmixing the observable high-spectral/low-spatial resolution hyperspectral and high-spatial/low-spectral resolution multispectral images. The obtained high-spectral/high-spatial resolution features are then recombined, according to the linear-quadratic mixing model, to obtain an unobservable multisharpened high-spectral/high-spatial resolution hyperspectral image. In the first designed approach, hyperspectral and multispectral variables are independently optimized, once they have been coherently initialized. These variables are alternately updated in the second designed approach. In the third approach, the considered hyperspectral and multispectral variables are jointly updated. Experiments, using synthetic and real data, are conducted to assess the efficiency, in spatial and spectral domains, of the designed approaches and of linear NMF-based approaches from the literature. Experimental results show that the designed methods globally yield very satisfactory spectral and spatial fidelities for the multisharpened hyperspectral data. They also prove that these methods significantly outperform the used literature approaches.

Simultaneous Spectral Temporal Adaptive Raman Spectrometer - SSTARS

NASA Technical Reports Server (NTRS)

Blacksberg, Jordana

2010-01-01

Raman spectroscopy is a prime candidate for the next generation of planetary instruments, as it addresses the primary goal of mineralogical analysis, which is structure and composition. However, large fluorescence return from many mineral samples under visible light excitation can render Raman spectra unattainable. Using the described approach, Raman and fluorescence, which occur on different time scales, can be simultaneously obtained from mineral samples using a compact instrument in a planetary environment. This new approach is taken based on the use of time-resolved spectroscopy for removing the fluorescence background from Raman spectra in the laboratory. In the SSTARS instrument, a visible excitation source (a green, pulsed laser) is used to generate Raman and fluorescence signals in a mineral sample. A spectral notch filter eliminates the directly reflected beam. A grating then disperses the signal spectrally, and a streak camera provides temporal resolution. The output of the streak camera is imaged on the CCD (charge-coupled device), and the data are read out electronically. By adjusting the sweep speed of the streak camera, anywhere from picoseconds to milliseconds, it is possible to resolve Raman spectra from numerous fluorescence spectra in the same sample. The key features of SSTARS include a compact streak tube capable of picosecond time resolution for collection of simultaneous spectral and temporal information, adaptive streak tube electronics that can rapidly change from one sweep rate to another over ranges of picoseconds to milliseconds, enabling collection of both Raman and fluorescence signatures versus time and wavelength, and Synchroscan integration that allows for a compact, low-power laser without compromising ultimate sensitivity.

Chandra Observations of Neutron Stars: An Overview

NASA Technical Reports Server (NTRS)

Weisskopf, Martin C.; Karovska, M.; Pavlov, G. G.; Zavlin, V. E.; Clarke, Tracy

2006-01-01

We present a brief review of Chandra X-ray Observatory observations of neutron stars. The outstanding spatial and spectral resolution of this great observatory have allowed for observations of unprecedented clarity and accuracy. Many of these observations have provided new insights into neutron star physics. We present an admittedly biased and overly brief overview of these observations, highlighting some new discoveries made possible by the Observatory's unique capabilities. We also include our analysis of recent multiwavelength observations of the putative pulsar and its pulsar-wind nebula in the IC 443 SNR.

Electron-bombarded CCD detectors for ultraviolet atmospheric remote sensing

NASA Technical Reports Server (NTRS)

Carruthers, G. R.; Opal, C. B.

1983-01-01

Electronic image sensors based on charge coupled devices operated in electron-bombarded mode, yielding real-time, remote-readout, photon-limited UV imaging capability are being developed. The sensors also incorporate fast-focal-ratio Schmidt optics and opaque photocathodes, giving nearly the ultimate possible diffuse-source sensitivity. They can be used for direct imagery of atmospheric emission phenomena, and for imaging spectrography with moderate spatial and spectral resolution. The current state of instrument development, laboratory results, planned future developments and proposed applications of the sensors in space flight instrumentation is described.

Searching for Dark Matter Signatures in the GLAST LAT Electron Flux

NASA Technical Reports Server (NTRS)

Moiseev, Alexander; Profumo, Stefano

2008-01-01

We explored several viable scenarios of how LAT might observe DM, when the spectral feature is predicted to be observed in the HE electron flux It has been demonstrated elsewhere that LAT will be capable to detect HE electrons flux in energy range from 20 GeV to - 1 TeV with 520% energy resolution and good statistics If there is a DM-caused feature in the HE electron flux (in the range 20 GeV - 1 TeV), LAT will be the best current instrument to observe it!

Automated feature extraction and classification from image sources

USGS Publications Warehouse

,

1995-01-01

The U.S. Department of the Interior, U.S. Geological Survey (USGS), and Unisys Corporation have completed a cooperative research and development agreement (CRADA) to explore automated feature extraction and classification from image sources. The CRADA helped the USGS define the spectral and spatial resolution characteristics of airborne and satellite imaging sensors necessary to meet base cartographic and land use and land cover feature classification requirements and help develop future automated geographic and cartographic data production capabilities. The USGS is seeking a new commercial partner to continue automated feature extraction and classification research and development.

Assessment of spectral, misregistration, and spatial uncertainties inherent in the cross-calibration study

USGS Publications Warehouse

Chander, G.; Helder, D.L.; Aaron, David; Mishra, N.; Shrestha, A.K.

2013-01-01

Cross-calibration of satellite sensors permits the quantitative comparison of measurements obtained from different Earth Observing (EO) systems. Cross-calibration studies usually use simultaneous or near-simultaneous observations from several spaceborne sensors to develop band-by-band relationships through regression analysis. The investigation described in this paper focuses on evaluation of the uncertainties inherent in the cross-calibration process, including contributions due to different spectral responses, spectral resolution, spectral filter shift, geometric misregistrations, and spatial resolutions. The hyperspectral data from the Environmental Satellite SCanning Imaging Absorption SpectroMeter for Atmospheric CartograpHY and the EO-1 Hyperion, along with the relative spectral responses (RSRs) from the Landsat 7 Enhanced Thematic Mapper (TM) Plus and the Terra Moderate Resolution Imaging Spectroradiometer sensors, were used for the spectral uncertainty study. The data from Landsat 5 TM over five representative land cover types (desert, rangeland, grassland, deciduous forest, and coniferous forest) were used for the geometric misregistrations and spatial-resolution study. The spectral resolution uncertainty was found to be within 0.25%, spectral filter shift within 2.5%, geometric misregistrations within 0.35%, and spatial-resolution effects within 0.1% for the Libya 4 site. The one-sigma uncertainties presented in this paper are uncorrelated, and therefore, the uncertainties can be summed orthogonally. Furthermore, an overall total uncertainty was developed. In general, the results suggested that the spectral uncertainty is more dominant compared to other uncertainties presented in this paper. Therefore, the effect of the sensor RSR differences needs to be quantified and compensated to avoid large uncertainties in cross-calibration results.

Cris-atms Retrievals Using an AIRS Science Team Version 6-like Retrieval Algorithm

NASA Technical Reports Server (NTRS)

Susskind, Joel; Kouvaris, Louis C.; Iredell, Lena

2014-01-01

CrIS is the infrared high spectral resolution atmospheric sounder launched on Suomi-NPP in 2011. CrISATMS comprise the IRMW Sounding Suite on Suomi-NPP. CrIS is functionally equivalent to AIRS, the high spectral resolution IR sounder launched on EOS Aqua in 2002 and ATMS is functionally equivalent to AMSU on EOS Aqua. CrIS is an interferometer and AIRS is a grating spectrometer. Spectral coverage, spectral resolution, and channel noise of CrIS is similar to AIRS. CrIS spectral sampling is roughly twice as coarse as AIRSAIRS has 2378 channels between 650 cm-1 and 2665 cm-1. CrIS has 1305 channels between 650 cm-1 and 2550 cm-1. Spatial resolution of CrIS is comparable to AIRS.

Fluorescent marker-based and marker-free discrimination between healthy and cancerous human tissues using hyper-spectral imaging

NASA Astrophysics Data System (ADS)

Arnold, Thomas; De Biasio, Martin; Leitner, Raimund

2015-06-01

Two problems are addressed in this paper (i) the fluorescent marker-based and the (ii) marker-free discrimination between healthy and cancerous human tissues. For both applications the performance of hyper-spectral methods are quantified. Fluorescent marker-based tissue classification uses a number of fluorescent markers to dye specific parts of a human cell. The challenge is that the emission spectra of the fluorescent dyes overlap considerably. They are, furthermore disturbed by the inherent auto-fluorescence of human tissue. This results in ambiguities and decreased image contrast causing difficulties for the treatment decision. The higher spectral resolution introduced by tunable-filter-based spectral imaging in combination with spectral unmixing techniques results in an improvement of the image contrast and therefore more reliable information for the physician to choose the treatment decision. Marker-free tissue classification is based solely on the subtle spectral features of human tissue without the use of artificial markers. The challenge in this case is that the spectral differences between healthy and cancerous tissues are subtle and embedded in intra- and inter-patient variations of these features. The contributions of this paper are (i) the evaluation of hyper-spectral imaging in combination with spectral unmixing techniques for fluorescence marker-based tissue classification, (ii) the evaluation of spectral imaging for marker-free intra surgery tissue classification. Within this paper, we consider real hyper-spectral fluorescence and endoscopy data sets to emphasize the practical capability of the proposed methods. It is shown that the combination of spectral imaging with multivariate statistical methods can improve the sensitivity and specificity of the detection and the staging of cancerous tissues compared to standard procedures.

Nano-scale imaging and spectroscopy of plasmonic systems, thermal near-fields, and phase separation in complex oxides

NASA Astrophysics Data System (ADS)

Jones, Andrew C.

Optical spectroscopy represents a powerful characterization technique with the ability to directly interact with the electronic, spin, and lattice excitations in matter. In addition, through implementation of ultrafast techniques, further insight into the real-time dynamics of elementary interactions can be gained. However, the resolution of far-field microscopy techniques is restricted by the diffraction limit setting a spatial resolution limit in the 100s nm to micron range for visible and IR light, respectively. This resolution is too coarse for the characterization of mesoscopic phenomena in condensed matter physics. The development of experimental techniques with nanoscale resolution and sensitivity to optical fields has been a long standing obstacle to the characterization of condensed matter systems on their natural length scales. This dissertation focuses on the fundamental near-field optical properties of surfaces and nanoscale systems as well as the utilization of nano-optical techniques, specifically apertureless scattering-type Scanning Near-field Optical Microscopy (s-SNOM), to characterize said optical properties with nanometer scale resolution. First, the s-SNOM characterization of the field enhancement associated with the localized surface plasmon resonances on metallic structures is discussed. With their ability to localize light, plasmonic nano-structures are promising candidate systems to serve as molecular sensors and nano-photonic devices; however, it is well known that particle morphology and the plasmon resonance alone do not uniquely reflect the details of the local field distribution. Here, I demonstrate the use interferometric s-SNOM for imaging of the near-fields associated with plasmonic resonances of crystalline triangular silver nano-prisms in the visible spectral range. I subsequently show the extension of the concept of a localized plasmon into the mid-IR spectral range with the characterization of near-fields of silver nano-rods. Strong spatial field variation on lengths scales as short as 20 nm is observed associated with the dipolar and quadrupolar modes of both systems with details sensitively depending on the nanoparticle structure and environment. In light of recent publications predicting distinct spectral characteristics of thermal electromagnetic near-fields, I demonstrate the extension of s-SNOM techniques through the implementation of a heated atomic force microscope (AFM) tip acting as its own intrinsic light source for the characterization of thermal near-fields. Here, I detail the spectrally distinct and orders of magnitude enhanced resonant spectral near-field energy density associated with vibrational, phonon, and phonon-polariton modes. Modeling the thermal light scattering by the AFM, the scattering cross-section for thermal light may be related to the electromagnetic local density of states (EM-LDOS) above a surface. Lastly, the unique capability of s-SNOM techniques to characterize phase separation phenomena in correlated electron systems is discussed. This measurement capability provides new microscopic insight into the underlying mechanisms of the rich phase transition behavior exhibited by these materials. As a specific example, the infrared s-SNOM mapping of the metal-insulator transition and the associated nano-domain formation in individual VO2 micro-crystals subject to substrate stress is presented. Our results have important implications for the interpretation of the investigations of conventional polycrystalline thin films where the mutual interaction of constituent crystallites may affect the nature of phase separation processes.

The Importance of Solar Spectral Irradiance to the Sun-Earth Connection: Lessons-learned from SORCE and Their Relevance to Future Missions

NASA Astrophysics Data System (ADS)

Harder, J. W.; Snow, M. A.; Richard, E. C.; Rast, M.; Merkel, A. W.; Woods, T. N.

2014-12-01

The Solar Radiation and Climate Experiment (SORCE) mission has provided for the first time solar spectral irradiance (SSI) observations over a full solar cycle time period with wavelength coverage from the X-ray through the near infrared. This paper will discuss the lessons-learned from SORCE including the need to develop more effective methods to track on-orbit spectroscopic response and sensitivity degradation. This is especially important in using these data products as input to modern day chemistry-climate models that require very broad spectral coverage with moderate-to-high spectral and temporal resolution to constrain the solar component to the atmospheric response. A basic requirement to obtain this essential climate record is to 1) perform preflight radiometric calibrations that are traceable SI standards along with a complete specification of the instruments spectroscopic response, and 2) design the instrument to have the ability to perform instrument-only sensitivity corrections to objectively account for on-orbit degradation. The development of the NIST SIRCUS (National Institute of Science and Technology, Sources for Irradiance and Radiance Calibration with Uniform Sources) now permits the full characterization of the spectral radiometer's response, and on-orbit degradation characterization through comparisons of redundant detectors and spectrometers appears to be the most practical method to perform these corrections for the near ultraviolet through the near infrared. Going forward, we discuss a compact spectral radiometer development that will couple with advances in CubeSat technology to allow for shorter mission lengths, relatively inexpensive development and launch costs, and reduce the risk of data gaps between successive missions without compromising measurement accuracy. We also discuss the development of a radiometric solar imager that will both greatly improve the interpretation of existing Sun-as-a-star irradiance observations and provide a bridge from our current irradiance capabilities to future high spatial/temporal resolution solar physics assets such as the Daniel K. Inouye Solar Telescope (DKIST).

Real-time high-resolution heterodyne-based measurements of spectral dynamics in fibre lasers

PubMed Central

Sugavanam, Srikanth; Fabbri, Simon; Le, Son Thai; Lobach, Ivan; Kablukov, Sergey; Khorev, Serge; Churkin, Dmitry

2016-01-01

Conventional tools for measurement of laser spectra (e.g. optical spectrum analysers) capture data averaged over a considerable time period. However, the generation spectrum of many laser types may involve spectral dynamics whose relatively fast time scale is determined by their cavity round trip period, calling for instrumentation featuring both high temporal and spectral resolution. Such real-time spectral characterisation becomes particularly challenging if the laser pulses are long, or they have continuous or quasi-continuous wave radiation components. Here we combine optical heterodyning with a technique of spatio-temporal intensity measurements that allows the characterisation of such complex sources. Fast, round-trip-resolved spectral dynamics of cavity-based systems in real-time are obtained, with temporal resolution of one cavity round trip and frequency resolution defined by its inverse (85 ns and 24 MHz respectively are demonstrated). We also show how under certain conditions for quasi-continuous wave sources, the spectral resolution could be further increased by a factor of 100 by direct extraction of phase information from the heterodyned dynamics or by using double time scales within the spectrogram approach. PMID:26984634

Assessing the capabilities of hyperspectral remote sensing to map oil films on waters

NASA Astrophysics Data System (ADS)

Liu, Bingxin; Li, Ying; Zhu, Xueyuan

2014-11-01

The harm of oil spills has caused extensive public concern. Remote sensing technology has become one of the most effective means of monitoring oil spill. However, how to evaluate the information extraction capabilities of various sensors and choose the most effective one has become an important issue. The current evaluation of sensors to detect oil films was mainly using in-situ measured spectra as a reference to determine the favorable band, but ignoring the effects of environmental noise and spectral response function. To understand the precision and accuracy of environment variables acquired from remote sensing, it is important to evaluate the target detection sensitivity of the entire sensor-air-target system corresponding to the change of reflectivity. The measurement data associated with the evaluation is environmental noise equivalent reflectance difference (NEΔRE ), which depends on the instrument signal to noise ratio(SNR) and other image data noise (such as atmospheric variables, scattered sky light scattering and direct sunlight, etc.). Hyperion remote sensing data is taken as an example for evaluation of its oil spill detection capabilities with the prerequisite that the impact of the spatial resolution is ignored. In order to evaluate the sensor's sensitivity of the film of water, the reflectance spectral data of light diesel and crude oil film were used. To obtain Hyperion reflectance data, we used FLAASH to do the atmospheric correction. The spectral response functions of Hyperion sensor was used for filtering the measured reflectance of the oil films to the theoretic spectral response. Then, these spectral response spectra were normalized to NEΔRE, according to which, the sensitivity of the sensor in oil film detecting could be evaluated. For crude oil, the range for Hyperion sensor to identify the film is within the wavelength from 518nm to 610nm (Band 17 to Band 26 of Hyperion sensors), within which the thin film and thick film can also be distinguished. For light diesel oil film, the range for Hyperion sensor to identify the film is within the wavelength from 468nm to 752nm (Band 12 to Band 40 of Hyperion sensors).

Achieving the resolution of the spectrograph of the 6m large Azimuthal telescope

NASA Astrophysics Data System (ADS)

Sazonenko, Dmitrii; Kukushkin, Dmitrii; Bakholdin, Alexey; Valyavin, Gennady

2016-08-01

Special Astrophysical Observatory of Russian Academy of Sciences (SAO RAS) creates a spectrograph with high spectral resolution for the 6-meter telescope. The spectrograph consists of a mobile unit located at the focus of the telescope's main mirror, a stationary part located under the telescope and optical fibers which transmit light from the mobile part to the stationary one. The spectral resolution of the stationary part should be R=100000. To achieve such a value, the scheme has two spectral elements, with cross-dispersion. The main spectral element is an echelle grating. The second spectral element is a prism with a diffraction grating on one facet.

X-ray spectroscopy of SNR E0102-72 with the ASCA satellite

NASA Technical Reports Server (NTRS)

Hayashi, Ichizo; Koyama, Katsuji; Ozaki, Masanobu; Miyata, Emi; Tsumeni, Hiroshi; Hughes, John P.; Petre, Robert

1994-01-01

The Advanced Satellite for Cosmology and Astrophysics (ASCA) satellite has obtained a moderate-resolution energy spectrum of E0102-72, the brightest Supernova Remnant (SNR) in the Small Magellanic Cloud (SMC). This paper reports on the first results of the analysis of the high quality spectrum of E0102-72. The spectrum shows resolved emission lines of He-like K alpha, H-like K alpha and K beta from oxygen, neon, and magnesium. The intensity ratios of these lines cannot be explained by a multi-component plasma model with uniform abundances, but requires abundance inhomogeneity in the plasma. We demonstrate how the spectral capabilities of the ASCA SIS make available new diagnostics of X-ray plasmas in a state of non-equilibrium ionization. Some interpretation based on the spectral analysis is also given.

Upgraded airborne scanner for commercial remote sensing

NASA Astrophysics Data System (ADS)

Chang, Sheng-Huei; Rubin, Tod D.

1994-06-01

Traditional commercial remote sensing has focused on the geologic market, with primary focus on mineral identification and mapping in the visible through short-wave infrared spectral regions (0.4 to 2.4 microns). Commercial remote sensing users now demand airborne scanning capabilities spanning the entire wavelength range from ultraviolet through thermal infrared (0.3 to 12 microns). This spectral range enables detection, identification, and mapping of objects and liquids on the earth's surface and gases in the air. Applications requiring this range of wavelengths include detection and mapping of oil spills, soil and water contamination, stressed vegetation, and renewable and non-renewable natural resources, and also change detection, natural hazard mitigation, emergency response, agricultural management, and urban planning. GER has designed and built a configurable scanner that acquires high resolution images in 63 selected wave bands in this broad wavelength range.

Nanoparticle discrimination based on wavelength and lifetime-multiplexed cathodoluminescence microscopy.

PubMed

Garming, Mathijs W H; Weppelman, I Gerward C; de Boer, Pascal; Martínez, Felipe Perona; Schirhagl, Romana; Hoogenboom, Jacob P; Moerland, Robert J

2017-08-31

Nanomaterials can be identified in high-resolution electron microscopy images using spectrally-selective cathodoluminescence. Capabilities for multiplex detection can however be limited, e.g., due to spectral overlap or availability of filters. Also, the available photon flux may be limited due to degradation under electron irradiation. Here, we demonstrate single-pass cathodoluminescence-lifetime based discrimination of different nanoparticles, using a pulsed electron beam. We also show that cathodoluminescence lifetime is a robust parameter even when the nanoparticle cathodoluminescence intensity decays over an order of magnitude. We create lifetime maps, where the lifetime of the cathodoluminescence emission is correlated with the emission intensity and secondary-electron images. The consistency of lifetime-based discrimination is verified by also correlating the emission wavelength and the lifetime of nanoparticles. Our results show how cathodoluminescence lifetime provides an additional channel of information in electron microscopy.

High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fletcher, L. B., E-mail: lbfletch@slac.stanford.edu; Galtier, E.; Gamboa, E. J.

2016-11-15

We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen and focusedmore » on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].« less

Quality evaluation of pansharpened hyperspectral images generated using multispectral images

NASA Astrophysics Data System (ADS)

Matsuoka, Masayuki; Yoshioka, Hiroki

2012-11-01

Hyperspectral remote sensing can provide a smooth spectral curve of a target by using a set of higher spectral resolution detectors. The spatial resolution of the hyperspectral images, however, is generally much lower than that of multispectral images due to the lower energy of incident radiation. Pansharpening is an image-fusion technique that generates higher spatial resolution multispectral images by combining lower resolution multispectral images with higher resolution panchromatic images. In this study, higher resolution hyperspectral images were generated by pansharpening of simulated lower hyperspectral and higher multispectral data. Spectral and spatial qualities of pansharpened images, then, were accessed in relation to the spectral bands of multispectral images. Airborne hyperspectral data of AVIRIS was used in this study, and it was pansharpened using six methods. Quantitative evaluations of pansharpened image are achieved using two frequently used indices, ERGAS, and the Q index.

Adaptive hyperspectral imager: design, modeling, and control

NASA Astrophysics Data System (ADS)

McGregor, Scot; Lacroix, Simon; Monmayrant, Antoine

2015-08-01

An adaptive, hyperspectral imager is presented. We propose a system with easily adaptable spectral resolution, adjustable acquisition time, and high spatial resolution which is independent of spectral resolution. The system yields the possibility to define a variety of acquisition schemes, and in particular near snapshot acquisitions that may be used to measure the spectral content of given or automatically detected regions of interest. The proposed system is modelled and simulated, and tests on a first prototype validate the approach to achieve near snapshot spectral acquisitions without resorting to any computationally heavy post-processing, nor cumbersome calibration

Recent advances in high-throughput QCL-based infrared microspectral imaging (Conference Presentation)

NASA Astrophysics Data System (ADS)

Rowlette, Jeremy A.; Fotheringham, Edeline; Nichols, David; Weida, Miles J.; Kane, Justin; Priest, Allen; Arnone, David B.; Bird, Benjamin; Chapman, William B.; Caffey, David B.; Larson, Paul; Day, Timothy

2017-02-01

The field of infrared spectral imaging and microscopy is advancing rapidly due in large measure to the recent commercialization of the first high-throughput, high-spatial-definition quantum cascade laser (QCL) microscope. Having speed, resolution and noise performance advantages while also eliminating the need for cryogenic cooling, its introduction has established a clear path to translating the well-established diagnostic capability of infrared spectroscopy into clinical and pre-clinical histology, cytology and hematology workflows. Demand for even higher throughput while maintaining high-spectral fidelity and low-noise performance continues to drive innovation in QCL-based spectral imaging instrumentation. In this talk, we will present for the first time, recent technological advances in tunable QCL photonics which have led to an additional 10X enhancement in spectral image data collection speed while preserving the high spectral fidelity and SNR exhibited by the first generation of QCL microscopes. This new approach continues to leverage the benefits of uncooled microbolometer focal plane array cameras, which we find to be essential for ensuring both reproducibility of data across instruments and achieving the high-reliability needed in clinical applications. We will discuss the physics underlying these technological advancements as well as the new biomedical applications these advancements are enabling, including automated whole-slide infrared chemical imaging on clinically relevant timescales.

Mineral Information Extraction Based on GAOFEN-5'S Thermal Infrared Data

NASA Astrophysics Data System (ADS)

Liu, L.; Shang, K.

2018-04-01

Gaofen-5 carries six instruments aimed at various land and atmosphere applications, and it's an important unit of China High-resolution Earth Observation System. As Gaofen-5's thermal infrared payload is similar to that of ASTER, which is widely used in mineral exploration, application of Gaofen-5's thermal infrared data is discussed regarding its capability in mineral classification and silica content estimation. First, spectra of silicate, carbonate, sulfate minerals from a spectral library are used to conduct spectral feature analysis on Gaofen-5's thermal infrared emissivities. Spectral indices of band emissivities are proposed, and by setting thresholds of these spectral indices, it can classify three types of minerals mentioned above. This classification method is tested on a simulated Gaofen-5 emissivity image. With samples acquired from the study area, this method is proven to be feasible. Second, with band emissivities of silicate and their silica content from the same spectral library, correlation models have been tried to be built for silica content inversion. However, the highest correlation coefficient is merely 0.592, which is much lower than that of correlation model built on ASTER thermal infrared emissivity. It can be concluded that GF-5's thermal infrared data can be utilized in mineral classification but not in silica content inversion.

Extending color primary set in spectral vector error diffusion by multilevel halftoning

NASA Astrophysics Data System (ADS)

Norberg, Ole; Nyström, Daniel

2013-02-01

Ever since its origin in the late 19th century, a color reproduction technology has relied on a trichromatic color reproduction approach. This has been a very successful method and also fundamental for the development of color reproduction devices. Trichromatic color reproduction is sufficient to approximate the range of colors perceived by the human visual system. However, tricromatic systems only have the ability to match colors when the viewing illumination for the reproduction matches that of the original. Furthermore, the advancement of digital printing technology has introduced printing systems with additional color channels. These additional color channels are used to extend the tonal range capabilities in light and dark regions and to increase color gamut. By an alternative approach the addition color channels can also be used to reproduce the spectral information of the original color. A reproduced spectral match will always correspond to original independent of lighting situation. On the other hand, spectral color reproductions also introduce a more complex color processing by spectral color transfer functions and spectral gamut mapping algorithms. In that perspective, spectral vector error diffusion (sVED) look like a tempting approach with a simple workflow where the inverse color transfer function and halftoning is performed simultaneously in one single operation. Essential for the sVED method are the available color primaries, created by mixing process colors. Increased numbers of as well as optimal spectral characteristics of color primaries are expected to significantly improve the color accuracy of the spectral reproduction. In this study, sVED in combination with multilevel halftoning has been applied on a ten channel inkjet system. The print resolution has been reduced and the underlying physical high resolution of the printer has been used to mix additional primaries. With ten ink channels and halfton cells built-up by 2x2 micro dots where each micro dot can be a combination of all ten inks the number of possible ink combinations gets huge. Therefore, the initial study has been focused on including lighter colors to the intrinsic primary set. Results from this study shows that by this approach the color reproduction accuracy increases significantly. The RMS spectral difference to target color for multilevel halftoning is less than 1/6 of the difference achieved by binary halftoning.

High Resolution Airborne Laser Scanning and Hyperspectral Imaging with a Small Uav Platform

NASA Astrophysics Data System (ADS)

Gallay, Michal; Eck, Christoph; Zgraggen, Carlo; Kaňuk, Ján; Dvorný, Eduard

2016-06-01

The capabilities of unmanned airborne systems (UAS) have become diverse with the recent development of lightweight remote sensing instruments. In this paper, we demonstrate our custom integration of the state-of-the-art technologies within an unmanned aerial platform capable of high-resolution and high-accuracy laser scanning, hyperspectral imaging, and photographic imaging. The technological solution comprises the latest development of a completely autonomous, unmanned helicopter by Aeroscout, the Scout B1-100 UAV helicopter. The helicopter is powered by a gasoline two-stroke engine and it allows for integrating 18 kg of a customized payload unit. The whole system is modular providing flexibility of payload options, which comprises the main advantage of the UAS. The UAS integrates two kinds of payloads which can be altered. Both payloads integrate a GPS/IMU with a dual GPS antenna configuration provided by OXTS for accurate navigation and position measurements during the data acquisition. The first payload comprises a VUX-1 laser scanner by RIEGL and a Sony A6000 E-Mount photo camera. The second payload for hyperspectral scanning integrates a push-broom imager AISA KESTREL 10 by SPECIM. The UAS was designed for research of various aspects of landscape dynamics (landslides, erosion, flooding, or phenology) in high spectral and spatial resolution.

Reconstruction of full high-resolution HSQC using signal split in aliased spectra.

PubMed

Foroozandeh, Mohammadali; Jeannerat, Damien

2015-11-01

Resolution enhancement is a long-sought goal in NMR spectroscopy. In conventional multidimensional NMR experiments, such as the (1) H-(13) C HSQC, the resolution in the indirect dimensions is typically 100 times lower as in 1D spectra because it is limited by the experimental time. Reducing the spectral window can significantly increase the resolution but at the cost of ambiguities in frequencies as a result of spectral aliasing. Fortunately, this information is not completely lost and can be retrieved using methods in which chemical shifts are encoded in the aliased spectra and decoded after processing to reconstruct high-resolution (1) H-(13) C HSQC spectrum with full spectral width and a resolution similar to that of 1D spectra. We applied a new reconstruction method, RHUMBA (reconstruction of high-resolution using multiplet built on aliased spectra), to spectra obtained from the differential evolution for non-ambiguous aliasing-HSQC and the new AMNA (additional modulation for non-ambiguous aliasing)-HSQC experiments. The reconstructed spectra significantly facilitate both manual and automated spectral analyses and structure elucidation based on heteronuclear 2D experiments. The resolution is enhanced by two orders of magnitudes without the usual complications due to spectral aliasing. Copyright © 2015 John Wiley & Sons, Ltd.

Landsat-Swath Imaging Spectrometer Design

NASA Technical Reports Server (NTRS)

Mouroulis, Pantazis; Green, Robert O.; Van Gorp, Byron; Moore, Lori; Wilson, Daniel W.; Bender, Holly A.

2015-01-01

We describe the design of a high-throughput pushbroom imaging spectrometer and telescope system that is capable of Landsat swath and resolution while providing better than 10 nm per pixel spectral resolution. The design is based on a 3200 x 480 element x 18 µm pixel size focal plane array, two of which are utilized to cover the full swath. At an optical speed of F/1.8, the system is the fastest proposed to date to our knowledge. The utilization of only two spectrometer modules fed from the same telescope reduces system complexity while providing a solution within achievable detector technology. Predictions of complete system response are shown. Also, it is shown that detailed ghost analysis is a requirement for this type of spectrometer and forms an essential part of a complete design.

Uranus' cloud structure and scattering particle properties from IRTF SpeX observations

NASA Astrophysics Data System (ADS)

Tice, D. S.; Irwin, P. G. J.; Fletcher, L. N.; Teanby, N. A.; Orton, G. S.; Davis, G. R.

2011-10-01

Observations of Uranus were made in August 2009 with the SpeX spectrograph at the NASA Infrared Telescope Facility (IRTF). Analysed spectra range from 0.8 to 1.8 μm at a spatial resolution of 0.5" and a spectral resolution of R = 1,200. Spectra from 0.818 to 0.834 μm, a region characterised by both strong hydrogen quadrupole and methane absorptions are considered to determine methane content. Evidence indicates that methane abundance varies with latitude. NEMESIS, an optimal estimation retrieval code with full-scattering capability, is employed to analyse the full range of data. Cloud and haze properties in the upper troposphere and stratosphere are characterised, and are consistent with other current literature. New information on single scattering albedos and particle size distributions are inferred.

A stand-alone compact EUV microscope based on gas-puff target source.

PubMed

Torrisi, Alfio; Wachulak, Przemyslaw; Węgrzyński, Łukasz; Fok, Tomasz; Bartnik, Andrzej; Parkman, Tomáš; Vondrová, Šárka; Turňová, Jana; Jankiewicz, Bartłomiej J; Bartosewicz, Bartosz; Fiedorowicz, Henryk

2017-02-01

We report on a very compact desk-top transmission extreme ultraviolet (EUV) microscope based on a laser-plasma source with a double stream gas-puff target, capable of acquiring magnified images of objects with a spatial (half-pitch) resolution of sub-50 nm. A multilayer ellipsoidal condenser is used to focus and spectrally narrow the radiation from the plasma, producing a quasi-monochromatic EUV radiation (λ = 13.8 nm) illuminating the object, whereas a Fresnel zone plate objective forms the image. Design details, development, characterization and optimization of the EUV source and the microscope are described and discussed. Test object and other samples were imaged to demonstrate superior resolution compared to visible light microscopy. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Lynx mission concept study

NASA Astrophysics Data System (ADS)

Vikhlinin, Alexey

2018-01-01

Lynx is an observatory-class mission, featuring high throughput, exquisite angular resolution over a substantial field of view, and high spectral resolution for point and extended X-ray sources. The design requirements provide a tremendous leap in capabilities relative to missions such as Chandra and Athena. Lynx will observe the dawn of supermassive black holes through detection of very faint X-ray sources in the early universe and will reveal the "invisible drivers" of galaxy and structure formation through observations of hot, diffuse baryons in and around the galaxies. Lynx will enable breakthroughs across all of astrophysics, ranging from detailed understanding of stellar activity including effects on habitability of associated planets to population statistics of neutron stars and black holes in the Local Group galaxies, to earliest groups and clusters of galaxies, and to cosmology

SETI at X-energies - parasitic searches from astrophysical observations.

NASA Astrophysics Data System (ADS)

Corbet, R. H. D.

1997-01-01

If a sufficiently advanced civilization can either modulate the emission from an X-ray binary, or make use of the natural high luminosity to power an artificial transmitter, these can serve as good beacons for interstellar communication without involving excessive energy costs to the broadcasting civilization. In addition, the small number of X-ray binaries in the Galaxy considerably reduces the number of targets that must be investigated compared to searches in other energy bands. Low mass X-ray binaries containing neutron stars in particular are considered as prime potential natural and artificial beacons and high time resolution (better than 1ms) observations are encouraged. All sky monitors provide the capability of detecting brief powerful artificial signals from isolated neutron stars. New capabilities of X-ray astronomy satellites developed for astrophysical purposes are enabling SETI in new parameter regimes. For example, the X-ray Timing Explorer satellite provides the capability of exploring the sub-millisecond region. Other planned X-ray astronomy satellites should provide significantly improved spectral resolution. While SETI at X-ray energies is highly speculative (and rather unfashionable) by using a parasitic approach little additional cost is involved. The inclusion of X-ray binaries in target lists for SETI at radio and other wavebands is also advocated.

Spectral images browsing using principal component analysis and set partitioning in hierarchical tree

NASA Astrophysics Data System (ADS)

Ma, Long; Zhao, Deping

2011-12-01

Spectral imaging technology have been used mostly in remote sensing, but have recently been extended to new area requiring high fidelity color reproductions like telemedicine, e-commerce, etc. These spectral imaging systems are important because they offer improved color reproduction quality not only for a standard observer under a particular illuminantion, but for any other individual exhibiting normal color vision capability under another illuminantion. A possibility for browsing of the archives is needed. In this paper, the authors present a new spectral image browsing architecture. The architecture for browsing is expressed as follow: (1) The spectral domain of the spectral image is reduced with the PCA transform. As a result of the PCA transform the eigenvectors and the eigenimages are obtained. (2) We quantize the eigenimages with the original bit depth of spectral image (e.g. if spectral image is originally 8bit, then quantize eigenimage to 8bit), and use 32bit floating numbers for the eigenvectors. (3) The first eigenimage is lossless compressed by JPEG-LS, the other eigenimages were lossy compressed by wavelet based SPIHT algorithm. For experimental evalution, the following measures were used. We used PSNR as the measurement for spectral accuracy. And for the evaluation of color reproducibility, ΔE was used.here standard D65 was used as a light source. To test the proposed method, we used FOREST and CORAL spectral image databases contrain 12 and 10 spectral images, respectively. The images were acquired in the range of 403-696nm. The size of the images were 128*128, the number of bands was 40 and the resolution was 8 bits per sample. Our experiments show the proposed compression method is suitable for browsing, i.e., for visual purpose.

A novel approach to 32-channel peripheral nervous system myelin imaging in vivo, with single axon resolution.

PubMed

Grochmal, Joey; Teo, Wulin; Gambhir, Hardeep; Kumar, Ranjan; Stratton, Jo Anne; Dhaliwal, Raveena; Brideau, Craig; Biernaskie, Jeff; Stys, Peter K; Midha, Rajiv

2018-01-19

OBJECTIVE Intravital spectral imaging of the large, deeply situated nerves in the rat peripheral nervous system (PNS) has not been well described. Here, the authors have developed a highly stable platform for performing imaging of the tibial nerve in live rodents, thus allowing the capture of high-resolution, high-magnification spectral images requiring long acquisition times. By further exploiting the qualities of the topically applied myelin dye Nile red, this technique is capable of visualizing the detailed microenvironment of peripheral nerve demyelination injury and recovery, while allowing us to obtain images of exogenous Schwann cell myelination in a living animal. METHODS The authors caused doxorubicin-induced focal demyelination in the tibial nerves of 25 Thy-1 GFP rats, of which 2 subsets (n = 10 each) received either BFP-labeled SKP-SCs or SCs to the zone of injury. Prior to acquiring images of myelin recovery in these nerves, a tibial nerve window was constructed using a silicone hemitube, a fast drying silicone polymer, and a small coverslip. This construct was then affixed to a 3D-printed nerve stage, which in turn was affixed to an external fixation/microscope stage device. Myelin visualization was facilitated by the topical application of Nile red. RESULTS The authors reliably demonstrated intravital peripheral nerve myelin imaging with micron-level resolution and magnification, and minimal movement artifact. The detailed microenvironment of nerve remyelination can be vividly observed, while exogenously applied Schwann cells and skin-derived precursor Schwann cells can be seen myelinating axons. CONCLUSIONS Topically applied Nile red enables intravital study of myelin in the living rat PNS. Furthermore, the use of a tibial nerve window facilitates stable intravital peripheral nerve imaging, making possible high-definition spectral imaging with long acquisition times.

High-range resolution spectral analysis of precipitation through range imaging of the Chung-Li VHF radar

NASA Astrophysics Data System (ADS)

Tsai, Shih-Chiao; Chen, Jenn-Shyong; Chu, Yen-Hsyang; Su, Ching-Lun; Chen, Jui-Hsiang

2018-01-01

Multi-frequency range imaging (RIM) has been operated in the Chung-Li very high-frequency (VHF) radar, located on the campus of National Central University, Taiwan, since 2008. RIM processes the echo signals with a group of closely spaced transmitting frequencies through appropriate inversion methods to obtain high-resolution distribution of echo power in the range direction. This is beneficial to the investigation of the small-scale structure embedded in dynamic atmosphere. Five transmitting frequencies were employed in the radar experiment for observation of the precipitating atmosphere during the period between 21 and 23 August 2013. Using the Capon and Fourier methods, the radar echoes were synthesized to retrieve the temporal signals at a smaller range step than the original range resolution defined by the pulse width, and such retrieved temporal signals were then processed in the Doppler frequency domain to identify the atmosphere and precipitation echoes. An analysis called conditional averaging was further executed for echo power, Doppler velocity, and spectral width to verify the potential capabilities of the retrieval processing in resolving small-scale precipitation and atmosphere structures. Point-by-point correction of range delay combined with compensation of range-weighting function effect has been performed during the retrieval of temporal signals to improve the continuity of power spectra at gate boundaries, making the small-scale structures in the power spectra more natural and reasonable. We examined stratiform and convective precipitation and demonstrated their different structured characteristics by means of the Capon-processed results. The new element in this study is the implementation of RIM on spectral analysis, especially for precipitation echoes.

Concept and integration of an on-line quasi-operational airborne hyperspectral remote sensing system

NASA Astrophysics Data System (ADS)

Schilling, Hendrik; Lenz, Andreas; Gross, Wolfgang; Perpeet, Dominik; Wuttke, Sebastian; Middelmann, Wolfgang

2013-10-01

Modern mission characteristics require the use of advanced imaging sensors in reconnaissance. In particular, high spatial and high spectral resolution imaging provides promising data for many tasks such as classification and detecting objects of military relevance, such as camouflaged units or improvised explosive devices (IEDs). Especially in asymmetric warfare with highly mobile forces, intelligence, surveillance and reconnaissance (ISR) needs to be available close to real-time. This demands the use of unmanned aerial vehicles (UAVs) in combination with downlink capability. The system described in this contribution is integrated in a wing pod for ease of installation and calibration. It is designed for the real-time acquisition and analysis of hyperspectral data. The main component is a Specim AISA Eagle II hyperspectral sensor, covering the visible and near-infrared (VNIR) spectral range with a spectral resolution up to 1.2 nm and 1024 pixel across track, leading to a ground sampling distance below 1 m at typical altitudes. The push broom characteristic of the hyperspectral sensor demands an inertial navigation system (INS) for rectification and georeferencing of the image data. Additional sensors are a high resolution RGB (HR-RGB) frame camera and a thermal imaging camera. For on-line application, the data is preselected, compressed and transmitted to the ground control station (GCS) by an existing system in a second wing pod. The final result after data processing in the GCS is a hyperspectral orthorectified GeoTIFF, which is filed in the ERDAS APOLLO geographical information system. APOLLO allows remote access to the data and offers web-based analysis tools. The system is quasi-operational and was successfully tested in May 2013 in Bremerhaven, Germany.

First performance results of a new field-widened spatial heterodyne spectrometer for geocoronal Hα research

NASA Astrophysics Data System (ADS)

Gardner, D. D.; Mierkiewicz, E. J.; Roesler, F. L.; Harlander, J. M.; Jaehnig, K. P.; Nossal, S. M.; Haffner, L. M.

2017-01-01

A new, high-resolution field-widened spatial heterodyne spectrometer (FW-SHS) designed to observe geocoronal Balmer α (Hα, 6563 Å) emission was installed at Pine Bluff Observatory (PBO) near Madison, Wisconsin. FW-SHS observations were compared with an already well-characterized dual-etalon Fabry-Perot Interferometer (PBO FPI) optimized for Hα, also at PBO. The FW-SHS is a robust Fourier transform instrument that combines a large throughput advantage with high spectral resolution and a relatively long spectral baseline ( 10 times that of the PBO FPI) in a compact, versatile instrument with no moving parts. Coincident Hα observations by FW-SHS and PBO FPI were obtained over similar integration times, resolving powers ( 67,000 and 80,000 at Hα) and fields of view (1.8° and 1.4°, respectively). First light FW-SHS observations of Hα intensity and temperature (Doppler width) versus viewing geometry (shadow altitude) show excellent relative agreement with the geocoronal observations previously obtained at PBO by FPI. The FW-SHS has a 640 km/s (14 Å) spectral band pass and is capable of determining geocoronal Hα Doppler shifts on the order of 100 m/s with a temporal resolution on the order of minutes. These characteristics make the FW-SHS well suited for spectroscopic studies of relatively faint ( 12-2 R), diffuse-source geocoronal Hα emission from Earth's upper thermosphere and exosphere and the interstellar medium in our Galaxy. Current and future FW-SHS observations extend long-term geocoronal hydrogen observation data sets already spanning three solar minima. This paper describes the FW-SHS first light performance and Hα observational results collected from observing nights across 2013 and 2014.

First Performance Results of a New Geocoronal Balmer-alpha Field-Widened Spatial Heterodyne Spectrometer

NASA Astrophysics Data System (ADS)

Gardner, D.; Mierkiewicz, E. J.; Roesler, F. L.; Harlander, J.; Jaehnig, K.; Nossal, S. M.; Haffner, L. M.

2015-12-01

During 2013, a new, high resolution field-widened spatial heterodyne spectrometer (FW-SHS) uniquely designed to observe geocoronal Balmer-alpha emission ([Ha], 6563A) was installed at Pine Bluff Observatory (PBO) near Madison Wisconsin. FW-SHS observations were compared with an already well-characterized dual-etalon Fabry Perot Interferometer (FPI) optimized for [Ha], also at PBO. The FW-SHS is a robust new Fourier-transform instrument that combines a large throughput advantage with high spectral resolution and a relatively long spectral baseline (~10x that of the FPI) in a compact, versatile instrument with no moving parts. Coincident [Ha] observations by FW-SHS and FPI were obtained over similar integration times, resolving power (~80,000 at [Ha]) and field-of-view (1.8 and 1.4 degrees, respectively). This paper describes the FW-SHS first light performance and [Ha] observational results collected from observing nights across 2013 and 2014. Initial FW-SHS observations of Balmer-alpha intensity and temperature (doppler width) vs. viewing geometry (shadow altitude) show excellent relative agreement with the geocoronal observations previously obtained at PBO by FPI. The FW-SHS is capable of determining geocoronal Balmer-alpha doppler shifts on the order of 100 m/s across a 640km/s [Ha] spectral bandpass, with a temporal resolution on the order of minutes. These characteristics make the FW-SHS well suited for spectroscopic studies of relatively faint, diffuse-source geocoronal Balmer-alpha emission from Earth's upper atmosphere (~2-14R) and the interstellar medium in our Galaxy. Current and future observations expand long-term geocoronal hydrogen observation data sets already spanning two solar maximums.

An Extension of the Time-Spectral Method to Overset Solvers

NASA Technical Reports Server (NTRS)

Leffell, Joshua Isaac; Murman, Scott M.; Pulliam, Thomas

2013-01-01

Relative motion in the Cartesian or overset framework causes certain spatial nodes to move in and out of the physical domain as they are dynamically blanked by moving solid bodies. This poses a problem for the conventional Time-Spectral approach, which expands the solution at every spatial node into a Fourier series spanning the period of motion. The proposed extension to the Time-Spectral method treats unblanked nodes in the conventional manner but expands the solution at dynamically blanked nodes in a basis of barycentric rational polynomials spanning partitions of contiguously defined temporal intervals. Rational polynomials avoid Runge's phenomenon on the equidistant time samples of these sub-periodic intervals. Fourier- and rational polynomial-based differentiation operators are used in tandem to provide a consistent hybrid Time-Spectral overset scheme capable of handling relative motion. The hybrid scheme is tested with a linear model problem and implemented within NASA's OVERFLOW Reynolds-averaged Navier- Stokes (RANS) solver. The hybrid Time-Spectral solver is then applied to inviscid and turbulent RANS cases of plunging and pitching airfoils and compared to time-accurate and experimental data. A limiter was applied in the turbulent case to avoid undershoots in the undamped turbulent eddy viscosity while maintaining accuracy. The hybrid scheme matches the performance of the conventional Time-Spectral method and converges to the time-accurate results with increased temporal resolution.

Characterization and modelling of the spatially- and spectrally-varying point-spread function in hyperspectral imaging systems for computational correction of axial optical aberrations

NASA Astrophysics Data System (ADS)

Špiclin, Žiga; Bürmen, Miran; Pernuš, Franjo; Likar, Boštjan

2012-03-01

Spatial resolution of hyperspectral imaging systems can vary significantly due to axial optical aberrations that originate from wavelength-induced index-of-refraction variations of the imaging optics. For systems that have a broad spectral range, the spatial resolution will vary significantly both with respect to the acquisition wavelength and with respect to the spatial position within each spectral image. Variations of the spatial resolution can be effectively characterized as part of the calibration procedure by a local image-based estimation of the pointspread function (PSF) of the hyperspectral imaging system. The estimated PSF can then be used in the image deconvolution methods to improve the spatial resolution of the spectral images. We estimated the PSFs from the spectral images of a line grid geometric caliber. From individual line segments of the line grid, the PSF was obtained by a non-parametric estimation procedure that used an orthogonal series representation of the PSF. By using the non-parametric estimation procedure, the PSFs were estimated at different spatial positions and at different wavelengths. The variations of the spatial resolution were characterized by the radius and the fullwidth half-maximum of each PSF and by the modulation transfer function, computed from images of USAF1951 resolution target. The estimation and characterization of the PSFs and the image deconvolution based spatial resolution enhancement were tested on images obtained by a hyperspectral imaging system with an acousto-optic tunable filter in the visible spectral range. The results demonstrate that the spatial resolution of the acquired spectral images can be significantly improved using the estimated PSFs and image deconvolution methods.

The Warm-Hot Intergalactic Medium Explorer (WHIMex) Mission Concept

NASA Astrophysics Data System (ADS)

Lillie, Charles F.; Cash, W. C.; McEntaffer, R. L.; Zhang, W.; O'Dell, S.; Bautz, M.; Elvis, M.

2011-05-01

WHIMEx is a low-cost, highly capable, single instrument X-ray observatory proposed as a NASA Explorer 2011 mission. WHIMEx will use high resolution X-ray spectroscopy (R ≥ 4000) to probe the hot, tenuous gas that populates the great stretches between the galaxies - the place where most of the baryons in the Universe reside. The bulk of this gas is so hot that it can only be studied in the soft X-ray region where the atomic diagnostics for highly ionized species reside. And this gas is so tenuous that it can only be observed in absorption. To detect the absorption lines of O VII and O VIII along the line of sight to distant AGN requires an order of magnitude improvement in both spectral resolution and collecting area over the current best X-ray spectrographs on Chandra and XMM-Newton. WHIMEx achieves this goal in a compact and affordable package through the application of technologies that were developed over the last decade for the International X-ray Observatory. WHIMex uses ultra-thin, light, densely nested parabolic-hyperbolic mirror pairs to create a telescope with a high collecting area and 15 arcsecond resolution. The X-ray beam is dispersed in wavelength by an array of radial gratings in the extreme off-plane mount. Spectral resolving power of 4000 (λ/δλ) is expected in the 0.15 to 2keV band to bring weak absorption lines out of the noise. A collecting area up to 360 cm2 will enable spectral observations of high red shift AGNs.If selected WHIMEx could be launched in mid- 2017 on a Taurus or Athena II from Vandenberg AFB into its 540 km, 70° inclination low earth orbit. In flight, it would open up a new field of exploration with high resolution observations of AGN outflows, the IGM, interstellar medium, mass transfer binaries, stellar coronae and much more

The Warm-Hot Intergalactic Medium Explorer (WHIMex)

NASA Astrophysics Data System (ADS)

Lillie, Charles F.; Cash, W. C.; Science, WHIMex; Instrument Teams

2011-09-01

WHIMex is a low-cost, highly capable, single instrument X-ray observatory proposed as a NASA Explorer 2011 mission. WHIMex will use high resolution X-ray spectroscopy (R ≥ 4000) to probe the hot, tenuous gas that populates the great stretches between the galaxies - the place where most of the baryons in the Universe reside. The bulk of this gas is so hot that it can only be studied in the soft X-ray region where the atomic diagnostics for highly ionized species reside. And this gas is so tenuous that it can only be observed in absorption. To detect the absorption lines of O VII and O VIII along the line of sight to distant AGN requires an order of magnitude improvement in both spectral resolution and collecting area over the current best X-ray spectrographs on Chandra and XMM-Newton. WHIMex achieves this goal in a compact and affordable package through the application of technologies that were developed over the last decade for the International X-ray Observatory. WHIMex uses ultra-thin, light, densely nested parabolic-hyperbolic mirror pairs to create a telescope with a high collecting area and <15 arcsecond resolution. The X-ray s are dispersed in wavelength by an array of radial gratings in the extreme off-plane mount. Spectral resolving power of 4000 (λ/δλ) is expected in the 0.3 to 0.8 keV band to bring weak absorption lines out of the noise. A collecting area up to 360 cm2 will enable spectral observations of high red shift AGNs. If selected WHIMex could be launched in mid- 2017 on a Taurus or Athena II from Vandenberg AFB into a 540 km, 70° inclination low earth orbit. In flight, it would open a new field of exploration with high resolution observations of AGN outflows, the IGM, Interstellar Medium, mass transfer binaries, stellar coronae and much more.

Modeling the 2012-2013 lava flows of Tolbachik, Russia using thermal infrared satellite data and PyFLOWGO

NASA Astrophysics Data System (ADS)

Ramsey, M. S.; Chevrel, O.; Harris, A. J. L.

2017-12-01

Satellite-based thermal infrared (TIR) observations of new volcanic activity and ongoing lava flow emplacement become increasingly more detailed with improved spatial, spectral and/or temporal resolution data. The cooling of the glassy surface is directly imaged by TIR instruments in order to determine temperature, which is then used to initiate thermo-rheological-based models. Higher temporal resolution data (i.e., minutes to hours), are used to detect new eruptions and determine the time-averaged discharge rate (TADR). Calculation of the TADR along with new observations later in time and accurate digital elevation models (DEMs) enable modeling of the advancing flow's down-slope inundation area. Better spectral and spatial resolution data, on the other hand, allow the flow's composition, small-scale morphological changes and real-time DEMs to be determined, in addition to confirming prior model predictions. Combined, these data help improve the accuracy of models such as FLOWGO. A new adaptation of this model in python (PyFLOWGO) has been used to produce the best fit eruptive conditions to the final flow morphology for the 2012-2013 eruption of Tolbachik volcano, Russia. This was the largest and most thermally-intense flow-forming eruption in the past 50 years, producing longer lava flows than that of typical Kilauea or Etna eruptions. The progress of these flows were imaged by a multiple TIR sensors at various spatial, spectral and temporal scales throughout the flow field emplacement. We have refined the model based on the high resolution data to determine the TADR and make improved estimates of cooling, viscosity, velocity and crystallinity with distance. Understanding the cooling and dynamics of basaltic surfaces ultimately produces an improved hazard forecast capability. In addition, the direct connection of the final flow morphology to the specific eruption conditions that produced it allows the eruptive conditions of older flows to be estimated.

A Satellite-Based Imaging Instrumentation Concept for Hyperspectral Thermal Remote Sensing

PubMed Central

Udelhoven, Thomas; Schlerf, Martin; Segl, Karl; Mallick, Kaniska; Bossung, Christian; Rock, Gilles; Fischer, Peter; Müller, Andreas; Storch, Tobias; Eisele, Andreas; Weise, Dennis; Hupfer, Werner; Knigge, Thiemo

2017-01-01

This paper describes the concept of the hyperspectral Earth-observing thermal infrared (TIR) satellite mission HiTeSEM (High-resolution Temperature and Spectral Emissivity Mapping). The scientific goal is to measure specific key variables from the biosphere, hydrosphere, pedosphere, and geosphere related to two global problems of significant societal relevance: food security and human health. The key variables comprise land and sea surface radiation temperature and emissivity, surface moisture, thermal inertia, evapotranspiration, soil minerals and grain size components, soil organic carbon, plant physiological variables, and heat fluxes. The retrieval of this information requires a TIR imaging system with adequate spatial and spectral resolutions and with day-night following observation capability. Another challenge is the monitoring of temporally high dynamic features like energy fluxes, which require adequate revisit time. The suggested solution is a sensor pointing concept to allow high revisit times for selected target regions (1–5 days at off-nadir). At the same time, global observations in the nadir direction are guaranteed with a lower temporal repeat cycle (>1 month). To account for the demand of a high spatial resolution for complex targets, it is suggested to combine in one optic (1) a hyperspectral TIR system with ~75 bands at 7.2–12.5 µm (instrument NEDT 0.05 K–0.1 K) and a ground sampling distance (GSD) of 60 m, and (2) a panchromatic high-resolution TIR-imager with two channels (8.0–10.25 µm and 10.25–12.5 µm) and a GSD of 20 m. The identified science case requires a good correlation of the instrument orbit with Sentinel-2 (maximum delay of 1–3 days) to combine data from the visible and near infrared (VNIR), the shortwave infrared (SWIR) and TIR spectral regions and to refine parameter retrieval. PMID:28671575

High spatial sampling light-guide snapshot spectrometer

PubMed Central

Wang, Ye; Pawlowski, Michal E.; Tkaczyk, Tomasz S.

2017-01-01

A prototype fiber-based imaging spectrometer was developed to provide snapshot hyperspectral imaging tuned for biomedical applications. The system is designed for imaging in the visible spectral range from 400 to 700 nm for compatibility with molecular imaging applications as well as satellite and remote sensing. An 81 × 96 pixel spatial sampling density is achieved by using a custom-made fiber-optic bundle. The design considerations and fabrication aspects of the fiber bundle and imaging spectrometer are described in detail. Through the custom fiber bundle, the image of a scene of interest is collected and divided into discrete spatial groups, with spaces generated in between groups for spectral dispersion. This reorganized image is scaled down by an image taper for compatibility with following optical elements, dispersed by a prism, and is finally acquired by a CCD camera. To obtain an (x, y, λ) datacube from the snapshot measurement, a spectral calibration algorithm is executed for reconstruction of the spatial–spectral signatures of the observed scene. System characterization of throughput, resolution, and crosstalk was performed. Preliminary results illustrating changes in oxygen-saturation in an occluded human finger are presented to demonstrate the system’s capabilities. PMID:29238115

Determining fast orientation changes of multi-spectral line cameras from the primary images

NASA Astrophysics Data System (ADS)

Wohlfeil, Jürgen

2012-01-01

Fast orientation changes of airborne and spaceborne line cameras cannot always be avoided. In such cases it is essential to measure them with high accuracy to ensure a good quality of the resulting imagery products. Several approaches exist to support the orientation measurement by using optical information received through the main objective/telescope. In this article an approach is proposed that allows the determination of non-systematic orientation changes between every captured line. It does not require any additional camera hardware or onboard processing capabilities but the payload images and a rough estimate of the camera's trajectory. The approach takes advantage of the typical geometry of multi-spectral line cameras with a set of linear sensor arrays for different spectral bands on the focal plane. First, homologous points are detected within the heavily distorted images of different spectral bands. With their help a connected network of geometrical correspondences can be built up. This network is used to calculate the orientation changes of the camera with the temporal and angular resolution of the camera. The approach was tested with an extensive set of aerial surveys covering a wide range of different conditions and achieved precise and reliable results.

Evaluating Hyperspectral Imaging of Wetland Vegetation as a Tool for Detecting Estuarine Nutrient Enrichment

DTIC Science & Technology

2008-05-01

the vegetation’s uptake of water column nutrients produces a spectral response; and 3) the spectral and spatial resolutions ...analysis. This allowed us to evaluate these assumptions at the landscape level, by using the high spectral and spatial resolution of the hyperspectral... spatial resolution (2.5 m pixels) HyMap hyperspectral imagery of the entire wetland. After using a hand-held spectrometer to characterize

Comparison of Skylab and LANDSAT images for geologic mapping in Northern Arizona. [Shivwits Plateau, Verde Valley, Coconino Plateau, and Red Lake in Arizona

NASA Technical Reports Server (NTRS)

Goetz, A. F. H. (Principal Investigator); Abrams, M. J.; Gillespie, A. R.; Siegal, B. S.; Elston, D. P.; Lucchitta, I.; Wu, S. S. C.; Sanchez, A.; Dipaola, W. D.; Schafer, F. J.

1976-01-01

The author has identified the following significant results. It was found that based on resolution, the Skylab S190A products were superior to LANDSAT images. Based on measurements of shoreline features in Lake Mead S190A images had 1.5 - 3 times greater resolution than LANDSAT. In general, the higher resolution of the Skylab data yielded better discrimination among rock units, but in the case of structural features, lower sun angle LANDSAT images (50 deg) were superior to higher sun angle Skylab images (77 deg). The most valuable advantage of the Skylab over the LANDSAT image products is the capability of producing stereo images. Field spectral reflectance measurements on the Coconino Plateau were made in an effort to determine the best spectral band for discrimination of the six geologic units in question, and these bands were 1.3, 1.2, 1.0, and 0.5 microns. The EREP multispectral scanner yielded data with a low signal to noise ratio which limited its usefulness for image enhancement work. Sites that were studied in Arizona were Shivwits Plateau, Verde Valley, Coconino Plateau, and Red Lake. Thematic maps produced by the three classification algorithms analyzed were not as accurate as the maps produced by photointerpretation of composites of enhanced images.

The X-Ray Integral Field Unit and the Athena mission

NASA Astrophysics Data System (ADS)

Piro, Luigi; Barret, Didier; Den herder, Jan-willem

The Athena+ mission concept is designed to implement the Hot and Energetic Universe science theme submitted to the European Space Agency in response to the call for White Papers for the definition of the L2 and L3 missions of its science program. The Athena+ science payload consists of a large aperture high angular resolution X-ray optics and twelve meters away, two interchangeable focal plane instruments: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager (WFI). The X-IFU is a cryogenic X-ray spectrometer, based on a large array of Transition Edge Sensors (TES), offering 2.5 eV spectral resolution, with ˜ 5’’ pixels, over a field of view of 5 arc minutes in diameter. In this talk, we briefly describe the Athena+ mission concept and the X-IFU performance being driven by science requirements. We then present the X-IFU detector and readout electronics principles, the current design of the focal plane assembly, the cooling chain and review the global architecture design. Finally, we describe the current performance estimates, in terms of effective area, particle background rejection, count rate capability and velocity measurements. Finally, we emphasize on the latest technology developments concerning TES array fabrication, spectral resolution and readout performance achieved to show that significant progresses are being accomplished towards the demanding X-IFU requirements.

Airborne infrared-hyperspectral mapping for detection of gaseous and solid targets

NASA Astrophysics Data System (ADS)

Puckrin, E.; Turcotte, C. S.; Lahaie, P.; Dubé, D.; Farley, V.; Lagueux, P.; Marcotte, F.; Chamberland, M.

2010-04-01

Airborne hyperspectral ground mapping is being used in an ever-increasing extent for numerous applications in the military, geology and environmental fields. The different regions of the electromagnetic spectrum help produce information of differing nature. The visible, near-infrared and short-wave infrared radiation (400 nm to 2.5 μm) has been mostly used to analyze reflected solar light, while the mid-wave (3 to 5 μm) and long-wave (8 to 12 μm or thermal) infrared senses the self-emission of molecules directly, enabling the acquisition of data during night time. The Telops Hyper-Cam is a rugged and compact infrared hyperspectral imager based on the Fourier-transform technology. It has been used on the ground in several field campaigns, including the demonstration of standoff chemical agent detection. More recently, the Hyper-Cam has been integrated into an airplane to provide airborne measurement capabilities. The technology offers fine spectral resolution (up to 0.25 cm-1) and high accuracy radiometric calibration (better than 1 degree Celsius). Furthermore, the spectral resolution, spatial resolution, swath width, integration time and sensitivity are all flexible parameters that can be selected and optimized to best address the specific objectives of each mission. The system performance and a few measurements have been presented in previous publications. This paper focuses on analyzing additional measurements in which detection of fertilizer and Freon gas has been demonstrated.

Detection of trace nitric oxide concentrations using 1-D laser-induced fluorescence imaging

NASA Astrophysics Data System (ADS)

Yoo, J.; Lee, T.; Jeffries, J. B.; Hanson, R. K.

2008-06-01

Spectrally resolved laser-induced fluorescence (LIF) with one-dimensional spatial imaging was investigated as a technique for detection of trace concentrations of nitric oxide (NO) in high-pressure flames. Experiments were performed in the burnt gases of premixed methane/argon/oxygen flames with seeded NO (15 to 50 ppm), pressures of 10 to 60 bar, and an equivalence ratio of 0.9. LIF signals were dispersed with a spectrometer and recorded on a 2-D intensified CCD array yielding both spectral resolution and 1-D spatial resolution. This method allows isolation of NO-LIF from interference signals due to alternative species (mainly hot O2 and CO2) while providing spatial resolution along the line of the excitation laser. A fast data analysis strategy was developed to enable pulse-by-pulse NO concentration measurements from these images. Statistical analyses as a function of laser energy of these single-shot data were used to determine the detection limits for NO concentration as well as the measurement precision. Extrapolating these results to pulse energies of ˜ 16 mJ/pulse yielded a predicted detection limit of ˜ 10 ppm for pressures up to 60 bar. Quantitative 1-D LIF measurements were performed in CH4/air flames to validate capability for detection of nascent NO in flames at 10-60 bar.

Nyquist-WDM filter shaping with a high-resolution colorless photonic spectral processor.

PubMed

Sinefeld, David; Ben-Ezra, Shalva; Marom, Dan M

2013-09-01

We employ a spatial-light-modulator-based colorless photonic spectral processor with a spectral addressability of 100 MHz along 100 GHz bandwidth, for multichannel, high-resolution reshaping of Gaussian channel response to square-like shape, compatible with Nyquist WDM requirements.

Observational capabilities of solar satellite "Coronas-Photon"

NASA Astrophysics Data System (ADS)

Kotov, Yu.

Coronas-Photon mission is the third satellite of the Russian Coronas program on solar activity observation The main goal of the Coronas-Photon is the study of solar hard electromagnetic radiation in the wide energy range from UV up to high energy gamma-radiation sim 2000MeV Scientific payload for solar radiation observation consists of three type of instruments 1 monitors Natalya-2M Konus-RF RT-2 Penguin-M BRM Phoka Sphin-X Sokol for spectral and timing measurements of full solar disk radiation with timing in flare burst mode up to one msec Instruments Natalya-2M Konus-RF RT-2 will cover the wide energy range of hard X-rays and soft Gamma rays 15keV to 2000MeV and will together constitute the largest area detectors ever used for solar observations Detectors of gamma-ray monitors are based on structured inorganic scintillators with energy resolution sim 5 for nuclear gamma-line band to 35 for GeV-band PSD analysis is used for gamma neutron separation for solar neutron registration T 30MeV Penguin-M has capability to measure linear polarization of hard X-rays using azimuth are measured by Compton scattering asymmetry in case of polarization of an incident flux For X-ray and EUV monitors the scintillation phoswich detectors gas proportional counter CZT assembly and Filter-covered Si-diodes are used 2 Telescope-spectrometer TESIS for imaging solar spectroscopy in X-rays with angular resolution up to 1 in three spectral lines and RT-2 CZT assembly of CZT

Contrast enhancement of subcutaneous blood vessel images by means of visible and near-infrared hyper-spectral imaging

NASA Astrophysics Data System (ADS)

Katrašnik, Jaka; Bürmen, Miran; Pernuš, Franjo; Likar, Boštjan

2009-02-01

Visualization of subcutaneous veins is very difficult with the naked eye, but important for diagnosis of medical conditions and different medical procedures such as catheter insertion and blood withdrawal. Moreover, recent studies showed that the images of subcutaneous veins could be used for biometric identification. The majority of methods used for enhancing the contrast between the subcutaneous veins and surrounding tissue are based on simple imaging systems utilizing CMOS or CCD cameras with LED illumination capable of acquiring images from the near infrared spectral region, usually near 900 nm. However, such simplified imaging methods cannot exploit the full potential of the spectral information. In this paper, a new highly versatile method for enhancing the contrast of subcutaneous veins based on state-of-the-art high-resolution hyper-spectral imaging system utilizing the spectral region from 550 to 1700 nm is presented. First, a detailed analysis of the contrast between the subcutaneous veins and the surrounding tissue as a function of wavelength, for several different positions on the human arm, was performed in order to extract the spectral regions with the highest contrast. The highest contrast images were acquired at 1100 nm, however, combining the individual images from the extracted spectral regions by the proposed contrast enhancement method resulted in a single image with up to ten-fold better contrast. Therefore, the proposed method has proved to be a useful tool for visualization of subcutaneous veins.

Photoplethysmographic imaging via spectrally demultiplexed erythema fluctuation analysis for remote heart rate monitoring

NASA Astrophysics Data System (ADS)

Deglint, Jason; Chung, Audrey G.; Chwyl, Brendan; Amelard, Robert; Kazemzadeh, Farnoud; Wang, Xiao Yu; Clausi, David A.; Wong, Alexander

2016-03-01

Traditional photoplethysmographic imaging (PPGI) systems use the red, green, and blue (RGB) broadband measurements of a consumer digital camera to remotely estimate a patients heart rate; however, these broadband RGB signals are often corrupted by ambient noise, making the extraction of subtle fluctuations indicative of heart rate difficult. Therefore, the use of narrow-band spectral measurements can significantly improve the accuracy. We propose a novel digital spectral demultiplexing (DSD) method to infer narrow-band spectral information from acquired broadband RGB measurements in order to estimate heart rate via the computation of motion- compensated skin erythema fluctuation. Using high-resolution video recordings of human participants, multiple measurement locations are automatically identified on the cheeks of an individual, and motion-compensated broadband reflectance measurements are acquired at each measurement location over time via measurement location tracking. The motion-compensated broadband reflectance measurements are spectrally demultiplexed using a non-linear inverse model based on the spectral sensitivity of the camera's detector. A PPG signal is then computed from the demultiplexed narrow-band spectral information via skin erythema fluctuation analysis, with improved signal-to-noise ratio allowing for reliable remote heart rate measurements. To assess the effectiveness of the proposed system, a set of experiments involving human motion in a front-facing position were performed under ambient lighting conditions. Experimental results indicate that the proposed system achieves robust and accurate heart rate measurements and can provide additional information about the participant beyond the capabilities of traditional PPGI methods.

Spectral resolution control of acousto-optical cells operating with collimated and divergent beams

NASA Astrophysics Data System (ADS)

Voloshinov, Vitaly B.; Mishin, Dimitry D.

1994-01-01

The paper is devoted to theoretical and experimental investigations of acousto-optical interactions in crystals which may be used for spectral filtration of light in tunable acousto- optical filters. Attention is paid to spectral resolution control during operation with divergent or collimated noncoherent optical beams. In all examined cases spectral bands of anisotropic Bragg diffraction were regulated by means of novel electronical methods. Resolution control was achieved in paratellurite cells with non-collinear and quasi-collinear regimes of the diffraction. Filtration spectral bandwidths for visible light were electronically changed by a factor of 10 divided by 20 by drive electrical signals switching and drive electrical power regulations.

Slitless Solar Spectroscopy

NASA Technical Reports Server (NTRS)

Davila, Joseph M.; Jones, Sahela

2011-01-01

Spectrographs have traditionally suffered from the inability to obtain line intensities, widths, and Doppler shifts over large spatial regions of the Sun quickly because of the narrow instantaneous field of view. This has limited the spectroscopic analysis of rapidly varying solar features like, flares, CME eruptions, coronal jets, and reconnection regions. Imagers have provided high time resolution images of the full Sun with limited spectral resolution. In this paper we present recent advances in deconvolving spectrally dispersed images obtained through broad slits. We use this new theoretical formulation to examine the effectiveness of various potential observing scenarios, spatial and spectral resolutions, signal to noise ratio, and other instrument characteristics. This information will lay the foundation for a new generation of spectral imagers optimized for slitless spectral operation, while retaining the ability to obtain spectral information in transient solar events.

Spectral optical coherence tomography: a novel technique for cornea imaging.

PubMed

Kaluzny, Bartłomiej J; Kaluzy, Bartłomiej J; Kałuzny, Jakub J; Szkulmowska, Anna; Gorczyńska, Iwona; Szkulmowski, Maciej; Bajraszewski, Tomasz; Wojtkowski, Maciej; Targowski, Piotr

2006-09-01

Spectral optical coherence tomography (SOCT) is a new, noninvasive, noncontact, high-resolution technique that provides cross-sectional images of the objects that weakly absorb and scatter light. SOCT, because of very short acquisition time and high sensitivity, is capable of providing tomograms of substantially better quality than the conventional OCT. The aim of this paper is to show the application of the SOCT to cross-sectional imaging of the cornea and its pathologies. Eleven eyes with different corneal pathologies were examined with a slit lamp and the use of a prototype SOCT instrument constructed in the Institute of Physics, Nicolaus Copernicus University, Toruń, Poland. Our SOCT system provides high-resolution (4 microm axial, 10 microm transversal) tomograms composed of 3000-5000 A-scans with an acquisition time of 120-200 ms. The quality of the images is adequate for detailed cross-sectional evaluation of various corneal pathologies. Objective assessment of the localization, size, shape, and light-scattering properties of the changed tissue is possible. Corneal and epithelial thickness and the depth and width of lesions can be estimated. SOCT technique allows acquiring clinically valuable cross-sectional optical biopsy of the cornea and its pathologies.

Measuring high spectral resolution specific absorption coefficients for use with hyperspectral imagery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, M.; Bostater, C.

1997-06-01

A portable, long path length (50 cm), flow through, absorption tube system is utilized to obtain in-situ specific absorption coefficients from various water environments consisting of both clear and turbid water conditions from an underway ship or vessel. The high spectral resolution absorption signatures can be obtained and correlated with measured water quality parameters along a ship track. The long path cuvette system is capable of measuring important water quality parameters such as chlorophyll-a, seston or total suspended matter, tannins, humics, fulvic acids, or dissolved organic matter (dissolved organic carbon, DOC). The various concentrations of these substances can be determinedmore » and correlated with laboratory measurements using the double inflection ratio (DIR) of the spectra based upon derivative spectroscopy. The DIR is determined for all of the possible combinations of the bands ranging from 362-1115 nm using 252 channels, as described previously by Bostater. The information gathered from this system can be utilized in conjunction with hyperspectral imagery that allows one to relate reflectance and absorption to water quality of a particular environment. A comparison is made between absorption signatures and reflectance obtained from the Banana River, Florida.« less

X-ray verification of an optically-aligned off-plane grating module

NASA Astrophysics Data System (ADS)

Donovan, Benjamin; McEntaffer, Randall; Tutt, James; DeRoo, Casey; Allured, Ryan; Gaskin, Jessica; Kolodziejczak, Jeffery

2017-08-01

The next generation of X-ray spectrometer missions are baselined to have order-of-magnitude improvements in both spectral resolving power and effective area when compared to existing X-ray spectrometer missions. Off-plane X-ray reflection gratings are capable of achieving high resolution and high diffraction efficiencies over the entire X-ray bandpass, making them an ideal technology to implement on these future missions. To achieve the high effective area desired while maintaining high spectral resolution, many off-plane gratings must be precisely aligned such that their diffraction arcs overlap at the focal plane. Methods are under development to align a number of these gratings into a grating module using optical metrology techniques in support of the Off-plane Grating Rocket Experiment (OGRE), a suborbital rocket payload scheduled to launch in late 2018. X-ray testing was performed on an aligned grating module at the Straylight Test Facility (SLTF) at NASA Marshall Space Flight Center (MSFC) to assess the current alignment methodology and its ability to meet the desired performance of OGRE. We report on the results from the test campaign at MSFC, as well as plans for future development.

Hyperspectral imaging from space: Warfighter-1

NASA Astrophysics Data System (ADS)

Cooley, Thomas; Seigel, Gary; Thorsos, Ivan

1999-01-01

The Air Force Research Laboratory Integrated Space Technology Demonstrations (ISTD) Program Office has partnered with Orbital Sciences Corporation (OSC) to complement the commercial satellite's high-resolution panchromatic imaging and Multispectral imaging (MSI) systems with a moderate resolution Hyperspectral imaging (HSI) spectrometer camera. The program is an advanced technology demonstration utilizing a commercially based space capability to provide unique functionality in remote sensing technology. This leveraging of commercial industry to enhance the value of the Warfighter-1 program utilizes the precepts of acquisition reform and is a significant departure from the old-school method of contracting for government managed large demonstration satellites with long development times and technology obsolescence concerns. The HSI system will be able to detect targets from the spectral signature measured by the hyperspectral camera. The Warfighter-1 program will also demonstrate the utility of the spectral information to theater military commanders and intelligence analysts by transmitting HSI data directly to a mobile ground station that receives and processes the data. After a brief history of the project origins, this paper will present the details of the Warfighter-1 system and expected results from exploitation of HSI data as well as the benefits realized by this collaboration between the Air Force and commercial industry.

Applications of Cavity-Enhanced Direct Frequency Comb Spectroscopy

NASA Astrophysics Data System (ADS)

Cossel, Kevin C.; Adler, Florian; Maslowski, Piotr; Ye, Jun

2010-06-01

Cavity-enhanced direct frequency comb spectroscopy (CE-DFCS) is a unique technique that provides broad bandwidth, high resolution, and ultra-high detection sensitivities. This is accomplished by combining a femtosecond laser based optical frequency comb with an enhancement cavity and a broadband, multichannel imaging system. These systems are capable of simultaneously recording many terahertz of spectral bandwidth with sub-gigahertz resolution and absorption sensitivities of 1×10-7 cm-1 Hz-1/2. In addition, the ultrashort pulses enable efficient nonlinear processes, which makes it possible to reach spectral regions that are difficult to access with conventional laser sources. We will present an application of CE-DFCS for trace impurity detection in the semiconductor processing gas arsine near 1.8 μm and the development of a high-power, mid-infrared frequency comb for breath analysis in the 2.8-4.8 μm region. M. J. Thorpe, K. D. Moll, R. J. Jones, B. Safdi, and J. Ye. Science 311, 1595-1599 (2006) F. Adler, M. J. Thorpe, K. C. Cossel, and J. Ye. Annu. Rev. Anal. Chem. 3, 175-205 (2010) F. Adler, K. C. Cossel, M. J. Thorpe, I. Hartl, M. E. Fermann, and J. Ye. Opt. Lett. 34, 1330-1332 (2009)

Identifying Organic Molecules in Space: The AstroBiology Explorer (ABE) Mission Concept

NASA Technical Reports Server (NTRS)

Ennico, Kimberly; Sandford, S.; Allamandola, L.; Bregman, J.; Cohen, M.; Cruikshank, D.; Dumas, C.; Greene, T.; Hudgins, D.; Kwok, S.

2004-01-01

The AstroBiology Explorer (ABE) mission concept consists of a modest dedicated space observatory having a 60 cm class primary mirror cooled to T less than 50 K equipped with medium resolution cross-dispersed spectrometers having cooled large format near- and mid-infrared detector arrays. Such a system would be capable of addressing outstanding problems in Astrochemistry and Astrophysics that are particularly relevant to Astrobiology and addressable via astronomical observation. The mission's observaticxiai program woiild make fundamental scieztific: prngress in establishing the nature, distribution, formation and evolution of organic and other molecular materials in the following extra-terrestrial environments: 1) The Outflow of Dying Stars; 2) The Diffuse Interstellar Medium (DISM); 3) Dense Molecular Clouds, Star Formation Regions, and Young Stellar/Planetary Systems; 4) Planets, Satellites, and Small Bodies within the Solar System; and 5) The Interstellar Media of Other Galaxies ABE could make fundamental progress in all of these area by conducting a 1 to 2 year mission to obtain a coordinated set of infrared spectroscopic observations over the 2.5 - 20 micron spectral range at a spectral resolution of R greater than 2500 of about 1500 galaxies, stars, planetary nebulae, young stellar objects, and solar system objects.

Image sharpening for mixed spatial and spectral resolution satellite systems

NASA Technical Reports Server (NTRS)

Hallada, W. A.; Cox, S.

1983-01-01

Two methods of image sharpening (reconstruction) are compared. The first, a spatial filtering technique, extrapolates edge information from a high spatial resolution panchromatic band at 10 meters and adds it to the low spatial resolution narrow spectral bands. The second method, a color normalizing technique, is based on the ability to separate image hue and brightness components in spectral data. Using both techniques, multispectral images are sharpened from 30, 50, 70, and 90 meter resolutions. Error rates are calculated for the two methods and all sharpened resolutions. The results indicate that the color normalizing method is superior to the spatial filtering technique.

Assessment of the performance of a compact concentric spectrometer system for Atmospheric Differential Optical Absorption Spectroscopy

NASA Astrophysics Data System (ADS)

Whyte, C.; Leigh, R. J.; Lobb, D.; Williams, T.; Remedios, J. J.; Cutter, M.; Monks, P. S.

2009-12-01

A breadboard demonstrator of a novel UV/VIS grating spectrometer has been developed based upon a concentric arrangement of a spherical meniscus lens, concave spherical mirror and curved diffraction grating suitable for a range of atmospheric remote sensing applications from the ground or space. The spectrometer is compact and provides high optical efficiency and performance benefits over traditional instruments. The concentric design is capable of handling high relative apertures, owing to spherical aberration and comma being near zero at all surfaces. The design also provides correction for transverse chromatic aberration and distortion, in addition to correcting for the distortion called "smile", the curvature of the slit image formed at each wavelength. These properties render this design capable of superior spectral and spatial performance with size and weight budgets significantly lower than standard configurations. This form of spectrometer design offers the potential for exceptionally compact instrument for differential optical absorption spectroscopy (DOAS) applications from LEO, GEO, HAP or ground-based platforms. The breadboard demonstrator has been shown to offer high throughput and a stable Gaussian line shape with a spectral range from 300 to 450 nm at 0.5 nm resolution, suitable for a number of typical DOAS applications.

Quantitative identification of chemical compounds by dual-soliton based coherent anti-Stokes Raman scattering spectroscopy

NASA Astrophysics Data System (ADS)

Chen, Kun; Wu, Tao; Li, Yan; Wei, Haoyun

2017-12-01

Coherent anti-Stokes Raman scattering (CARS) is a powerful nonlinear spectroscopy technique that is rapidly gaining recognition of different molecules. Unfortunately, molecular concentration information is generally not immediately accessible from the raw CARS signal due to the nonresonant background. In addition, mainstream biomedical applications of CARS are currently hampered by a complex and bulky excitation setup. Here, we establish a dual-soliton Stokes based CARS spectroscopy scheme capable of quantifying the sample molecular, using a single fiber laser. This dual-soliton CARS scheme takes advantage of a differential configuration to achieve efficient suppression of nonresonant background and therefore allows extraction of quantitative composition information. Besides, our all-fiber based excitation source can probe the most fingerprint region (1100-1800 cm-1) with a spectral resolution of 15 cm-1 under the spectral focusing mechanism, where is considerably more information contained throughout an entire spectrum than at just a single frequency within that spectrum. Systematic studies of the scope of application and several fundamental aspects are discussed. Quantitative capability is further experimentally demonstrated through the determination of oleic acid concentration based on the linear dependence of signal on different Raman vibration bands.

The NPOESS Crosstrack Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) as a Companion to the New Generation AIRS/AMSU and IASI/AMSU Sounder Suites

NASA Astrophysics Data System (ADS)

Bingham, G. E.; Pougatchev, N. S.; Zavyalov, V.; Esplin, M.; Blackwell, W. J.; Barnet, C.

2009-12-01

The NPOESS Preparatory Project is serving the operations and research community as the bridge mission between the Earth Observing System and the National Polar-orbiting Operational Environmental Satellite System. The Cross-track Infrared Sounder (CrIS), combined with the Advanced Technology Microwave Sounder (ATMS) are the core instruments to provide the key performance temperature and humidity profiles (along with some other atmospheric constituent information). Both the high spectral resolution CrIS and the upgraded microwave sounder (ATMS) will be working in parallel with already orbiting Advanced Atmospheric Infrared Sounder (AIRS/AMSU) on EOS AQUA platform and Infrared Atmospheric Sounding Interferometer (IASI/AMSU) on METOP-A satellite. This presentation will review the CrIS/ATMS capabilities in the context of continuity with the excellent performance records established by AIRS and IASI. The CrIS sensor is in the process of its final calibration and characterization testing and the results and Sensor Data Record process are being validated against this excellent dataset. The comparison between CrIS, AIRS, and IASI will include spectral, spatial, radiometric performance and sounding capability comparisons.

Hyperspectral retinal imaging with a spectrally tunable light source

NASA Astrophysics Data System (ADS)

Francis, Robert P.; Zuzak, Karel J.; Ufret-Vincenty, Rafael

2011-03-01

Hyperspectral retinal imaging can measure oxygenation and identify areas of ischemia in human patients, but the devices used by current researchers are inflexible in spatial and spectral resolution. We have developed a flexible research prototype consisting of a DLP®-based spectrally tunable light source coupled to a fundus camera to quickly explore the effects of spatial resolution, spectral resolution, and spectral range on hyperspectral imaging of the retina. The goal of this prototype is to (1) identify spectral and spatial regions of interest for early diagnosis of diseases such as glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR); and (2) define required specifications for commercial products. In this paper, we describe the challenges and advantages of using a spectrally tunable light source for hyperspectral retinal imaging, present clinical results of initial imaging sessions, and describe how this research can be leveraged into specifying a commercial product.

The U. S. Geological Survey, Digital Spectral Library: Version 1 (0.2 to 3.0um)

USGS Publications Warehouse

Clark, Roger N.; Swayze, Gregg A.; Gallagher, Andrea J.; King, Trude V.V.; Calvin, Wendy M.

1993-01-01

We have developed a digital reflectance spectral library, with management and spectral analysis software. The library includes 498 spectra of 444 samples (some samples include a series of grain sizes) measured from approximately 0.2 to 3.0 um . The spectral resolution (Full Width Half Maximum) of the reflectance data is <= 4 nm in the visible (0.2-0.8 um) and <= 10 nm in the NIR (0.8-2.35 um). All spectra were corrected to absolute reflectance using an NIST Halon standard. Library management software lets users search on parameters (e.g. chemical formulae, chemical analyses, purity of samples, mineral groups, etc.) as well as spectral features. Minerals from borate, carbonate, chloride, element, halide, hydroxide, nitrate, oxide, phosphate, sulfate, sulfide, sulfosalt, and the silicate (cyclosilicate, inosilicate, nesosilicate, phyllosilicate, sorosilicate, and tectosilicate) classes are represented. X-Ray and chemical analyses are tabulated for many of the entries, and all samples have been evaluated for spectral purity. The library also contains end and intermediate members for the olivine, garnet, scapolite, montmorillonite, muscovite, jarosite, and alunite solid-solution series. We have included representative spectra of H2O ice, kerogen, ammonium-bearing minerals, rare-earth oxides, desert varnish coatings, kaolinite crystallinity series, kaolinite-smectite series, zeolite series, and an extensive evaporite series. Because of the importance of vegetation to climate-change studies we have include 17 spectra of tree leaves, bushes, and grasses. The library and software are available as a series of U.S.G.S. Open File reports. PC user software is available to convert the binary data to ascii files (a separate U.S.G.S. open file report). Additionally, a binary data files are on line at the U.S.G.S. in Denver for anonymous ftp to users on the Internet. The library search software enables a user to search on documentation parameters as well as spectral features. The analysis system includes general spectral analysis routines, plotting packages, radiative transfer software for computing intimate mixtures, routines to derive optical constants from reflectance spectra, tools to analyze spectral features, and the capability to access imaging spectrometer data cubes for spectral analysis. Users may build customized libraries (at specific wavelengths and spectral resolution) for their own instruments using the library software. We are currently extending spectral coverage to 150 um. The libraries (original and convolved) will be made available in the future on a CD-ROM.

Module for multiphoton high-resolution hyperspectral imaging and spectroscopy

NASA Astrophysics Data System (ADS)

Zeytunyan, Aram; Baldacchini, Tommaso; Zadoyan, Ruben

2018-02-01

We developed a module for dual-output, dual-wavelength lasers that facilitates multiphoton imaging and spectroscopy experiments and enables hyperspectral imaging with spectral resolution up to 5 cm-1. High spectral resolution is achieved by employing spectral focusing. Specifically, two sets of grating pairs are used to control the chirps in each laser beam. In contrast with the approach that uses fixed-length glass rods, grating pairs allow matching the spectral resolution and the linewidths of the Raman lines of interest. To demonstrate the performance of the module, we report the results of spectral focusing CARS and SRS microscopy experiments for various test samples and Raman shifts. The developed module can be used for a variety of multimodal imaging and spectroscopy applications, such as single- and multi-color two-photon fluorescence, second harmonic generation, third harmonic generation, pump-probe, transient absorption, and others.

The fusion of satellite and UAV data: simulation of high spatial resolution band

NASA Astrophysics Data System (ADS)

Jenerowicz, Agnieszka; Siok, Katarzyna; Woroszkiewicz, Malgorzata; Orych, Agata

2017-10-01

Remote sensing techniques used in the precision agriculture and farming that apply imagery data obtained with sensors mounted on UAV platforms became more popular in the last few years due to the availability of low- cost UAV platforms and low- cost sensors. Data obtained from low altitudes with low- cost sensors can be characterised by high spatial and radiometric resolution but quite low spectral resolution, therefore the application of imagery data obtained with such technology is quite limited and can be used only for the basic land cover classification. To enrich the spectral resolution of imagery data acquired with low- cost sensors from low altitudes, the authors proposed the fusion of RGB data obtained with UAV platform with multispectral satellite imagery. The fusion is based on the pansharpening process, that aims to integrate the spatial details of the high-resolution panchromatic image with the spectral information of lower resolution multispectral or hyperspectral imagery to obtain multispectral or hyperspectral images with high spatial resolution. The key of pansharpening is to properly estimate the missing spatial details of multispectral images while preserving their spectral properties. In the research, the authors presented the fusion of RGB images (with high spatial resolution) obtained with sensors mounted on low- cost UAV platforms and multispectral satellite imagery with satellite sensors, i.e. Landsat 8 OLI. To perform the fusion of UAV data with satellite imagery, the simulation of the panchromatic bands from RGB data based on the spectral channels linear combination, was conducted. Next, for simulated bands and multispectral satellite images, the Gram-Schmidt pansharpening method was applied. As a result of the fusion, the authors obtained several multispectral images with very high spatial resolution and then analysed the spatial and spectral accuracies of processed images.

Super-resolution reconstruction of hyperspectral images.

PubMed

Akgun, Toygar; Altunbasak, Yucel; Mersereau, Russell M

2005-11-01

Hyperspectral images are used for aerial and space imagery applications, including target detection, tracking, agricultural, and natural resource exploration. Unfortunately, atmospheric scattering, secondary illumination, changing viewing angles, and sensor noise degrade the quality of these images. Improving their resolution has a high payoff, but applying super-resolution techniques separately to every spectral band is problematic for two main reasons. First, the number of spectral bands can be in the hundreds, which increases the computational load excessively. Second, considering the bands separately does not make use of the information that is present across them. Furthermore, separate band super-resolution does not make use of the inherent low dimensionality of the spectral data, which can effectively be used to improve the robustness against noise. In this paper, we introduce a novel super-resolution method for hyperspectral images. An integral part of our work is to model the hyperspectral image acquisition process. We propose a model that enables us to represent the hyperspectral observations from different wavelengths as weighted linear combinations of a small number of basis image planes. Then, a method for applying super resolution to hyperspectral images using this model is presented. The method fuses information from multiple observations and spectral bands to improve spatial resolution and reconstruct the spectrum of the observed scene as a combination of a small number of spectral basis functions.

A review of potential image fusion methods for remote sensing-based irrigation management: Part II

USDA-ARS?s Scientific Manuscript database

Satellite-based sensors provide data at either greater spectral and coarser spatial resolutions, or lower spectral and finer spatial resolutions due to complementary spectral and spatial characteristics of optical sensor systems. In order to overcome this limitation, image fusion has been suggested ...

Thermal Infrared Airborne Field Studies: Applications to the Mars Global Surveyor Thermal Emission Spectrometer

NASA Astrophysics Data System (ADS)

Herr, K.; Kirkland, L.; Keim, E.; Hackwell, J.

2002-12-01

A primary goal of the Mars exploration program is to reconnoiter the planet from orbit using infrared remote sensing. Currently the Global Surveyor Thermal Emission Spectrometer (TES) and the 2001 Mars Odyssey 9-band radiometer THEMIS provide this capability. Landing site selection and modeling of the geologic and climate history depend on accurate interpretations of these data sets. Interpretations use terrestrial analog remote sensing and laboratory studies. Until recently, there have been no airborne thermal infrared spectrometer ("hyspectral") data sets available to NASA researchers that are comparable to TES. As a result, studies relied on airborne multi-channel radiometer ("multispectral") measurements (e.g. TIMS, MASTER). A radiometer has the advantage that measurement of broad bands makes it easier to measure with higher sensitivity. However, radiometers lack the spectral resolution to investigate details of spectral signatures. This gap may be partially addressed using field samples collected and measured in the laboratory. However, that leaves questions unanswered about the field environment and potentially leaves important complicating issues undiscovered. Two questions that haunt thermal infrared remote sensing investigations of Mars are: (1) If a mineral is not detected in a given data set, how definitively should we state that it is not there? (2) When does the method provide quantitative mineral mapping? In order to address these questions, we began collaborating with Department of Defense (DoD) oriented researchers and drawing on the unique instrumentation they developed. Both Mars and DoD researchers have a common need to identify materials without benefit of ground truth. Such collaborations provide a fresh perspective as well as unique data. Our work addresses uncertainties in stand-off identification of solid phase surface materials when the identification must proceed without benefit of ground truth. We will report on the results applied to TES, with a focus on the two primary questions above. We use images recorded by a unique airborne imaging spectrometer, the Spatially Enhanced Broadband Array Spectrograph System. SEBASS uses cooled prisms to measure 2.4-5.3 and 7.6-13.5 microns. Each range is measured in 128 channels, with a spectral resolution of 7 wavenumbers at 890 wavenumbers, and a one milliradian field of view per pixel. SEBASS operates as a pushbroom instrument, using two 128 x 128 detector arrays, and the entire optical bench is cooled to 4K using liquid helium. It is operated by The Aerospace Corporation, which is a non-profit Federally Funded Research and Development Center. Images are typically 128 pixels wide and 2000 pixels long, measured with a surface spatial resolution of ~1 or 2 square meters. TES measures ~6.5-50 microns in 143 channels, with a spectral resolution of 10 or 20 wavenumbers. Issues that affect the spectral signature include surface roughness, particle size, coatings, reflected downwelling radiance, atmospheric transmission, and atmospheric reemission. A full understanding of these effects is required in order to determine the uncertainties in field interpretations, whether terrestrially or on Mars. SEBASS data fill this need by measuring with a sensitivity comparable to laboratory data, and sufficient spectral resolution to examine subtle spectral effects that are not resolvable in multi-channel radiometer data.

Spatial-Spectral Approaches to Edge Detection in Hyperspectral Remote Sensing

NASA Astrophysics Data System (ADS)

Cox, Cary M.

This dissertation advances geoinformation science at the intersection of hyperspectral remote sensing and edge detection methods. A relatively new phenomenology among its remote sensing peers, hyperspectral imagery (HSI) comprises only about 7% of all remote sensing research - there are five times as many radar-focused peer reviewed journal articles than hyperspectral-focused peer reviewed journal articles. Similarly, edge detection studies comprise only about 8% of image processing research, most of which is dedicated to image processing techniques most closely associated with end results, such as image classification and feature extraction. Given the centrality of edge detection to mapping, that most important of geographic functions, improving the collective understanding of hyperspectral imagery edge detection methods constitutes a research objective aligned to the heart of geoinformation sciences. Consequently, this dissertation endeavors to narrow the HSI edge detection research gap by advancing three HSI edge detection methods designed to leverage HSI's unique chemical identification capabilities in pursuit of generating accurate, high-quality edge planes. The Di Zenzo-based gradient edge detection algorithm, an innovative version of the Resmini HySPADE edge detection algorithm and a level set-based edge detection algorithm are tested against 15 traditional and non-traditional HSI datasets spanning a range of HSI data configurations, spectral resolutions, spatial resolutions, bandpasses and applications. This study empirically measures algorithm performance against Dr. John Canny's six criteria for a good edge operator: false positives, false negatives, localization, single-point response, robustness to noise and unbroken edges. The end state is a suite of spatial-spectral edge detection algorithms that produce satisfactory edge results against a range of hyperspectral data types applicable to a diverse set of earth remote sensing applications. This work also explores the concept of an edge within hyperspectral space, the relative importance of spatial and spectral resolutions as they pertain to HSI edge detection and how effectively compressed HSI data improves edge detection results. The HSI edge detection experiments yielded valuable insights into the algorithms' strengths, weaknesses and optimal alignment to remote sensing applications. The gradient-based edge operator produced strong edge planes across a range of evaluation measures and applications, particularly with respect to false negatives, unbroken edges, urban mapping, vegetation mapping and oil spill mapping applications. False positives and uncompressed HSI data presented occasional challenges to the algorithm. The HySPADE edge operator produced satisfactory results with respect to localization, single-point response, oil spill mapping and trace chemical detection, and was challenged by false positives, declining spectral resolution and vegetation mapping applications. The level set edge detector produced high-quality edge planes for most tests and demonstrated strong performance with respect to false positives, single-point response, oil spill mapping and mineral mapping. False negatives were a regular challenge for the level set edge detection algorithm. Finally, HSI data optimized for spectral information compression and noise was shown to improve edge detection performance across all three algorithms, while the gradient-based algorithm and HySPADE demonstrated significant robustness to declining spectral and spatial resolutions.

MetaboID: a graphical user interface package for assignment of 1H NMR spectra of bodyfluids and tissues.

PubMed

MacKinnon, Neil; Somashekar, Bagganahalli S; Tripathi, Pratima; Ge, Wencheng; Rajendiran, Thekkelnaycke M; Chinnaiyan, Arul M; Ramamoorthy, Ayyalusamy

2013-01-01

Nuclear magnetic resonance based measurements of small molecule mixtures continues to be confronted with the challenge of spectral assignment. While multi-dimensional experiments are capable of addressing this challenge, the imposed time constraint becomes prohibitive, particularly with the large sample sets commonly encountered in metabolomic studies. Thus, one-dimensional spectral assignment is routinely performed, guided by two-dimensional experiments on a selected sample subset; however, a publicly available graphical interface for aiding in this process is currently unavailable. We have collected spectral information for 360 unique compounds from publicly available databases including chemical shift lists and authentic full resolution spectra, supplemented with spectral information for 25 compounds collected in-house at a proton NMR frequency of 900 MHz. This library serves as the basis for MetaboID, a Matlab-based user interface designed to aid in the one-dimensional spectral assignment process. The tools of MetaboID were built to guide resonance assignment in order of increasing confidence, starting from cursory compound searches based on chemical shift positions to analysis of authentic spike experiments. Together, these tools streamline the often repetitive task of spectral assignment. The overarching goal of the integrated toolbox of MetaboID is to centralize the one dimensional spectral assignment process, from providing access to large chemical shift libraries to providing a straightforward, intuitive means of spectral comparison. Such a toolbox is expected to be attractive to both experienced and new metabolomic researchers as well as general complex mixture analysts. Copyright © 2012 Elsevier Inc. All rights reserved.

Fusion and quality analysis for remote sensing images using contourlet transform

NASA Astrophysics Data System (ADS)

Choi, Yoonsuk; Sharifahmadian, Ershad; Latifi, Shahram

2013-05-01

Recent developments in remote sensing technologies have provided various images with high spatial and spectral resolutions. However, multispectral images have low spatial resolution and panchromatic images have low spectral resolution. Therefore, image fusion techniques are necessary to improve the spatial resolution of spectral images by injecting spatial details of high-resolution panchromatic images. The objective of image fusion is to provide useful information by improving the spatial resolution and the spectral information of the original images. The fusion results can be utilized in various applications, such as military, medical imaging, and remote sensing. This paper addresses two issues in image fusion: i) image fusion method and ii) quality analysis of fusion results. First, a new contourlet-based image fusion method is presented, which is an improvement over the wavelet-based fusion. This fusion method is then applied to a case study to demonstrate its fusion performance. Fusion framework and scheme used in the study are discussed in detail. Second, quality analysis for the fusion results is discussed. We employed various quality metrics in order to analyze the fusion results both spatially and spectrally. Our results indicate that the proposed contourlet-based fusion method performs better than the conventional wavelet-based fusion methods.

Hyperspectral imagery super-resolution by compressive sensing inspired dictionary learning and spatial-spectral regularization.

PubMed

Huang, Wei; Xiao, Liang; Liu, Hongyi; Wei, Zhihui

2015-01-19

Due to the instrumental and imaging optics limitations, it is difficult to acquire high spatial resolution hyperspectral imagery (HSI). Super-resolution (SR) imagery aims at inferring high quality images of a given scene from degraded versions of the same scene. This paper proposes a novel hyperspectral imagery super-resolution (HSI-SR) method via dictionary learning and spatial-spectral regularization. The main contributions of this paper are twofold. First, inspired by the compressive sensing (CS) framework, for learning the high resolution dictionary, we encourage stronger sparsity on image patches and promote smaller coherence between the learned dictionary and sensing matrix. Thus, a sparsity and incoherence restricted dictionary learning method is proposed to achieve higher efficiency sparse representation. Second, a variational regularization model combing a spatial sparsity regularization term and a new local spectral similarity preserving term is proposed to integrate the spectral and spatial-contextual information of the HSI. Experimental results show that the proposed method can effectively recover spatial information and better preserve spectral information. The high spatial resolution HSI reconstructed by the proposed method outperforms reconstructed results by other well-known methods in terms of both objective measurements and visual evaluation.

Fusion of spectral and panchromatic images using false color mapping and wavelet integrated approach

NASA Astrophysics Data System (ADS)

Zhao, Yongqiang; Pan, Quan; Zhang, Hongcai

2006-01-01

With the development of sensory technology, new image sensors have been introduced that provide a greater range of information to users. But as the power limitation of radiation, there will always be some trade-off between spatial and spectral resolution in the image captured by specific sensors. Images with high spatial resolution can locate objects with high accuracy, whereas images with high spectral resolution can be used to identify the materials. Many applications in remote sensing require fusing low-resolution imaging spectral images with panchromatic images to identify materials at high resolution in clutter. A pixel-based false color mapping and wavelet transform integrated fusion algorithm is presented in this paper, the resulting images have a higher information content than each of the original images and retain sensor-specific image information. The simulation results show that this algorithm can enhance the visibility of certain details and preserve the difference of different materials.

MUSE, the Multi-Slit Solar Explorer

NASA Astrophysics Data System (ADS)

Lemen, J. R.; Tarbell, T. D.; De Pontieu, B.; Wuelser, J. P.

2017-12-01

The Multi-Slit Solar Explorer (MUSE) has been selected for a Phase A study for the NASA Heliophysics Small Explorer program. The science objective of MUSE is to make high spatial and temporal resolution imaging and spectral observations of the solar corona and transition region in order to probe the mechanisms responsible for energy release in the corona and understand the dynamics of the solar atmosphere. The physical processes are responsible for heating the corona, accelerating the solar wind, and the rapid release of energy in CMEs and flares. The observations will be tightly coupled to state-of-the-art numerical modeling to provide significantly improved estimates for understanding and anticipating space weather. MUSE contains two instruments: an EUV spectrograph and an EUV context imager. Both have similar spatial resolutions and leverage extensive heritage from previous high-resolution instruments such as IRIS and the HiC rocket payload. The MUSE spectrograph employs a novel multi-slit design that enables a 100x improvement in spectral scanning rates, which will reveal crucial information about the dynamics (e.g., temperature, velocities) of the physical processes that are not observable with current instruments. The MUSE investigation builds on the success of IRIS by combining numerical modeling with a uniquely capable observatory: MUSE will obtain EUV spectra and images with the highest resolution in space (1/3 arcsec) and time (1-4 s) ever achieved for the transition region and corona, along 35 slits and a large context FOV simultaneously. The MUSE consortium includes LMSAL, SAO, Stanford, ARC, HAO, GSFC, MSFC, MSU, and ITA Oslo.

(LMRG): Microscope Resolution, Objective Quality, Spectral Accuracy and Spectral Un-mixing

PubMed Central

Bayles, Carol J.; Cole, Richard W.; Eason, Brady; Girard, Anne-Marie; Jinadasa, Tushare; Martin, Karen; McNamara, George; Opansky, Cynthia; Schulz, Katherine; Thibault, Marc; Brown, Claire M.

2012-01-01

The second study by the LMRG focuses on measuring confocal laser scanning microscope (CLSM) resolution, objective lens quality, spectral imaging accuracy and spectral un-mixing. Affordable test samples for each aspect of the study were designed, prepared and sent to 116 labs from 23 countries across the globe. Detailed protocols were designed for the three tests and customized for most of the major confocal instruments being used by the study participants. One protocol developed for measuring resolution and objective quality was recently published in Nature Protocols (Cole, R. W., T. Jinadasa, et al. (2011). Nature Protocols 6(12): 1929–1941). The first study involved 3D imaging of sub-resolution fluorescent microspheres to determine the microscope point spread function. Results of the resolution studies as well as point spread function quality (i.e. objective lens quality) from 140 different objective lenses will be presented. The second study of spectral accuracy looked at the reflection of the laser excitation lines into the spectral detection in order to determine the accuracy of these systems to report back the accurate laser emission wavelengths. Results will be presented from 42 different spectral confocal systems. Finally, samples with double orange beads (orange core and orange coating) were imaged spectrally and the imaging software was used to un-mix fluorescence signals from the two orange dyes. Results from 26 different confocal systems will be summarized. Time will be left to discuss possibilities for the next LMRG study.

Spectral interferences in the determination of rhenium in molybdenum and copper concentrates by inductively coupled plasma optical emission spectrometry (ICP-OES)

NASA Astrophysics Data System (ADS)

Karadjov, Metody; Velitchkova, Nikolaya; Veleva, Olga; Velichkov, Serafim; Markov, Pavel; Daskalova, Nonka

2016-05-01

This paper deals with spectral interferences of complex matrix containing Mo, Al, Ti, Fe, Mg, Ca and Cu in the determination of rhenium in molybdenum and copper concentrates by inductively coupled plasma optical emission spectrometry (ICP-OES). By radial viewing 40.68 MHz ICP equipped with a high resolution spectrometer (spectral bandwidth = 5 pm) the hyperfine structure (HFS) of the most prominent lines of rhenium (Re II 197.248 nm, Re II 221.426 nm and Re II 227.525 nm) was registered. The HFS components under high resolution conditions were used as separate prominent line in order to circumvent spectral interferences. The Q-concept was applied for quantification of spectral interferences. The quantitative databases for the type and the magnitude of the spectral interferences in the presence of above mentioned matrix constituents were obtained by using a radial viewing 40.68 MHz ICP with high resolution and an axial viewing 27.12 MHz ICP with middle resolution. The data for the both ICP-OES systems were collected chiefly with a view to spectrochemical analysis for comparing the magnitude of line and wing (background) spectral interference and the true detection limits with spectroscopic apparatus with different spectral resolution. The sample pretreatment methods by sintering with magnesium oxide and oxidizing agents as well as a microwave acid digestion were applied. The feasibility, accuracy and precision of the analytical results were experimentally demonstrated by certified reference materials.

Spectral resolution of SU(3)-invariant solutions of the Yang-Baxter equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alishauskas, S.I.; Kulish, P.P.

1986-11-20

The spectral resolution of invariant R-matrices is computed on the basis of solution of the defining equation. Multiple representations in the Clebsch-Gordon series are considered by means of the classifying operator A: a linear combination of known operators of third and fourth degrees in the group generators. The matrix elements of A in a nonorthonormal basis are found. Explicit expressions are presented for the spectral resolutions for a number of representations.

Spectral resolution of SU(3)-invariant solutions of the Yang-Baxter equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alishavskas, S.I.; Kulish, P.P.

1986-11-01

The spectral resolution of invariant R-matrices is computed on the basis of solution of the defining equation. Multiple representations in the Clebsch-Gordon series are considered by means of the classifying operator A: a linear combination of known operators of third and fourth degrees in the group generators. The matrix elements of A in a nonorthonormal basis are found. Explicit expressions are presented for the spectral resolutions for a number of representations.

Multi-Spectral Stereo Atmospheric Remote Sensing (STARS) for Retrieval of Cloud Properties and Cloud-Motion Vectors

NASA Astrophysics Data System (ADS)

Kelly, M. A.; Boldt, J.; Wilson, J. P.; Yee, J. H.; Stoffler, R.

2017-12-01

The multi-spectral STereo Atmospheric Remote Sensing (STARS) concept has the objective to provide high-spatial and -temporal-resolution observations of 3D cloud structures related to hurricane development and other severe weather events. The rapid evolution of severe weather demonstrates a critical need for mesoscale observations of severe weather dynamics, but such observations are rare, particularly over the ocean where extratropical and tropical cyclones can undergo explosive development. Coincident space-based measurements of wind velocity and cloud properties at the mesoscale remain a great challenge, but are critically needed to improve the understanding and prediction of severe weather and cyclogenesis. STARS employs a mature stereoscopic imaging technique on two satellites (e.g. two CubeSats, two hosted payloads) to simultaneously retrieve cloud motion vectors (CMVs), cloud-top temperatures (CTTs), and cloud geometric heights (CGHs) from multi-angle, multi-spectral observations of cloud features. STARS is a pushbroom system based on separate wide-field-of-view co-boresighted multi-spectral cameras in the visible, midwave infrared (MWIR), and longwave infrared (LWIR) with high spatial resolution (better than 1 km). The visible system is based on a pan-chromatic, low-light imager to resolve cloud structures under nighttime illumination down to ¼ moon. The MWIR instrument, which is being developed as a NASA ESTO Instrument Incubator Program (IIP) project, is based on recent advances in MWIR detector technology that requires only modest cooling. The STARS payload provides flexible options for spaceflight due to its low size, weight, power (SWaP) and very modest cooling requirements. STARS also meets AF operational requirements for cloud characterization and theater weather imagery. In this paper, an overview of the STARS concept, including the high-level sensor design, the concept of operations, and measurement capability will be presented.

High Resolution Spectrograph for the Hobby-Eberly Telescope

NASA Astrophysics Data System (ADS)

Tull, R. G.; MacQueen, P. J.; Good, J.; Epps, H. W.; HET HRS Team

1998-12-01

A fiber fed high-resolution spectrograph (HRS) is under construction for the Hobby-Eberly Telescope (HET). The primary resolving power originally specified, from astrophysical considerations, was R = 60,000 with a fiber of diameter at least 1 arc-second, with full spectral coverage limited only by the combined band-pass of the HET, the optical fiber, and the image detector. This was achieved in the final design with a high blaze angle R-4 echelle mosaic, white pupil design, image slicing, and a large area CCD mosaic illuminated by an eight element refractive camera. Two back-to-back, user selectable first-order diffraction gratings are employed for cross dispersion, to separate echelle spectral orders; the entire spectral range (420 - 1,000 nm) can be covered in as few as two exposures. Critical issues addressed in the design are cross dispersion and order spacing, sky subtraction, echelle and CCD selection, fiber optic feed and scrambling, and image or pupil slicing. In the final design meeting the requirements we exploited the large-area 4096 square CCD, image slicing, and the optical performance of the white-pupil design to acquire a range of 30,000 < R < 120,000 with fibers of diameter 2 and 3 arc-seconds, without sacrificing full spectral coverage. Design details will be presented. Limiting magnitude is projected to be about V = 19 (for S/N = 10) at the nominal R = 60,000 resolving power. The poster display will outline performance characteristics expected in relation to projected astrophysical research capabilities outlined by Sneden et al., in this conference. HRS is supported by generous grants from NSF, NASA, the State of Texas, and private philanthropy, with matching funds granted by the University of Texas and by McDonald Observatory.

New Solar Irradiance Measurements from the Miniature X-Ray Solar Spectrometer Cubesat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woods, Thomas N.; Jones, Andrew; Kohnert, Richard

The goal of the Miniature X-ray Solar Spectrometer ( MinXSS ) CubeSat is to explore the energy distribution of soft X-ray (SXR) emissions from the quiescent Sun, active regions, and during solar flares and to model the impact on Earth's ionosphere and thermosphere. The energy emitted in the SXR range (0.1–10 keV) can vary by more than a factor of 100, yet we have limited spectral measurements in the SXRs to accurately quantify the spectral dependence of this variability. The MinXSS primary science instrument is an Amptek, Inc. X123 X-ray spectrometer that has an energy range of 0.5–30 keV withmore » a nominal 0.15 keV energy resolution. Two flight models have been built. The first, MinXSS -1, has been making science observations since 2016 June 9 and has observed numerous flares, including more than 40 C-class and 7 M-class flares. These SXR spectral measurements have advantages over broadband SXR observations, such as providing the capability to derive multiple-temperature components and elemental abundances of coronal plasma, improved irradiance accuracy, and higher resolution spectral irradiance as input to planetary ionosphere simulations. MinXSS spectra obtained during the M5.0 flare on 2016 July 23 highlight these advantages and indicate how the elemental abundance appears to change from primarily coronal to more photospheric during the flare. MinXSS -1 observations are compared to the Geostationary Operational Environmental Satellite ( GOES ) X-ray Sensor (XRS) measurements of SXR irradiance and estimated corona temperature. Additionally, a suggested improvement to the calibration of the GOES XRS data is presented.« less

New Solar Irradiance Measurements from the Miniature X-Ray Solar Spectrometer CubeSat

NASA Astrophysics Data System (ADS)

Woods, Thomas N.; Caspi, Amir; Chamberlin, Phillip C.; Jones, Andrew; Kohnert, Richard; Mason, James Paul; Moore, Christopher S.; Palo, Scott; Rouleau, Colden; Solomon, Stanley C.; Machol, Janet; Viereck, Rodney

2017-02-01

The goal of the Miniature X-ray Solar Spectrometer (MinXSS) CubeSat is to explore the energy distribution of soft X-ray (SXR) emissions from the quiescent Sun, active regions, and during solar flares and to model the impact on Earth's ionosphere and thermosphere. The energy emitted in the SXR range (0.1-10 keV) can vary by more than a factor of 100, yet we have limited spectral measurements in the SXRs to accurately quantify the spectral dependence of this variability. The MinXSS primary science instrument is an Amptek, Inc. X123 X-ray spectrometer that has an energy range of 0.5-30 keV with a nominal 0.15 keV energy resolution. Two flight models have been built. The first, MinXSS-1, has been making science observations since 2016 June 9 and has observed numerous flares, including more than 40 C-class and 7 M-class flares. These SXR spectral measurements have advantages over broadband SXR observations, such as providing the capability to derive multiple-temperature components and elemental abundances of coronal plasma, improved irradiance accuracy, and higher resolution spectral irradiance as input to planetary ionosphere simulations. MinXSS spectra obtained during the M5.0 flare on 2016 July 23 highlight these advantages and indicate how the elemental abundance appears to change from primarily coronal to more photospheric during the flare. MinXSS-1 observations are compared to the Geostationary Operational Environmental Satellite (GOES) X-ray Sensor (XRS) measurements of SXR irradiance and estimated corona temperature. Additionally, a suggested improvement to the calibration of the GOES XRS data is presented.

Review and latest news from the VEGA/CHARA facility

NASA Astrophysics Data System (ADS)

Nardetto, N.; Mourard, D.; Perraut, K.; Tallon-Bosc, I.; Meilland, A.; Stee, P.; Ligi, R.; Challouf, M.; Clausse, J.-M.; Berio, P.; Spang, A.

2014-12-01

The VEGA instrument located at the focus of the Center for High Angular Resolution Astronomy (CHARA) array in California is a collaborating project between the Lagrange laboratory in Nice, where it has been developed (Mourard et al. 2009, 2011), the IPAG (Grenoble) and CRAL (Lyon) laboratories, and the CHARA group at Mount Wilson Observatory. The outcome from this international collaboration is to provide to the community a visible spectro-interferometer with an unprecedented angular resolution of 0.3 milli-second of arc (mas) together with a spectral resolution of 5000 or 30000. With such an instrument it becomes possible to determine simultaneously the size and the kinematic of the photosphere and/or of the circumstellar environment of the star as a function of the wavelength, which basically means for each spectral channel in the continuum and/or within spectral lines (in Hα for instance). The only limitation is to get enough signal to noise ratio in each spectral channel. We can currently reach a limiting magnitude of 8 in visible in medium spectral resolution (5000) and 4.5 in high resolution (30000). In this proceeding, we illustrate the two main subjects studied with the VEGA instrument, namely (1) how angular diameters are useful to accurately derive the fundamental parameters of stars, (2) how the spectral resolution can allow to study the kinematical structure of stars or even to derive chromatic images of stellar objects.

Recent Developments in Transition-Edge Strip Detectors for Solar X-Rays

NASA Technical Reports Server (NTRS)

Rausch, Adam J.; Deiker, Steven W.; Hilton, Gene; Irwin, Kent D.; Martinez-Galarce, Dennis S.; Shing, Lawrence; Stern, Robert A.; Ullom, Joel N.; Vale, Leila R.

2008-01-01

LMSAL and NIST are developing position-sensitive x-ray strip detectors based on Transition Edge Sensor (TES) microcalorimeters optimized for solar physics. By combining high spectral (E/ delta E approximately equals 1600) and temporal (single photon delta t approximately equals 10 micro s) resolutions with imaging capabilities, these devices will be able to study high-temperature (>l0 MK) x-ray lines as never before. Diagnostics from these lines should provide significant new insight into the physics of both microflares and the early stages of flares. Previously, the large size of traditional TESs, along with the heat loads associated with wiring large arrays, presented obstacles to using these cryogenic detectors for solar missions. Implementing strip detector technology at small scales, however, addresses both issues: here, a line of substantially smaller effective pixels requires only two TESs, decreasing both the total array size and the wiring requirements for the same spatial resolution. Early results show energy resolutions of delta E(sub fwhm) approximately equals 30 eV and spatial resolutions of approximately 10-15 micron, suggesting the strip-detector concept is viable.

Magnetic resonance spectroscopic imaging at superresolution: Overview and perspectives

NASA Astrophysics Data System (ADS)

Kasten, Jeffrey; Klauser, Antoine; Lazeyras, François; Van De Ville, Dimitri

2016-02-01

The notion of non-invasive, high-resolution spatial mapping of metabolite concentrations has long enticed the medical community. While magnetic resonance spectroscopic imaging (MRSI) is capable of achieving the requisite spatio-spectral localization, it has traditionally been encumbered by significant resolution constraints that have thus far undermined its clinical utility. To surpass these obstacles, research efforts have primarily focused on hardware enhancements or the development of accelerated acquisition strategies to improve the experimental sensitivity per unit time. Concomitantly, a number of innovative reconstruction techniques have emerged as alternatives to the standard inverse discrete Fourier transform (DFT). While perhaps lesser known, these latter methods strive to effect commensurate resolution gains by exploiting known properties of the underlying MRSI signal in concert with advanced image and signal processing techniques. This review article aims to aggregate and provide an overview of the past few decades of so-called "superresolution" MRSI reconstruction methodologies, and to introduce readers to current state-of-the-art approaches. A number of perspectives are then offered as to the future of high-resolution MRSI, with a particular focus on translation into clinical settings.

Feasibility Study of LANDSAT-8 Imagery for Retrieving Sea Surface Temperature (case Study Persian Gulf)

NASA Astrophysics Data System (ADS)

Bayat, F.; Hasanlou, M.

2016-06-01

Sea surface temperature (SST) is one of the critical parameters in marine meteorology and oceanography. The SST datasets are incorporated as conditions for ocean and atmosphere models. The SST needs to be investigated for various scientific phenomenon such as salinity, potential fishing zone, sea level rise, upwelling, eddies, cyclone predictions. On the other hands, high spatial resolution SST maps can illustrate eddies and sea surface currents. Also, near real time producing of SST map is suitable for weather forecasting and fishery applications. Therefore satellite remote sensing with wide coverage of data acquisition capability can use as real time tools for producing SST dataset. Satellite sensor such as AVHRR, MODIS and SeaWIFS are capable of extracting brightness values at different thermal spectral bands. These brightness temperatures are the sole input for the SST retrieval algorithms. Recently, Landsat-8 successfully launched and accessible with two instruments on-board: (1) the Operational Land Imager (OLI) with nine spectral bands in the visual, near infrared, and the shortwave infrared spectral regions; and (2) the Thermal Infrared Sensor (TIRS) with two spectral bands in the long wavelength infrared. The two TIRS bands were selected to enable the atmospheric correction of the thermal data using a split window algorithm (SWA). The TIRS instrument is one of the major payloads aboard this satellite which can observe the sea surface by using the split-window thermal infrared channels (CH10: 10.6 μm to 11.2 μm; CH11: 11.5 μm to 12.5 μm) at a resolution of 30 m. The TIRS sensors have three main advantages comparing with other previous sensors. First, the TIRS has two thermal bands in the atmospheric window that provide a new SST retrieval opportunity using the widely used split-window (SW) algorithm rather than the single channel method. Second, the spectral filters of TIRS two bands present narrower bandwidth than that of the thermal band on board on previous Landsat sensors. Third, TIRS is one of the best space born and high spatial resolution with 30 m. in this regards, Landsat-8 can use the Split-Window (SW) algorithm for retrieving SST dataset. Although several SWs have been developed to use with other sensors, some adaptations are required in order to implement them for the TIRS spectral bands. Therefore, the objective of this paper is to develop a SW, adapted for use with Landsat-8 TIRS data, along with its accuracy assessment. In this research, that has been done for modelling SST using thermal Landsat 8-imagery of the Persian Gulf. Therefore, by incorporating contemporary in situ data and SST map estimated from other sensors like MODIS, we examine our proposed method with coefficient of determination (R2) and root mean square error (RMSE) on check point to model SST retrieval for Landsat-8 imagery. Extracted results for implementing different SW's clearly shows superiority of utilized method by R2 = 0.95 and RMSE = 0.24.

An advanced wide area chemical sensor testbed

NASA Astrophysics Data System (ADS)

Seeley, Juliette A.; Kelly, Michael; Wack, Edward; Ryan-Howard, Danette; Weidler, Darryl; O'Brien, Peter; Colonero, Curtis; Lakness, John; Patel, Paras

2005-11-01

In order to meet current and emerging needs for remote passive standoff detection of chemical agent threats, MIT Lincoln Laboratory has developed a Wide Area Chemical Sensor (WACS) testbed. A design study helped define the initial concept, guided by current standoff sensor mission requirements. Several variants of this initial design have since been proposed to target other applications within the defense community. The design relies on several enabling technologies required for successful implementation. The primary spectral component is a Wedged Interferometric Spectrometer (WIS) capable of imaging in the LWIR with spectral resolutions as narrow as 4 cm-1. A novel scanning optic will enhance the ability of this sensor to scan over large areas of concern with a compact, rugged design. In this paper, we shall discuss our design, development, and calibration process for this system as well as recent testbed measurements that validate the sensor concept.

A temporally and spatially resolved electron density diagnostic method for the edge plasma based on Stark broadening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zafar, A., E-mail: zafara@ornl.gov; Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830; Martin, E. H.

2016-11-15

An electron density diagnostic (≥10{sup 10} cm{sup −3}) capable of high temporal (ms) and spatial (mm) resolution is currently under development at Oak Ridge National Laboratory. The diagnostic is based on measuring the Stark broadened, Doppler-free spectral line profile of the n = 6–2 hydrogen Balmer series transition. The profile is then fit to a fully quantum mechanical model including the appropriate electric and magnetic field operators. The quasi-static approach used to calculate the Doppler-free spectral line profile is outlined here and the results from the model are presented for H-δ spectra for electron densities of 10{sup 10}–10{sup 13} cm{supmore » −3}. The profile shows complex behavior due to the interaction between the magnetic substates of the atom.« less

Mapping forest vegetation with ERTS-1 MSS data and automatic data processing techniques

NASA Technical Reports Server (NTRS)

Messmore, J.; Copeland, G. E.; Levy, G. F.

1975-01-01

This study was undertaken with the intent of elucidating the forest mapping capabilities of ERTS-1 MSS data when analyzed with the aid of LARS' automatic data processing techniques. The site for this investigation was the Great Dismal Swamp, a 210,000 acre wilderness area located on the Middle Atlantic coastal plain. Due to inadequate ground truth information on the distribution of vegetation within the swamp, an unsupervised classification scheme was utilized. Initially pictureprints, resembling low resolution photographs, were generated in each of the four ERTS-1 channels. Data found within rectangular training fields was then clustered into 13 spectral groups and defined statistically. Using a maximum likelihood classification scheme, the unknown data points were subsequently classified into one of the designated training classes. Training field data was classified with a high degree of accuracy (greater than 95%), and progress is being made towards identifying the mapped spectral classes.

Mapping forest vegetation with ERTS-1 MSS data and automatic data processing techniques

NASA Technical Reports Server (NTRS)

Messmore, J.; Copeland, G. E.; Levy, G. F.

1975-01-01

This study was undertaken with the intent of elucidating the forest mapping capabilities of ERTS-1 MSS data when analyzed with the aid of LARS' automatic data processing techniques. The site for this investigation was the Great Dismal Swamp, a 210,000 acre wilderness area located on the Middle Atlantic coastal plain. Due to inadequate ground truth information on the distribution of vegetation within the swamp, an unsupervised classification scheme was utilized. Initially pictureprints, resembling low resolution photographs, were generated in each of the four ERTS-1 channels. Data found within rectangular training fields was then clustered into 13 spectral groups and defined statistically. Using a maximum likelihood classification scheme, the unknown data points were subsequently classified into one of the designated training classes. Training field data was classified with a high degree of accuracy (greater than 95 percent), and progress is being made towards identifying the mapped spectral classes.

AKARI/IRC NEAR-INFRARED SPECTRAL ATLAS OF GALACTIC PLANETARY NEBULAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohsawa, Ryou; Onaka, Takashi; Sakon, Itsuki

2016-04-15

Near-infrared (2.5–5.0 μm) low-resolution (λ/Δλ ∼ 100) spectra of 72 Galactic planetary nebulae (PNe) were obtained with the Infrared Camera (IRC) in the post-helium phase. The IRC, equipped with a 1′ × 1′ window for spectroscopy of a point source, was capable of obtaining near-infrared spectra in a slit-less mode without any flux loss due to a slit. The spectra show emission features including hydrogen recombination lines and the 3.3–3.5 μm hydrocarbon features. The intensity and equivalent width of the emission features were measured by spectral fitting. We made a catalog providing unique information on the investigation of the near-infrared emission ofmore » PNe. In this paper, details of the observations and characteristics of the catalog are described.« less

Plasmonic piezoelectric nanomechanical resonator for spectrally selective infrared sensing

PubMed Central

Hui, Yu; Gomez-Diaz, Juan Sebastian; Qian, Zhenyun; Alù, Andrea; Rinaldi, Matteo

2016-01-01

Ultrathin plasmonic metasurfaces have proven their ability to control and manipulate light at unprecedented levels, leading to exciting optical functionalities and applications. Although to date metasurfaces have mainly been investigated from an electromagnetic perspective, their ultrathin nature may also provide novel and useful mechanical properties. Here we propose a thin piezoelectric plasmonic metasurface forming the resonant body of a nanomechanical resonator with simultaneously tailored optical and electromechanical properties. We experimentally demonstrate that it is possible to achieve high thermomechanical coupling between electromagnetic and mechanical resonances in a single ultrathin piezoelectric nanoplate. The combination of nanoplasmonic and piezoelectric resonances allows the proposed device to selectively detect long-wavelength infrared radiation with unprecedented electromechanical performance and thermal capabilities. These attributes lead to the demonstration of a fast, high-resolution, uncooled infrared detector with ∼80% absorption for an optimized spectral bandwidth centered around 8.8 μm. PMID:27080018

Comparative study of mobile Raman instrumentation for art analysis.

PubMed

Vandenabeele, P; Castro, K; Hargreaves, M; Moens, L; Madariaga, J M; Edwards, H G M

2007-04-04

In archaeometry, one of the main concerns is to extract information from an art object, without damaging it. Raman spectroscopy is being applied in this research field with recent developments in mobile instrumentation facilitating more routine analysis. This research paper evaluates the performances of five mobile Raman instruments (Renishaw RA100, Renishaw Portable Raman Analyser RX210, Ocean Optics RSL-1, Delta Nu Inspector Raman, Mobile Art Analyser--MArtA) in three different laboratories. A set of samples were collected, in order to obtain information on the spectral performances of the instruments including: spectral resolution, calibration, laser cut-off, the ability to record spectra of organic and inorganic pigments through varnish layers and on the possibilities to identify biomaterials. Spectra were recorded from predefined regions on a canvas painting to simulate the investigation of artworks and the capabilities to record spectra from hardly accessible areas was evaluated.

High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source

DOE PAGES

Fletcher, L. B.; Zastrau, U.; Galtier, E.; ...

2016-08-15

Here, we present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen andmore » focused on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].« less

Single-shot ultrafast tomographic imaging by spectral multiplexing

NASA Astrophysics Data System (ADS)

Matlis, N. H.; Axley, A.; Leemans, W. P.

2012-10-01

Computed tomography has profoundly impacted science, medicine and technology by using projection measurements scanned over multiple angles to permit cross-sectional imaging of an object. The application of computed tomography to moving or dynamically varying objects, however, has been limited by the temporal resolution of the technique, which is set by the time required to complete the scan. For objects that vary on ultrafast timescales, traditional scanning methods are not an option. Here we present a non-scanning method capable of resolving structure on femtosecond timescales by using spectral multiplexing of a single laser beam to perform tomographic imaging over a continuous range of angles simultaneously. We use this technique to demonstrate the first single-shot ultrafast computed tomography reconstructions and obtain previously inaccessible structure and position information for laser-induced plasma filaments. This development enables real-time tomographic imaging for ultrafast science, and offers a potential solution to the challenging problem of imaging through scattering surfaces.

Astigmatism-corrected echelle spectrometer using an off-the-shelf cylindrical lens.

PubMed

Fu, Xiao; Duan, Fajie; Jiang, Jiajia; Huang, Tingting; Ma, Ling; Lv, Changrong

2017-10-01

As a special kind of spectrometer with the Czerny-Turner structure, the echelle spectrometer features two-dimensional dispersion, which leads to a complex astigmatic condition. In this work, we propose an optical design of astigmatism-corrected echelle spectrometer using an off-the-shelf cylindrical lens. The mathematical model considering astigmatism introduced by the off-axis mirrors, the echelle grating, and the prism is established. Our solution features simplified calculation and low-cost construction, which is capable of overall compensation of the astigmatism in a wide spectral range (200-600 nm). An optical simulation utilizing ZEMAX software, astigmatism assessment based on Zernike polynomials, and an instrument experiment is implemented to validate the effect of astigmatism correction. The results demonstrated that astigmatism of the echelle spectrometer was corrected to a large extent, and high spectral resolution better than 0.1 nm was achieved.

Science with Constellation-X, Choice of Instrumentation

NASA Technical Reports Server (NTRS)

Hornscheimeier, Ann; White, Nicholas; Tananbaum, Harvey; Garcia, Michael; Bookbinder, Jay; Petre, Robert; Cottam, Jean

2007-01-01

The Constellation X-ray Observatory is one of the two Beyond Einstein Great Observatories and will provide a 100-fold increase in collecting area in high spectral resolving power X-ray instruments over the Chandra and XMM-Newton gratings instruments. The mission has four main science objectives which drive the requirements for the mission. This contribution to the Garmire celebration conference describes these four science areas: Black Holes, Dark Energy, Missing Baryons, and the Neutron Star Equation of State as well as the requirements flow-down that give rise to the choice of instrumentation and implementation for Constellation-X. As we show, each of these science areas place complementary constraints on mission performance parameters such as collecting area, spectral resolving power, timing resolution, and field of view. The mission's capabilities will enable a great breadth of science, and its resources will be open to the community through its General Observer program.

Immersion echelle spectrograph

DOEpatents

Stevens, Charles G.; Thomas, Norman L.

2000-01-01

A small spectrograph containing no moving components and capable of providing high resolution spectra of the mid-infrared region from 2 microns to 4 microns in wavelength. The resolving power of the spectrograph exceeds 20,000 throughout this region and at an optical throughput of about 10.sup.-5 cm.sup.2 sr. The spectrograph incorporates a silicon immersion echelle grating operating in high spectral order combined with a first order transmission grating in a cross-dispersing configuration to provide a two-dimensional (2-D) spectral format that is focused onto a two-dimensional infrared detector array. The spectrometer incorporates a common collimating and condensing lens assembly in a near aberration-free axially symmetric design. The spectrometer has wide use potential in addition to general research, such as monitoring atmospheric constituents for air quality, climate change, global warming, as well as monitoring exhaust fumes for smog sources or exhaust plumes for evidence of illicit drug manufacture.

First Application of the Zeeman Technique to Remotely Measure Auroral Electrojet Intensity From Space

NASA Technical Reports Server (NTRS)

Yee, J. H.; Gjerloev, J.; Wu, D.; Schwartz, M. J.

2017-01-01

Using the O2 118 GHz spectral radiance measurements obtained by the Microwave Limb Sounder instrument on board the Aura spacecraft, we demonstrate that the Zeeman effect can be used to remotely measure the magnetic field perturbations produced by the auroral electrojet near the Hall current closure altitudes. Our derived current-induced magnetic field perturbations are found to be highly correlated with those coincidently obtained by ground magnetometers. These perturbations are also found to be linearly correlated with auroral electrojet strength. The statistically derived polar maps of our measured magnetic field perturbation reveal a spatial-temporal morphology consistent with that produced by the Hall current during substorms and storms. With today's technology, a constellation of compact, low-power, high spectral-resolution cubesats would have the capability to provide high precision and spatiotemporal magnetic field samplings needed for auroral electrojet measurements to gain insights into the spatiotemporal behavior of the auroral electrojet system.

IRIS: a novel spectral imaging system for the analysis of cultural heritage objects

NASA Astrophysics Data System (ADS)

Papadakis, V. M.; Orphanos, Y.; Kogou, S.; Melessanaki, K.; Pouli, P.; Fotakis, C.

2011-06-01

A new portable spectral imaging system is herein presented capable of acquiring images of high resolution (2MPixels) ranging from 380 nm up to 950 nm. The system consists of a digital color CCD camera, 15 interference filters covering all the sensitivity range of the detector and a robust filter changing system. The acquisition software has been developed in "LabView" programming language allowing easy handling and modification by end-users. The system has been tested and evaluated on a series of objects of Cultural Heritage (CH) value including paintings, encrusted stonework, ceramics etc. This paper aims to present the system, as well as, its application and advantages in the analysis of artworks with emphasis on the detailed compositional and structural information of layered surfaces based on reflection & fluorescence spectroscopy. Specific examples will be presented and discussed on the basis of system improvements.

Titan

NASA Technical Reports Server (NTRS)

Flasar, F. M.

1999-01-01

With a launch in December 2001, Space Infrared Telescope Facility (SIRTF) can observe Titan in the interval after Infrared Space Observatory (ISO) but before the onset of observations by Cassini. By virtue of its broad spectral coverage in the thermal infrared, 10-180 micron, its moderately high spectral resolution, approaching lambda/delta lambda=600 over part of this wavelength range, and the very high sensitivity of its helium- cooled detectors, the Infrared Spectrometer (IRS) and MIPS on SIRTF can address several issues raised through earlier observations by the Voyager IRIS experiment and by ISO. These include, for example, a better characterization of the vertical distribution of water in Titan's middle and upper atmospheres and the discovery of new compounds, such as allene or proprionitrile. This talk will address the temperature- and composition-sounding capabilities of SIRTF, particularly in the context of how they will complement Cassini observations and aid in their planning.

Maximum-likelihood spectral estimation and adaptive filtering techniques with application to airborne Doppler weather radar. Thesis Technical Report No. 20

NASA Technical Reports Server (NTRS)

Lai, Jonathan Y.

1994-01-01

This dissertation focuses on the signal processing problems associated with the detection of hazardous windshears using airborne Doppler radar when weak weather returns are in the presence of strong clutter returns. In light of the frequent inadequacy of spectral-processing oriented clutter suppression methods, we model a clutter signal as multiple sinusoids plus Gaussian noise, and propose adaptive filtering approaches that better capture the temporal characteristics of the signal process. This idea leads to two research topics in signal processing: (1) signal modeling and parameter estimation, and (2) adaptive filtering in this particular signal environment. A high-resolution, low SNR threshold maximum likelihood (ML) frequency estimation and signal modeling algorithm is devised and proves capable of delineating both the spectral and temporal nature of the clutter return. Furthermore, the Least Mean Square (LMS) -based adaptive filter's performance for the proposed signal model is investigated, and promising simulation results have testified to its potential for clutter rejection leading to more accurate estimation of windspeed thus obtaining a better assessment of the windshear hazard.

Master-slave interferometry for parallel spectral domain interferometry sensing and versatile 3D optical coherence tomography.

PubMed

Podoleanu, Adrian Gh; Bradu, Adrian

2013-08-12

Conventional spectral domain interferometry (SDI) methods suffer from the need of data linearization. When applied to optical coherence tomography (OCT), conventional SDI methods are limited in their 3D capability, as they cannot deliver direct en-face cuts. Here we introduce a novel SDI method, which eliminates these disadvantages. We denote this method as Master - Slave Interferometry (MSI), because a signal is acquired by a slave interferometer for an optical path difference (OPD) value determined by a master interferometer. The MSI method radically changes the main building block of an SDI sensor and of a spectral domain OCT set-up. The serially provided signal in conventional technology is replaced by multiple signals, a signal for each OPD point in the object investigated. This opens novel avenues in parallel sensing and in parallelization of signal processing in 3D-OCT, with applications in high- resolution medical imaging and microscopy investigation of biosamples. Eliminating the need of linearization leads to lower cost OCT systems and opens potential avenues in increasing the speed of production of en-face OCT images in comparison with conventional SDI.

Observed Spectral Invariant Behavior of Zenith Radiance in the Transition Zone Between Cloud-Free and Cloudy Regions

NASA Technical Reports Server (NTRS)

Marshak, A.; Knyazikhin, Y.; Chiu, C.; Wiscombe, W.

2010-01-01

The Atmospheric Radiation Measurement Program's (ARM) new Shortwave Spectrometer (SWS) looks straight up and measures zenith radiance at 418 wavelengths between 350 and 2200 nm. Because of its 1-sec sampling resolution, the SWS provides a unique capability to study the transition zone between cloudy and clear sky areas. A surprising spectral invariant behavior is found between ratios of zenith radiance spectra during the transition from cloudy to cloud-free atmosphere. This behavior suggests that the spectral signature of the transition zone is a linear mixture between the two extremes (definitely cloudy and definitely clear). The weighting function of the linear mixture is found to be a wavelength-independent characteristic of the transition zone. It is shown that the transition zone spectrum is fully determined by this function and zenith radiance spectra of clear and cloudy regions. This new finding may help us to better understand and quantify such physical phenomena as humidification of aerosols in the relatively moist cloud environment and evaporation and activation of cloud droplets.

Quantitative chemical imaging with background-free multiplex coherent anti-Stokes Raman scattering by dual-soliton Stokes pulses

PubMed Central

Chen, Kun; Wu, Tao; Wei, Haoyun; Zhou, Tian; Li, Yan

2016-01-01

Coherent anti-Stokes Raman microscopy (CARS) is a quantitative, chemically specific, and label-free optical imaging technique for studying inhomogeneous systems. However, the complicating influence of the nonresonant response on the CARS signal severely limits its sensitivity and specificity and especially limits the extent to which CARS microscopy has been used as a fully quantitative imaging technique. On the basis of spectral focusing mechanism, we establish a dual-soliton Stokes based CARS microspectroscopy and microscopy scheme capable of quantifying the spatial information of densities and chemical composition within inhomogeneous samples, using a single fiber laser. Dual-soliton Stokes scheme not only removes the nonresonant background but also allows robust acquisition of multiple characteristic vibrational frequencies. This all-fiber based laser source can cover the entire fingerprint (800-2200 cm−1) region with a spectral resolution of 15 cm−1. We demonstrate that quantitative degree determination of lipid-chain unsaturation in the fatty acids mixture can be achieved by the characterization of C = C stretching and CH2 deformation vibrations. For microscopy purposes, we show that the spatially inhomogeneous distribution of lipid droplets can be further quantitatively visualized using this quantified degree of lipid unsaturation in the acyl chain for contrast in the hyperspectral CARS images. The combination of compact excitation source and background-free capability to facilitate extraction of quantitative composition information with multiplex spectral peaks will enable wider applications of quantitative chemical imaging in studying biological and material systems. PMID:27867704

Bayer Filter Snapshot Hyperspectral Fundus Camera for Human Retinal Imaging

PubMed Central

Liu, Wenzhong; Nesper, Peter; Park, Justin; Zhang, Hao F.; Fawzi, Amani A.

2016-01-01

Purpose To demonstrate the versatility and performance of a compact Bayer filter snapshot hyperspectral fundus camera for in-vivo clinical applications including retinal oximetry and macular pigment optical density measurements. Methods 12 healthy volunteers were recruited under an Institutional Review Board (IRB) approved protocol. Fundus images were taken with a custom hyperspectral camera with a spectral range of 460–630 nm. We determined retinal vascular oxygen saturation (sO2) for the healthy population using the captured spectra by least squares curve fitting. Additionally, macular pigment optical density was localized and visualized using multispectral reflectometry from selected wavelengths. Results We successfully determined the mean sO2 of arteries and veins of each subject (ages 21–80) with excellent intrasubject repeatability (1.4% standard deviation). The mean arterial sO2 for all subjects was 90.9% ± 2.5%, whereas the mean venous sO2 for all subjects was 64.5% ± 3.5%. The mean artery–vein (A–V) difference in sO2 varied between 20.5% and 31.9%. In addition, we were able to reveal and quantify macular pigment optical density. Conclusions We demonstrated a single imaging tool capable of oxygen saturation and macular pigment density measurements in vivo. The unique combination of broad spectral range, high spectral–spatial resolution, rapid and robust imaging capability, and compact design make this system a valuable tool for multifunction spectral imaging that can be easily performed in a clinic setting. PMID:27767345

An Imaging Spectral Line Survey of IRC+10216 using the Expanded Very Large Array (EVLA)

NASA Astrophysics Data System (ADS)

Claussen, Mark J.; EVLA Scientific Commissioning Team

2011-01-01

The Expanded Very Large Array (EVLA) is currently undergoing scientific commissioning, with full scientific operations expected in 2013. During the commissioning, we have performed a rather coarse ( 25 km/s) and shallow imaging spectral survey of the circumstellar environment of the well-known and nearby carbon-rich asymptotic giant branch (AGB) star IRC+10°216 (CW Leo) in the frequency range 18 - 26.5 GHz, using the capability of the WIDAR correlator to simultaneously observe 2 GHz of bandwidth. In addition we have used the additional capability of WIDAR to observe widely spaced sub-bands to observe eight pairs of targeted lines with much better spectral resolution (1.0 - 2.0 km/s) in the 18 - 26.5 GHz receiver band (selected from the coarse survey) and the 26.5 - 40 GHz receiver band (selected from the single-dish survey of Kawaguchi et al. (1995, PASJ, 47, 853). In the coarse survey, we detected twenty-one transitions of eleven molecules including eight transitions of HC7N, ranging from 18.049 GHz to 25.946 GHz, the J = 1 - 0 maser transition of SiS at 18.156 GHz, and three transitions of HC5N. We will present further results of the survey and images of the emission from the targeted lines. The National Radio Astronomy is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

Point-and-stare operation and high-speed image acquisition in real-time hyperspectral imaging

NASA Astrophysics Data System (ADS)

Driver, Richard D.; Bannon, David P.; Ciccone, Domenic; Hill, Sam L.

2010-04-01

The design and optical performance of a small-footprint, low-power, turnkey, Point-And-Stare hyperspectral analyzer, capable of fully automated field deployment in remote and harsh environments, is described. The unit is packaged for outdoor operation in an IP56 protected air-conditioned enclosure and includes a mechanically ruggedized fully reflective, aberration-corrected hyperspectral VNIR (400-1000 nm) spectrometer with a board-level detector optimized for point and stare operation, an on-board computer capable of full system data-acquisition and control, and a fully functioning internal hyperspectral calibration system for in-situ system spectral calibration and verification. Performance data on the unit under extremes of real-time survey operation and high spatial and high spectral resolution will be discussed. Hyperspectral acquisition including full parameter tracking is achieved by the addition of a fiber-optic based downwelling spectral channel for solar illumination tracking during hyperspectral acquisition and the use of other sensors for spatial and directional tracking to pinpoint view location. The system is mounted on a Pan-And-Tilt device, automatically controlled from the analyzer's on-board computer, making the HyperspecTM particularly adaptable for base security, border protection and remote deployments. A hyperspectral macro library has been developed to control hyperspectral image acquisition, system calibration and scene location control. The software allows the system to be operated in a fully automatic mode or under direct operator control through a GigE interface.

Space technology and the optical sciences.

PubMed

Yates, H W

1982-01-15

The earth-orbiting satellites and the deep-space probes have provided for the optical sciences platforms from which to study the earth, the solar system, and the universe with truly revolutionary capability. For the terrestrial sciences the orbiting platforms for optical measurements in both low and geostationary orbits have given us a view of our planet and a global coverage never before possible. For the astronomical applications of optical instruments that "cataract of the telescopic eye," the atmosphere of the earth has been left behind and through proximity, including actual contact, we now have resolution and spectral coverage limited only by money and motive.

Identification, definition and mapping of terrestrial ecosystems in interior Alaska

NASA Technical Reports Server (NTRS)

Anderson, J. H. (Principal Investigator)

1973-01-01

The author has identified the following significant results. The primary objective is to identify and analyze vegetation types in as great of detail as possible on ERTS-1 imagery and to classify and delineate them through mapping. This is basic to the identification, definition, and mapping of ecosystems. Major conclusions are: (1) the ERTS-1 system is useful for regional scale studies of broadly defined Alaskan vegetation types; (2) the resolution and spectral capabilities of ERTS-1 MSS imagery in photographic formats is adequate for certain phytecenologic purposes; and (3) preparation of an improved State vegetation map will be feasible.

High-contrast imaging with the JWST-NIRSpec Integral Field Unit

NASA Astrophysics Data System (ADS)

Ygouf, M.; Beichman, C.; Hodapp, K.; Roellig, T.

2017-12-01

With its integral field unit, the near-infrared spectrograph NIRSPEC on JWST will allow to measure high-resolution spectra into the 3-\\SI{5}μm range with an increased sensitivity over ground-based systems. This capability will considerably extend our knowledge of brown dwarfs and bright exoplanets at large separations from their host star. But because there is not any coronagraph on NIRSPEC, the performance in term of contrast at close separation will be extremely limited. In this communication, we explore possibilities to further push this limitation by exploiting the wavelength diversity offered by the spectral differential imaging strategy.

Measurements of the vertical profile of water vapor abundance in the Martian atmosphere from Mars Observer

NASA Technical Reports Server (NTRS)

Schofield, J. T.; Mccleese, Daniel J.

1988-01-01

An analysis is presented of the Pressure Modulator Infrared Radiometer (PMIRR) capabilities along with how the vertical profiles of water vapor will be obtained. The PMIRR will employ filter and pressure modulation radiometry using nine spectral channels, in both limb scanning and nadir sounding modes, to obtain daily, global maps of temperature, dust extinction, condensate extinction, and water vapor mixing ratio profiles as a function of pressure to half scale height or 5 km vertical resolution. Surface thermal properties will also be mapped, and the polar radiactive balance will be monitored.

The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII)

NASA Technical Reports Server (NTRS)

Rinehart, Stephen

2012-01-01

The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-meter baseline far-infrared interferometer to fly on a high altitude balloon. BETTII uses a double-Fourier Michelson interferometer to simultaneously obtain spatial and spectral information on science targets; the long baseline provides subarcsecond angular resolution, a capability unmatched by other far-infrared facilities. Here, we present key aspects of the overall design of the mission and provide an overview of the current status of the project. We also discuss briefly the implications of this experiment for future space-based far-infrared interferometers.

Navy Exploitation of SeaWiFS and MODIS Satellite Imagery for Detection of Desert Dust Storms Over Land and Water

NASA Astrophysics Data System (ADS)

Miller, S. D.

2002-12-01

The United States Navy gives serious consideration to the subject of dust detection. In a recent study of Naval aviation mishaps over the period 1990-1998 (Cantu, 2001), it was found that 70% were associated with visibility problems and accounted for annual equipment losses of nearly 50 million dollars. This figure does not include the tax dollars lost in jettisoned or off-target ordnance owing to obscured targets or failure of laser-guided systems in the presence of significant dust. Nor can it account for the loss of life during a subset of these mishaps. As such, a strong research emphasis has been placed on detecting and quantifying dust over data-sparse/denied parts of the world. The prolific and complex dust climatology of Southwest Asia has posed considerable challenges to Navy operations over the course of Operation Enduring Freedom. In an effort to support the ongoing needs of the Meteorology/Oceanography (METOC) officers afloat, the Satellite Applications Section of the Naval Research Laboratory (NRL) Marine Meteorology Division has developed a novel approach to enhancing significant dust events that appeals to high spatial and spectral resolution satellite data currently available from state of the art ocean/atmospheric radiometers. This paper summarizes progress made on daytime enhancements of desert dust storms over both land and ocean using multispectral imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS; aboard Earth Observing System Terra and Aqua platforms) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS; aboard the NASA/Orbimage SeaStar platform). The approach leverages the multi-spectral visible capability of these sensors to distinguish dust from clouds over water bodies, and the high spatial resolution required to refine the fine-scale structures that often accompany these events. The MODIS algorithm combines this information with that of several near-to-far infrared channels, taking advantage of unique spectral properties of dust found in these regimes, to extend the capability to detection of dust over land (bright backgrounds). An account for enhancement contamination in the presence of sun glint is also provided in these products. The SeaWiFS and MODIS telemetries are made available to NRL in near real-time, with product turn-around ranging from 3-6 hours from initial capture. An unprecedented intra-agency collaboration forged between NOAA, NASA (Goddard Space Flight Center), and the Department of Defense has resulted in the recent availability of a global Terra MODIS data stream, with the companion Aqua telemetry soon to follow. Preliminary METOC feedback regarding these products has been overwhelmingly positive, and provides the impetus for continued refinement. Examples of the current product's capabilities and limitations will be presented.

Depth resolved hyperspectral imaging spectrometer based on structured light illumination and Fourier transform interferometry

PubMed Central

Choi, Heejin; Wadduwage, Dushan; Matsudaira, Paul T.; So, Peter T.C.

2014-01-01

A depth resolved hyperspectral imaging spectrometer can provide depth resolved imaging both in the spatial and the spectral domain. Images acquired through a standard imaging Fourier transform spectrometer do not have the depth-resolution. By post processing the spectral cubes (x, y, λ) obtained through a Sagnac interferometer under uniform illumination and structured illumination, spectrally resolved images with depth resolution can be recovered using structured light illumination algorithms such as the HiLo method. The proposed scheme is validated with in vitro specimens including fluorescent solution and fluorescent beads with known spectra. The system is further demonstrated in quantifying spectra from 3D resolved features in biological specimens. The system has demonstrated depth resolution of 1.8 μm and spectral resolution of 7 nm respectively. PMID:25360367

SpS1-SOFIA studies of stellar evolution

NASA Astrophysics Data System (ADS)

Gehrz, R. D.; Becklin, E. E.; Roellig, T. L.

2010-11-01

The U.S./German Stratospheric Observatory for Infrared Astronomy (SOFIA, Figure 1) is a 2.5-meter infrared airborne telescope in a Boeing 747-SP flying in the stratosphere at altitudes as high as 45,000 feet where the atmospheric transmission averages ≥ 80% throughout the 0.3 - 1600 μm spectral region. SOFIA's first-generation instruments include broadband imagers, moderate resolution spectrographs capable of resolving broad features due to dust and large molecules, and high resolution spectrometers suitable for kinematic studies of molecular and atomic gas lines at km s-1 resolution. These and future instruments will enable SOFIA to make unique contributions to studies of the physics and chemistry of stellar evolution for many decades. Science flights will begin in 2010. A full operations schedule of at least 100 flights per year will begin in 2014 and will continue for 20 years. The SOFIA Guest Investigator (GI) program, open to investigators worldwide, will constitute the major portion of the SOFIA observing program.

PUCHEROS: a cost-effective solution for high-resolution spectroscopy with small telescopes

NASA Astrophysics Data System (ADS)

Vanzi, L.; Chacon, J.; Helminiak, K. G.; Baffico, M.; Rivinius, T.; Štefl, S.; Baade, D.; Avila, G.; Guirao, C.

2012-08-01

We present PUCHEROS, the high-resolution echelle spectrograph, developed at the Center of Astro-Engineering of Pontificia Universidad Catolica de Chile to provide an effective tool for research and teaching of astronomy. The instrument is fed by a single-channel optical fibre and it covers the visible range from 390 to 730 nm in one shot, reaching a spectral resolution of about 20 000. In the era of extremely large telescopes our instrument aims to exploit the capabilities offered by small telescopes in a cost-effective way, covering the observing needs of a community of astronomers, in Chile and elsewhere, which do not necessarily need large collecting areas for their research. In particular the instrument is well suited for long-term spectroscopic monitoring of bright variable and transient targets down to a V magnitude of about 10. We describe the instrument and present a number of text case examples of observations obtained during commissioning and early science.

Characterization of turbulent processes by the Raman lidar system BASIL during the HD(CP)2 observational prototype experiment - HOPE

NASA Astrophysics Data System (ADS)

Di Girolamo, Paolo; Summa, Donato; Stelitano, Dario; Cacciani, Marco; Scoccione, Andrea; Behrendt, Andreas; Wulfmeyer, Volker

2017-02-01

Measurements carried out by the Raman lidar system BASIL are reported to demonstrate the capability of this instrument to characterize turbulent processes within the Convective Boundary Layer (CBL). In order to resolve the vertical profiles of turbulent variables, high resolution water vapour and temperature measurements, with a temporal resolution of 10 sec and a vertical resolution of 90 and 30 m, respectively, are considered. Measurements of higher-order moments of the turbulent fluctuations of water vapour mixing ratio and temperature are obtained based on the application of spectral and auto-covariance analyses to the water vapour mixing ratio and temperature time series. The algorithms are applied to a case study (IOP 5, 20 April 2013) from the HD(CP)2 Observational Prototype Experiment (HOPE), held in Central Germany in the spring 2013. The noise errors are demonstrated to be small enough to allow the derivation of up to fourth-order moments for both water vapour mixing ratio and temperature fluctuations with sufficient accuracy.

Non-invasive measurement of frog skin reflectivity in high spatial resolution using a dual hyperspectral approach.

PubMed

Pinto, Francisco; Mielewczik, Michael; Liebisch, Frank; Walter, Achim; Greven, Hartmut; Rascher, Uwe

2013-01-01

Most spectral data for the amphibian integument are limited to the visible spectrum of light and have been collected using point measurements with low spatial resolution. In the present study a dual camera setup consisting of two push broom hyperspectral imaging systems was employed, which produces reflectance images between 400 and 2500 nm with high spectral and spatial resolution and a high dynamic range. We briefly introduce the system and document the high efficiency of this technique analyzing exemplarily the spectral reflectivity of the integument of three arboreal anuran species (Litoria caerulea, Agalychnis callidryas and Hyla arborea), all of which appear green to the human eye. The imaging setup generates a high number of spectral bands within seconds and allows non-invasive characterization of spectral characteristics with relatively high working distance. Despite the comparatively uniform coloration, spectral reflectivity between 700 and 1100 nm differed markedly among the species. In contrast to H. arborea, L. caerulea and A. callidryas showed reflection in this range. For all three species, reflectivity above 1100 nm is primarily defined by water absorption. Furthermore, the high resolution allowed examining even small structures such as fingers and toes, which in A. callidryas showed an increased reflectivity in the near infrared part of the spectrum. Hyperspectral imaging was found to be a very useful alternative technique combining the spectral resolution of spectrometric measurements with a higher spatial resolution. In addition, we used Digital Infrared/Red-Edge Photography as new simple method to roughly determine the near infrared reflectivity of frog specimens in field, where hyperspectral imaging is typically difficult.

Apertureless near-field optical microscopy

NASA Astrophysics Data System (ADS)

Kazantsev, D. V.; Kuznetsov, E. V.; Timofeev, S. V.; Shelaev, A. V.; Kazantseva, E. A.

2017-05-01

We discuss the operating principles of the apertureless scanning near-field optical microscope (ASNOM), in which the probe acts as a rod antenna and its electromagnetic radiation plays the role of the registered signal. The phase and amplitude of the emitted wave vary depending on the ‘grounding conditions’ of the antenna tip at the sample point under study. Weak radiation from a tiny (2-15 μm long) tip is detected using optical homo- and heterodyning and the nonlinear dependence of the tip polarizability on the tip-surface distance. The lateral resolution of ASNOMs is determined by the tip curvature radius (1- 20 nm), regardless of the wavelength (500 nm-100 μm). ASNOMs are shown to be capable of providing a surface optical map with nanometer resolution and carrying out spectral- and time-resolved measurements at a selected point on the surface.

McIDAS-V: A Data Analysis and Visualization Tool for Global Satellite Data

NASA Astrophysics Data System (ADS)

Achtor, T. H.; Rink, T. D.

2011-12-01

The Man-computer Interactive Data Access System (McIDAS-V) is a java-based, open-source, freely available system for scientists, researchers and algorithm developers working with atmospheric data. The McIDAS-V software tools provide powerful new data manipulation and visualization capabilities, including 4-dimensional displays, an abstract data model with integrated metadata, user defined computation, and a powerful scripting capability. As such, McIDAS-V is a valuable tool for scientists and researchers within the GEO and GOESS domains. The advancing polar and geostationary orbit environmental satellite missions conducted by several countries will carry advanced instrumentation and systems that will collect and distribute land, ocean, and atmosphere data. These systems provide atmospheric and sea surface temperatures, humidity sounding, cloud and aerosol properties, and numerous other environmental products. This presentation will display and demonstrate some of the capabilities of McIDAS-V to analyze and display high temporal and spectral resolution data using examples from international environmental satellites.

High-Resolution, Low-Cost Spectrometer-on-Chip

DTIC Science & Technology

2015-01-02

extracted for each PhCs for λ=400 and 500 nm, respectively; d) example of the spectral response of our prototype to two input filtered lights. aBeam...packed into the size of a USB key. Nano-spectrometers with a resolution down to 0.5 nm and a spectral range up to 229 nm were successfully demonstrated...Our miniaturized spectrometers are defining the state-of-the-art for on-chip spectroscopy, as well as in terms of spectral resolution and bandwidth

Information Content of Bistatic Lidar Observations of Aerosols from Space

NASA Technical Reports Server (NTRS)

Alexandrov, Mikhail D.; Mishchenko, Michael I.

2017-01-01

We present, for the first time, a quantitative retrieval error-propagation study for a bistatic high spectral resolution lidar (HSRL) system intended for detailed quasi-global monitoring of aerosol properties from space. Our results demonstrate that supplementing a conventional monostatic HSRL with an additional receiver flown in formation at a scattering angle close to 165 degrees dramatically increases the information content of the measurements and allows for a sufficiently accurate characterization of tropospheric aerosols. We conclude that a bistatic HSRL system would far exceed the capabilities of currently flown or planned orbital instruments in monitoring global aerosol effects on the environment and on the Earth's climate. We also demonstrate how the commonly used a priori 'regularization' methodology can artificially reduce the propagated uncertainties and can thereby be misleading as to the real retrieval capabilities of a measurement system.

UNMANNED AERIAL VEHICLE (UAV) HYPERSPECTRAL REMOTE SENSING FOR DRYLAND VEGETATION MONITORING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nancy F. Glenn; Jessica J. Mitchell; Matthew O. Anderson

2012-06-01

UAV-based hyperspectral remote sensing capabilities developed by the Idaho National Lab and Idaho State University, Boise Center Aerospace Lab, were recently tested via demonstration flights that explored the influence of altitude on geometric error, image mosaicking, and dryland vegetation classification. The test flights successfully acquired usable flightline data capable of supporting classifiable composite images. Unsupervised classification results support vegetation management objectives that rely on mapping shrub cover and distribution patterns. Overall, supervised classifications performed poorly despite spectral separability in the image-derived endmember pixels. Future mapping efforts that leverage ground reference data, ultra-high spatial resolution photos and time series analysis shouldmore » be able to effectively distinguish native grasses such as Sandberg bluegrass (Poa secunda), from invasives such as burr buttercup (Ranunculus testiculatus) and cheatgrass (Bromus tectorum).« less

Scanning lidar fluorosensor for remote diagnostic of surfaces

NASA Astrophysics Data System (ADS)

Caneve, Luisa; Colao, Francesco; Fantoni, Roberta; Fiorani, Luca

2013-08-01

Scanning hyperspectral systems based on laser induced fluorescence (LIF) have been developed and realized at the ENEA allowing to obtain information of analytical and qualitative interest on different materials by the study of the emission of fluorescence. This technique, for a surface analysis, is fast, remote, not invasive and specific. A new compact setup capable of fast 2D monochromatic images acquisition on up to 90 different spectral channels in the visible/UV range will be presented. It has been recently built with the aim to increase the performances in terms of space resolution, time resolved capabilities and data acquisition speed. Major achievements have been reached by a critical review of the optical design. The results recently obtained with in-situ measurements of interest for applications in the field of cultural heritage will be shown. 2001 Elsevier Science. All rights reserved

High Vertically Resolved Atmospheric and Surface/Cloud Parameters Retrieved with Infrared Atmospheric Sounding Interferometer (IASI)

NASA Technical Reports Server (NTRS)

Zhou, Daniel K.; Liu, Xu; Larar, Allen M.; Smith, WIlliam L.; Taylor, Jonathan P.; Schluessel, Peter; Strow, L. Larrabee; Mango, Stephen A.

2008-01-01

The Joint Airborne IASI Validation Experiment (JAIVEx) was conducted during April 2007 mainly for validation of the IASI on the MetOp satellite. IASI possesses an ultra-spectral resolution of 0.25/cm and a spectral coverage from 645 to 2760/cm. Ultra-spectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. An advanced retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. This physical inversion scheme has been developed, dealing with cloudy as well as cloud-free radiance observed with ultraspectral infrared sounders, to simultaneously retrieve surface, atmospheric thermodynamic, and cloud microphysical parameters. A fast radiative transfer model, which applies to the cloud-free and/or clouded atmosphere, is used for atmospheric profile and cloud parameter retrieval. A one-dimensional (1-d) variational multi-variable inversion solution is used to improve an iterative background state defined by an eigenvector-regression-retrieval. The solution is iterated in order to account for non-linearity in the 1-d variational solution. It is shown that relatively accurate temperature and moisture retrievals are achieved below optically thin clouds. For optically thick clouds, accurate temperature and moisture profiles down to cloud top level are obtained. For both optically thin and thick cloud situations, the cloud top height can be retrieved with relatively high accuracy (i.e., error < 1 km). Preliminary retrievals of atmospheric soundings, surface properties, and cloud optical/microphysical properties with the IASI observations are obtained and presented. These retrievals will be further inter-compared with those obtained from airborne FTS system, such as the NPOESS Airborne Sounder Testbed - Interferometer (NAST-I), dedicated dropsondes, radiosondes, and ground based Raman Lidar. The capabilities of satellite ultra-spectral sounder such as the IASI are investigated indicating a high vertical structure of atmosphere is retrieved.

Submillimeter Spectroscopic Study of Semiconductor Processing Plasmas

NASA Astrophysics Data System (ADS)

Helal, Yaser H.

Plasmas used for manufacturing processes of semiconductor devices are complex and challenging to characterize. The development and improvement of plasma processes and models rely on feedback from experimental measurements. Current diagnostic methods are not capable of measuring absolute densities of plasma species with high resolution without altering the plasma, or without input from other measurements. At pressures below 100 mTorr, spectroscopic measurements of rotational transitions in the submillimeter/terahertz (SMM) spectral region are narrow enough in relation to the sparsity of spectral lines that absolute specificity of measurement is possible. The frequency resolution of SMM sources is such that spectral absorption features can be fully resolved. Processing plasmas are a similar pressure and temperature to the environment used to study astrophysical species in the SMM spectral region. Many of the molecular neutrals, radicals, and ions present in processing plasmas have been studied in the laboratory and their absorption spectra have been cataloged or are in the literature for the purpose of astrophysical study. Recent developments in SMM devices have made its technology commercially available for applications outside of specialized laboratories. The methods developed over several decades in the SMM spectral region for these laboratory studies are directly applicable for diagnostic measurements in the semiconductor manufacturing industry. In this work, a continuous wave, intensity calibrated SMM absorption spectrometer was developed as a remote sensor of gas and plasma species. A major advantage of intensity calibrated rotational absorption spectroscopy is its ability to determine absolute concentrations and temperatures of plasma species from first principles without altering the plasma environment. An important part of this work was the design of the optical components which couple 500 - 750 GHz radiation through a commercial inductively coupled plasma chamber. The measurement of transmission spectra was simultaneously fit for background and absorption signal. The measured absorption signal was used to calculate absolute densities and temperatures of polar species. Measurements of molecular species were demonstrated for inductively coupled plasmas.

Cross-calibration of Medium Resolution Earth Observing Satellites by Using EO-1 Hyperion-derived Spectral Surface Reflectance from "Lunar Cal Sites"

NASA Astrophysics Data System (ADS)

Ungar, S.

2017-12-01

Over the past 3 years, the Earth Observing-one (EO-1) Hyperion imaging spectrometer was used to slowly scan the lunar surface at a rate which results in up to 32X oversampling to effectively increase the SNR. Several strategies, including comparison against the USGS RObotic Lunar Observatory (ROLO) mode,l are being employed to estimate the absolute and relative accuracy of the measurement set. There is an existing need to resolve discrepancies as high as 10% between ROLO and solar based calibration of current NASA EOS assets. Although the EO-1 mission was decommissioned at the end of March 2017, the development of a well-characterized exoatmospheric spectral radiometric database, for a range of lunar phase angles surrounding the fully illuminated moon, continues. Initial studies include a comprehensive analysis of the existing 17-year collection of more than 200 monthly lunar acquisitions. Specific lunar surface areas, such as a lunar mare, are being characterized as potential "lunar calibration sites" in terms of their radiometric stability in the presence of lunar nutation and libration. Site specific Hyperion-derived lunar spectral reflectance are being compared against spectrographic measurements made during the Apollo program. Techniques developed through this activity can be employed by future high-quality orbiting imaging spectrometers (such as HyspIRI and EnMap) to further refine calibration accuracies. These techniques will enable the consistent cross calibration of existing and future earth observing systems (spectral and multi-spectral) including those that do not have lunar viewing capability. When direct lunar viewing is not an option for an earth observing asset, orbiting imaging spectrometers can serve as transfer radiometers relating that asset's sensor response to lunar values through near contemporaneous observations of well characterized stable CEOS test sites. Analysis of this dataset will lead to the development of strategies to ensure more accurate cross calibrations when employing the more capable, future imaging spectrometers.

Navy Calibration/Validation Protocols and Procedures for Visible and Thermal Satellites: Preparing for NPOESS

DTIC Science & Technology

2007-05-01

difficult but it determines the long-term stability of the sensor. This step includes sensor drift ( spectral response) and spectral (channel...and Navy products using high spectral resolution satellites. This program (Hyperspectral 34 Characterization of the Coastal Zone) is a core NRLSSC...absorption and total attenuation) the standard accepted instrument is the WetLab’s Inc., ac-9, with a higher resolution spectral instrument in final

Global-scale surface spectral variations on Titan seen from Cassini/VIMS

USGS Publications Warehouse

Barnes, J.W.; Brown, R.H.; Soderblom, L.; Buratti, B.J.; Sotin, Christophe; Rodriguez, S.; Le, Mouelic S.; Baines, K.H.; Clark, R.; Nicholson, P.

2007-01-01

We present global-scale maps of Titan from the Visual and Infrared Mapping Spectrometer (VIMS) instrument on Cassini. We map at 64 near-infrared wavelengths simultaneously, covering the atmospheric windows at 0.94, 1.08, 1.28, 1.6, 2.0, 2.8, and 5 ??m with a typical resolution of 50 km/pixel or a typical total integration time of 1 s. Our maps have five to ten times the resolution of ground-based maps, better spectral resolution across most windows, coverage in multiple atmospheric windows, and represent the first spatially resolved maps of Titan at 5 ??m. The VIMS maps provide context and surface spectral information in support of other Cassini instruments. We note a strong latitudinal dependence in the spectral character of Titan's surface, and partition the surface into 9 spectral units that we describe in terms of spectral and spatial characteristics. ?? 2006 Elsevier Inc. All rights reserved.

Laboratory measurements of upwelled radiance and reflectance spectra of Calvert, Ball, Jordan, and Feldspar soil sediments

NASA Technical Reports Server (NTRS)

Whitlock, C. H.; Usry, J. W.; Witte, W. G.; Gurganus, E. A.

1977-01-01

An effort to investigate the potential of remote sensing for monitoring nonpoint source pollution was conducted. Spectral reflectance characteristics for four types of soil sediments were measured for mixture concentrations between 4 and 173 ppm. For measurements at a spectral resolution of 32 mm, the spectral reflectances of Calvert, Ball, Jordan, and Feldspar soil sediments were distinctly different over the wavelength range from 400 to 980 nm at each concentration tested. At high concentrations, spectral differences between the various sediments could be detected by measurements with a spectral resolution of 160 nm. At a low concentration, only small differences were observed between the various sediments when measurements were made with 160 nm spectral resolution. Radiance levels generally varied in a nonlinear manner with sediment concentration; linearity occurred in special cases, depending on sediment type, concentration range, and wavelength.

Spectrotemporal modulation sensitivity for hearing-impaired listeners: dependence on carrier center frequency and the relationship to speech intelligibility.

PubMed

Mehraei, Golbarg; Gallun, Frederick J; Leek, Marjorie R; Bernstein, Joshua G W

2014-07-01

Poor speech understanding in noise by hearing-impaired (HI) listeners is only partly explained by elevated audiometric thresholds. Suprathreshold-processing impairments such as reduced temporal or spectral resolution or temporal fine-structure (TFS) processing ability might also contribute. Although speech contains dynamic combinations of temporal and spectral modulation and TFS content, these capabilities are often treated separately. Modulation-depth detection thresholds for spectrotemporal modulation (STM) applied to octave-band noise were measured for normal-hearing and HI listeners as a function of temporal modulation rate (4-32 Hz), spectral ripple density [0.5-4 cycles/octave (c/o)] and carrier center frequency (500-4000 Hz). STM sensitivity was worse than normal for HI listeners only for a low-frequency carrier (1000 Hz) at low temporal modulation rates (4-12 Hz) and a spectral ripple density of 2 c/o, and for a high-frequency carrier (4000 Hz) at a high spectral ripple density (4 c/o). STM sensitivity for the 4-Hz, 4-c/o condition for a 4000-Hz carrier and for the 4-Hz, 2-c/o condition for a 1000-Hz carrier were correlated with speech-recognition performance in noise after partialling out the audiogram-based speech-intelligibility index. Poor speech-reception and STM-detection performance for HI listeners may be related to a combination of reduced frequency selectivity and a TFS-processing deficit limiting the ability to track spectral-peak movements.

Stratospheric Observatory for Infrared Astronomy (SOFIA): Infrared Sensor Development and Science Capabilities

NASA Astrophysics Data System (ADS)

Nelson, J.; Ruzek, M.

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a unique airborne observatory designed to operate in the lower stratosphere to altitudes as high as 45,000 feet and above 99.8 percent of Earths obscuring atmospheric water vapor. SOFIA's capabilities enable science and observations that will complement and extend past, present and future infrared (IR) telescopes in wavelength range, angular and spectral resolution, and observing flexibility. The joint U.S. and German SOFIA project to develop and operate a 2.5-meter infrared airborne telescope in a Boeing 747-SP is nearing readiness for for open door flights and demonstration of early science results. Flying in the stratosphere, SOFIA allows observations throughout the infrared and submillimeter region. The SOFIA instrument complement includes broadband imagers, moderate resolution spectrographs capable of resolving broad features due to dust and large molecules, and high resolution spectrometers suitable for kinematic studies of molecular and atomic gas lines at high resolution. First science flights will begin in early 2010. A great strength of SOFIA is the enormous breadth of its capabilities and the flexibility with which those capabilities can be modified and improved to take advantage of advances in infrared technology. This paper and presentation will highlight the following points: A 2.5-meter effective-diameter optical-quality telescope for diffraction-limited imaging beyond 25 micrometers, giving the sharpest view of the sky provided by any current or developmental IR telescope operating in the 30-60 micrometers region; Wavelength coverage from 0.3 micrometers to 1.6 mm and high resolution spectroscopy (R to 105) at wavelengths between 5 and 150 micrometers; An 8 arcmin FOV allowing use of very large detector arrays; Ready observer access to science instruments which can be serviced in flight and changed between flights; A low-risk ability to incorporate new science-enabling instrument technologies and to create a whole "new" observatory several times during the lifetime of the facility; Opportunity for continuous training of instrumentalists to develop and test the next generation of instrumentation for both suborbital and space applications; Mobility, which allows access to the entire sky and a vastly increased number of stellar occultation events; Unique opportunities for educators and journalists to participate first-hand in exciting astronomical observations. The mid- and far-IR wavelength regions are key to studying the dusty universe. SOFIA science emphasizes four major themes: Star and planet formation; the interstellar medium of the Milky Way; Galaxies and the galactic center; and Planetary science. These capabilities will enable a wide range of science investigations over SOFIA's 20-year operational lifetime. This paper will address SOFIA's nine first-light science instruments, capabilities, and development.

Micromega/IR: Design and status of a near-infrared spectral microscope for in situ analysis of Mars samples

NASA Astrophysics Data System (ADS)

Leroi, Vaitua; Bibring, Jean-Pierre; Berthe, Michel

2009-07-01

MicrOmega is an ultra miniaturized spectral microscope for in situ analysis of samples. It is composed of 2 microscopes; one with a spatial sampling less or equal to 4 μm, working in 4 colors in the visible range: MicrOmega/VIS, and a NIR hyperspectral microscope working in the spectral range 0.9-4 μm with a spatial sampling of 20 μm per pixel: MicrOmega/IR (described in this paper). MicrOmega/IR illuminates and images samples a few mm in size and acquires the NIR spectrum of each resolved pixel in up to 320 contiguous spectral channels. The goal of this instrument is to analyze in situ the composition of collected samples at almost their grain size scale, in a non-destructive way. With the chosen spectral range and resolution, a wide variety of constituents can be identified: minerals, such as pyroxene and olivine, ferric oxides, hydrated phyllosilicates, sulfates and carbonates and ices and organics. The composition of the various phases within a given sample is a critical record of its formation and evolution. Coupled to the mapping information, it provides unique clues to describe the history of the parent body (planet, satellite and small body). In particular, the capability to identify hydrated grains and to characterize their adjacent phases has a huge potential in the search for possible bio-relics.

Calibration of the ROSAT HRI Spectral Response

NASA Technical Reports Server (NTRS)

Prestwich, Andrea

1998-01-01

The ROSAT High Resolution Imager has a limited (2-band) spectral response. This spectral capability can give X-ray hardness ratios on spatial scales of 5 arcseconds. The spectral response of the center of the detector was calibrated before the launch of ROSAT, but the gain decreases-with time and also is a function of position on the detector. To complicate matters further, the satellite is "wobbled", possibly moving a source across several spatial gain states. These difficulties have prevented the spectral response of the ROSAT HRI from being used for scientific measurements. We have used Bright Earth data and in-flight calibration sources to map the spatial and temporal gain changes, and written software which will allow ROSAT users to generate a calibrated XSPEC response matrix and hence determine a calibrated hardness ratio. In this report, we describe the calibration procedure and show how to obtain a response matrix. In Section 2 we give an overview of the calibration procedure, in Section 3 we give a summary of HRI spatial and temporal gain variations. Section 4 describes the routines used to determine the gain distribution of a source. In Sections 5 and 6, we describe in detail how the Bright Earth database and calibration sources are used to derive a corrected response matrix for a given observation. Finally, Section 7 describes how to use the software.

Building a laboratory foundation for interpreting spectral emission from x-ray binary and black hole accretion disks

NASA Astrophysics Data System (ADS)

Loisel, Guillaume

2016-10-01

Emission from accretion powered objects accounts for a large fraction of all photons in the universe and is a powerful diagnostic for their behavior and structure. Quantitative interpretation of spectrum emission from these objects requires a spectral synthesis model for photoionized plasma, since the ionizing luminosity is so large that photon driven atomic processes dominate over collisions. This is a quandary because laboratory experiments capable of testing the spectral emission models are non-existent. The models must predict the photoionized charge state distribution, the photon emission processes, and the radiation transport influence on the observed emission. We have used a decade of research at the Z facility to achieve the first simultaneous measurements of emission and absorption from photoionized plasmas. The extraordinary spectra are reproducible to within +/-2% and the E/dE 500 spectral resolution has enabled unprecedented tests of atomic structure calculations. The absorption spectra enable determination of plasma density, temperature, and charge state distribution. The emission spectra then enable tests of spectral emission models. The emission has been measured from plasmas with varying size to elucidate the radiation transport effects. This combination of measurements will provide strong constraints on models used in astrophysics. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.

Insight into resolution enhancement in generalized two-dimensional correlation spectroscopy.

PubMed

Ma, Lu; Sikirzhytski, Vitali; Hong, Zhenmin; Lednev, Igor K; Asher, Sanford A

2013-03-01

Generalized two-dimensional correlation spectroscopy (2D-COS) can be used to enhance spectral resolution in order to help differentiate highly overlapped spectral bands. Despite the numerous extensive 2D-COS investigations, the origin of the 2D spectral resolution enhancement mechanism(s) is not completely understood. In the work here, we studied the 2D-COS of simulated spectra in order to develop new insights into the dependence of 2D-COS spectral features on the overlapping band separations, their intensities and bandwidths, and their band intensity change rates. We found that the features in the 2D-COS maps that are derived from overlapping bands were determined by the spectral normalized half-intensities and the total intensity changes of the correlated bands. We identified the conditions required to resolve overlapping bands. In particular, 2D-COS peak resolution requires that the normalized half-intensities of a correlating band have amplitudes between the maxima and minima of the normalized half-intensities of the overlapping bands.

Insight into Resolution Enhancement in Generalized Two-Dimensional Correlation Spectroscopy

PubMed Central

Ma, Lu; Sikirzhytski, Vitali; Hong, Zhenmin; Lednev, Igor K.; Asher, Sanford A.

2014-01-01

Generalized two-dimensional correlation spectroscopy (2D COS) can be used to enhance spectral resolution in order to help differentiate highly overlapped spectral bands. Despite the numerous extensive 2D COS investigations, the origin of the 2D spectral resolution enhancement mechanism(s) are not completely understood. In the work here we studied the 2D COS of simulated spectra in order to develop new insights into the dependence of the 2D COS spectral features on the overlapping band separations, their intensities and bandwidths, and their band intensity change rates. We find that the features in the 2D COS maps that derive from overlapping bands are determined by the spectral normalized half-intensities and the total intensity changes of the correlated bands. We identify the conditions required to resolve overlapping bands. In particular, 2D COS peak resolution requires that the normalized half-intensities of a correlating band have amplitudes between the maxima and minima of the normalized half-intensities of the overlapping bands. PMID:23452492

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

NASA Astrophysics Data System (ADS)

McFarlane, S. A.; Gaustad, K. L.; Mlawer, E. J.; Long, C. N.; Delamere, J.

2011-09-01

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.

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

NASA Astrophysics Data System (ADS)

McFarlane, S. A.; Gaustad, K. L.; Mlawer, E. J.; Long, C. N.; Delamere, J.

2011-05-01

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.

Modified tandem gratings anastigmatic imaging spectrometer with oblique incidence for spectral broadband

NASA Astrophysics Data System (ADS)

Cui, Chengguang; Wang, Shurong; Huang, Yu; Xue, Qingsheng; Li, Bo; Yu, Lei

2015-09-01

A modified spectrometer with tandem gratings that exhibits high spectral resolution and imaging quality for solar observation, monitoring, and understanding of coastal ocean processes is presented in this study. Spectral broadband anastigmatic imaging condition, spectral resolution, and initial optical structure are obtained based on geometric aberration theory. Compared with conventional tandem gratings spectrometers, this modified design permits flexibility in selecting gratings. A detailed discussion of the optical design and optical performance of an ultraviolet spectrometer with tandem gratings is also included to explain the advantage of oblique incidence for spectral broadband.