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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,189 records · Page 66
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

Analysis of He I 1083 nm Imaging Spectroscopy Using a Spectral Standard

We develop a technique. for the analysis of He I 1083 nanometer spectra which addresses several difficulties through determination of a continuum background by comparison with a well calibrated standard and through removal of nearby solar and telluric blends by differential comparison to an average spectrum. The method is compared with earlier analysis of imaging spectroscopy obtained at the National Solar Observatory/Kitt Peak Vacuum Telescope (NSO/KPVT) with the NASA/NSO Spectromagnetograph (SPM). We examine distributions of Doppler velocity and line width as a function of central intensity for an active region, filament, quiet Sun, and coronal hole. For our example, we find that line widths and central intensity are oppositely correlated in a coronal hole and quiet Sun. Line widths are comparable to the quiet sun in the active region, are systematically lower in the filament, and extend to higher values in the coronal hole. Outward velocities of approximately equal to 2 to 4 kilometers per second are typically observed in the coronal hole. The sensitivity of these results to analysis technique is discussed.

Malanushenko, Elena V.↗
NASA NTRS1994

Theory, Image Simulation, and Data Analysis of Chemical Release Experiments

The final phase of Grant NAG6-1 involved analysis of physics of chemical releases in the upper atmosphere and analysis of data obtained on previous NASA sponsored chemical release rocket experiments. Several lines of investigation of past chemical release experiments and computer simulations have been proceeding in parallel. This report summarizes the work performed and the resulting publications. The following topics are addressed: analysis of the 1987 Greenland rocket experiments; calculation of emission rates for barium, strontium, and calcium; the CRIT 1 and 2 experiments (Collisional Ionization Cross Section experiments); image calibration using background stars; rapid ray motions in ionospheric plasma clouds; and the NOONCUSP rocket experiments.

Wescott, Eugene M.↗
NASA NTRS1989

Reduction and analysis techniques for infrared imaging data

Infrared detector arrays are becoming increasingly available to the astronomy community, with a number of array cameras already in use at national observatories, and others under development at many institutions. As the detector technology and imaging instruments grow more sophisticated, more attention is focussed on the business of turning raw data into scientifically significant information. Turning pictures into papers, or equivalently, astronomy into astrophysics, both accurately and efficiently, is discussed. Also discussed are some of the factors that can be considered at each of three major stages; acquisition, reduction, and analysis, concentrating in particular on several of the questions most relevant to the techniques currently applied to near infrared imaging.

Mccaughrean, Mark↗
NASA NTRS1992

Formulation and error analysis for a generalized image point correspondence algorithm

A Generalized Image Point Correspondence (GIPC) algorithm, which enables the determination of 3-D motion parameters of an object in a configuration where both the object and the camera are moving, is discussed. A detailed error analysis of this algorithm has been carried out. Furthermore, the algorithm was tested on both simulated and video-acquired data, and its accuracy was determined.

Shapiro, Linda↗
DOE OSTI2026

Imaging Three-Dimensional Molecular Structure and Dynamics with Multiparticle Covariance and Cumulant Coulomb Explosion Analysis

Coulomb explosion imaging (CEI) provides a direct means of imaging molecular geometry by correlating fragment ion momenta following the fragmentation of a molecular polycation. Here, we demonstrate the use of three-body covariance and four-body cumulant analysis to extract three-dimensional (3D) structural information from the X-ray-induced Coulomb explosion of tert-butyl iodide (C4H9I). Site-selective ionization at the iodine 4d edge with intense femtosecond soft X-ray pulses from an X-ray free-electron laser (XFEL) enables rapid charge buildup and molecular breakup. By correlating ionic fragments in the molecular frame, we isolate complete dissociation channels and reveal subtle structural changes, such as umbrella-type motion of the branched alkyl chain, during the ionization process. Comparison with point-charge simulations of the Coulomb explosion shows close agreement, validating the approach. Furthermore, these results establish covariance/cumulant mapping as a powerful strategy for imaging complex three-dimensional molecular structures and point the way toward time-resolved CEI using both XFEL and tabletop sources for capturing ultrafast structural dynamics.

Imaging↗
NASA NTRS1973

Design and analysis of a star image motion compensator

The feasibility of designing and fabricating a small optical system to compensate for motions of a stellar field image on the focal plane of a large orbiting telescope is examined for a single-axis system. An all-reflecting two-mirror star image motion compensator maintains both a flat focal plane and image focus for one or more star images. Both theoretical and experimental evaluations show that only one adjustment is needed to aline the system since the change in focus is linearly related to the misalinements of all critical components. Results of an error analysis show that the focus error resulting from fabrication tolerances is very small compared to the adjustment capability of the system.

Romanczyk, K. C.↗
DOE OSTI2023

EDS-PhaSe: Phase Segmentation and Analysis from EDS Elemental Map Images Using Markers of Elemental Segregation

Scanning electron microscopy (SEM), combined with energy-dispersive spectroscopy (EDS), is an extensively used technique for in-depth microstructural analysis. Here, we present the EDS-Phase Segmentation (EDS-PhaSe) tool that enables phase segmentation and phase analysis using the EDS elemental map images. Importantly, it converts the EDS map images into estimated composition maps for calculating markers of selective elemental redistribution in the scanned area and creates a phase-segmented micrograph while providing approximate fraction and composition of each identified phase. EDS-PhaSe offers two unique advantages. Firstly, it enables the direct processing of EDS elemental map images without requiring any raw or proprietary data/software, thereby allowing the analysis of EDS results available in the published literature as images. Secondly, it enables segmentation and analysis of phases even when the phase contrast is missing in backscattered micrographs, assisting in correlating the XRD and SEM-EDS data as shown in this work for a AlCoCrFeNi high-entropy alloy.

36 MATERIALS SCIENCE↗
NASA NTRS1984

Preliminary evaluation of the airborne imaging spectrometer for vegetation analysis

The primary goal of the project was to provide ground truth and manual interpretation of data from an experimental flight of the Airborne Infrared Spectrometer (AIS) for a naturally vegetated test site. Two field visits were made; one trip to note snow conditions and temporally related vegetation states at the time of the sensor overpass, and a second trip following acquisition of prints of the AIS images for field interpretation. Unfortunately, the ability to interpret the imagery was limited by the quality of the imagery due to the experimental nature of the sensor.

Strahler, A. H.↗
NASA NTRS1977

Numerical image manipulation and display in solar astronomy

The paper describes the system configuration and data manipulation capabilities of a solar image display system which allows interactive analysis of visual images and on-line manipulation of digital data. Image processing features include smoothing or filtering of images stored in the display, contrast enhancement, and blinking or flickering images. A computer with a core memory of 28,672 words provides the capacity to perform complex calculations based on stored images, including computing histograms, selecting subsets of images for further analysis, combining portions of images to produce images with physical meaning, and constructing mathematical models of features in an image. Some of the processing modes are illustrated by some image sequences from solar observations.

Levine, R. H.↗
NASA NTRS1981

1979J3 - Discovery of a previously unknown satellite of Jupiter

During a detailed search of Voyager 1 frames for additional observations of the satellite 1979J1, two small dark spots were observed in transit in several consecutive wide-angle frames of the Jovian atmosphere. The size, spacing, and motion of these pairs of dark spots indicated that they were the images of 1979J1 and its shadow. Subsequent analysis of images spanning 6 days, however, proved that the satellite observed in these Voyager 1 frames would have been occulted by Jupiter at the times of the Voyager 2 images of 1979J1 and was, therefore, a new satellite. It was subsequently found in transit on Voyager 2 images within 13 deg of the Voyager 1 prediction. Its period is 7 hrs 4 min 30 sec + or - 3 sec, and its mean distance is 1.793 Jupiter radii (Jupiter radius = 71,400 km). The observable profile appears to be roughly circular with a diameter of 40 km, and the albedo is approximately 0.05, similar to Amalthea's.

Synnott, S. P.↗
NASA NTRS1995

Calibration to surface reflectance of terrestrial imaging spectrometry data: Comparison of methods

Many algorithms for spectral analysis of imaging spectroscopy data of the Earth's surface require that the data be calibrated to surface reflectance. Calibration requires removing instrumental response, solar irradiance, atmospheric transmittance, and atmospheric scattering from the radiance detected at the sensor. Depending on the amount of support data, this can be a formidable task. This paper examines four methods of calibration: (1) a radiative transfer model from the University of Colorado (ATREM: Gao and Goetz, 1990; Gao et al., 1992), (2) a MODTRAN-based method developed at the Jet Propulsion Lab by Green et al., (1191), (3) a ground calibration using known sites as standards, and (4) a combined approach using radiative transfer methods and ground calibration. Data from the Airborne Visual and Infra-Red Imaging Spectrometer (AVIRIS) instrument were evaluated from data sets obtained over multiple years and multiple sites.

Clark, Roger N.↗
NASA NTRS2005

Aerial Vehicle Surveys of other Planetary Atmospheres and Surfaces: Imaging, Remote-sensing, and Autonomy Technology Requirements

The objective of this paper is to review the anticipated imaging and remote-sensing technology requirements for aerial vehicle survey missions to other planetary bodies in our Solar system that can support in-atmosphere flight. In the not too distant future such planetary aerial vehicle (a.k.a. aerial explorers) exploration missions will become feasible. Imaging and remote-sensing observations will be a key objective for these missions. Accordingly, it is imperative that optimal solutions in terms of imaging acquisition and real-time autonomous analysis of image data sets be developed for such vehicles.

Young, Larry A.↗
NASA NTRS1993

Spectral Analysis of an AVIRIS Image of San Pedro Channel

Optical case-2 waters near an ocean outfall were examined, using a combination fo AVIRIS imagery and ship-based surface and profile bio-optical measurements. Bio-optical mooring data were useful in determining the hydrodynamics of the area.

San Pedro Channel Spectral Analysis↗
NASA NTRS1985

Quantitative analysis of geomorphic processes using satellite image data at different scales

When aerial and satellite photographs and images are used in the quantitative analysis of geomorphic processes, either through direct observation of active processes or by analysis of landforms resulting from inferred active or dormant processes, a number of limitations in the use of such data must be considered. Active geomorphic processes work at different scales and rates. Therefore, the capability of imaging an active or dormant process depends primarily on the scale of the process and the spatial-resolution characteristic of the imaging system. Scale is an important factor in recording continuous and discontinuous active geomorphic processes, because what is not recorded will not be considered or even suspected in the analysis of orbital images. If the geomorphic process of landform change caused by the process is less than 200 m in x to y dimension, then it will not be recorded. Although the scale factor is critical, in the recording of discontinuous active geomorphic processes, the repeat interval of orbital-image acquisition of a planetary surface also is a consideration in order to capture a recurring short-lived geomorphic process or to record changes caused by either a continuous or a discontinuous geomorphic process.

Williams, R. S., Jr.↗
DOE OSTI2024

Stereo-DIC Challenge 1.0 – Rigid Body Motion of a Complex Shape

Background Stereo-DIC is a widely used optical measurement technique that provides a dense full-field 3D measurement of the shape, displacement, and strain of a solid sample. When compared with 2D-DIC, Stereo-DIC provides greater flexibility and expands its use beyond flat, planar specimens. Furthermore, the widespread availability of commercial systems has led to the adoption of the technique throughout industry, academia, and government research labs. Objective Even though some research has been done to understand the effects of different experimental and stereo-DIC parameters, no reference is available to benchmark and compare the performance of current stereo-DIC algorithms to each other. Methods This paper provides the description and analysis of a carefully controlled 3D experiment and associated images used to compare the results from five subset based DIC software packages. Both the images and analysis codes used in this paper to compare the results are described here and are available for download and use for continued research. Results We show that over a very large range of motion, the 3D errors are very small, less than 80μm over a travel of ±20 mm out-of-plane and ±20 mm in-plane. While all codes performed similarly, there are important differences noted in the paper. Conclusion The image sets and results comparison software are hosted by the International DIC Society (www.iDICs.org) and are freely available for download and analysis for comparison with results in this paper. Furthermore, it is hoped that this set of images can be used for future research in improving stereo-DIC by future authors.

Algorithms comparison↗
NASA NTRS1989

The reduction of wide field/planetary camera images

An overview of the procedures required for reduction of Hubble Space Telescope Wide Field/Planetary Camera images is presented, based on WFPC performance as observed during ground tests. Camera artifacts that must be removed prior to analysis of WFPC images are characterized. WFPC flat-field and dark-current images are also presented. Special emphasis is given to the design of WFPC imaging programs that minimize the effects of camera artifacts on image analysis.

Lauer, Tod R.↗
DOE OSTI2024

Destructive Examination Protocol for 3013-Container-Package Storing Plutonium-Bearing Materials

The 3013-container-package consists of a convenience, inner and outer container and is used for long-term storage of plutonium-bearing materials. A destructive examination (DE) protocol has been developed to examine the container package visually and with microscopic aid to find any corrosion conditions that could result in the loss of the integrity of the container package over its lifetime. The DE protocol contains three main steps: initial container examination, helium (He) leak testing, and detailed imaging and analysis of the inner container closure weld region (ICCWR). The ICCWR has been determined to be bounding, defined as exhibiting worst case conditions for stress corrosion cracking (SCC) of the inner container. To assess SCC in the ICCWR, the inner container lid is cut into quarters and the weld and He-leak testing gasket are removed. Then a citric acid wash is performed to remove adherent chlorides from the ICCWR. The wash is then sent for analysis to determine the concentration of chlorides in the ICCWR. While the analysis for chloride concentration is being performed, the quarter sections are further sectioned into 1/8th subsections by cutting each section in half. These subsections are washed using nitric acid to remove corrosion products. Then each subsection is imaged using a Wide Angle 3-D Measurement System (WAMS). After analysis of microscope images for potential SCC, additional imaging can be performed, including subsurface imaging. After review, a determination is made of whether the container integrity may potentially affect the safe storage of the material.

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