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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Incorporating the effects of objects in an approximate model of light transport in scattering media

A computationally efficient radiative transport model is presented that predicts a camera measurement and accounts for the light reflected and blocked by an object in a scattering medium. The model is in good agreement with experimental data acquired at the Sandia National Laboratory Fog Chamber Facility (SNLFC). The model is applicable in computational imaging to detect, localize, and image objects hidden in scattering media. Here, a statistical approach was implemented to study object detection limits in fog.

42 ENGINEERING↗
DOE OSTI2020

The road to atomically thin metasurface optics

Abstract The development of flat optics has taken the world by storm. The initial mission was to try and replace conventional optical elements by thinner, lightweight equivalents. However, while developing this technology and learning about its strengths and limitations, researchers have identified a myriad of exciting new opportunities. It is therefore a great moment to explore where flat optics can really make a difference and what materials and building blocks are needed to make further progress. Building on its strengths, flat optics is bound to impact computational imaging, active wavefront manipulation, ultrafast spatiotemporal control of light, quantum communications, thermal emission management, novel display technologies, and sensing. In parallel with the development of flat optics, we have witnessed an incredible progress in the large-area synthesis and physical understanding of atomically thin, two-dimensional (2D) quantum materials. Given that these materials bring a wealth of unique physical properties and feature the same dimensionality as planar optical elements, they appear to have exactly what it takes to develop the next generation of high-performance flat optics.

Brongersma, Mark L.↗
DOE OSTI2025

AI-Driven Accelerated Inclusion Analysis for Energy Efficient Steelmaking (Final CRADA Report)

This was a collaborative effort between Lawrence Livermore National Security, LLC (LLNS) as manager and operator of Lawrence Livermore National Laboratory (LLNL) and ArcelorMittal USA Research LLC (“ArcelorMittal” as the Participant), to use scanning electron microscopy (SEM) images, computer vision and machine learning methods, and high-performance computing to accelerate the inclusion analysis process of liquid steel so that new methods can be used for near-real time process control on the shop floor.

36 MATERIALS SCIENCE↗
NASA NTRS1977

Improved scene generator capability

Components of an integrated system having all functions for model preparation and generation, image computation and scene generation, and collision detection and reporting for the visual simulation of space shuttle maneuvers and its interaction with the manipular arm and other objects, as well as during earth landing exercises are described. High surface solution by range priority allows for correct views of dynamically moving objects from any viewpoint. Smooth shading, anti-aliasing and edge smoothing techniques provide a high quality picture. The collision detection system allows for simulation of impenetrable objects and docking maneuvers, and the modeling systems permit production of new data bases for desired simulations.

Source record↗
NASA NTRS1977

Spontaneous emission from ScF in a supersonic mixing flame

An investigation was conducted of the two reactions: Sc + F2 yields ScF(asterisk) + F and Y + Cl2 yields YCl(asterisk) + Cl. Experiments were designed for studying the reactions under the relatively high pressure conditions (5-20 torr) appropriate for chemical laser operation. A shock tube was used to provide a short duration flow through a supersonic nozzle array. Shock wave heating is used to dissociate the ScCl3 or YCl3 at temperatures of about 6000 K, before the gases are accelerated and expanded through the supersonic nozzle array. The expanded primary flow is then mixed with a secondary flow of F2 introduced through slots at the trailing edge of each nozzle blade. Graphs show the temporal behavior of the visible spontaneous emission over the range from 3000 to 9000 A for a typical test condition, a microdensitometer tracing of the visible emission over the range from 4000 to 7000 A, and the spontaneous emission from ScF(asterisk) obtained by computer image processing of intensity data.

Fischell, D. R.↗
NASA NTRS1981

Reindeer ranges inventory in western Alaska

The use of LANDSAT data as a tool for reindeer range inventory on the tundra of northwestern Alaska is addressed. The specific goal is to map the range resource and estimate plant productivity of the Seward Peninsula. Information derived from these surveys is needed to develop range management plans for reindeer herding and to evaluate potential conflicting use between reindeer and caribou. The development of computer image classification techniques is discussed.

George, T. H.↗
NASA NTRS1983

Research and analysis of head-directed area-of-interest visual system concepts

An analysis and survey with conjecture supporting a preliminary data base design is presented. The data base is intended for use in a Computer Image Generator visual subsystem for a rotorcraft flight simulator that is used for rotorcraft systems development, not training. The approach taken was to attempt to identify the visual perception strategies used during terrain flight, survey environmental and image generation factors, and meld these into a preliminary data base design. This design is directed at Data Base developers, and hopefully will stimulate and aid their efforts to evolve such a Base that will support simulation of terrain flight operations.

Sinacori, J. B.↗
NASA NTRS1983

Archival of aircraft scatterometer data from AAFE RADSCAT missions

Aircraft scatterometer data obtained over the ocean with the Radiometer-Scatterometer (RADSCAT) instrument is documented. The normalized radar cross section data was obtained at 13.9 GHz for a variety of ocean surface wind conditions, which are also presented. All such valid RADSCAT ocean scatterometer data for which surface truth was obtained are included, except for ice research missions during the last year of RADSCAT's lifetime. Aircraft scatterometer data obtained for the SEASAT underflights were with a second instrument, the Airborne Microwave Scatterometer (AMSCAT). The RADSCAT data are archived on card image computer tapes and on microfiche.

Schroeder, L. C.↗
NASA NTRS1984

Edge analyzing properties of center/surround response functions in cybernetic vision

The ability of center/surround response functions to make explicit high resolution spatial information in optical images was investigated by performing convolutions of two dimensional response functions and image intensity functions (mainly edges). The center/surround function was found to have the unique property of separating edge contrast from shape variations and of providing a direct basis for determining contrast and subsequently shape of edges in images. Computationally simple measures of contrast and shape were constructed for potential use in cybernetic vision systems. For one class of response functions these measures were found to be reasonably resilient for a range of scan direction and displacements of the response functions relative to shaped edges. A pathological range of scan directions was also defined and methods for detecting and handling these cases were developed. The relationship of these results to biological vision is discussed speculatively.

Jobson, D. J.↗
NASA NTRS1984

Search for solar signals in GOES imagery and cloud climatology analysis

The digitization and analysis of 16mm GOES IR imagery to identify spatial and temporal variation in clouds is discussed, along with a cloud climatology analysis. Recently added to the Interactive Graphics Package was a Computer Image Analysis System. This system allows many new imaging techniques. One of the possibilities is the analysis of overall light intensity variations in six 10 degree square boxes across the intertropical convergence zone. This technique is discussed, as is a preliminary analysis of unnormalized data.

Markson, R. J.↗
NASA NTRS1990

Cycle life machine for AX-5 space suit

In order to accurately test the AX-5 space suit, a complex series of motions needed to be performed which provided a unique opportunity for mechanism design. The cycle life machine design showed how 3-D computer images can enhance mechanical design as well as help in visualizing mechanisms before manufacturing them. In the early stages of the design, potential problems in the motion of the joint and in the four bar linkage system were resolved using CAD. Since these problems would have been very difficult and tedious to solve on a drawing board, they would probably not have been addressed prior to fabrication, thus limiting the final design or requiring design modification after fabrication.

Schenberger, Deborah S.↗
NASA NTRS1990

Intraocular pressure, retinal vascular, and visual acuity changes during 48 hours of 10-deg head-down tilt

Intraocular pressures, retinal vascular diameters, and visual acuities of nine men, were repeatedly measured while the subjects were tilted 10 deg head-down for 48 h and while they were seated before (baseline), and after the tilt. An immediate increase in intraocular pressure, measured by pneumatonometer was recorded when subjects assumed the head-down position, and diurnal variations in intraocular pressures were observed for the 48 h. The initial and final head-down intraocular pressures were not significantly different. However, when subjects resumed the sitting position, intraocular pressures fell below the initial sitting values. Computer image analysis of the retinal vasculature detected a 6 percent and 2 percent reduction in the caliber of arteries and veins, respectively, as compared with sitting baseline values. No changes in visual acuity were documented during the 48 h of head-down tilt. The data suggest that the choroidal blood reservoir increases in volume over 48 h at continuous head-down position with a compensatory decrease in aqueous volume. These findings may explain intraocular pressure changes noted in astronauts during previous space missions and in studies associated with change in body position.

Mader, Thomas H.↗
NASA NTRS1991

Helicopter control response types for hover and low-speed near-earth tasks in degraded visual conditions

The NASA-Ames Vertical Motion Simulator and Dig 1 Computer Image Generator (CIG) have been used to simulate a helicopter cockpit in a degraded visual environment in order to assess several control-response types during low-level flight. CIG visibility was reduced to the point where the horizon and other far-field cues were indiscernible. The control-response types encompassed a rate command, an attitude command/hold, and a translational rate command; piloting tasks were hover, vertical landing, a pirouette, acceleration/deceleration, and a sidestep maneuver. Visual cue ratings with a rate-command response type were initially collected to set the usable cue environment at 3. A rate-command response type provided poor Level 2 handling qualities.

Blanken, Christopher L.↗
NASA NTRS1991

Supervised autonomous rendezvous and docking system technology evaluation

Technology for manned space flight is mature and has an extensive history of the use of man-in-the-loop rendezvous and docking, but there is no history of automated rendezvous and docking. Sensors exist that can operate in the space environment. The Shuttle radar can be used for ranges down to 30 meters, Japan and France are developing laser rangers, and considerable work is going on in the U.S. However, there is a need to validate a flight qualified sensor for the range of 30 meters to contact. The number of targets and illumination patterns should be minimized to reduce operation constraints with one or more sensors integrated into a robust system for autonomous operation. To achieve system redundancy, it is worthwhile to follow a parallel development of qualifying and extending the range of the 0-12 meter MSFC sensor and to simultaneously qualify the 0-30(+) meter JPL laser ranging system as an additional sensor with overlapping capabilities. Such an approach offers a redundant sensor suite for autonomous rendezvous and docking. The development should include the optimization of integrated sensory systems, packaging, mission envelopes, and computer image processing to mimic brain perception and real-time response. The benefits of the Global Positioning System in providing real-time positioning data of high accuracy must be incorporated into the design. The use of GPS-derived attitude data should be investigated further and validated.

Marzwell, Neville I.↗
NASA NTRS1992

Optimization of the parameters for a rotating, mixed-phase reactor

The motion of small, monodisperse particles in fluid was studied in a horizontal, cylindrical container rotating about its axis. One instigation for the study was the common requirement for mixed-phase, chemical or biological reactors to maintain particles in suspension for extended periods. A cylindrical, rotating reactor can allow long-term particle suspension without particle collisions and resulting agglomeration. The purpose of this study was to verify parametric effects and optimize the time of particle suspension. The theoretical and experimental results were obtained for inert, constant-diameter particles of nearly neutral buoyancy. The centrifugal buoyancy and gravitation terms were both included in the equations of motion. Laser illumination, photography and computer imaging were used to measure experimental particle concentration.

Cleland, J. G.↗
NASA NTRS1991

New optical approaches to the quantitative characterization of crystal growth, segregation and defect formation

Elemental and compound semiconductors were characterized using new optical approach based on NIR microscopy in conjunction with computational image analysis and contrast enhancement. The approach made it possible to perform a quantitative microsegregation analysis of GaAs and InP. NIR dark file illumination in transmission mode makes it possible to detect submicron precipitates in semiinsulating GaAs.

Carlson, D. J.↗
NASA NTRS1994

Removing cosmic-ray hits from multiorbit HST Wide Field Camera images

We present an optimized algorithm that removes cosmic rays ('CRs') from multiorbit Hubble Space Telescope (HST) Wide Field/Planetary Camera ('WF/PC') images. It computes the image noise in every iteration from the WF/PC CCD equation. This includes all known sources of random and systematic calibration errors. We test this algorithm on WF/PC stacks of 2-12 orbits as a function of the number of available orbits and the formal Poissonian sigma-clipping level. We find that the algorithm needs greater than or equal 4 WF/PC exposures to locate the minimal sky signal (which is noticeably affected by CRs), with an optimal clipping level at 2-2.5 x sigma(sub Poisson). We analyze the CR flux detected on multiorbit 'CR stacks,' which are constructed by subtracting the best CR filtered images from the unfiltered 8-12 orbit average. We use an automated object finder to determine the surface density of CRS as a function of the apparent magnitude (or ADU flux) they would have generated in the images had they not been removed. The power law slope of the CR 'counts' (gamma approximately = 0.6 for N(m) m(exp gamma)) is steeper than that of the faint galaxy counts down to V approximately = 28 mag. The CR counts show a drop off between 28 less than or approximately V less than or approximately 30 mag (the latter is our formal 2 sigma point source sensitivity without spherical aberration). This prevents the CR sky integral from diverging, and is likely due to a real cutoff in the CR energy distribution below approximately 11 ADU per orbit. The integral CR surface density is less than or approximately 10(exp 8)/sq. deg, and their sky signal is V approximately = 25.5-27.0 mag/sq. arcsec, or 3%-13% of our NEP sky background (V = 23.3 mag/sq. arcsec), and well above the EBL integral of the deepest galaxy counts (B(sub J) approximately = 28.0 mag/sq. arcsec). We conclude that faint CRs will always contribute to the sky signal in the deepest WF/PC images. Since WFPC2 has approximately 2.7x lower read noise and a thicker CCD, this will result in more CR detections than in WF/PC, potentially affecting approximately 10%-20% of the pixels in multiorbit WFPC2 data cubes.

Windhorst, Rogier A.↗