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Results for “image alignment”

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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Winston Solar Concentrators and Evaluation Support. Phase 2: Non-imaging Concentrators for Space Applications

A 4.67X, plus or minus 5 deg. compound parabolic concentrator (CPC) for a large photovoltaic array in space was analyzed. The design was demonstrated to be effective in achieving a net power gain which can be varied from more than a factor of 3 down to approximately unity. A method for reducing nonuniformities in illumination to a given desired level was found. The effectiveness of this method, which involves the introduction of a degree of non-specularity in the reflector surface, was confirmed by direct measurements with prepared foil reflectors in a CPC in terrestrial sunshine as well as by computer ray tracing. Further ray tracing confirms that the CPC design is extremely tolerant to pointing and alignment errors, minor distortions, etc. A two stage non-imaging design was shown, by preliminary measurements and analysis, to provide both the desired angular tolerance and the required degree of intensity uniformity if higher concentrations (4X-10X) are necessary.

Winston, R.↗
DOE OSTI2026

Topology-driven compressive behavior of Inconel 718 lattice structures with Z-strut reinforcement fabricated by laser powder bed fusion

This study investigates the compressive deformation behavior and mechanical performance of Inconel 718 lattice structures fabricated by laser powder bed fusion (LPBF). Four unit-cell topologies—BCC, FCC, BCCZ, and FCCZ—were designed with a unit-cell size of 3 mm and fabricated under identical process conditions to isolate the effect of topology. Measured relative densities ranged from 14.65% to 17.72%. Compressive testing showed that Z-strut-reinforced topologies (BCCZ: 54.6 MPa; FCCZ: 80.2 MPa) exhibited higher strength than their unreinforced counterparts, which may be associated with mixed-mode deformation behavior enabled by the vertically aligned Z-struts. Finite element simulations and Digital Image Correlation (DIC) analysis support the observation of a transition from node-dominated deformation in BCC/FCC to mixed-mode deformation in BCCZ/FCCZ. These findings suggest that unit-cell topology is a key design variable for tailoring deformation mechanisms in LPBF lattice structures.

36 MATERIALS SCIENCE↗
NASA NTRS1975

The McIDAS system

The man-computer interactive data access system (McIDAS) hardware and software design is outlined, with emphasis on meteorological applications. The McIDAS system features a flexible digital image enhancement device. Theory of operation, the McIDAS language, the McIDAS executive monitor, image acquisition, image parameters, image display, graphics, image navigation, and image massaging are explained. The WINDCO/CLDHGT system, developed to align time sequences of geosynchronous satellite pictures and to determine the motion and height of selected cloud targets, is also described.

Smith, E. A.↗
NASA NTRS1978

The High Energy Astronomy Observatory X-ray Telescope

The High Energy Astronomy Observatory-Mission B (HEAO-B) is a satellite observatory for the purpose of performing a detailed X-ray survey of the celestial sphere. Measurements will be made of stellar radiation in the range 0.2 through 20 keV. The primary viewing requirement is to provide final aspect solution and internal alignment information to correlate an observed X-ray image with the celestial sphere to within one-and-one-half arc seconds. The Observatory consists of the HEAO Spacecraft together with the X-ray Telescope. The Spacecraft provides the required attitude control and determination system, data telemetry system, space solar power system, and interface with the launch vehicle. The X-ray Telescope includes a high resolution mirror assembly, optical bench metering structure, X-ray detectors, detector positioning system, detector electronics and aspect sensing system.

Miller, R.↗
NASA NTRS1987

Small Martian valcanoes

Various types of volcanoes were identified on Mars, mainly on the basis of qualitative morphologic criteria such as relief, circularity, summit craters, and alignment with structural trends. A survey of Viking Orbiter images is being conducted to identify possible candidates for Martian volcanoes. The topographic profiles of the selected Martian volcanoes that are currently being acquired will be compared with tabulated data for terrestrial and lunar volcanoes. Variation in volcanic style with age will also be examined.

Davis, Philip A.↗
NASA NTRS2005

Conceptual Design and Dynamics Testing and Modeling of a Mars Tumbleweed Rover

The NASA Langley Research Center has been developing a novel concept for a Mars planetary rover called the Mars Tumbleweed. This concept utilizes the wind to propel the rover along the Mars surface, bringing it the potential to cover vast distances not possible with current Mars rover technology. This vehicle, in its deployed configuration, must be large and lightweight to provide the ratio of drag force to rolling resistance necessary to initiate motion from rest on the Mars surface. One Tumbleweed design concept that satisfies these considerations is called the Eggbeater-Dandelion. This paper describes the basic design considerations and a proposed dynamics model of the concept for use in simulation studies. It includes a summary of rolling/bouncing dynamics tests that used videogrammetry to better understand, characterize, and validate the dynamics model assumptions, especially the effective rolling resistance in bouncing/rolling dynamic conditions. The dynamics test used cameras to capture the motion of 32 targets affixed to a test article s outer structure. Proper placement of the cameras and alignment of their respective fields of view provided adequate image resolution of multiple targets along the trajectory as the test article proceeded down the ramp. Image processing of the frames from multiple cameras was used to determine the target positions. Position data from a set of these test runs was compared with results of a three dimensional, flexible dynamics model. Model input parameters were adjusted to match the test data for runs conducted. This process presented herein provided the means to characterize the dynamics and validate the simulation of the Eggbeater-Dandelion concept. The simulation model was used to demonstrate full scale Tumbleweed motion from a stationary condition on a flat-sloped terrain using representative Mars environment parameters.

Calhoun Philip C.↗
NASA NTRS2012

Very High Resolution Solar X-ray Imaging Using Diffractive Optics

This paper describes the development of X-ray diffractive optics for imaging solar flares with better than 0.1 arcsec angular resolution. X-ray images with this resolution of the greater than or equal to 10 MK plasma in solar active regions and solar flares would allow the cross-sectional area of magnetic loops to be resolved and the coronal flare energy release region itself to be probed. The objective of this work is to obtain X-ray images in the iron-line complex at 6.7 keV observed during solar flares with an angular resolution as fine as 0.1 arcsec - over an order of magnitude finer than is now possible. This line emission is from highly ionized iron atoms, primarily Fe xxv, in the hottest flare plasma at temperatures in excess of approximately equal to 10 MK. It provides information on the flare morphology, the iron abundance, and the distribution of the hot plasma. Studying how this plasma is heated to such high temperatures in such short times during solar flares is of critical importance in understanding these powerful transient events, one of the major objectives of solar physics.We describe the design, fabrication, and testing of phase zone plate X-ray lenses with focal lengths of approximately equal to 100 m at these energies that would be capable of achieving these objectives. We show how such lenses could be included on a two-spacecraft formation-flying mission with the lenses on the spacecraft closest to the Sun and an X-ray imaging array on the second spacecraft in the focal plane approximately equal to 100 m away. High resolution X-ray images could be obtained when the two spacecraft are aligned with the region of interest on the Sun. Requirements and constraints for the control of the two spacecraft are discussed together with the overall feasibility of such a formation-flying mission.

Dennis, B. R.↗
DOE OSTI2025

Dark-field X-ray microscopy with structured illumination for three-dimensional imaging

Dark-field X-ray microscopy is a lens-based technique that enables real-space imaging of heterogeneous micro- and meso-scale ordered materials. However, achieving accurate three-dimensional (3D) reconstruction often requires meticulous sample alignment or rastering, requiring complex rotational setups and extended acquisition times. To address these challenges, we introduce a structured illumination technique optimized for 3D imaging of ordered materials at sub-micrometer length scales. Our approach employs a coded aperture to spatially modulate the incident X-ray beam, enabling 3D structural reconstruction from images captured at various aperture positions. Unlike current 3D imaging approaches, which often rely on rotational or rastering methods, our technique uses scanning X-ray silhouettes of the coded aperture for depth resolution along the diffraction axis. This eliminates the need for sample rotation or rastering, resulting in a highly stable and efficient imaging modality. We validated the efficacy of this approach through experimental imaging of an isolated twin domain within a bulk single crystal of an iron pnictide using a dark-field X-ray microscope. This advancement aligns with the enhanced brightness upgrades of modern synchrotron radiation facilities, unlocking new possibilities for high-resolution imaging of ordered materials.

47 OTHER INSTRUMENTATION↗
NASA NTRS1989

Image quality on the Kuiper Airborne Observatory. I - Results of the first flight series

The NASA Kuiper Airborne Observatory (KAO) was flown three times during June and July, 1984 in order to study the causes of the poor seeing obtained with the 0.9-m telescope. High-speed pressure and temperature sensors were placed in the telescope cavity. Several thousand stellar images were recorded under various flight and optical configurations. It is found that the long-exposure image size is affected by telescope tracking errors, imperfect optics, poor optical alignment, telescope and instrument vibration, thermal fluctuations in the telescope cavity, and density fluctuations in the shear layer that forms the boundary between the cavity air and outside air. Possible ways to improve the quality of the images are discussed.

Elliot, J. L.↗
NASA NTRS1979

System and method for obtaining wide screen Schlieren photographs

A system for use in Schlieren photography includes (1) a viewing screen adjacently related to a large grating; (2) a small grating disposed in spaced relation with the large grating; (3) a transparent retainer for confining a transparent medium between the gratings; and (4) optics for imaging the small grating on the large grating. A light source and optically aligned lens are used to project a beam of light along axes extending through the small grating and strike the large grating, subsequent to passing through the medium. A Schlieren image of striations resulting from distortions of light rays proposed by the medium are formed on the screen. A camera is used to photograph the Schlieren image projected on the large screen.

Parthasarathy, S. P.↗
NASA NTRS1992

Near-infrared images and color maps of Arp 220

Near-infrared images (1.3-3.7 microns) are presented for the nuclear region of Arp 220. Color maps in J - H and H - K reveal steep gradients, and the two nuclei previously detected at 20 cm and 2.2 microns appear on the J - H image as peaks separated by 1 arcsec. Hot dust emission (T about 1000 K) at 3.7 microns and extremely red J - H and H - K colors are found for both nuclei. The increasingly red color approaching the center of the galaxy are explained most naturally by a mixture of extinction and emission by increasing amounts of hot dust. The near-infrared emission is consistent with a circumnuclear starburst extending to a radius of about 1.5 kpc from the nuclei; further from the center the colors are consistent with a normal late-type stellar population. Inside a radius of 1 kpc the color maps show a NE-SW elongation that aligns with the concentration of molecular gas seen in CO images. The observed 3.7-micron luminosity, when corrected for nuclear extinction determined by 10-micron silicate absorption measurements and normalized by the bolometric luminosity, is consistent with UV-excess quasars and is about 10 times greater than that found in infrared luminous starburst galaxies.

Mazzarella, J. M.↗
NASA NTRS1994

Radio and X-ray observations of the gamma-ray bright quasar PKS 0528+134

We present a study of the z = 2.07 quasar PKS 0528+134, which has been detected as an extraordinarily luminous gamma-ray source. Its radio properties are highly variable in both total and polarized flux density. Milliarcsecond-scale maps from global very long base interferometry (VLBI) experiments, an X-ray spectrum from ROSAT Position Sensitive Proportional Counter (PSPC) observations, and light curves in total flux density and polarization are used to investigate the geometry, radiation mechanism, and physical environment of the emission region in the source. The VLBI images reveal a bent jet extending toward the northeast on parsec scales, with less intense knots of emission appearing on the opposite side of the brightest spot. The position of the core usually found in such sources is unclear. The polarization angle is stable despite strong variability in polarized flux density and indicates that the magnetic field is aligned with the jet axis as defined by our 8.4 GHz image. The ROSAT X-ray flux density of PKS 0528+134 in 1991 March is measured to be 1.6 micro Jy at 1 keV, with a very steep spectral (`energy') index sigma(sub x) approximately equal to 2.2. The X-ray observations reveal the presence of cold gas along the line of sight significantly in excess of that present in the Galaxy. A strong radio flare began within two months of the first observation of a high flux of gamma-rays from PKS 0528+134 by Hunter et al. Using the geometry and spectral chacateristics determined by our VLBI observations, a synchrotron self-Compton calculation indicates that relativistic bulk motion is required in PKS 0528+134, with an estimated Doppler beaming factor delta approximately greater than 4.3, similar to the value delta approximately greater than 7 required to explain the low optical depth of the gamma-rays to photon-photon pair production. We suggest that the core activity of PKS 0528+134 is sporadic in nature, with the nonthermal outburst starting in 1991 representing a violent period involving ejection of relativistic plasma along a compact jet pointed almost directly toward us.

Zhang, Yun Fei↗
NASA NTRS2011

Fine Guidance Sensing for Coronagraphic Observatories

Three options have been developed for Fine Guidance Sensing (FGS) for coronagraphic observatories using a Fine Guidance Camera within a coronagraphic instrument. Coronagraphic observatories require very fine precision pointing in order to image faint objects at very small distances from a target star. The Fine Guidance Camera measures the direction to the target star. The first option, referred to as Spot, was to collect all of the light reflected from a coronagraph occulter onto a focal plane, producing an Airy-type point spread function (PSF). This would allow almost all of the starlight from the central star to be used for centroiding. The second approach, referred to as Punctured Disk, collects the light that bypasses a central obscuration, producing a PSF with a punctured central disk. The final approach, referred to as Lyot, collects light after passing through the occulter at the Lyot stop. The study includes generation of representative images for each option by the science team, followed by an engineering evaluation of a centroiding or a photometric algorithm for each option. After the alignment of the coronagraph to the fine guidance system, a "nulling" point on the FGS focal point is determined by calibration. This alignment is implemented by a fine alignment mechanism that is part of the fine guidance camera selection mirror. If the star images meet the modeling assumptions, and the star "centroid" can be driven to that nulling point, the contrast for the coronagraph will be maximized.

Brugarolas, Paul↗
NASA NTRSDate not supplied

Recent Development Work with Self-Aligned Focusing Schlieren

A novel compact focusing schlieren instrument has recently been developed that eliminates the need for a separate source and cutoff grid. The technique works by projecting an image of a grid onto a retroreflective surface and then reimaging the projection back onto the original grid. By manipulating the polarization state of the light passing through the instrument, a single Rochon polarizing prism can be used to adjust the schlieren sensitivity by translating it along the instrument’s optical axis, which changes the in-plane offset between the reimaged projection and the original grid. This arrangement makes the instrument inherently self-aligned. Relative to conventional focusing schlieren instruments, which require alignment of a separate source grid and cutoff grid to achieve sensitivity, the setup time required in order to obtain high quality focusing schlieren images is significantly reduced. Further, the self-aligned nature of this instrument makes it insensitive to vibrations and allows for on-the-fly adjustments to field-of-view. In this paper we discuss recent work that has been performed to expand the capabilities of this self-aligned focusing schlieren instrument including: schlieren visualization at extreme angles for optically-restricted test facilities, 3D schlieren visualization using a light field camera, acquisition of high quality focusing schlieren images from facilities with low quality windows, and obtaining focusing schlieren images in full-scale ground test facilities.

Brett Bathel↗
NASA NTRS2018

Imaging Technique for High Precision Measurement of Detector Stability for the Ocean Color Instrument

One of the new projects by NASA to explore environmental change is the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) spacecraft. The primary instrument aboard the PACE spacecraft is the Ocean Color Instrument (OCI), an advanced optical spectrometer that will measure the color of the ocean from the ultraviolet to shortwave infrared range for the purpose of observing and monitoring ocean and coastal biology. As part of the optical alignment testing that must be completed before the instrument is built, the measurement stability of the detectors at space flight operating temperatures must be determined to ensure alignment is maintained. Therefore, this project focuses on the development of an imaging technique that adheres to testing requirements and can be used to determine the stability of the OCI detector. The movements of targets affixed to a high-precision stage were analyzed through an image processing program to test the ability of the imaging technique to detect very small (under 10 micrometers) movements. It was found that movements as small as half a pixel (~6 microns) and 1 pixel (~12 microns) were able to be accurately and consistently detected with this imaging technique. This project found that the designed image analysis technique fulfills testing and measurement requirements and will be an effective metrology technique for the OCI detector stability test.

Optics↗
NASA NTRS1985

X-ray determination of parts alignment

A method for determining the alignment of adjoining metal objects is provided. The method comprises producing an X-ray image of adjoining surfaces of the two metal objects. The X-ray beam is tangential to the point the surfaces are joined. The method is particularly applicable where the alignment of the two metal objects is not readily susceptible to visual inspection.

Nelson, C. W.↗
NASA NTRS1998

STS-95 Day 07 Highlights

On this seventh day of the STS-95 mission, the flight crew, Cmdr. Curtis L. Brown, Pilot Steven W. Lindsey, Mission Specialists Scott E. Parazynski, Stephen K. Robinson, and Pedro Duque, and Payload Specialists Chiaki Mukai and John H. Glenn, again test the Orbiter Space Vision System. OSVS uses special markings on Spartan and the shuttle cargo bay to provide an alignment aid for the arm's operator using shuttle television images. It will be used extensively on the next Space Shuttle flight in December as an aid in using the arm to join together the first two modules of the International Space Station. Specialist John Glenn will complete a daily back-pain questionnaire by as part of a study of how the muscle, intervertebral discs and bone marrow change after exposure to microgravity.

Source record↗
NASA NTRS2012

Science Opportunities with the Near-IR Camera (NIRCam) on the James Webb Space Telescope (JWST)

The Near-Infrared Camera (NIRCam) on the James Webb Space Telescope (JWST) offers revolutionary gains in sensitivity throughout the 1-5 micrometer region. NIRCam will enable great advances in all areas of astrophysics, from the composition of objects in our own Kuiper Belt and the physical properties of planets orbiting nearby stars to the formation of stars and the detection of the youngest galaxies in the Universe. NIRCam also plays an important role in initial alignment of JWST and the long term maintenance of its image quality. NIRCam is presently undergoing instrument Integration and Test in preparation for delivery to the JWST project. Key near-term milestones include the completion of cryogenic testing of the entire instrument; demonstration of scientific and wavefront sensing performance requirements; testing of replacement H2RG detectors arrays; and an analysis of coronagraphic performance in light of measured telescope wavefront characteristics. This paper summarizes the performance of NIRCam, the scientific and education/outreach goals of the science team, and some results of the on-going testing program.

solar system↗