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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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DOE OSTI2022

Robust Wheel Detection for Vehicle Re-Identification

Vehicle re-identification is a demanding and challenging task in automated surveillance systems. The goal of vehicle re-identification is to associate images of the same vehicle to identify re-occurrences of the same vehicle. Robust re-identification of individual vehicles requires reliable and discriminative features extracted from specific parts of the vehicle. In this work, we construct an efficient and robust wheel detector that precisely locates and selects vehicular wheels from vehicle images. The associated hubcap geometry can hence be utilized to extract fundamental signatures from vehicle images and exploit them for vehicle re-identification. Wheels pattern information can yield additional information about vehicles in questions. To that end, we utilized a vehicle imagery dataset that has thousands of side-view vehicle collected under different illumination conditions and elevation angles. The collected dataset was used for training and testing the wheel detector. Experiments show that our approach could detect vehicular wheels accurately for 99.41% of the vehicles in the dataset.

47 OTHER INSTRUMENTATION↗

NASA NTRS1991

Microscope Would Image X and Gamma Rays

Microscope contains Bragg-reflecting, grazing-incidence reflectors, filter wheel, and detector. Multiple nested coaxial pairs of reflectors used to form images simultaneously at multiple wavelengths. Collects and focuses radiation to produce images with moderate spectral resolution and high spatial resolution. Enables use of smaller, cheaper, better-shielded detectors. Combination of features provides new information of unprecedented value in several fields of research; probing fine structures of pulsed plasmas, investigating minute variations in structures of material specimens penetrated only by hard-x or gamma rays, or in producing maps of distributions of radioisotopes in biological specimens.

Hoover, Richard B.↗

NASA NTRS1966

Twin helix system produces fast scan in infrared detector

Two rotating wheels in orthogonal relationship with helicoidal reflecting surfaces mounted on their outer rims achieve a linear speed without normal time loss in their return motion. The pitch of the helicoidal surfaces equals the displacement that the mirrors must traverse.

Vanzetti, R.↗

DOE OSTI2023

The New Small Wheel electronics

The increase in luminosity, and consequent higher backgrounds, of the LHC upgrades require improved rejection of fake tracks in the forward region of the ATLAS Muon Spectrometer. The New Small Wheel upgrade of the Muon Spectrometer aims to reduce the large background of fake triggers from track segments that don't originate from the interaction point. The New Small Wheel employs two detector technologies, the resistive strip Micromegas detectors and the “small” Thin Gap Chambers, with a total of 2.45 million electrodes to be sensed. The two technologies require the design of a complex electronics system given that it consists of two different detector technologies and is required to provide both precision readout and a fast trigger. It will operate in a high background radiation region up to about 20 kHz/cm 2 at the expected HL-LHC luminosity of $\mathcal{L}$= 7.5 × 10 34 cm -2 s -1 . The architecture of the system is strongly defined by the GBTx data aggregation ASIC, the newly-introduced FELIX data router and the software based data handler of the ATLAS detector. The electronics complex of this new detector was designed and developed in the last ten years and consists of multiple radiation tolerant Application Specific Integrated Circuits, multiple front-end boards, dense boards with FPGA's and purpose-built Trigger Processor boards within the ATCA standard. The New Small Wheel has been installed in 2021 and is undergoing integration within ATLAS for LHC Run 3. It should operate through the end of Run 4 (December 2032). In this manuscript, the overall design of the New Small Wheel electronics is presented.

47 OTHER INSTRUMENTATION↗

NASA NTRS2008

Chromatic Modulator for a High-Resolution CCD or APS

A chromatic modulator has been proposed to enable the separate detection of the red, green, and blue (RGB) color components of the same scene by a single charge-coupled device (CCD), active-pixel sensor (APS), or similar electronic image detector. Traditionally, the RGB color-separation problem in an electronic camera has been solved by use of either (1) fixed color filters over three separate image detectors; (2) a filter wheel that repeatedly imposes a red, then a green, then a blue filter over a single image detector; or (3) different fixed color filters over adjacent pixels. The use of separate image detectors necessitates precise registration of the detectors and the use of complicated optics; filter wheels are expensive and add considerably to the bulk of the camera; and fixed pixelated color filters reduce spatial resolution and introduce color-aliasing effects. The proposed chromatic modulator would not exhibit any of these shortcomings. The proposed chromatic modulator would be an electromechanical device fabricated by micromachining. It would include a filter having a spatially periodic pattern of RGB strips at a pitch equal to that of the pixels of the image detector. The filter would be placed in front of the image detector, supported at its periphery by a spring suspension and electrostatic comb drive. The spring suspension would bias the filter toward a middle position in which each filter strip would be registered with a row of pixels of the image detector. Hard stops would limit the excursion of the spring suspension to precisely one pixel row above and one pixel row below the middle position. In operation, the electrostatic comb drive would be actuated to repeatedly snap the filter to the upper extreme, middle, and lower extreme positions. This action would repeatedly place a succession of the differently colored filter strips in front of each pixel of the image detector. To simplify the processing, it would be desirable to encode information on the color of the filter strip over each row (or at least over some representative rows) of pixels at a given instant of time in synchronism with the pixel output at that instant.

Hartley, Frank↗

NASA NTRS1982

Airborne multispectral linear array instruments at Goddard Space Flight Center

The fabrication of airborne instruments is contributing to the development of multispectral linear array technology at NASA's Goddard Space Flight Center. The linear array pushbroom radiometer (LAPR-I), was built to demonstrate capabilities for acquiring digital image data using linear arrays. The LAPR-I employed three arrays of 512 silicon photodiodes each to simultaneously acquire three channels of data for spectral bands within the visible and near-infrared portions of the spectrum. A second instrument, LAPR-II, uses four arrays each consisting of 512 silicon detectors. A filter wheel containing six spectral filters is used in conjunction with each array to allow filter changes in flight. This capability will facilitate studies into the utility of various bands within the visible and near infrared portions of the spectrum. The LAPR-II's aircraft mounting will allow off-nadir pointing (plus-or-minus 50 deg fore-and-aft and side-to-side) which will enable investigations of the radiometric and geometric effects of off-nadir viewing. A short wave infrared radiometer is also described.

Irons, J. R.↗

NASA NTRS2001

Airborne Spectral Measurements of Surface-Atmosphere Anisotropy for Skukuza and Mongu Sites

The Cloud Absorption Radiometer (CAR) was flown aboard the University of Washington Convair CV-580 research aircraft and took measurements on 23 flights between August 15 and September 16. On 12 of those flights, BRF (bidirectional reflection function) measurements were obtained over different natural surfaces and ecosystems in southern Africa. The BRF measurements were done to characterize surface anisotropy in support of SAFARI 2000 science objectives principally to validate products from NASA's EOS (Earth Observing System) satellites, and to parameterize and validate BRF models. In this paper we present results of BRFs taken over two EOS validation sites: Skukuza tower, South Africa (25.0 S, 31.5 E) and Mongu tower, Zambia (15.4 S, 23.3 E). The CAR is capable of measuring scattered light in fourteen spectral bands. The scan mirror, rotating at 100 rpm, directs the light into a Dall-Kirkham telescope where the beam is split into nine paths. Eight light beams pass through beam splitters, dichroics, and lenses to individual detectors (0.34-1.27 microns), and finally are registered by eight data channels. They are sampled simultaneously and continuously. The ninth beam passes through a spinning filter wheel to an InSb detector cooled by a Stirling cycle cooler. Signals registered by the ninth data channel are selected from among six spectral channels (1.55-2.30 microns). The filter wheel can either cycle through all six spectral bands at a prescribed interval (usually changing filter every fifth scan line), or lock onto any one of the six spectral bands and sample it continuously. To measure the BRF of the surface-atmosphere system, the University of Washington CV-580 had to bank at a comfortable roll angle of approximately 20 degrees and fly in a circle about 3 km in diameter above the surface for roughly two minutes. Replicated observations (multiple circular orbits) were acquired over selected surfaces so that average BRF smooth out small-scale surface and atmospheric inhomogeneities. At an altitude of 600 m above the targeted surface area and with a 1 degree IFOV, the pixel resolution is about 10 m at nadir and about 270 m at an 80 degree viewing angle from the CAR.

Gatebe, C. K.↗

NASA NTRS2001

Airborne spectral Measurements of Surface-Atmosphere Anisotropy for Several Surfaces and Ecosystem over Southern Africa

The Cloud Absorption Radiometer (CAR) was flown aboard the University of Washington Convair CV-580 research aircraft and took measurements on 23 flights between August 15 and September 16. On 12 of those flights, BRF measurements were obtained over different natural surfaces and ecosystem in southern Africa. The BRF measurements were done to characterize surface anisotropy in support of SAFARI 2000 science objectives principally to validate products from NASA's EOS satellites, and to parameterize and validate BRF models. In this paper we present results of BRFs taken over two EOS validation sites: Skukuza tower, South Africa (25.0 deg S, 31.5 deg E) and Mongu tower, Zambia (15.4 deg S, 23.3 deg E). Additional sites are also considered and include, Maun tower, Botswana (20.0 deg S, 23.5 deg E), Sowa Pan, Botswana (20.6 deg S, 26.2 deg E) and Etosha Pan, Namibia (19.0 deg S, 16.0 deg E). The CAR is capable of measuring scattered light in fourteen spectral bands. The scan mirror, rotating at 100 rpm, directs the light into a Dall-Kirkham telescope where the beam is split into nine paths. Eight light beams pass through beam splitters, dichroics, and lenses to individual detectors (0.34-1.27 micrometers), and finally are registered by eight data channels. They are sampled simultaneously and continuously. The ninth beam passes through a spinning filter wheel to an InSb detector cooled by a Stirling cycle cooler. Signals registered by the ninth data channel are selected from among six spectral channels (1.55-2.30 micrometers). The filter wheel can either cycle through all six spectral bands at a prescribed interval (usually changing filter every fifth scan line), or lock onto any one of the six spectral bands and sample it continuously. To measure the BRF of the surface-atmosphere system, the University of Washington CV-580 had to bank at a comfortable roll angle of approximately 20 degrees and fly in a circle about 3 km in diameter above the surface for roughly two minutes. Replicated observations (multiple circular orbits) were acquired over selected surfaces so that average BRF smooth out small-scale surface and atmospheric inhomogeneities. At an altitude of 600 m above the targeted surface area and with a 1 deg IFOV, the pixel resolution is about 10 m at nadir and about 270 m at an 80 deg viewing angle from the CAR.

Gatebe, Charles K.↗

NASA NTRS2002

Airborne Spectral Measurements of Ocean Anisotropy during CLAMS

The Cloud Absorption Radiometer (CAR) aboard the University of Washington Convair CV-580 research aircraft obtained bidirectional reflectance-distribution function (BRDF) of Atlantic Ocean and Dismal Swamp between July 10 and August 2, 2001. The BRDF measurements (15 in total, 8 uncontaminated by clouds) obtained under a variety of sun angles and wind conditions, will be used to characterize ocean anisotropy in support of Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) science objectives principally to validate products from NASA's EOS satellites, and to parameterize and validate BRDF models of the ocean. In this paper we present results of BRDF of the Ocean under different sun angles and wind conditions. The CAR is capable of measuring scattered light in fourteen spectral bands. The scan mirror, rotating at 100 rpm, directs the light into a Dall-Kirkham telescope where the beam is split into nine paths. Eight light beams pass through beam splitters, dichroics, and lenses to individual detectors (0.34-1.27 micron), and finally are registered by eight data channels. They are sampled simultaneously and continuously. The ninth beam passes through a spinning filter wheel to an InSb detector cooled by a Stirling cycle cooler. Signals registered by the ninth data channel are selected from among six spectral channels (1.55-2.30 micron). The filter wheel can either cycle through all six spectral bands at a prescribed interval (usually changing filter every fifth scan line), or lock onto any one of the six spectral bands and sample it continuously. To measure the BRF of the surface-atmosphere system, the University of Washington CV-580 had to fly in a circle about 3 km in diameter above the surface for roughly two minutes. Replicated observations (multiple circular orbits) were acquired over selected surfaces so that average BRF smooth out small-scale surface and atmospheric inhomogeneities. At an altitude of 600 m above the targeted surface area and with a 1 degree IFOV, the pixel resolution is about 10 m at nadir and about 270 m at an 80 deg. viewing angle from the CAR.

Gatebe, C. K.↗

NASA NTRS1983

System description

The VAS, carried onboard the GOES 4 and 5 satellites, is a radiometer with 8 visible channel detectors and 6 thermal detectors that detect infrared radiation in 12 spectral bands. A filter wheel in front of the detector is used to achieve the spectral selection. The spatial resolution is 0.9 kilometer in the visible and 7 or 14 kilometers in the infrared depending on the detector used. Full Earth disk coverage is accomplished by spinning in the west to east direction at 100 rpm and by stepping a scan mirror from north to south. Additional VAS instrument characteristics are summarized. The VAS has three operating modes: the operational VISSR mode, the multispectral imaging (MSI) mode, and the dwell sounding (DS) mode. The operational VISSR mode is used by NOAA/NESS for its operational products, which include a visible picture and an 11 micrometer infrared (channel 8) picture at half hour intervals. The other modes are VAS unique. The MSI mode combines the operational VISSR capability (visible plus infrared window) with two additional spectral channels to provide half hourly full Earth disk imagery of atmospheric water vapor, temperature, and cloud distribution. The DS mode is used primarily for sounding to obtain the temperature and moisture profiles. In this mode, multiple spins on the same scan line in a given band are averaged to obtain the required signal to noise ratio for sounding.

Montgomery, H.↗

NASA NTRS2001

Development of a Submillimeter-Wavelength Immersion Grating Spectrometer

The broad goal of this project was to develop a broadband, moderate-resolution spectrometer for submillimeter wavelengths. Our original approach was to build an immersion grating spectrometer, and as such, the first step was to identify the best material (lowest loss, highest index) for the grating medium, and to characterize its properties at the foreseen optical-bench operating temperature of 1.5 K. To this end, we put our initial efforts into upgrading an existing laboratory submillimeter Fourier transform spectrometer, which allowed us to carry out the requisite materials measurements. The associated cryogenic detector dewar was also redesigned and rebuilt to carry out this work. This dewar houses the 1.5 K detector and the filter wheel used in the materials characterization. Our goal was to have the beam propagate through the samples as uniformly as possible, so the optics were redesigned to allow for the samples to be traversed by a well-defined collimated beam. The optics redesign also placed the samples at an image of the aperture stop located within the FTS. After the rebuild, we moved into the testing phase.

Phillips, T. G.↗

NASA NTRS1978

High resolution spectroscopy from low altitude satellites

The P 78 1 satellite to be placed in a synchronous polar orbit at an altitude of 550-660 km will carry two identical high resolution spectrometers each consisting of a single (approximately 85 cc) intrinsic germanium IGE detector. The payload also includes a pair of phoswitch scintillators, an array of CdTe detectors and several particle detectors, all of which are mounted on the wheel of the satellite. The intrinsic high purity IGE detectors receive cooling from two Stirling cycle refrigerators and facilitate the assembly of large and complex detector arrays planned for the next generation of high sensitivity instruments such as those planned for the gamma ray observatory. The major subsystems of the spectrometer are discussed as well as its capabilities.

Nakano, G. H.↗

NASA NTRS2016

The Matsu Wheel: A Cloud-Based Framework for Efficient Analysis and Reanalysis of Earth Satellite Imagery

Project Matsu is a collaboration between the Open Commons Consortium and NASA focused on developing open source technology for cloud-based processing of Earth satellite imagery with practical applications to aid in natural disaster detection and relief. Project Matsu has developed an open source cloud-based infrastructure to process, analyze, and reanalyze large collections of hyperspectral satellite image data using OpenStack, Hadoop, MapReduce and related technologies. We describe a framework for efficient analysis of large amounts of data called the Matsu "Wheel." The Matsu Wheel is currently used to process incoming hyperspectral satellite data produced daily by NASA's Earth Observing-1 (EO-1) satellite. The framework allows batches of analytics, scanning for new data, to be applied to data as it flows in. In the Matsu Wheel, the data only need to be accessed and preprocessed once, regardless of the number or types of analytics, which can easily be slotted into the existing framework. The Matsu Wheel system provides a significantly more efficient use of computational resources over alternative methods when the data are large, have high-volume throughput, may require heavy preprocessing, and are typically used for many types of analysis. We also describe our preliminary Wheel analytics, including an anomaly detector for rare spectral signatures or thermal anomalies in hyperspectral data and a land cover classifier that can be used for water and flood detection. Each of these analytics can generate visual reports accessible via the web for the public and interested decision makers. The result products of the analytics are also made accessible through an Open Geospatial Compliant (OGC)-compliant Web Map Service (WMS) for further distribution. The Matsu Wheel allows many shared data services to be performed together to efficiently use resources for processing hyperspectral satellite image data and other, e.g., large environmental datasets that may be analyzed for many purposes.

0↗

NASA NTRS2007

A Scanning Hartmann Focus Test for the EUVI Telescopes aboard STEREO

The Solar TErrestrial RElations Observatory (STEREO), the third mission in NASA s Solar Terrestrial Probes program, was launched in 2006 on a two year mission to study solar phenomena like coronal mass ejections. STEREO consists of two nearly identical satellites, each carrying a suite of instruments that provide, among other data, simultaneous images of the Sun. One of these telescopes is the Extreme Ultraviolet Instrument (EUVI). There are two EUVI telescopes, one on each STEREO satellite (EUVI-A and EUVI-B). EUVI is a normal incidence, 98mm diameter, Ritchey-Chretien telescope designed to obtain wide field of view (approx.1deg) images of the Sun at short wavelengths (approx.20nm) using a CCD detector. The telescope entrance aperture is divided into four quadrants by a mask near the secondary mirror spider veins. A mechanism that rotates another mask allows only one of these sub-apertures to accept light from the Sun during an observation. The EUVI is thus four co-aligned, off-axis telescopes. Each off-axis segment on the primary and secondary mirrors has a different extreme ultraviolet coating stack. Furthermore, the aperture select mechanism is synchronized with a filter wheel mechanism near the CCD detector. The EUVI contains no focus mechanism. Models predict that the difference in on-orbit operating temperature and ambient clean room conditions yield a "best focus" difference between integration and operation of approx. 0.2mm.

Ohl, R.↗

NASA NTRS1973

Design and performance characteristics of the Vertical Temperature Profile Radiometer /VTPR/ for atmospheric temperature soundings.

Description of the design and operation of a radiometer which derives atmospheric temperature profiles on the basis of spectral measurements in eight optical filter channels. The radiometer achieves its eight-channel capability by sequentially viewing the eight optical filters mounted in a rotating filter wheel, with a single IR detector and electronic amplification channel processing the signal for all the filters. The advantages and disadvantages of this sequential approach as compared to eight 'parallel' radiometric channels are discussed. The proposed radiometer provides a relative calibration accuracy between seven out of the eight channels of better than 0.1% rms of the full dynamic range. The absolute accuracy achievable between in-flight calibrations of six minutes, or between two-hour calibrations using optical temperature correction factors, is better than an rms value of 0.15% of full scale. The radiometric correlation between the in-flight calibration source of the instrument and a reference standard blackbody is better than an rms value of 0.5% of full scale.

Falbel, G.↗

NASA NTRS1977

Real time reflectometer

A real time reflectometer with the particular utility of measuring fairly rapid (transient) changes in the specular reflectance of a sample which is continuously exposed to a perturbing environment is described. A fixed radiation source, a fixed detector, a uniformly rotating sample wheel, and a uniformly rotating optical wheel protect against misalignment problems. The reflectometer operates by comparing the measurings of a reflected signal with that of a reference signal made within fractions of a second of one another. Reflectance is measured in the infrared, visible, and vacuum ultraviolet regions.

Zwiener, J. M.↗

NASA NTRS1978

Determination of the structure and heating mechanisms of coronal loops from soft X-ray observations with the solar probe

High resolution soft X-ray imaging from the solar probe is justified in terms of the expected scientific returns which include the determination of the temperature and density structure of a coronal loop. The advantages of the grazing incidence telescope over the multiple pinhole camera are discussed. An instrument package is described which includes a grazing incidence mirror, a thermal prefilter, a three position filter wheel and a focal plane detector baselined as an 800 by 800 back-illuminated charge coupled device. The structural assembly together with the data processing equipment would draw heavily on the designs being developed for the Solar Polar Mission.

Davis, J. M.↗

NASA NTRS2018

WFIRST Coronagraph Flight Performance Modeling

As it has for the past few years, numerical modeling is being used to predict the on-orbit, high-contrast imaging performance of the WFIRST coronagraph, which was recently defined to be solely a technology demonstrator. A consequence has been a realignment of modeling priorities and revised applications of modeling uncertainty factors and margins, which apply to multiple factors such as pointing and wavefront jitter, thermally-induced deformations, polarization, and aberration sensitivities. At the same time, the models have increased in fidelity as additional parameters have been added, such as time-dependent pupil shear and mid-spatial-frequency deformations of the primary and secondary mirrors, detector effects, and reaction-wheel-speed-dependent pointing and wavefront jitter.

Trauger, John↗