Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “feature map”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20

Analysis of hydrological features of portions of the Lake Ontario basin using Skylab and aircraft data

The author has identified the following significant results. S190A and S190B photography proved to be useful for mapping large scale geomorophological features, and for assessing water depth and water quality. Available S192 data were affected by low frequency noise caused by diode light. Hydrological features were classified, and upland green herbaceous vegetation was separated into several classes based on percent vegetation cover. A model for estimating surface soil moisture based on red and near infrared reflectance data was developed and subsequently implemented.

Polcyn, F. C.↗

Communications systems evolutionary scenarios for Martian SEI support

A set of architectures for the Mars-earth SEI space communications link is identified and characterized. A 'road map' is defined that illustrates the most logical and efficient evolutionary paths for the SEI Mars-earth link. The major features of the road map include three alternative evolutionary paths meeting the data rate requirements that may grow from 10 Mbps to 1 Gbps in the 2008-2025 time frame. All three paths begin with a Ka-band MRS-EST baseline link in 2000, and diverge from this baseline as time progresses.

Kwong, P. W.↗

Climatological occurrences of hail and tornadoes associated with mesoscale convective systems in the United States

Hail and tornadoes are hazardous weather events responsible for significant property damage and economic loss worldwide. The most devastating occurrences of hail and tornadoes are commonly produced by supercells in the United States. However, these supercells may also grow upscale into mesoscale convective systems (MCSs) or be embedded within them. The relationship between hail and tornado occurrences with MCSs in the long-term climatology has not been thoroughly examined. In this study, radar features associated with MCSs are extracted from a 14-year MCS tracking database across the contiguous United States, and hazard reports are mapped to these MCS features. We investigate the characteristics of hail and tornadoes in relation to MCSs, considering seasonal and regional variabilities. On average, 8 %–17 % of hail events and 17 %–32 % of tornado events are associated with MCSs, depending on the criteria used to define MCSs. The highest total and MCS-associated hazard events occur from March to May, while the highest MCS-associated portion (23 % for hail and 45 % for tornadoes) is observed in winter (December–February) due to the dominance of MCSs caused by strong synoptic forcing. As hailstone size increases, the fraction associated with MCS decreases, but there is an increasing trend for tornado severity from EF0 to EF3 (Enhanced Fujita Scale). Violent tornadoes at EF4 and EF5 associated with MCSs were also observed, which are generated by supercells embedded within MCSs.

54 ENVIRONMENTAL SCIENCES↗

Utilization of satellite data for inventorying prairie ponds and lakes

ERTS-1 data were used in mapping open surface water features in the glaciated prairies. Emphasis was placed on the recognition of these features based upon water's uniquely low radiance in a single near-infrared waveband. On the basis of these results, thematic maps and statistics relating to open surface water were obtained. In a related effort, the added information content of multiple spectral wavebands was used for discriminating surface water at a level of detail finer than the virtual resolution of the data. The basic theory of this technique and some preliminary results are described.

Work, E. A., Jr.↗

Transforming AdaPT to Ada9x

How the concepts of AdaPT can be transformed into programs using the object oriented features proposed in the preliminary mapping for Ada9x are described. Emphasizing, as they do, the importance of data types as units of program, these features match well with the development of partitions as translations into Abstract Data Types which was exploited in the Ada83 translation covered in report R3. By providing a form of polymorphic type, the Ada83 version also gives support for the conformant partition idea which could be achieved in Ada83 only by using UNCHECKED CONVERSIONS. It is assumed that the reader understands AdaPT itself, but the translation into Ada83 is briefly reviewed, by applying it to a small example. This is then used to show how the same translation would be achieved in the 9x version. It is important to appreciate that the distribution features which are proposed in current mapping are not used or discussed in any detail, as those are not well matched to the AdaPT approach. Critical evaluation and comparison of these approaches is given in a separate report.

Goldsack, Stephen J.↗

The Use of Thermal Cameras for Pedestrian Detection

Visible-range camera sensors have been widely used for pedestrian detection. However, most of the methods, which employ visible-range color cameras, do not perform well under low-light and no-light conditions, e.g. during night time. Since the working principle of thermal camera sensors is mainly based on temperature and not light, they have been employed for person detection to overcome the drawbacks of visible-range sensors under these conditions. Every object gives off thermal energy, which is captured by a thermal camera sensor. When an object becomes hotter, it emits more thermal energy, and is therefore captured as much brighter or vice versa. Yet, compared to visible-range cameras, there are many additional challenges that need to be addressed when detecting pedestrians from thermal camera images. These challenges include bright hot objects close to humans, similar pixel values in an image due to weather conditions, or objects that block thermal cameras such as concrete or glass. Glass acts like a mirror for infrared radiation and reflects whatever is in front of the camera. Thus, novel methods are still required to accomplish pedestrian detection task from thermal camera images. To contribute to these efforts, we propose a new method and a modified object detection network incorporating saliency maps of thermal camera images. The features obtained from thermal images and their corresponding saliency maps are combined to obtain richer representations of pedestrian regions, and better detection performance. We perform extensive evaluations on five different datasets to compare the performance of the proposed approach with two baselines. Moreover, we evaluate and compare the transferability of these approaches by doing leave-one-out cross validation across different datasets. Furthermore, the results show that the proposed approach outperforms the baselines, and has better transferability properties across different thermal image datasets.

47 OTHER INSTRUMENTATION↗

Characterization of Io's volcanic activity by infrared polarimetry

The thermal emission from Io's volcanic hot spots is linearly polarized. Infrared measurements at 4.76 micrometers show disk-integrated polarization as large as 1.6 percent. The degree and position angle of linear polarization vary with Io's rotation in a manner characteristic of emission from a small number of hot spots. A model incorporating three hot spots best fits the data. The largest of these hot spots lies to the northeast of Loki Patera, as mapped from Voyager, and the other spot on the trailing hemisphere is near Ra Patera. The hot spot on the leading hemisphere corresponds to no named feature on the Voyager maps. The value determined for the index of refraction of the emitting surface is a lower bound; it is similar to that of terrestrial basalts and is somewhat less than that of sulfur.

Goguen, J. D.↗

Magellan - Early results from the Venus mapping mission

Some results obtained with the Magellan Venus Radar Mapper are presented. Mapping was initiated on October 26, 1990 and has completed over 714 orbits of image data, covering 40 percent of the surface of Venus. Mapping began at 330 deg east longitude, mapping from the north pole to about 78 deg south latitude. Included are the regions of Ishtar Terra, Sedna, Guinevere and Lavinia Planitiae, and Lada Terra. Features discernable from the mapping include high and lowland plains, evidence of volcanic activity, and impact craters from 6 km to over 50 km across. Some Magellan scientific discoveries are listed, including evidence of a predominant role of ballistic volcanism, extensive and intensive tectonics, a moderate rate of volcanic and tectonic resurfacing, and a low rate of weathering and wind erosion. Other discoveries concerning techntonics, volcanism, impact cratering, and exogenous resurfacing are also listed. Magellan image coverage is discussed, and a chronology of the development of VOIR and Magellan is provided.

Saunders, R. S.↗

Geological remote sensing of Palaeogene rocks in the Wind River Basin, Wyoming, USA

Remote sensing studies of Palaeogene sediments in the Wind River Basin (Wyoming) were used for mapping stratigraphic units, sedimentary features and facies, and structural patterns. Thematic Mapper principal component images for the central and eastern Wind River Basin along with geological investigations and spectral analyses allowed: mapping of the Fort Union, Wind River, and Wagon Bed formations (Fm) and their subunits; recognition of two subunits in the Wind River Fm, one of which can be traced for 75 km; determination of sediment source and depositional environment of units within the Wind River Fm; correlation of the Wagon Bed Fm across the basin; and apparent confirmation of different sources of volcanic debris in the western and southeastern exposures of the Wagon Bed Fm.

Krishtalka, L.↗

Finding curvilinear features in speckled images

A method for finding curves in digital images with speckle noise is described. The solution method differs from standard linear convolutions followed by thresholds in that it explicitly allows curvature in the features. Maximum a posteriori (MAP) estimation is used, together with statistical models for the speckle noise and for the curve-generation process, to find the most probable estimate of the feature, given the image data. The estimation process is first described in general terms. Then, incorporation of the specific neighborhood system and a multiplicative noise model for speckle allows derivation of the solution, using dynamic programming, of the estimation problem. The detection of curvilinear features is considered separately. The detection results allow the determination of the minimal size of detectable feature. Finally, the estimation of linear features, followed by a detection step, is shown for computer-simulated images and for a SAR image of sea ice.

Samadani, Ramin↗

Kilometer-Scale Topographic Roughness of Mercury: Correlation with Geologic Features and Units

We present maps of the topographic roughness of the northern circumpolar area of Mercury at kilometer scales. The maps are derived from range profiles obtained by the Mercury Laser Altimeter (MLA) instrument onboard the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission. As measures of roughness, we used the interquartile range of profile curvature at three baselines: 0.7 kilometers, 2.8 kilometers, and 11 kilometers. The maps provide a synoptic overview of variations of typical topographic textures. They show a dichotomy between the smooth northern plains and rougher, more heavily cratered terrains. Analysis of the scale dependence of roughness indicates that the regolith on Mercury is thicker than on the Moon by approximately a factor of three. Roughness contrasts within northern volcanic plains of Mercury indicate a younger unit inside Goethe basin and inside another unnamed stealth basin. These new data permit interplanetary comparisons of topographic roughness.

Kilometer-Scale↗

Terrain mapping for a roving planetary explorer

A prototype legged vehicle is being developed for an exploratory mission on another planet, conceivably Mars, where it is to traverse uncharted areas and collect material samples. The rover can construct from range imagery a geometric terrain representation; i.e., elevation map that includes uncertainty, unknown areas, and local features. An algorithm for constructing an elevation map from a single range image is presented: by virtue of working in spherical-polar space, the algorithm is independent of the desired map resolution and the orientation of the sensor, unlike algorithms that work in Cartesian space. Also presented is a two-stage matching technique (feature matching followed by iconic matching) that identifies the transformation T corresponding to the vehicle displacement between two viewing positions. To support legged locomotion over rough terrain, methods for evaluating regions of the constructed elevation maps as footholds are developed.

Hebert, M.↗

Hyperspectral Feature Detection Onboard the Earth Observing One Spacecraft using Superpixel Segmentation and Endmember Extraction

We present a demonstration of onboard hyperspectral image processing with the potential to reduce mission downlink requirements. The system detects spectral endmembers and then uses them to map units of surface material. This summarizes the content of the scene, reveals spectral anomalies warranting fast response, and reduces data volume by two orders of magnitude. We have integrated this system into the Autonomous Science craft Experiment for operational use onboard the Earth Observing One (EO-1) Spacecraft. The system does not require prior knowledge about spectra of interest. We report on a series of trial overflights in which identical spacecraft commands are effective for autonomous spectral discovery and mapping for varied target features, scenes and imaging conditions.

Superpixel Endmember Detection↗

Statistics of galaxy orientations - Morphology and large-scale structure

Using the Uppsala General Catalog of bright galaxies and the northern and southern maps of the Lick counts of galaxies, statistical evidence of a morphology-orientation effect is found. Major axes of elliptical galaxies are preferentially oriented along the large-scale features of the Lick maps. However, the orientations of the major axes of spiral and lenticular galaxies show no clear signs of significant nonrandom behavior at a level of less than about one-fifth of the effect seen for ellipticals. The angular scale of the detected alignment effect for Uppsala ellipticals extends to at least theta of about 2 deg, which at a redshift of z of about 0.02 corresponds to a linear scale of about 2/h Mpc.

Lambas, Diego G.↗

Crystallographic Mapping and Tuning of Water Adsorption in Metal–Organic Frameworks Featuring Distinct Open Metal Sites

Crucial steps toward designing water sorption materials and fine-tuning their properties for specific applications include precise identification of adsorption sites and establishment of rigorous molecular-level insight into the water adsorption process. We report stepwise crystallographic mapping and DFT computations of adsorbed water molecules in ALP-MOF-1, a metal-organic framework decorated with distinct open metal sites and carbonyl functional groups that serve as water anchoring sites for seeding the nucleation of a complex water network. Identification of an unusual water adsorption step in ALP-MOF-1 motivated the tuning of metal ion composition to carefully adjust water uptake. These studies provide direct evidence that the identity of the open metal sites in MOFs can dramatically affect water adsorption behavior between 0 and ~20% RH and that multiple proximal water anchoring sites along the MOF skeleton facilitate water uptake steps which could be potentially useful for applications requiring rapid and energetically facile water sorption.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Tethys geology and tectonics revisited

Tethys, a medium sized icy satellite of Saturn, was imaged by both Voyager 1 and 2 spacecraft at sufficiently high resolution to allow some geologic analysis. One fairly complete and several brief descriptions of Tethys' geology have been given. Partial results are given herein of a new analysis of Tethys' geology done as part of a comparative tectonic and cryovolcanic study of the saturnian satellites. A new geologic sketch map of Tethys' north polar area is given. This map is based on a sequence of images transformed to a polar stereographic projection at the same scale. The images present the same area under different illuminations, each of which brings out different features. A new global map is in progress.

Croft, Steven K.↗

Neutron Imaging Using Grating Interferometry: Exploiting phase contrast and dark-field imaging for <1μm feature detection in bulk materials (Summary Report)

Radiography is an important non-destructive characterization tool for many LANL missions. Contrast in conventional radiography results from attenuation of the incoming x-ray or neutron beam by the object. Neutrons have a great benefit in detecting light elements (e.g. hydrogen) in the presence of heavier elements and penetrate deeper than X-rays into many materials, but neutron radiography resolution is typically limited to ~50 μm. Cracks, voids, pores and a variety of other features smaller than this resolution are therefore undetectable in attenuation based neutron imaging. However, novel neutron imaging modalities leveraging off of interferometric methods, so-called neutron grating interferometry (NGI), are able to spatially map sub-micron features and interfacial features while also exploiting the neutron’s sensitivity to light elements and isotope specific contrast to enable material characterization otherwise impossible.

36 MATERIALS SCIENCE↗

The new Martian nomenclature of the International Astronomical Union

A new nomenclature for Martian regions and topographic features uncovered by Mariner 9, as officially adopted by the International Astronomical Union, is described. About 180 craters generally of diameters greater than 100 km have been named, as well as 13 classes of topographic features designated catena, chasma, dorsum, fossa, labyrinthus, mensa, mons, patera, planitia, planum, tholus, vallis, and vastitas. In addition seven craters and the Kepler Dorsum are named on Phobos, and two craters on Deimos. Coordinates and maps of each named feature are displayed.

De Vaucouleurs, G.↗