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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Use of satellite pictures for determining major shield fractures relevant for ore prospecting, northern Finland

The author has identified the following significant results. A combined analysis of LANDSAT 1 imagery, aeromagnetic and other maps, and aerial photos has revealed a dense network of bedrock fractures in northern Finland. They form several fracturing zones, which obviously represent surficial manifestations of major fractures. The fractures follow, in general, the eight main trends of crustal shear characteristics of the Baltic Shield, but show distinct deviations from them in detail. The major fracture zones divide the bedrock into a mosaic of polygonal blocks, which in many cases coincide with the main rock units of the area and are characterized by different patterns of internal fracturing. Known mineralizations show a tendency to concentrate along the fracture zones. Optical filtering of original LANDSAT images might provide a rapid tool for the analysis of major structural trends in extensive areas such as shields or entire continents.

Tuominen, H. V.↗
NASA NTRS1977

Investigations using data from LANDSAT-2

The author has identified the following significant results. New lands for forestation were set aside in the coastal area of Bangladesh, based on LANDSAT mosaics (Chittagong - 195,000 acres, Noakhali - 450,000 acres, Barisal - 360,000 acres, and Patuakhali - 225,000 acres). LANDSAT imageries were used for identification of drainage patterns in both the old and and new Comilla district.

Hossain, A.↗
NASA NTRS1977

LISP: Program is data. A historical perspective on MACLISP

There was a continuing development of the MACLISP system, spurred in great measure by the needs of MACSYMA development. In a mosaic, historical style, the major features of the system are reported. For each feature discussed, an attempt is made to mention the year of initial development, and the names of persons or projects primarily responsible for requiring, needing, or suggesting such features.

White, J. L.↗
NASA NTRS1976

General pattern of the turbid water in the Seto-inland sea extracted from multispectral imageries by the LANDSAT-1 and 2

The author has identified the following significant results. Each distribution pattern of turbid water changes with the time in accordance with daily tides, seasonal variation of tides, and occasional rainfall. Two cases of successfully repeated LANDSAT observations for the same sea regions suggested a general pattern of turbid water could be extracted for each region. Photographic and digital processes were used to extract patterns of turbid water separately from the cloud and smog-layer in MSS 4, 5, and 7 imageries. A mosaic of image-masked imageries displays a general pattern of turbid water for almost the entire Seto Inland Sea. No such pattern was extracted for the Aki-Nada south of Hiroshima City where the water is fairly polluted, nor for the Iyo-Nada where the water is generally clearer than in other regions of the Seto Inland Sea.

Maruyasu, T.↗
NASA NTRS1976

Mineralogy of the Ibitira eucrite and comparison with other eucrites and lunar samples

The mineralogy of the Ibitira meteorite is studied using single-crystal X-ray and energy-dispersive electron-probe techniques. It is shown that this strongly metamorphosed unbrecciated vesicular eucrite has a primary variolitic and secondary hornfelsic texture dominated by equant grains of pale-brown pyroxene (60%) set in an irregular matrix of plagioclase (30%). Minor phases are detected which indicate igneous crystallization, a prolonged metamorphic history, and vapor deposition. The following sequence of events is suggested as the simplest explanation for the mineralogical features observed: (1) crystallization of the meteorite in a lava flow; (2) prolonged annealing, reduction of primary spinel, and vapor deposition; (3) strong shock sufficient to modify the texture of the plagioclase grains; and (4) sufficient annealing to allow crystallization of the plagioclase as a subparallel mosaic and partial conversion to the low structural state. Evidence for this sequence is examined in detail, particularly in relation to the general features of eucrites, howardites, and mesosiderites

Steele, I. M.↗
NASA NTRS1978

Proposal for a study of computer mapping of terrain using multispectral data from ERTS-A for the Yellowstone National Park test site

The author has identified the following significant results. A terrain map of Yellowstone National Park showed plant community types and other classes of ground cover in what is basically a wild land. The map comprised 12 classes, six of which were mapped with accuracies of 70 to 95%. The remaining six classes had spectral reflectances that overlapped appreciably, and hence, those were mapped less accurately. Techniques were devised for quantitatively comparing the recognition map of the park with control data acquired from ground inspection and from analysis of sidelooking radar images, a thermal IR mosaic, and IR aerial photos of several scales. Quantitative analyses were made in ten 40 sq km test areas. Comparison mechanics were performed by computer with the final results displayed on line printer output. Forested areas were mapped by computer using ERTS data for less than 1/4 the cost of the conventional forest mapping technique for topographic base maps.

Smedes, H. W.↗
NASA NTRS1978

Computer image processing: Geologic applications

Computer image processing of digital data was performed to support several geological studies. The specific goals were to: (1) relate the mineral content to the spectral reflectance of certain geologic materials, (2) determine the influence of environmental factors, such as atmosphere and vegetation, and (3) improve image processing techniques. For detection of spectral differences related to mineralogy, the technique of band ratioing was found to be the most useful. The influence of atmospheric scattering and methods to correct for the scattering were also studied. Two techniques were used to correct for atmospheric effects: (1) dark object subtraction, (2) normalization of use of ground spectral measurements. Of the two, the first technique proved to be the most successful for removing the effects of atmospheric scattering. A digital mosaic was produced from two side-lapping LANDSAT frames. The advantages were that the same enhancement algorithm can be applied to both frames, and there is no seam where the two images are joined.

Abrams, M. J.↗
NASA NTRS1976

Computer image processing in marine resource exploration

Pictographic data or imagery is commonly used in marine exploration. Pre-existing image processing techniques (software) similar to those used on imagery obtained from unmanned planetary exploration were used to improve marine photography and side-scan sonar imagery. Features and details not visible by conventional photo processing methods were enhanced by filtering and noise removal on selected deep-sea photographs. Information gained near the periphery of photographs allows improved interpretation and facilitates construction of bottom mosaics where overlapping frames are available. Similar processing techniques were applied to side-scan sonar imagery, including corrections for slant range distortion, and along-track scale changes. The use of digital data processing and storage techniques greatly extends the quantity of information that can be handled, stored, and processed.

Paluzzi, P. R.↗
NASA NTRS1977

OSO-8 X-ray polarimeter and Bragg crystal spectrometer observations

Results are discussed for observations of the Crab Nebula, Cyg X-1, and Cyg X-2 with the focusing mosaic graphite crystal X-ray polarimeter aboard OSO-8 as well as for observations of A0620-00 with the Bragg crystal spectrometer aboard the same satellite. The observed X-ray polarization of the Crab Nebula is shown to be in agreement with a previous measurement of the optical polarization and to confirm with very high confidence the earlier conclusion that the X-ray emission occurs by the synchrotron process. No evidence is found for polarization of X-rays from Cyg X-1, but a preliminary result of 4.8% + or 1.0% polarization at an energy of 2.6 keV and a position angle of 141.7 + or - 6.6 deg is reported for Cyg X-2. It is noted that this value is within the range expected for accretion disks. The spectrometry of A0620-00 yielded a continuous spectrum that can be accurately fitted with a thermal bremsstrahlung spectrum at a temperature of 15 million K.

Novick, R.↗
NASA NTRS1978

Coded aperture imaging with uniformly redundant arrays

The paper discusses uniformly redundant arrays (URA) as applied to coded aperture imaging. The URA system offers the high-transmission characteristics of random arrays as well as a flat sidelobe advantage. The high-transmission yields the imaging of very low-intensity sources and the flat sidelobes provide the suppression of inherent noise which obscures low-contrast sources. Simulations have shown that the URA with shot and background noise produces a better reconstructed object than random arrays without shot or background noise. The URA also offers an arrangement which involves a mosaic of basic URA patterns forming a circular correlation of the object on the picture plane. Thus the information needed to reconstruct the object is contained in an area equal to that of the basic aperture pattern. This smaller required detector is important in applications including X-ray astronomy.

Fenimore, E. E.↗
NASA NTRS1977

Digital processing of the Mariner 10 images of Venus and Mercury

An extensive effort was devoted to the digital processing of the Mariner 10 images of Venus and Mercury at the Image Processing Laboratory of the Jet Propulsion Laboratory. This effort was designed to optimize the display of the considerable quantity of information contained in the images. Several image restoration, enhancement, and transformation procedures were applied; examples of these techniques are included. A particular task was the construction of large mosaics which characterize the surface of Mercury and the atmospheric structure of Venus.

Soha, J. M.↗
NASA NTRS1978

Venus in motion

A comprehensive set of television pictures of Venus taken by the Mariner 10 spacecraft is presented. Included is a chronological sequence of television images illustrating the development, variety, and circulation of Venus upper-atmospheric phenomena as viewed in the near-ultraviolet. The higher-resolution images have been assembled into global mosaics to facilitate comparison. Figures and tables describing the imaging sequences have been included to provide a guide to the more complete set of 3400 Venus images on file at the National Space Science Data Center.

Anderson, J. L.↗
NASA NTRS1977

A TiO2 abundance map for the northern maria

A map of TiO2 abundance for most of the northern maria is presented. The telescopic data base used is the 0.38/0.56-micron ratio mosaic from Johnson et at. (1977). The titanium content has been estimated using the correlation established by Charette et al. (1974). The combination of observational, processing, and calibration errors indicates that the TiO2 map is accurate to + or - 2% (wt% TiO2) for high TiO2 content (more than 5%) and + or - 1% for low values of TiO2. Analysis of the lunar sample and telescopic data suggests strongly that the spectral parameter mapped is sensitive primarily to TiO2 abundance in the range 3-9% and does not correlate directly with iron content. It is suggested, however, that for the low TiO2 mare regions (less than 2-3% TiO2) there may be a relation between the spectral ratio and iron content and that some of the reddest mare areas in the Imbrium region may have low iron contents as well as low titanium abundances.

Johnson, T. V.↗
NASA NTRS1975

The problem of the origin of symplectites in olivine-bearing lunar rocks

In a study of its origin in olivine-bearing lunar rocks, symplectite is grouped into the following types: (1) very abundant blebs in olivine phenocrysts, (2) scattered blebs in dunite, (3) scattered elongated masses along grain boundaries in troctolite, (4) scattered mosaic assemblages of coarser minerology along grain boundaries, (5) very abundant needle-like arrays, and (6) very abundant grains dispersed in rows. Four theories are proposed to explain the various symplectite distributions.

Bell, P. M.↗
NASA NTRS1975

Shock-induced subsolidus reduction-decomposition of orthopyroxene and shock-induced melting in norite 78235

Lunar rock 78235 is a coarse-grained igneous rock which was chipped from the top of a boulder about 1/2 m in size at Station 8 at the base of the Sculptured Hills, Taurus-Littrow Valley. The rock is a shocked coarse-grained norite with a relict subophitic texture; it is composed of about equal proportions of chromian bronzite and anorthite. Evidence is presented for the shock history of the rock. It is concluded that 78235 is a deep-seated norite of cumulate origin which has been intensely shocked. Although it may be possible to account for the observed shock-induced features by invoking a single shock event, the evidence is best explained by a history which includes at least two discrete shock events. In the first identifiable shock event much of the plagioclase was transformed to maskelynite and the associated bronzite was deformed and acquired a mosaic structure. In a later shock event, localized melting of both plagioclase pyroxene occurred.

Sclar, C. B.↗
NASA NTRS1978

Remote sensing applications to resource problems in South Dakota

The author has identified the following significant results. Change in the vegetative structure was taking place in the Black Hills. Temporal analysis of the areal extent of open meadows was accomplished using black and white and color infrared aerial photography. A reduction of nearly 1100 hectares of open meadows was determined using photointerpretation. Techniques were developed for the management of meandering lakes, including use of LANDSAT imagery for continuous monitoring, classification of hydrophytes on low altitude CIR imagery, and planning and evaluation of improvements and multiple uses on aerial photography and photo mosaics. LANDSAT data were analyzed statistically from small and entire study scene areas to determine the effect of soils stratifications of corn signatures. Band 5 early season and band 7 later season recorded the strongest evidence of the influence of soils on corn signatures. Significant strata were determined by a multiple range test.

Myers, V. I.↗
NASA NTRS1978

Information extraction from digital images of the earth and the planets

An overview is presented of recent developments at the JPL Image Processing Laboratory which emphasize the utilization of a digital computer to automate the process of information extraction from digital imagery. Consideration is given to: (1) the analysis of Viking Orbiter stereo imagery to determine elevation profiles of the Mars surface, (2) the use of Viking Lander stereo imagery to determine nonhazardous surface sample acquisition strategies, (3) the correlation of Landsat imagery with geographically referenced cultural data to determine land use trends, and (4) the generation of mosaics using digital computer techniques.

Green, W. B.↗
NASA NTRS1979

Recent developments at JPL in the application of image processing to astronomy

Four applications of image processing to astronomy, automated location and analysis of star and galaxy images, geometric and radiometric decalibration of vidicon spectra, display of multiband radio images, and generation of high resolution polarization direction and magnitude maps from images are presented with illustrative examples. The technique by which a digital image can be analyzed automatically to locate and segregate between stars and galaxies and the steps performed by the classifier to determine the nature of each object are outlined. The classification program executed on a 48 inch Schmidt plate of the cluster of galaxies 655 is described. The calibration and decalibration steps to remove geometric and radiometric distortions from a silicon vidicon camera digital spectra are discussed. Three methods of displaying multispectral radio data, generating a mosaic of each image, producing a color coded image to depict radio velocity, and producing a stereo pair with radial velocity as depth are described. The generation of polarization information from images obtained through linear polarizing filters is illustrated, and it is concluded that in each case information was displayed using digital techniques which could not readily have been provided visually.

Lorre, J. J.↗