Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Imagery”

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 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Hydrographic charting from LANDSAT Satellite: A comparison with aircraft imagery

The relative capabilities of two remote-sensing systems in measuring depth and, consequently, bottom contours in sandy-bottomed and sediment-laden coastal waters were determined quantitatively. The multispectral scanner (MSS), orbited on the LANDSAT-2 Satellite, and the ocean color scanner (OCS), flown on U-2 aircraft, were used. Analysis of imagery taken simultaneously indicates a potential for hydrographic charting of marine coastal and shallow shelf areas, even when water turbidity is a factor. Several of the eight optical channels examined on the OCS were found to be sensitive to depth or depth-related information. The greatest sensitivity was in OCS-4(0.544 + or - 0.012 microns) from which contours corresponding to depths up to 12m were determined. The sharpness of these contours and their spatial stability through time suggests that upwelling radiance is a measure of bottom reflectance and not of water turbidity. The two visible channels on LANDSAT's MSS were less sensitive in the discrimination of contours, with depths up to 8m in the high-gain mode (3x) determined in MSS-4(0.5 to 0.6 microns).

Middleton, E. M.↗
NASA NTRS1976

The use of ERTS/LANDSAT imagery in relation to airborne remote sensing for terrain analysis in western Queensland, Australia

The author has identified the following significant results. Series of linears were identified on the March imagery of Lady Annie-Mt. Gordon fault zone area. The series with a WSW-ENE orientation which is normal to the major structural units and also several linears with NNW-SSE orientation appears to be particularly important. Copper mineralization is known at several localities where these linears are intersected by faults. Automated outputs using supervised methods involving the selection of training sets selected by visual recognition of spectral signatures on the color composites obtained from combinations of MSS bands 4, 5 and 7 projected through appropriate filters, were generated.

Cole, M. M.↗
NASA NTRS1976

Digital processing of satellite imagery application to jungle areas of Peru

The author has identified the following significant results. The use of clustering methods permits the development of relatively fast classification algorithms that could be implemented in an inexpensive computer system with limited amount of memory. Analysis of CCTs using these techniques can provide a great deal of detail permitting the use of the maximum resolution of LANDSAT imagery. Potential cases were detected in which the use of other techniques for classification using a Gaussian approximation for the distribution functions can be used with advantage. For jungle areas, channels 5 and 7 can provide enough information to delineate drainage patterns, swamp and wet areas, and make a reasonable broad classification of forest types.

Pomalaza, J. C.↗
NASA NTRS1975

Exploiting the temporal coherence of repetitive satellite imagery

Imagery from ERTS or the Synchronous Meteorological Satellites, because of its precisely repetitive nature, is ideally suited both for subjective enhancement by time-lapse display and for objective measurements of changes with time. A hybrid system providing both viewing and image-processing functions is described. A representative application involves the measurement of changes in the aerial extent of snow cover within specified mountain watersheds. Subjective viewing of time-lapse sequences of the snow scenes provides valuable insight into the nature of numerous extraneous signals, permitting the interim implementation of operationally useful snow-measuring systems and hopefully leading toward the design of fully objective classifiers.

Evans, W. E.↗
NASA NTRS1976

Apollo 16 far ultraviolet imagery of the polar auroras, tropical airglow belts, and general airglow

Far-ultraviolet imagery of the earth in the wavelength ranges from 1050 to 1600 A and from 1250 to 1600 A was obtained from the lunar surface during the Apollo 16 mission on Apr. 21, 1972. The images have an angular resolution of about 2 arcmin (230-km linear resolution) and have been quantitatively analyzed to obtain absolute intensities and spatial distributions of the polar auroras (both wavelength ranges), the day and night airglow, and tropical airglow belts (1250-A to 1600-A wavelength range). The observations are consistent with previous results obtained from the OGO-4 spacecraft, but they have also provided details on the spatial distributions of the various emissions over an entire hemisphere at a single time. A general night airglow, at least in the Northern Hemisphere, is indicated.

Carruthers, G. R.↗
NASA NTRS1975

Stream pattern analysis using optical processing of ERTS imagery of Kansas

A spatial frequency analysis was carried out to obtain large-scale geologic and other ground pattern spatial frequency and orientational data from an optical data processing system using Earth Resources Technology Satellite-1 (ERTS-1) imagery of Kansas as input. The Diffraction Pattern Sampling Unit (DPSU) of the optical data processing system consists of a photodiode array containing 32 wedge-shaped photodiodes and 32 annular ring diodes. The curve obtained from the intensity distribution of the frequency spectrum yielded by the ring diodes gives the spatial frequency contributions due to ground features on the image. The curve obtained from the wedge-shaped diodes indicates the orientation of features in the sample area. Ten sample sites were used for each of eight geologic-physiographic regions. Comparison of ERTS-1 images with their respective spatial frequency and orientational curves reveals that preferred orientations of drainage produce recognizable peaks.

Mccauley, J.↗
NASA NTRS1976

Lunar cartography with the Apollo 17 ALSE radar imagery

Lunar position differences between thirteen craters in Mare Serenitatis were computed from VHF radar-imagery obtained by the Lunar Sounder instrument flown on the Apollo 17 command module. The radar-derived position differences agree with those obtained by conventional photogrammetric reductions of Apollo metric photography. This demonstrates the feasibility of using the Apollo Lunar Sounder data to determine the positions of lunar features along the Apollo 17 orbital tracks. This will be particularly useful for western limb and farside areas, where no Apollo metric camera pictures are available.

Tiernan, M.↗
NASA NTRS1976

Application of Landsat imagery to metallic mineral exploration in Utah

Standard interpretive techniques were used to study the mosaic of two Landsat images of north central Utah including several major mining districts. Correlation of major Landsat-identified lineaments with the major metallic mining districts suggests that the Landsat-identified lineaments are fractures and that their distribution may be a valuable guide for identifying other mineralized areas. The imagery provides a more complete understanding of the geological information for identifying major tectonic and structural trends in the area. Several of the major mines are located on or closely adjacent to the intersections of at least two major lineaments. Landsat data should therefore be used to complement current mineral exploration programs.

Anderson, A. T.↗
NASA NTRS1977

Autonomous rendezvous and feature detection system using TV imagery

Algorithms and equations are used for conversion of standard television imaging system information into directly usable spatial and dimensional information. System allows utilization of spacecraft imagery system as sensor in application to operations such as deriving spacecraft steering signal, tracking, autonomous rendezvous and docking and ranging.

Rice, R. B., Jr.↗
NASA NTRS1976

The use of ERTS/LANDSAT imagery in relation to airborne remote sensing for terrain analysis in western Queensland, Australia

The author has identified the following significant results. Distinctive spectral signatures were found associated with areas of near surface bedrock with covered ground east of Dugald River and along the Thorntonia River valley west of Lady Annie. Linears identified in the Dugald River area on LANDSAT 2 imagery taken in March and July 1975 over the Cloncurry-Dobbyn area, displayed preferred orientation. A linear group with NE-SW orientation was identified in the Lady Annie area. In this area, the copper mineralization in the Mt. Kelly area occurs along a well marked linear with NNW/SSE direction apparent on images for March, September, and November 1975. Geobotanical anomalies provided surface expression of the copper deposits in Mt. Kelley.

Cole, M. M.↗
NASA NTRS1976

Michigan resource inventories: Characteristics and costs of selected projects using high altitude color infrared imagery. Remote Sensing Project

The procedures and costs associated with mapping land cover/use and forest resources from high altitude color infrared (CIR) imagery are documented through an evaluation of several inventory efforts. CIR photos (1:36,000) were used to classify the forests of Mason County, Michigan into six species groups, three stocking levels, and three maturity classes at a cost of $4.58/sq. km. The forest data allow the pinpointing of marketable concentrations of selected timber types, and facilitate the establishment of new forest management cooperatives. Land cover/use maps and area tabulations were prepared from small scale CIR photography at a cost of $4.28/sq. km. and $3.03/sq. km. to support regional planning programs of two Michigan agencies. procedures were also developed to facilitate analysis of this data with other natural resource information. Eleven thematic maps were generated from Windsor Township, Michigan at a cost of $1,500 by integrating grid-geocoded land cover/use, soils, topographic, and well log data using an analytical computer program.

Enslin, W. R.↗
NASA NTRS1977

Preliminary analysis of remote infrared imagery of shuttle during entry: An aerothermodynamic flight experiment

The preliminary feasibility of remote high-resolution infrared imagery of the space shuttle orbiter lower surface during entry to obtain accurate measurements of aerodynamic heat transfer to that vehicle was examined. In general, it was determined that such such images can be taken from an existing aircraft/telescope system (the C-141 AIRO) with a minimum modification or addition of systems using available technology. These images will have a spatial resolution of about 0.3 m and a temperature resolution much better than 2.5 percent. The data from these images will be at conditions and at a scale not reproducible in ground based facilities and should aid in the reduction of the prudent factors of safety required to account for phenomenological uncertainties on the thermal protection system design. Principal phenomena to be observed include laminar heating, boundary-layer transition, turbulent heating, surface catalysis, and flow separation and reattachment.

Swenson, B. L.↗
NASA NTRS1977

The application of ERTS imagery to the FAO/Unesco soil map of the world

The author has identified the following significant results. It was concluded that direct identification and mapping of the various soil degradation forms and intensities from the color composite imager was generally difficult, if not impossible. The imagery, however, provided valuable information on some main environmental criteria which can be used in connection other available field data to assess actual soil degradation and estimate soil degradation hazards.

Dudal, R. J.↗
NASA NTRS1976

Optical vs. electronic enhancement of remote sensing imagery

Basic aspects of remote sensing are considered and a description is provided of the methods which are employed in connection with the optical or electronic enhancement of remote sensing imagery. The advantages and limitations of various image enhancement methods and techniques are evaluated. It is pointed out that optical enhancement methods and techniques are currently superior to electronic ones with respect to spatial resolution and equipment cost considerations. Advantages of electronic procedures, on the other hand, are related to a greater flexibility regarding the presentation of the information as an aid for the interpretation by the image analyst.

Colwell, R. N.↗
NASA NTRS1977

Picture processing of SAR L-band imagery

Data digitization and thresholding are applied to two scenes - sea ice and fresh-water lakes - to define the possible uses of automatic picture processing of uncalibrated SAR L-band imagery. It is shown that certain types of features, those which have constant returns which are also very high or very low in intensity can be effectively studied using simple automatic picture processing techniques applied to uncalibrated radar data. In areas which are generally inaccessible or in which monitoring of the changes of some types of earth surfaces are required, the uncalibrated SAR data can provide valuable inputs for modeling and mapping purposes.

Bryan, M. L.↗
NASA NTRS1977

An image-processing system applied to earth-resource imagery

The Harwell Image Processing System (HIPS) has been adapted for processing earth-resource imagery in either film or tape format. Data from film are obtained using a computer-controlled flying-spot scanner. Local rapid interactive processing is based on a PDP 11/20 minicomputer which has suitable display facilities for immediate visual appraisal of results and also a fast data link to an IBM 370/168 computer complex. An extensive subroutine library is being assembled for data preprocessing and feature extraction. This chapter includes a discussion of the basic principles of image analysis, a description of the HIPS system, and finally, for illustrative purposes, a description of several simple software routines.

Carter, P.↗
NASA NTRS1977

Landsat imagery for surface-mine inventory

The feasibility of using Landsat imagery for routine monitoring of surface mining and reclamation was tested in a two-county (1541 sq km) area of western Maryland. Two digital analysis methods were studied. The first, a four-band analysis distinguishing various strip mine associated classes and conditions, proved useful, but has limited extendibility over a seasonal or annual period. In the second approach, a band-ratio method was developed for measuring disturbed surface areas, and it proved to be both temporally and geographically extendible. For mines ranging between 31 and 244 acres, the measurement accuracy of total affected acreage was 92%. The use of Landsat satellite data together with multilevel sampling of aircraft and field verification inspections has shown that multispectral analysis of digital data is an effective means of monitoring the progress of surface mining operations.

Anderson, A. T.↗