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At least 235 records · Page 13

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NASA NTRS1972

The application of color display techniques for the analysis of Nimbus infrared radiation data

A color enhancement system designed for the Applications Technology Satellite (ATS) spin scan experiment has been adapted for the analysis of Nimbus infrared radiation measurements. For a given scene recorded on magnetic tape by the Nimbus scanning radiometers, a virtually unlimited number of color images can be produced at the ATS Operations Control Center from a color selector paper tape input. Linear image interpolation has produced radiation analyses in which each brightness-color interval has a smooth boundary without any mosaic effects. An annotated latitude-longitude gridding program makes it possible to precisely locate geophysical parameters, which permits accurate interpretation of pertinent meteorological, geological, hydrological, and oceanographic features.

Allison, L. J.↗

NASA NTRS1972

N-Color /Hg,Cd/Te photodetectors.

N-color (Hg,Cd)Te photodetectors capable of spectral band analysis have been fabricated, tested, and delivered. This paper discusses the state of the art in (Hg,Cd)Te n-color photoconductive detectors. Included is a discussion of narrow band two-color devices responsive in the region of 8-14 microns. Preliminary results are also included for a unique three-color (Hg,Cd)Te device with cutoff wavelengths of 9.1, 10.8, and 13.8 microns.

Halpert, H.↗

NASA NTRS1973

Intrinsic ultraviolet colors from OAO-2 Celescope observations for stars on the main sequence.

Intrinsic ultraviolet colors (Vi-V)o have been determined with ultraviolet magnitudes derived from several hundred observations taken with the photometers of OAO-2's Celescope experiment. Relationships between intrinsic ultraviolet color, (B-V)o, and spectral class are presented for main-sequence stars from B 0 to G 3. A brief description of the Celescope and its calibration is included, and a comparison of the determined colors is made with theoretical colors.

Haramundanis, K.↗

NASA NTRS1973

Application and evaluation of ERTS color composites for natural resources inventory

The author has identified the following significant results. Bolivia is participating the Earth Resources Technology Satellite Program. Within this program many interesting sets of images were received which were evaluated in the Bolivian ERTS Program. One of the images was obtained in color of the central part of the Bolivian Altiplano. The color composite and black and white images were compared in order to evaluate which class of ERTS-1 product furnishes more information about specific topics. It was found that the color composites give far more information, about 50% more data, in hydrology, geomorphology, vulcanism, geology, soils, and vegetation than can be obtained from black and white images of the same scene. For this reason, the project is processing with preference color composites of the whole country.

Brockmann, C. E.↗

NASA NTRS1974

Peripheral visual response time to colored stimuli imaged on the horizontal meridian

Two male observers were administered a binocular visual response time task to small (45 min arc), flashed, photopic stimuli at four dominant wavelengths (632 nm red; 583 nm yellow; 526 nm green; 464 nm blue) imaged across the horizontal retinal meridian. The stimuli were imaged at 10 deg arc intervals from 80 deg left to 90 deg right of fixation. Testing followed either prior light adaptation or prior dark adaptation. Results indicated that mean response time (RT) varies with stimulus color. RT is faster to yellow than to blue and green and slowest to red. In general, mean RT was found to increase from fovea to periphery for all four colors, with the curve for red stimuli exhibiting the most rapid positive acceleration with increasing angular eccentricity from the fovea. The shape of the RT distribution across the retina was also found to depend upon the state of light or dark adaptation. The findings are related to previous RT research and are discussed in terms of optimizing the color and position of colored displays on instrument panels.

Haines, R. F.↗

NASA NTRS1974

The use of color infrared aerial photography in determining salt marsh vegetation and delimiting man-made structures of Lynnhaven Bay, Virginia

Color infrared aerial photography was found to be superior to color aerial photography in an ecological study of Lynnhaven Bay, Virginia. The research was divided into three phases: (1) Determination of the feasibility of correlating color infrared aerial photography with saline wetland species composition and zonation patterns, (2) determination of the accuracy of the aerial interpretation and problems related to the aerial method used; and (3) comparison of developed with undeveloped areas along Lynnhaven Bay's shoreline. Wetland species composition and plant community zonation bands were compared with aerial infrared photography and resulted in a high degree of correlation. Problems existed with changing physical conditions; time of day, aircraft angle and sun angle, making it necessary to use several different characteristics in wetland species identification. The main characteristics used were known zonation patterns, textural signatures and color tones. Lynnhaven Bay's shoreline was 61.5 percent developed.

Holman, R. E., III↗

NASA NTRS1973

Satellite ocean color measurements

The application of pattern recognition to ocean color data analysis is considered. Due to weight, cost, and data transmission rate limitations, any mapping type remote sensor of ocean color must necessarily collect light from the sea in a finite number of channels. The optical properties of the sea are discussed together with the remote sensing of ocean color, an optical model of natural water, the microscopic optical model, the macroscopic optical model, multiple scattering theory, measurements of subsurface oceanographic parameters, measurements of bulk absorption and scattering properties, measurements of the up- and down-welling light field, and the techniques for ocean color data analysis.

Mccluney, W. R.↗

NASA NTRS1975

Human factors considerations for the use of color in display systems

Identified and assessed are those human factor considerations impacting an operator's ability to perform when information is displayed in color as contrasted to monochrome (black and white only). The findings provide valuable guidelines for the assessment of the advantages (and disadvantages) of using a color display system. The use of color provides an additional sensory channel (color perception) which is not available with black and white. The degree to which one can exploit the use of this channel is highly dependent on available display technology, mission information display requirements, and acceptable operational modes.

Demars, S. A.↗

NASA NTRS1976

Three-color photometry of HDE 226868 - The optical counterpart of Cygnus X-1

Results of UBV photoelectric observations of HDE 226868 (Cyg X-1) obtained on fifty nights during 1974 are presented. These observations show a light curve with the following characteristics: (1) two unequal light maxima and minima during the 5.6-day orbital period which exhibit a peak-to-peak magnitude change of about 0.07 mag in all colors; (2) a small phase-dependent color variation which results in a reddening in both color indices of about 0.003 mag at times of light minima; (3) erratic light variability on a general time scale of days with an amplitude of plus or minus 0.01 to 0.02 mag and no apparent color dependence.

Lester, D. F.↗

NASA NTRS1977

Full color hybrid display for aircraft simulators

A full spectrum color monitor, connected to the camera and lens system of a television camera supported by a gantry frame over a terrain model simulating an aircraft landing zone, projects the monitor image onto a lens or screen visually accessible to a trainee in the simulator. A digital computer produces a pattern corresponding to the lights associated with the landing strip onto a monochromatic display, and an optical system projects the calligraphic image onto the same lens so that it is superposed on the video representation of the landing field. The optical system includes a four-color wheel which is rotated between the calligraphic display and the lens, and an apparatus for synchronizing the generation of a calligraphic pattern with the color segments on the color wheel. A servo feedback system responsive to the servo motors on the gantry frame produces an input to the computer so that the calligraphically generated signal corresponds in shape, size and location to the video signal.

Chase, W. D.↗

NASA NTRS1978

A maximal chromatic expansion method of mapping multichannel imagery into color space

The author has identified the following significant results. A color film generation method that maximally expands the chromaticity and aligns Kauth brightness with the gray axis was presented. In comparison with the current LACIE film product, the new color film product has more contrast and more colors and appears to be brighter. The field boundaries in the new product were more pronounced than in the current LACIE product. The speckle effect was one problem in the new product. The yellowness speckle can be treated using an equation. This equation can be used to eliminate any speckle introduced by the greenness. This product leads logically toward another that will employ quantitative colorimetry which will account for some of the eye's perception of color stimuli.

Juday, R. D.↗

NASA NTRS1978

Color enhancement of landsat agricultural imagery: JPL LACIE image processing support task

Color enhancement techniques were applied to LACIE LANDSAT segments to determine if such enhancement can assist analysis in crop identification. The procedure involved increasing the color range by removing correlation between components. First, a principal component transformation was performed, followed by contrast enhancement to equalize component variances, followed by an inverse transformation to restore familiar color relationships. Filtering was applied to lower order components to reduce color speckle in the enhanced products. Use of single acquisition and multiple acquisition statistics to control the enhancement were compared, and the effects of normalization investigated. Evaluation is left to LACIE personnel.

Madura, D. P.↗

NASA NTRS1979

Automatic color map digitization by spectral classification

A method of converting polygon map information into a digital form which does not require manual tracing of polygon edges is discussed. The maps must be in color-coded format with a unique color for each category in the map. Color scanning using a microdensitometer is employed and a three-channel color separation digital data set is generated. The digital data are then classified by using a Gaussian maximum likelihood classifier, and the resulting digitized map is evaluated. Very good agreement is observed between the classified and original map.

Chu, N. Y.↗

NASA NTRS1979

Martian soil stratigraphy and rock coatings observed in color-enhanced Viking Lander images

Subtle color variations of martian surface materials were enhanced in eight Viking Lander (VL) color images. Well-defined soil units recognized at each site (six at VL-1 and four at VL-2), are identified on the basis of color, texture, morphology, and contact relations. The soil units at the Viking 2 site form a well-defined stratigraphic sequence, whereas the sequence at the Viking 1 site is only partially defined. The same relative soil colors occur at the two sites, suggesting that similar soil units are widespread on Mars. Several types of rock surface materials can be recognized at the two sites; dark, relatively 'blue' rock surfaces are probably minimally weathered igneous rock, whereas bright rock surfaces, with a green/(blue + red) ratio higher than that of any other surface material, are interpreted as a weathering product formed in situ on the rock. These rock surface types are common at both sites. Soil adhering to rocks is common at VL-2, but rare at VL-1. The mechanism that produces the weathering coating on rocks probably operates planet-wide.

Strickland, E. L., III↗

NASA NTRS1980

Initial coastal zone color scanner imagery

The characteristics of the Nimbus-7 Coastal Zone Color Scanner are presented and the atmospheric correction and bio-optical algorithms are reviewed. Comparison of imagery before and after atmospheric correction shows that water features such as color fronts and small scale eddies can be retrieved even through a hazy and horizontally inhomogeneous atmosphere. Imagery is also presented to show that features revealed in color are sometimes completely absent from simultaneous thermal imagery implying that color and thermal imagery can provide complementary rather than redundant information.

Gordon, H. R.↗

NASA NTRS1981

Use of ocean color scanner data in water quality mapping

Remotely sensed data, in combination with in situ data, are used in assessing water quality parameters within the San Francisco Bay-Delta. The parameters include suspended solids, chlorophyll, and turbidity. Regression models are developed between each of the water quality parameter measurements and the Ocean Color Scanner (OCS) data. The models are then extended to the entire study area for mapping water quality parameters. The results include a series of color-coded maps, each pertaining to one of the water quality parameters, and the statistical analysis of the OCS data and regression models. It is found that concurrently collected OCS data and surface truth measurements are highly useful in mapping the selected water quality parameters and locating areas having relatively high biological activity. In addition, it is found to be virtually impossible, at least within this test site, to locate such areas on U-2 color and color-infrared photography.

Khorram, S.↗

NASA NTRS1982

Analysis of ocean color scanner data from the Superflux III Experiment

The scanner collected data on October 15, 20, and 22, 1980. Single-channel gray-scale data products generated 5 minutes after the scanner were collected and showed details of the Chesapeake plume structure, suggesting that this quick-look capability could have potential use for experiments in real time. The Chesapeake Bay plume extended offshore about 5 nautical miles on October 15, and 7 nautical miles on October 20. Using the October 15 1980, data, a correlation coefficient of r = 0.889 was obtained between chlorophyll 'A' and the ratio of band 7 (664-684 nanometers) to band 9 (746-766 nanometers). This ratio was then used to calculate the average surface chlorophyll 'A' concentration of the water flowing out of the Chesapeak Bay. A ratio from the Ocean Color Scanner bands was created to simulate the ratio that the Multichannel Ocean Color Sensor uses to calculate chlorophyll A concentrations. Using the October 15, 1980, data set, this ratio has a correlation coefficient of r = -0.739 with the log of the chlorophyll 'A' and the ratio of band 2 minus band 4 to band 2 plus band 4 of the Ocean Color Scanner. No correlation is found between the Ocean Color Scanner data and total suspended solid measurements made on October 15, 1980.

Ohlhorst, C. W.↗

NASA NTRS1984

Color and Grey Scale in Sonar Displays

In spite of numerous publications 1 it is still rather unclear, whether color is of any help in sonar displays. The work presented here deals with a particular type of sonar data, i.e., LOFAR-grams (low frequency analysing and recording) where acoustic sensor data are continuously written as a time-frequency plot. The question to be answered quantitatively is, whether color coding does improve target detection when compared with a grey scale code. The data show significant differences in receiver-operating characteristics performance for the selected codes. In addition it turned out, that the background noise level affects the performance dramatically for some color codes, while others remain stable or even improve. Generally valid rules are presented on how to generate useful color scales for this particular application.

Kraiss, K. F.↗