Search NASA⌕ Search

SEARCH · Search NASA

Results for “color mapping”

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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Computability of five-color maps

Aside from the mathematical question as to whether any planar map can be colored with four or five colors so that no adjacent regions are assigned the same color, there is a computational problem of finding a coloration for a given map. This report presents an algorithm for the five-color problem which has an asymptotic computing time which is proportional to the square of the number of regions, at worst. The algorithm can be modified to produce six-color maps in linear time. The algorithm has been implemented for practical use in an image processing system and can be used in practical cases to produce four-color maps.

Mclemore, B. D.↗
NASA NTRS1990

Color maps of Arp 146

Four color maps of Arp 146 are given. The structure and color of the ring galaxy and its companion show evidence of a bridge of material between the companion and the remnant nucleus of the original galaxy now forming the ring. Broad band spatial coverage clearly defines regions of starburst occurrence.

Schultz, A. B.↗
NASA NTRS1988

Color maps of X-ray globular clusters

The results of a search for optical counterparts to X-ray sources in six globular clusters, 47 Tuc, NGC 1851, NGC 6441, NGC 6624, NGC 6712, and M15, are reported. Maps of the U-B color of the central regions of the clusters were prepared. A candidate for the optical counterpart of the source in NGC 6712 was found, along with a blue region near the X-ray source in 47 Tuc. Upper limits on the colors and magnitudes of possible optical counterparts are reported for the other three clusters. The use of color maps to determine color gradients in globular clusters is explored. It is found that, while such gradients do exist and vary from cluster to cluster, they can be explained by crowding effects. Crude limits are placed on the excess populations of blue objects such as CVs, which have been postulated to be concentrated in the centers of dense clusters.

Bailyn, Charles D.↗
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 NTRS1992

Near-infrared images and color maps of Arp 220

Near-infrared images (1.3-3.7 microns) are presented for the nuclear region of Arp 220. Color maps in J - H and H - K reveal steep gradients, and the two nuclei previously detected at 20 cm and 2.2 microns appear on the J - H image as peaks separated by 1 arcsec. Hot dust emission (T about 1000 K) at 3.7 microns and extremely red J - H and H - K colors are found for both nuclei. The increasingly red color approaching the center of the galaxy are explained most naturally by a mixture of extinction and emission by increasing amounts of hot dust. The near-infrared emission is consistent with a circumnuclear starburst extending to a radius of about 1.5 kpc from the nuclei; further from the center the colors are consistent with a normal late-type stellar population. Inside a radius of 1 kpc the color maps show a NE-SW elongation that aligns with the concentration of molecular gas seen in CO images. The observed 3.7-micron luminosity, when corrected for nuclear extinction determined by 10-micron silicate absorption measurements and normalized by the bolometric luminosity, is consistent with UV-excess quasars and is about 10 times greater than that found in infrared luminous starburst galaxies.

Mazzarella, J. M.↗
NASA NTRS1992

Compression of color-mapped images

In a standard image coding scenario, pixel-to-pixel correlation nearly always exists in the data, especially if the image is a natural scene. This correlation is what allows predictive coding schemes (e.g., DPCM) to perform efficient compression. In a color-mapped image, the values stored in the pixel array are no longer directly related to the pixel intensity. Two color indices which are numerically adjacent (close) may point to two very different colors. The correlation still exists, but only via the colormap. This fact can be exploited by sorting the color map to reintroduce the structure. The sorting of colormaps is studied and it is shown how the resulting structure can be used in both lossless and lossy compression of images.

Hadenfeldt, A. C.↗
NASA NTRS2018

It's Time for Color Vision Deficiency Friendly Color Maps in the Radar Community

Color Vision Deficiency (CVD) is a decreased ability to discern between particular colors. 8% of men and 0.4% of women have some form of CVD. An informal poll of AGU and AMS twitter followers yielded 10% of 70 respondents self identifying as having CVD. When presenting data on a two-dimensional plane it is common to use colors to represent values, the mapping between values and colors is known as a colormap. Colormap choice is personal and is influenced by: (1) Ability to highlight scientifically interesting data. (2) Institutional choices (supervisor insists on a certain colormap). (3) Domain dominance of a particular colormap (common in the radar community). Colormap choice should be influenced by: (1) Ability to highlight scientifically interesting data. (2) Perceptual uniformity (thus not creating artificial structure). (3) Approachability by those with visual impairments (CVD). (4) Ideally, but not always achievable, reproducibility in greyscale.

Colormap↗
NASA NTRS1990

Albedo and color maps of the Saturnian satellites

The paper discusses the production of maps of the albedos and colors of Mimas, Enceladus, Tethys, Dione, and Rhea over the full range of their imaged surfaces. Voyager images were used to prepare maps of the normal reflectances and color ratios (0.58/0.41 micron) of these satelites.

Buratti, Bonnie J.↗
NASA NTRS1991

Comparative global albedo and color maps of the Uranian satellites

The surfaces of the Uranian satellites Ariel, Miranda, Oberon, Titania, and Umbriel are characterized on the basis of Voyager observations. Tables of spectrophotometric data and maps of normal reflectances, green/violet ratios, and possible geological formations are presented and discussed in detail. Variations in albedo are found to be associated with impact features, and it is inferred from color differences that the upper surface of Ariel contains a higher proportion of redder material (tentatively identified as accreted low-albedo meteoritic dust) than those of the other moons.

Buratti, Bonnie J.↗
NASA NTRS2005

Self-Organizing-Map Program for Analyzing Multivariate Data

SOM_VIS is a computer program for analysis and display of multidimensional sets of Earth-image data typified by the data acquired by the Multi-angle Imaging Spectro-Radiometer [MISR (a spaceborne instrument)]. In SOM_VIS, an enhanced self-organizing-map (SOM) algorithm is first used to project a multidimensional set of data into a nonuniform three-dimensional lattice structure. The lattice structure is mapped to a color space to obtain a color map for an image. The Voronoi cell-refinement algorithm is used to map the SOM lattice structure to various levels of color resolution. The final result is a false-color image in which similar colors represent similar characteristics across all its data dimensions. SOM_VIS provides a control panel for selection of a subset of suitably preprocessed MISR radiance data, and a control panel for choosing parameters to run SOM training. SOM_VIS also includes a component for displaying the false-color SOM image, a color map for the trained SOM lattice, a plot showing an original input vector in 36 dimensions of a selected pixel from the SOM image, the SOM vector that represents the input vector, and the Euclidean distance between the two vectors.

Li, P. Peggy↗
NASA NTRS1987

A preliminary analysis of the Mariner 10 color ratio map of Mercury

A preliminary geological analysis of the Mariner 10 orange/UV color ratio map of Mercury is given, assuming a basaltic crust. Certain errors in the map are pointed out. The relationship between color and terrain are distinctly non-lunar. Rays and ejecta are bluer than average on Mercury, whereas they are redder on the Moon. This fact, along with the lack of the ferrous band in Mercury's spectral reflectance and smaller albedo contrasts, implies that the crust is low in Fe and Ti. There is no correlation between color boundaries and the smooth plains on Mercury, in contrast with the strong correlation between color and maria-highlands contacts on the Moon. The smooth plains are not Mercurian analogs of lunar maria, and a lunar-type of second wave melting did not occur. Ambiguous correlations between color and topography indicate that older, redder materials underlie younger, bluer rocks in many places on the planet, implying that the last stages of volcanism involved low-Fe lavas covering higher-Fe rocks. There is some evidence of late Fe-rich pyroclastic activity.

Rava, Barry↗
NASA NTRS1980

A color-ratio map of Mercury

Orange and UV frames are used to construct a color-ratio map of the portion of Mercury imaged by Mariner 10, with at least two independent color-ratio images being used for each region in order to prevent spurious, blemish-induced color. Color differences appear to be smaller than those of the moon, and many apparently fresh craters and their ray systems tend to be bluer than their surroundings. Regions of interesting color contrast are noted, and it is concluded that there is little evident correlation of color with either geology or topography.

Hapke, B.↗
NASA NTRS1986

Shaded-Color Picture Generation of Computer-Defined Arbitrary Shapes

SHADE computer program generates realistic color-shaded pictures from computer-defined arbitrary shapes. Objects defined for computer representation displayed as smooth, color-shaded surfaces, including varying degrees of transparency. Results also used for presentation of computational results. By performing color mapping, SHADE colors model surface to display analysis results as pressures, stresses, and temperatures. NASA has used SHADE extensively in sign and analysis of high-performance aircraft. Industry should find applications for SHADE in computer-aided design and computer-aided manufacturing. SHADE written in VAX FORTRAN and MACRO Assembler for either interactive or batch execution.

Cozzolongo, J. V.↗
NASA NTRS1987

An analysis of the Mariner 10 color ratio map of Mercury

Errors that emerged in the Hapke et al. (1980) geological analysis reproduction of the Mariner 10 orange/UV color ratio map of Mercury are presently noted, and it is judged that the relationships that emerge between the color and the terrain are nonlunar in that they lack Mercurian analogs of high Fe-Ti lunar maria basalts. The crust is found to be low in Fe(2+) and Ti(4+) in view of three major considerations: (1) rays and ejecta blankets are exceptionally blue; (2) the Fe(2+) band of the reflectance spectrum of Mercury is weak; and (3) Mercury albedo contrasts are less pronounced than the lunar ones. The extrusive origin of the smooth plains is supported by these observations.

Rava, Barry↗
NASA NTRS1974

Identification of irrigated crop types from ERTS-1 density contour maps and color infrared aerial photography

The author has identified the following significant results. The crop types of a Great Plains study area were mapped from color infrared aerial photography. Each field was positively identified from field checks in the area. Enlarged (50x) density contour maps were constructed from three ERTS-1 images taken in the summer of 1973. The map interpreted from the aerial photography was compared to the density contour maps and the accuracy of the ERTS-1 density contour map interpretations were determined. Changes in the vegetation during the growing season and harvest periods were detectable on the ERTS-1 imagery. Density contouring aids in the detection of such charges.

Marrs, R. W.↗
NASA NTRS1990

A comparison of ship and Coastal Zone Color Scanner mapped distribution of phytoplankton in the southeastern Bering Sea

Twenty-one Coastal Zone Color Scanner (CZCS) images of the southeastern Bering Sea are examined in order to map the near-surface distribution of phytoplankton during 1979 and 1980. The information is compared with the mesoscale (100-1000 km) distribution of phytoplankton inferred from pooled ship sampling obtained during the Processes and Resources of the Bering Shelf (PROBES) intensive field study during the late 1970s and early 1980s. The imagery indicates that open-water phytoplankton blooms occur first in late April in coastal waters, peak in early May over the middle shelf, and decay rapidly afterwards, reaching concentration minima in June in both regions. These patterns show that the earlier ship observations are valid for most of the eastern Bering shelf. A very tight correlation is found between the PROBES surface chlorophyll a concentrations and mean mixed-layer chlorophyll concentrations. The significant discrepancies between CZCS and ship-based chlorophyll estimates may be due to aliasing in time by the CZCS. It is concluded that neither satellite nor ship alone can do an adequate job of characterizing the physics or biological dynamics of the ocean.

Mcclain, C. R.↗