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The development of a multispectral scanner data analysis console is reported that incorporates a wideband tape unit, a teletypewriter, a digital computer, and color display as well as numeric display terminals. The device is able to digitize infrared scanner images and displays color differences according to signal differences between analog channels.
Two clustering techniques were used for terrain mapping by computer of test sites in Yellowstone National Park. One test was made with multispectral scanner data using a composite technique which consists of (1) a strictly sequential statistical clustering which is a sequential variance analysis, and (2) a generalized K-means clustering. In this composite technique, the output of (1) is a first approximation of the cluster centers. This is the input to (2) which consists of steps to improve the determination of cluster centers by iterative procedures. Another test was made using the three emulsion layers of color-infrared aerial film as a three-band spectrometer. Relative film densities were analyzed using a simple clustering technique in three-color space. Important advantages of the clustering technique over conventional supervised computer programs are (1) human intervention, preparation time, and manipulation of data are reduced, (2) the computer map, gives unbiased indication of where best to select the reference ground control data, (3) use of easy to obtain inexpensive film, and (4) the geometric distortions can be easily rectified by simple standard photogrammetric techniques.
Statistical results and conclusions are presented, based on direct comparisons of the ocean's color and chlorophyll concentration. The ocean color and ground truth data for this analysis were collected during Mission 140 of NASA's NP3A earth resources aircraft over the period from 6 through 14 August 1970. During this experiment, chlorophyll and light attenuation data were collected. All sets of comparative observations are simultaneous in the sense that the ship began sampling when the aircraft came overhead.
Black and white infrared imageries obtained from satellites over the oceans were transformed into color presentations. Investigations in different regions (Persian Gulf, Arabian Coast, Somali Coast and the Northwest Coast of Australia) revealed that temperature gradients and temperature differences of two degrees Celsius can be displayed by the color process from the imageries. This data display can be used for a rapid analysis of information obtained with an APT station.
Description of a one-stage approximation to the color-conversion model of Richards and Parks (1971). The modified model proposes three channels for color vision, each with different center-surround sensitivities. In its strongest form, the model predicts that the gain-setting control that alters the sensitivities of each channel is solely a function of achromatic contrast.
The use of color infrared film to measure spatial and temporal changes in vegetation is discussed. The subjects presented are: (1) selection of the sensor, (2) collection of the data, and (3) analysis of the data. The effects of climatology and meteorological parameters on interpretation of the data are analyzed. It is concluded that the color infrared film will enhance the imagery of green plants and will accentuate differences between plants.
High resolution observations of intensity, color (UBV) and polarization were obtained with scanning techniques for a number of lunar areas of special interest, including boundaries of some of the brightest and darkest lunar regions, certain Apollo landing sites and prominent craters. Two dimensional raster scans of colors were obtained for Alphonsus, Aristarchus, and Herodotus. The degree of polarization for any given phase angle appears to be roughly indicative of age. The darker younger mare surface are more highly polarized than the lighter and older mare surfaces, which appear to be more contaminated by lighter material from the highlands or by ray material thrown out from fresh craters. All mare surfaces are more highly polarized than the still older and lighter terra regions surrounding the maria. The very oldest craters are either dark-floored and show polarization characteristics similar to those of the mare surfaces, or if located in the highlands, they are less and less distinguishable from the highland background with greater age, and show the general highland polarization characteristics.
The distribution of subtle but definite color variations on the lunar surface is analyzed using Apollo 16 photographs. Results show the strongest color variations and most distinct boundaries are concentrated in the northwest quadrant of the moon, where major boundaries correspond with distal fronts of a complex and prominent series of lava flows.
The success of the effort to extract several subsurface oceanographic parameters from remotely sensed ocean color data will depend to a great extent upon the existence of adequate theoretical models relating the desired oceanographic parameters to the upwelling radiances to be observed. In order to guide the development of these models, and to check their accuracies, a considerable amount of experimental work must be performed. The theoretical and experimental work needed to develop techniques for the quantitative analysis of satellite ocean color data is described.
Selected color photographs of Jupiter taken with the 154-cm Catalina reflector from October 1965 to September 1973 are presented. Eight oppositions are covered showing the developments in cloud belt structure and color distribution of the Jovian atmosphere.
The detection of ocean color changes, thought to be due to chlorophyll concentrations and gelbstoffe variations, is attempted from high altitude (11.3km) and low altitude (0.3km). The atmospheric back scattering is shown to reduce contrast, but not sufficiently to obscure color change detection at high altitudes.
It is pointed out that there is a discrepancy in the color of beta Lyr as obtained by observers in 1959 and the results of an observation in 1958 reported by Wood and Walker (1960). The 1958 transformation to the UBV system is reinvestigated because of the importance of this color difference for the understanding of the physical processes of beta Lyr and the possible secular variation of these processes.
Selected color photographs of Jupiter taken with the 154-cm Catalina reflector from October 1965 to September 1973 are presented. Eight oppositions are covered showing the developments in cloud belt structure and color distribution of the Jovian atmosphere.
The design, development, and evaluation of a prototype modular lens assembly with a self-contained field sequential color wheel is presented. The design of a color wheel of maximum efficiency, the selection of spectral filters, and the design of a quiet, efficient wheel drive system are included. Design tradeoffs considered for each aspect of the modular assembly are discussed. Emphasis is placed on achieving a design which can be attached directly to an unmodified camera, thus permitting use of the assembly in evaluating various candidate camera and sensor designs. A technique is described which permits maintaining high optical efficiency with an unmodified camera. A motor synchronization system is developed which requires only the vertical synchronization signal as a reference frequency input. Equations and tradeoff curves are developed to permit optimizing the filter wheel aperture shapes for a variety of different design conditions.
Peripheral visual response time was measured in seven dark adapted subjects to the onset of small (45' arc diam), brief (50 msec), colored (blue, yellow, green, red) and white stimuli imaged at 72 locations within their binocular field of view. The blue, yellow, and green stimuli were matched for brightness at about 2.6 sub log 10 units above their absolute light threshold, and they appeared at an unexpected time and location. These data were obtained to provide response time and no-response data for use in various design disciplines involving instrument panel layout. The results indicated that the retina possesses relatively concentric regions within each of which mean response time can be expected to be of approximately the same duration. These regions are centered near the fovea and extend farther horizontally than vertically. Mean foveal response time was fastest for yellow and slowest for blue. Three and one-half percent of the total 56,410 trials presented resulted in no-responses. Regardless of stimulus color, the lowest percentage of no-responses occurred within 30 deg arc from the fovea and the highest within 40 deg to 80 deg arc below the fovea.
A pair of solid state electro-optic filters (SSEF) in a binocular holder were designed and fabricated for evaluation of field sequential stereo TV applications. The electronic circuitry for use with the stereo goggles was designed and fabricated, requiring only an external video input. A polarizing screen suitable for attachment to various size TV monitors for use in conjunction with the stereo goggles was designed and fabricated. An improved engineering model 2 filter was fabricated using the bonded holder technique developed previously and integrated to a GCTA color TV camera. An engineering model color filter was fabricated and assembled using PLZT control elements. In addition, a ruggedized holder assembly was designed, fabricated and tested. This assembly provides electrical contacts, high voltage protection, and support for the fragile PLZT disk, and also permits mounting and optical alignment of the associated polarizers.
The results from the Celescope Catalog of Ultraviolet Stellar Observations (Davis, Deutschman, and Haramundanis 1973) are studied, emphasizing statistical groups and subgroups of stars. In spite of the rather large observational errors, the great number of Celescope observations make it possible to do that kind of study with reasonable accuracy. Some stars have ultraviolet colors that differ significantly from those of the group to which they have been assigned on the basis of ground-based observations. An attempt is made to describe the general properties of the ultraviolet colors of the stars as observed by the Celescope experiment on board NASA's Orbiting Astronomical Observatory (OAO-2). Besides the direct applicability of these results to the general study of stellar atmospheres and of interstellar extinction, they are also considered as a frame of reference for further studies of individual stars and groups of stars.
Photometry obtained in 1973 on the uvby system yields high-precision rotational light curves for Io, Europa, and Ganymede at a mean phase angle of about 6 deg. By combining our observations with photometry obtained by others over a broader range of phase angle, we also derive improved values for the phase coefficients and opposition surges of the four Galilean satellites. The values of V(1, 0) obtained by linear extrapolation to zero phase are accurate to + or - 0.03 magnitudes. We also derive the colors of the sun on the uvby system and use these to obtain albedos of the satellites in four colors.