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At least 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Robot vision.

The work reported had been undertaken to develop hardware that would guide an automatic vehicle in the exploration of the surface of Mars, recognize objects, and report the findings to earth. Approaches for automatically determining the range and shape of objects are discussed, giving attention to the automatic comparison of one scan line of the left with one scan line of the right TV image. Methods of mapping binocular space into match space are considered together with the use of a model in match space, rules for processing random-dot stereograms, the elimination of spurious matches, random-square stereograms, questions of the processing of a real scene, and aspects of range accuracy. Methods of computation for extracting other features are also discussed along with stereo TV cameras and approaches for reconstructing the appearance of a scene.

Sutro, L. L.↗
NASA NTRS1975

Holographic direct-vision spectroscope

Spectroscope incorporates two prisms combined with holographic grating as dispersing element. This provides high dispersion with selective undeviated wavelength. Prisms with different indices of refraction and/or angles for construction and reconstruction may be used. Also, different prisms for input and output may be used.

Franke, J. M.↗
NASA NTRS1975

Orientational anisotropy in infant vision

Infants prefer to look at horizontal and vertical gratings rather than at oblique gratings only when they are at or near threshold spatial frequencies, as would be expected if acuity for oblique edges is lower than that for horizontal and vertical edges. That such a bias exists as early as 6 weeks of age suggests that the orientational asymmetry of the visual system depends on endogeneous maturation rather than exposure to a carpentered world.

Cohen Leehey, S.↗
NASA NTRS1975

Design parameters for a stereoptic television system based on direct vision depth perception cues

Remotely controlled systems which use television for visual feedback require that depth cues be available to the operator. A number of techniques have been developed to provide stereoptic video. An analysis of parameters of such systems as related to the depth cues of convergence and retinal disparity was carried out. Parameter requirements were determined for the provision of natural and exaggerated stereoptic cues and expressions were developed for range resolution limits based on the retinal disparity threshold. An empirical study was conducted using a stereoptic video system to determine threshold values

Shields, N. L., Jr.↗
NASA NTRS1978

Vision

Visual input methods are considered for the therapeutic treatment of autistic and brain-damaged patients, and to provide a controlled stress environment for visual perception problems.

Haines, R. F.↗
NASA NTRS1978

Visions of the future operational meteorological satellite system

Visionary concepts of the operational environmental satellite system of the 1990's are presented. These exploit planned and anticipated advances in technology. The system comprises 8 Low Earth Orbitors (LEOS) at 500 km height for global coverage at 3 hourly intervals and 3 Geosynchronous Earth Orbitors (GEOS) for Western Hemisphere coverage with stereo capability and near simultaneous viewing of several regional areas. The LEOS emphasize passive and active microwave and Lidar sensing; the GEOS focus on high resolution visible and IR imaging and passive soundings. The GEOS also serve as data relays from the LEOS and as data collection platforms for hazard-related data. An integrated data management system ties the space fleet together and blends the data with that from all other observing systems to process and distribute the data and products to all users.

Atlas, D.↗
NASA NTRS1986

Displacement thresholds in central and peripheral vision during tracking

The effects of stimulus duration and angular velocity on a subject's judgment of displacement threshold are examined. Twenty-six male subjects between 17-45 years with uncorrected 20:20 distance acuity and normal color perception and stereopsis studied a series of forced choice, paired comparison trials in which a long, thin, collimated horizontally oriented line moved downward through 12 angles ranging from 0.6-60 arcmin and judged which stimulus moved in each pair. The displacements were produced by 0.25, 0.5, 1, 2, and 4 sec stimulus duration and 2.5, 5, 10, and 15 deg/sec angular rates. Stimulus velocity, stimulus duration, mean threshold displacement, and mean confidence results are analyzed. It is observed that displacement judgment accuracy is increased with increasing stimulus duration. The data are compared with the results of Johnson and Leibowitz (1976) and Johnson and Scobey (1982), and good correlation with the Johnson and Leibowitz data is detected. The data reveal that threshold is based on a constant stimulus velocity over this range of durations and velocities. The data are applicable to the study of the final approach to landing of medium and large commercial jet aircraft.

Haines, R. F.↗
NASA NTRS1987

Computational models of human vision with applications

The research program supported by this grant was initiated in l977 by the Joint Institute for Aeronautics and Acoustics of the Department of Aeronautics and Astronautics at Stanford University. The purpose of the research was to study human performance with the goal of improving the design of flight instrumentation. By mutual agreement between the scientists at NASA-Ames and Stanford, all research activities in this area were consolidated into a single funding mechanism, NCC 2-307 (Center of Excellence Grant, 7/1/84 - present). This is the final report on this research grant.

Wandell, Brian A.↗
NASA NTRS1986

Space Station - Risks and vision

In assessing the prospects of the NASA Space Station program, it is important to take account of the long term perspective embodied in the proposal; its international participants are seen as entering a complex web of developmental and operational interdependence of indefinite duration. It is noted to be rather unclear, however, to what extent this is contemplated by such potential partners as the ESA, which has its own program goals. These competing hopes for eventual autonomy in space station operations will have considerable economic, technological, and political consequences extending well into the next century.

Pedersen, K.↗
NASA NTRS1986

Analysis of the retinex theory of color vision

Land's (1983) retinex algorithm is a model of human color constancy. The retinex algorithm is analyzed and its general properties are discussed. It is shown that the algorithm is too sensitive to changes in the color of nearby objects to serve as an adequate model of human color constancy.

Brainard, D. H.↗
NASA NTRS1987

Rekindled vision of hypersonic travel

NASA has joined with the DOD to conduct the National Aerospace Plane (NASP) program, whose experimental test vehicle will be designated the X-30. NASP will study the X-30's takeoff from a runway under its own power, acceleration to high Mach number on the basis of airbreathing propulsion, emergence into LEO, reentry into the earth atmosphere, and descent to a powered horizontal landing. NASP will thereby generate technology base data for three distinct types of aircraft: upper-atmosphere hypersonic-cruise aircraft, LEO space transports, and military transatmospheric vehicles. The current concept-validation phase of NASP focuses on airbreathing propulsion, lightweight/high-strength heat-resistant materials, and computational fluid dynamics.

Colladay, Raymond S.↗
NASA NTRS1987

Some vision algorithms

The ability to determine the contents of a scene by a machine has obvious applications. There are reasons for seeking horizontal, vertical and diagonal line segments of varying lengths in order to interpret the content of a scene. Such line segments aid in determining edges that determine the boundaries of objects within the scene. Algorithms for each of the above as well as for data compacting are presented.

Johnson, Gordon G.↗
NASA NTRS1988

An automated computerized vision technique for determination of three-dimensional object geometry

It is very important to determine three dimensional geometry of objects quickly in various military, space, construction, and industrial applications. An automatic scheme to obtain three dimensional geometry of objects by employing only one camera is presented. At present, this technique is applicable to a limited category of objects, satisfying the following constraints: they are flat-surfaces, and all the vertex points have to be recognized as corner points of the two dimensional image. The scheme consists of corner detection, data communication, camera calibration techniques and point searching and matching, edge cancelation, and creation procedures. An L shaped model is chosen as a test object. Experimental results demonstrated the reconstruction of this object geometry within 5 mm discrepancy. This scheme is quite convenient, efficient to use and can be applied to a wide range of problems in the real world.

Chiang, Pen-Tai↗
NASA NTRS1987

Visions of tomorrow: A focus on national space transportation issues; Proceedings of the Twenty-fifth Goddard Memorial Symposium, Greenbelt, MD, Mar. 18-20, 1987

The present conference on U.S. space transportation systems development discusses opportunities for aerospace students in prospective military, civil, industrial, and scientific programs, current strategic conceptualization and program planning for future U.S. space transportation, the DOD space transportation plan, NASA space transportation plans, medium launch vehicle and commercial space launch services, the capabilities and availability of foreign launch vehicles, and the role of commercial space launch systems. Also discussed are available upper stage systems, future space transportation needs for space science and applications, the trajectory analysis of a low lift/drag-aeroassisted orbit transfer vehicle, possible replacements for the Space Shuttle, LEO to GEO with combined electric/beamed-microwave power from earth, the National Aerospace Plane, laser propulsion to earth orbit, and a performance analysis for a laser-powered SSTO vehicle.

Soffen, Gerald A.↗
NASA NTRS1989

Shutter For VPPA-Welding Vision System

Conceptual electro-optical shutter subsystem regulates intensity of light entering video camera from variable-plasma-pulse-arc weld in process. Camera part of video system that enables welding technician to obtain better view of weld bead and puddle in light of arc. Electro-optical shutter opened during low-illumination viewing intervals near zero crossings of welding current, preventing overloading of video camera.

Lirette, Murray J.↗
NASA NTRS1987

Improved shape-signature and matching methods for model-based robotic vision

Researchers describe new techniques for curve matching and model-based object recognition, which are based on the notion of shape-signature. The signature which researchers use is an approximation of pointwise curvature. Described here is curve matching algorithm which generalizes a previous algorithm which was developed using this signature, allowing improvement and generalization of a previous model-based object recognition scheme. The results and the experiments described relate to 2-D images. However, natural extensions to the 3-D case exist and are being developed.

Schwartz, J. T.↗