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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.

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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Cartographic potential of a spacecraft line-array camera system - Stereosat

A study of the Stereosat mission, which may acquire analog/digital stereo image data of cartographic quality with linear array camera systems, is presented, with attention given to the Stereosat system and the mission parameters, the utilization of the Stereosat studies in order to indicate the nature and scope of the problems associated with recording image data of high geometric fidelity from spacecraft equipped with line array sensors, and the assessing of the possibilities of meeting the completeness and accuracy requirements of cartographic products. A 713-km circular, sun-synchronous, near polar orbit, with an inclination of 98.24 deg and a repeat cycle of 48 days is designed to insure global coverage of the earth's land masses during the three-year lifetime of the mission. Three cameras (fore, vertical, and aft looking), mounted so as to record stereotriplets for a 61.4 km wide swath at a nominal focal plane scale of 1:1,000,000, are considered. The IFOV of 15 m should be adequate for producing thematic and image maps at scales of 1:50,000 to 1:250,000. The value of the coverage to cartographers will be dictated by the accuracy of the digital image data, which is largely a function of satellite control.

Welch, R.↗
NASA NTRS2005

Automated generation of image products for Mars Exploration Rover Mission tactical operations

This paper will discuss, from design to implementation, the methodologies applied to MIPL's automated pipeline processing as a 'system of systems' integrated with the MER GDS. Overviews of the interconnected product generating systems will also be provided with emphasis on interdependencies, including those for a) geometric rectificationn of camera lens distortions, b) generation of stereo disparity, c) derivation of 3-dimensional coordinates in XYZ space, d) generation of unified terrain meshes, e) camera-to-target ranging (distance) and f) multi-image mosaicking.

products↗
NASA NTRS2004

Systematic Errors in Stereo PIV When Imaging through a Glass Window

This document assesses the magnitude of velocity measurement errors that may arise when performing stereo particle image velocimetry (PIV) with cameras viewing through thick, refractive window and where the calibration is performed in one plane only. The effect of the window is to introduce a refractive error that increases with window thickness and the camera angle of incidence. The calibration should be performed while viewing through the test section window, otherwise a potentially significant error may be introduced that affects each velocity component differently. However, even when the calibration is performed correctly, another error may arise during the stereo reconstruction if the perspective angle determined for each camera does not account for the displacement of the light rays as they refract through the thick window. Care should be exercised when applying in a single-plane calibration since certain implicit assumptions may in fact require conditions that are extremely difficult to meet in a practical laboratory environment. It is suggested that the effort expended to ensure this accuracy may be better expended in performing a more lengthy volumetric calibration procedure, which does not rely upon the assumptions implicit in the single plane method and avoids the need for the perspective angle to be calculated.

Green, Richard↗
NASA NTRS2000

Passive Night Vision Sensor Comparison for Unmanned Ground Vehicle Stereo Vision Navigation

One goal of the "Demo III" unmanned ground vehicle program is to enable autonomous nighttime navigation at speeds of up to 10 m.p.h. To perform obstacle detection at night with stereo vision will require night vision cameras that produce adequate image quality for the driving speeds, vehicle dynamics, obstacle sizes, and scene conditions that will be encountered. This paper analyzes the suitability of four classes of night vision cameras (3-5 micrometer cooled FLIR, 8-12 micrometer cooled FLIR, 8-12 micrometer uncooled FLIR, and image intensifiers) for night stereo vision, using criteria based on stereo matching quality, image signal to noise ratio, motion blur and synchronization capability. We find that only cooled FLIRs will enable stereo vision performance that meets the goals of the Demo III program for nighttime autonomous mobility.

Owens, Ken↗
NASA NTRS1985

Angle-Measurement and Ranging System

Optical system automatically supplies information on angular position and range of object. Stereo rangefinder video signals from cameras processed to determine center of brightness for images of beacon on target vehicle. Range updated by onboard computer. Originally developed for spacecraft rendezvous and guidance, features of system adapted to angle-measurement and ranging problems on Earth. Technique also used for tool alinement inspections and color recognition.

Tietz, J. C.↗
NASA NTRS2000

A Structured Light Sensor System for Tree Inventory

Tree Inventory is referred to measurement and estimation of marketable wood volume in a piece of land or forest for purposes such as investment or for loan applications. Exist techniques rely on trained surveyor conducting measurements manually using simple optical or mechanical devices, and hence are time consuming subjective and error prone. The advance of computer vision techniques makes it possible to conduct automatic measurements that are more efficient, objective and reliable. This paper describes 3D measurements of tree diameters using a uniquely designed ensemble of two line laser emitters rigidly mounted on a video camera. The proposed laser camera system relies on a fixed distance between two parallel laser planes and projections of laser lines to calculate tree diameters. Performance of the laser camera system is further enhanced by fusion of information induced from structured lighting and that contained in video images. Comparison will be made between the laser camera sensor system and a stereo vision system previously developed for measurements of tree diameters.

Chien, Chiun-Hong↗
NASA NTRS1987

Image Processing

A new spinoff product was derived from Geospectra Corporation's expertise in processing LANDSAT data in a software package. Called ATOM (for Automatic Topographic Mapping), it's capable of digitally extracting elevation information from stereo photos taken by spaceborne cameras. ATOM offers a new dimension of realism in applications involving terrain simulations, producing extremely precise maps of an area's elevations at a lower cost than traditional methods. ATOM has a number of applications involving defense training simulations and offers utility in architecture, urban planning, forestry, petroleum and mineral exploration.

Source record↗
NASA NTRS2004

2D Analysis of In-flight Light Particles

One of the primary uses of the in-flight icing research performed aboard NASA Glenn s DHC-6 Twin Otter is for Icing Research Tunnel (IRT) and icing prediction code (Lewice) validation. Using the in-flight data to establish the IRT and Lewice as accurate simulators of actual icing conditions is crucial for supporting the research done in the Icing Branch. During test flights during the 2003 and 2004 flight season, a Natural Ice Shape Database was collected. For flights where conditions were appropriate, the aircraft is flown in an icing cloud with all ice protection systems deactivated. The duration of this period is usually determined by the pilot s ability to safely control the aircraft. When safe flight is no longer possible, the aircraft is maneuvered into clear air above the cloud layer. At this point several photographs are taken of the ice shape that was accreted on the wing test section during this icing encounter using a stereo photograph system (Figure 1). The stereo photograph system utilizes two cameras located at different locations on the fuselage that are both pointed at the same location on the wing. When both cameras take photographs of the same location at the same time, the negatives can be combined digitally to generate a two dimensional plot describing the cross-section of the ice shape. After these photographs are taken, the wing de-icing boots are activated and the ice shape is removed.

Shearer, Jonathan↗
NASA NTRS2013

Phoenix Telemetry Processor

Phxtelemproc is a C/C++ based telemetry processing program that processes SFDU telemetry packets from the Telemetry Data System (TDS). It generates Experiment Data Records (EDRs) for several instruments including surface stereo imager (SSI); robotic arm camera (RAC); robotic arm (RA); microscopy, electrochemistry, and conductivity analyzer (MECA); and the optical microscope (OM). It processes both uncompressed and compressed telemetry, and incorporates unique subroutines for the following compression algorithms: JPEG Arithmetic, JPEG Huffman, Rice, LUT3, RA, and SX4. This program was in the critical path for the daily command cycle of the Phoenix mission. The products generated by this program were part of the RA commanding process, as well as the SSI, RAC, OM, and MECA image and science analysis process. Its output products were used to advance science of the near polar regions of Mars, and were used to prove that water is found in abundance there. Phxtelemproc is part of the MIPL (Multi-mission Image Processing Laboratory) system. This software produced Level 1 products used to analyze images returned by in situ spacecraft. It ultimately assisted in operations, planning, commanding, science, and outreach.

Stanboli, Alice↗
NASA NTRS1991

Dynamic edge warping - An experimental system for recovering disparity maps in weakly constrained systems

Dynamic edge warping (DEW), a technique for recovering reasonably accurate disparity maps from uncalibrated stereo image pairs, is presented. No precise knowledge of the epipolar camera geometry is assumed. The technique is embedded in a system including structural stereopsis on the front end and robust estimation in digital photogrammetry on the other for the purpose of self-calibrating stereo image pairs. Once the relative camera orientation is known, the epipolar geometry is computed and the system can use this information to refine its representation of the object space. Such a system will find application in the autonomous extraction of terrain maps from stereo aerial photographs, for which camera position and orientation are unknown a priori, and for online autonomous calibration maintenance for robotic vision applications, in which the cameras are subject to vibration and other physical disturbances after calibration. This work thus forms a component of an intelligent system that begins with a pair of images and, having only vague knowledge of the conditions under which they were acquired, produces an accurate, dense, relative depth map. The resulting disparity map can also be used directly in some high-level applications involving qualitative scene analysis, spatial reasoning, and perceptual organization of the object space. The system as a whole substitutes high-level information and constraints for precise geometric knowledge in driving and constraining the early correspondence process.

Boyer, K. L.↗
NASA NTRS2017

The Mars Science Laboratory Curiosity Rover Mastcam Instruments: Preflight and In-Flight Calibration, Validation, and Data Archiving

The NASA Curiosity rover Mast Camera (Mastcam) system is a pair of fixed-focal length, multispectral, color CCD imagers mounted approximately 2 m above the surface on the rover's remote sensing mast, along with associated electronics and an onboard calibration target. The left Mastcam (M-34) has a 34 mm focal length, an instantaneous field of view (IFOV) of 0.22 mrad, and a FOV of 20 deg × 15 deg over the full 1648 × 1200 pixel span of its Kodak KAI-2020 CCD. The right Mastcam (M-100) has a 100 mm focal length, an IFOV of 0.074 mrad, and a FOV of 6.8 deg × 5.1 deg using the same detector. The cameras are separated by 24.2 cm on the mast, allowing stereo images to be obtained at the resolution of the M-34 camera. Each camera has an eight-position filter wheel, enabling it to take Bayer pattern red, green, and blue (RGB) 'true color' images, multispectral images in nine additional bands spanning approximately 400-1100 nm, and images of the Sun in two colors through neutral density-coated filters. An associated Digital Electronics Assembly provides command and data interfaces to the rover, 8 Gb of image storage per camera, 11 bit to 8 bit companding, JPEG compression, and acquisition of high-definition video. Here we describe the preflight and in-flight calibration of Mastcam images, the ways that they are being archived in the NASA Planetary Data System, and the ways that calibration refinements are being developed as the investigation progresses on Mars. We also provide some examples of data sets and analyses that help to validate the accuracy and precision of the calibration.

MSL Mastcam; quantitative multispectral↗
NASA NTRS1971

Study and interpretation of lunar close-up stereo photography

The lunar close-up steroscopic camera was used successfully on Apollo 11, 12, and 14 flights. It functioned without any technical faults and was judged convenient to use by all three crews. It recorded a variety of surface textures in the lunar soil, both disturbed and undisturbed, a number of rock surfaces in the undisturbed condition, and a number of surface samples of materials brought to the moon whose interaction with the lunar soil was to be tested. A resolution of approximately 80 microns was aimed for in the design of the camera and was indeed obtained on all pictures. Stereoscopy played a major part in interpreting surface textures and small scale structure.

Gold, T.↗
NASA NTRS1982

An automated mapping satellite system

Topographic maps are compiled by manually operated stereoplotters that recreate the geometry of two wide-angle overlapping stereo frame photographs. Continuous imaging systems such as strip cameras, electro-optical scanners, or linear arrays of detectors (push brooms) can also create stereo coverage from which topography can be compiled; however, the instability of an aircraft in the atmosphere makes this approach impractical. The benign environment of space permits a satellite to orbit the Earth with very high stability as long as no local perturbing forces are involved. Solid-state linear-array sensors have no moving parts and create no perturbing force on the satellite. Digital data from highly stabilized stereo linear arrays are amenable to simplified processing to produce both planimetric imagery and elevation data. A proposed satellite, called MAPSAT, could accomplish automated mapping in near real time. Image maps as large as 1:50,000 scale with contours as close as 20-m interval may be produced from MAPSAT data.

Colvocoreses, A. P.↗
NASA NTRS1978

Monitoring of particulate contamination and background brightness from IECM based instrumentation

Of particular concern to the astronomical community is the effect of Shuttle Transportation System induced contamination in the form of individual particles and general background on astronomical experiments. In an effort to investigate this problem, two camera/photometers in the Induced Environment Contamination Monitor (IECM) will be used to determine the size and velocity distribution of contaminant particles, their origin, and the extent of sunlit background brightness resulting from spacecraft contamination. The cameras will operate synchronously as a stereo pair to make continuous photographic measurements throughout the missions.

Clifton, K. S.↗
NASA NTRS1987

Shuttle bay telerobotics demonstration

A demonstration of NASA's robotics capabilities should be a balanced agenda of servicing and assembly tasks combined with selected key technical experiments. The servicing tasks include refueling and module replacement. Refueling involves the mating of special fluid connectors while module replacement requires an array of robotic technologies such as special tools, the arm of a logistics tool, and the precision mating of orbital replacement units to guides. The assembly task involves the construction of a space station node and truss structure. The technological experiments will focus on a few important issues: the precision manipulation of the arms by a teleoperator, the additional use of several mono camera views in conjunction with the stereo system, the use of a general purpose end effector versus a caddy of tools, and the dynamics involved with using a robot with a stabilizer.

Chun, W.↗
NASA NTRS1990

Evaluation of off-road terrain with static stereo and monoscopic displays

The National Aeronautics and Space Administration is currently funding research into the design of a Mars rover vehicle. This unmanned rover will be used to explore a number of scientific and geologic sites on the Martian surface. Since the rover can not be driven from Earth in real-time, due to lengthy communication time delays, a locomotion strategy that optimizes vehicle range and minimizes potential risk must be developed. In order to assess the degree of on-board artificial intelligence (AI) required for a rover to carry out its' mission, researchers conducted an experiment to define a no AI baseline. In the experiment 24 subjects, divided into stereo and monoscopic groups, were shown video snapshots of four terrain scenes. The subjects' task was to choose a suitable path for the vehicle through each of the four scenes. Paths were scored based on distance travelled and hazard avoidance. Study results are presented with respect to: (1) risk versus range; (2) stereo versus monocular video; (3) vehicle camera height; and (4) camera field-of-view.

Yorchak, John P.↗
NASA NTRS1992

A Full Field, 3-D Velocimeter for NASA's Microgravity Science Program

One of NASA's new Advanced Technology Development projects is stereo imaging velocimetry. Using multiple CCD cameras, the velocimeter will digitize and store images of microscopic seed particles suspended in flowing transparent fluid systems. The data will be processed to obtain full-field, three-dimensional, quantitative velocity data. With successful evolution of the technology, the velocimeter will become part of NASA's flight hardware arsenal, available to both established experiments and new proposals.

Meyer, Maryjo B.↗
NASA NTRS1994

Observations by the Mars 1994 orbiter and possible correlations with Mars Pathfinder

The Mars '94 spacecraft will still be operational when Mars Pathfinder begins its observations. While it will probably not be possible to detect the lander directly, the terrain, including the landing error ellipse, can be covered in high resolution (10 m) in various color bands. The stereo capability of the high resolution camera will provide a three-dimensional terrain map. The landing site of Pathfinder could possibly be chosen so that correlated observations of IMP and the remote sensing instruments onboard Mars '94 may be possible. We will discuss this scenario based on the presently adopted Mars '94 orbit and resulting enhancements stemming from correlations of data obtained by both spacecraft.

Keller, H. Uwe↗