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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 127 records · Page 7

All sources NASA NTRS DOE OSTI

NASA NTRS1972

Advanced study of video signal processing in low signal to noise environments

The frame to frame correlation properties of the video process are utilized to reduce the mean squared error of the demodulated video where zero mean noise is a factor. An interpolative estimator is used for continuous estimation with the output process delayed in time by one frame. Theoretical development shows that for the model herein developed reduction of the mean squared error by 1.0 to 4.0 db possible for parameter ranges of interest. Interpolative estimation using inter-frame correlation properties of a video process is then applied to the Apollo 17 parameters to yield a model for application on that mission.

Carden, F.↗

NASA NTRS1973

Video-to-film color-image recorder.

A precision video-to-film recorder for use in image data processing systems, being developed for NASA, will convert three video input signals (red, blue, green) into a single full-color light beam for image recording on color film. Argon ion and krypton lasers are used to produce three spectral lines which are independently modulated by the appropriate video signals, combined into a single full-color light beam, and swept over the recording film in a raster format for image recording. A rotating multi-faceted spinner mounted on a translating carriage generates the raster, and an annotation head is used to record up to 512 alphanumeric characters in a designated area outside the image area.

Montuori, J. S.↗

NASA NTRS1977

Low-light-level integrating video system

System consists of television camera using 25 mm SEC vidicon, low dispersion spectrograph, and digital video image system used for buffer storage of video data during tube readout scanning. Six-bit ADC converts video to digital data which are stored on magnetic tape for future evaluation.

Duncan, B. J.↗

NASA NTRS1975

Video guidance, landing, and imaging systems

The adaptive potential of video guidance technology for earth orbital and interplanetary missions was explored. The application of video acquisition, pointing, tracking, and navigation technology was considered to three primary missions: planetary landing, earth resources satellite, and spacecraft rendezvous and docking. It was found that an imaging system can be mechanized to provide a spacecraft or satellite with a considerable amount of adaptability with respect to its environment. It also provides a level of autonomy essential to many future missions and enhances their data gathering ability. The feasibility of an autonomous video guidance system capable of observing a planetary surface during terminal descent and selecting the most acceptable landing site was successfully demonstrated in the laboratory. The techniques developed for acquisition, pointing, and tracking show promise for recognizing and tracking coastlines, rivers, and other constituents of interest. Routines were written and checked for rendezvous, docking, and station-keeping functions.

Schappell, R. T.↗

NASA NTRS1976

Multi-star processing and gyro filtering for the video inertial pointing system

The video inertial pointing (VIP) system is being developed to satisfy the acquisition and pointing requirements of astronomical telescopes. The VIP system uses a single video sensor to provide star position information that can be used to generate three-axis pointing error signals (multi-star processing) and for input to a cathode ray tube (CRT) display of the star field. The pointing error signals are used to update the telescope's gyro stabilization system (gyro filtering). The CRT display facilitates target acquisition and positioning of the telescope by a remote operator. Linearized small angle equations are used for the multistar processing and a consideration of error performance and singularities lead to star pair location restrictions and equation selection criteria. A discrete steady-state Kalman filter which uses the integration of the gyros is developed and analyzed. The filter includes unit time delays representing asynchronous operations of the VIP microprocessor and video sensor. A digital simulation of a typical gyro stabilized gimbal is developed and used to validate the approach to the gyro filtering.

Murphy, J. P.↗

NASA NTRS1977

Orbiter CCTV video signal noise analysis

The amount of steady state and transient noise which will couple to orbiter CCTV video signal wiring is predicted. The primary emphasis is on the interim system, however, some predictions are made concerning the operational system wiring in the cabin area. Noise sources considered are RF fields from on board transmitters, precipitation static, induced lightning currents, and induced noise from adjacent wiring. The most significant source is noise coupled to video circuits from associated circuits in common connectors. Video signal crosstalk is the primary cause of steady state interference, and mechanically switched control functions cause the largest induced transients.

Lawton, R. M.↗

NASA NTRS1977

An ultraviolet video technique for visualization of stack plumes and for measuring sulfur dioxide concentration and effluent velocity

Absorption spectroscopy utilizing a video sensing technique was investigated as a means of visualizing SO2 in power plant stack plumes and for measuring SO2 concentration and effluent velocity in these plumes. The absorption of SO2 is measured in the ultraviolet region by using the sky as a background source. An additional spectral channel is used to correct for particulate scattering encountered in coal fired power plant plumes. The video system also tracks fluctuations in the SO2 concentration which leads to the determination of an eddy convection velocity. Field measurements were performed to show that the eddy convection velocity is proportional to the average in-stack velocity and to empirically determine their relationship. It was concluded that the video absorption technique is an attractive method for remotely determining both SO2 concentration and plume velocity with the same instrument.

Exton, R. J.↗

NASA NTRS1976

A computer-aided telescope pointing system utilizing a video star tracker

The Video Inertial Pointing (VIP) System is being developed to satisfy the acquisition and pointing requirements of astronomical telescopes. VIP employs a single video sensor to generate three-axis pointing error signals and to provide inputs for a cathode ray tube (CRT) display of the star field. The pointing error signals update the telescope's gyro stabilization system. The CRT display facilitates target acquisition and positioning of the telescope by a remote operator. The present paper describes the analysis, simulation, and hardware development of a prototype, advanced VIP system. An early model of the system utilizing a silicon-intensified target vidicon camera has flown on a balloon-borne telescope and is briefly described. The advanced system, which can employ either a vidicon camera or a charge-coupled device video sensor, has been tested using an analog/digital hybrid simulation. The advanced VIP hardware is described, and the simulation results presented.

Lorell, K. R.↗

NASA NTRS1977

Viking 1975 Mars lander interactive computerized video stereophotogrammetry

A novel computerized interactive video stereophotogrammetry system has been developed for analysis of Viking 1975 lander imaging data. Prompt, accurate, and versatile performance is achieved. Earth-returned digital imagery data are driven from a computer to a pair of video monitors. Powerful computer support enables a photogrammetrist, stereoscopically viewing the video displays, to create diverse topographic products. Profiles, representing the intersection of any definable surface with the Martian relief, are readily generated. Vertical profiles and elevation contour maps, including stereo versions, are produced. Computer overlays of map products on stereo images aid map interpretation and permit independent quality evaluation. Slaved monitors enable parallel viewing. Maps span from the immediate foreground to the remote limits of ranging capability. Surface sampler arm specific vertical profiles enable direct reading of arm commands required for sample acquisition, rock rolling, and trenching. The ranging accuracy of plus or minus 2 cm throughout the sample area degrades to plus or minus 20 m at 100-m range.

Liebes, S., Jr.↗

NASA NTRS1979

Real-time video-image analysis

Digitizer and storage system allow rapid random access to video data by computer. RAPID (random-access picture digitizer) uses two commercially-available, charge-injection, solid-state TV cameras as sensors. It can continuously update its memory with each frame of video signal, or it can hold given frame in memory. In either mode, it generates composite video output signal representing digitized image in memory.

Eskenazi, R.↗

NASA NTRS1982

A functional video-based anthropometric measuring system

A high-speed anthropometric three dimensional measurement system using the Selcom Selspot motion tracking instrument for visual data acquisition is discussed. A three-dimensional scanning system was created which collects video, audio, and performance data on a single standard video cassette recorder. Recording rates of 1 megabit per second for periods of up to two hours are possible with the system design. A high-speed off-the-shelf motion analysis system for collecting optical information as used. The video recording adapter (VRA) is interfaced to the Selspot data acquisition system.

Nixon, J. H.↗

NASA NTRS1981

Entropy encoding applied to a video DM bit stream

This paper investigates bandwidth compression of delta modulated video signals using a variety of novel techniques. The video signal is encoded at 16 MHz with an adaptive delta modulator (ADM) using the Song video mode algorithm. One method of achieving bandwidth compression is through the detection and reduction of steady state patterns in the DM bit stream. Further reduction is obtained by deleting the horizontal and vertical drive information. Finally, a modified ADM algorithm is introduced to increase the frequency of steady state patterns. When the modified ADM is combined with entropy coding a 30-50% data compression can be realized.

Barba, J.↗

NASA NTRS1984

Measurement of thigmomorphogenesis and gravitropism by non-intrusive computerized video image processing

A video image processing instrument, DARWIN (Digital Analyser of Resolvable Whole-pictures by Image Numeration), was developed. It was programmed to measure stem or root growth and bending, and coupled to a specially mounted video camera to be able to automatically generate growth and bending curves during gravitropism. The growth of the plant is recorded on a video casette recorder with a specially modified time lapse function. At the end of the experiment, DARWIN analyses the growth or movement and prints out bending and growth curves. This system was used to measure thigmomorphagenesis in light grown corn plants. If the plant is rubbed with an applied force load of 0.38 N., it grows faster than the unrubbed control, whereas 1.14 N. retards its growth. Image analysis shows that most of the change in the rate of growth is caused in the first hour after rubbing. When DARWIN was used to measure gravitropism in dark grown oat seedlings, it was found that the top side of the shoot contracts during the first hour of gravitational stimulus, whereas the bottom side begins to elongate after 10 to 15 minutes.

Jaffe, M. J.↗

NASA NTRS1986

Intermediate-Frequency-to-Video-Band Converter

Analog and digital circuits combined to frequency-convert from intermediate frequencies directly to video-band frequencies to meet stringent requirements. IF-to-video-band converter operates on principle of signal-band cancellation in phase-quadrature circuits. Downconverts intermediate frequencies directly to video-band frequencies to near-zero frequency with good image-band rejection and low phase variation within passband.

Ham, N. C.↗

NASA NTRS1985

Close-range photogrammetry with video cameras

Examples of photogrammetric measurements made with video cameras uncorrected for electronic and optical lens distortions are presented. The measurement and correction of electronic distortions of video cameras using both bilinear and polynomial interpolation are discussed. Examples showing the relative stability of electronic distortions over long periods of time are presented. Having corrected for electronic distortion, the data are further corrected for lens distortion using the plumb line method. Examples of close-range photogrammetric data taken with video cameras corrected for both electronic and optical lens distortion are presented.

Burner, A. W.↗

NASA NTRS1987

A digital video model deformation system

The use of solid-state array cameras and a PC-controlled image acquisition system to measure model deformation in a wind tunnel is discussed. This digital system improves an earlier video model deformation system that used high-resolution tube cameras and required the manual measurement of targets on video hardcopy images. The new system eliminates both the vibration-induced distortion associated with tube cameras and the manual readup of video images necessary in the earlier version. Camera calibration and data reduction procedures necessary to convert pixel image plane data from two cameras into wing deflections are presented. Laboratory tests to establish the uncertainty of the system with the geometry to be used are described.

Burner, A. W.↗

NASA NTRS1988

ExpertVision - A video-based non-contact system for motion measurement

A system known as ExpertVision for obtaining noncontact kinematic measurements using standard video signals is described. In the system, a video processor extracts edge information from video images using a proprietary thresholding technique. Images can be examined in real time at up to 200 fields/s, and as many as four synchronized inputs can be treated simultaneously by buffering the edge coordinates for each view in dedicated RAM memory. Mechanical applications for ExpertVision include the study of simple impacts, ballistics, wing flutter, the kinematics of helicopter rotor blades, and fluid and gas flow problems.

Walton, James S.↗

NASA NTRS1990

Recent advances in nondestructive evaluation made possible by novel uses of video systems

Complex materials are being developed for use in future advanced aerospace systems. High temperature materials have been targeted as a major area of materials development. The development of composites consisting of ceramic matrix and ceramic fibers or whiskers is currently being aggressively pursued internationally. These new advanced materials are difficult and costly to produce; however, their low density and high operating temperature range are needed for the next generation of advanced aerospace systems. These materials represent a challenge to the nondestructive evaluation community. Video imaging techniques not only enhance the nondestructive evaluation, but they are also required for proper evaluation of these advanced materials. Specific research examples are given, highlighting the impact that video systems have had on the nondestructive evaluation of ceramics. An image processing technique for computerized determination of grain and pore size distribution functions from microstructural images is discussed. The uses of video and computer systems for displaying, evaluating, and interpreting ultrasonic image data are presented.

Generazio, Edward R.↗