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Kelly, W. L., IV

Publications and source records attributed to Kelly, W. L., IV.

17 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

A design approach to real-time formatting of high speed multispectral image data

A design approach to formatting multispectral image data in real time at very high data rates is presented for future onboard processing applications. The approach employs a microprocessor-based alternating buffer memory configuration whose formatting function is completely programmable. Data are read from an output buffer in the desired format by applying the proper sequence of addresses to the buffer via a lookup table memory. Sensor data can be processed using this approach at rates limited by the buffer memory access time and the buffer switching process delay time. This design offers flexible high speed data processing and benefits from continuing increases in the performance of digital memories.

Meredith, B. D.↗
NASA NTRS1980

High speed lookup table approach to radiometric calibration of multispectral image data

A concept for performing radiometric correction of multispectral image data onboard a spacecraft at very high data rates is presented and demonstrated. This concept utilized a lookup table approach, implemented in hardware, to convert the raw sensor data into the desired corrected output data. The digital lookup table memory was interfaced to a microprocessor to allow the data correction function to be completely programmable. Sensor data was processed with this approach at rates equal to the access time of the lookup table memory. This concept offers flexible high speed data processing for a wide range of applications and will benefit from the continuing improvements in performance of digital memories.

Kelly, W. L., IV↗
NASA NTRS1979

LED instrument approach instruction display

A display employing light emitting diodes (LED's) was developed to demonstrate the feasibility of such displays for presenting landing and navigation information to reduce the workload of general aviation pilots during IFR flight. The display consists of a paper tape reader, digital memory, control electronics, digital latches, and LED alphanumeric displays. A presentable digital countdown clock-timer is included as part of the system to provide a convenient means of monitoring time intervals for precise flight navigation. The system is a limited capability prototype assembled to test pilot reaction to such a device under simulated IFR operation. Pilot opinion indicates that the display is helpful in reducing the IFR pilots workload when used with a runway approach plate. However, the development of a compact, low power second generation display was recommended which could present several instructions simultaneously and provide information update capability. A microprocessor-based display could fulfill these requirements.

Meredith, B. D.↗
NASA NTRS1978

Analytical models and system topologies for remote multispectral data acquisition and classification

Simple analytical models are presented of the radiometric and statistical processes that are involved in multispectral data acquisition and classification. Also presented are basic system topologies which combine remote sensing with data classification. These models and topologies offer a preliminary but systematic step towards the use of computer simulations to analyze remote multispectral data acquisition and classification systems.

Huck, F. O.↗
NASA NTRS1978

Device for measuring the contour of a surface

Light from a source is imaged by a lens onto a surface so that the energy from the source is concentrated into a spot. As the spot across the surface is scanned, the surface moves relative to the point of perfect focus. When the surface moves away from perfect focus the spot increases in size, while the total energy in the spot remains virtually constant. The lens then reimages the light reflected by the surface onto two detectors through two different sized apertures. The light energy going to the two detectors is separated by a beam splitter. This second path of the light energy through the lens further defocuses the spot, but as a result of the different sizes of the apertures in each light detector path, the amount of defocus for each is different. The ratio of the outputs of the two detectors which are indicative of the contour of the surface is obtained by a divider.

Burcher, E. E.↗
NASA NTRS1977

An optical profilometer for spatial characterization of three-dimensional surfaces

The design concept and system operation of an optical profilometer are discussed, and a preliminary evaluation of a breadboard system is presented to demonstrate the feasibility of the optical profilometer technique. Measurement results are presented for several test surfaces; and to illustrate a typical application, results are shown for a cleft palate cast used by dental surgeons. Finally, recommendations are made for future development of the optical profilometer technique for specific engineering or scientific applications.

Kelly, W. L., IV↗
NASA NTRS1977

Optical profilometer

Device, consisting of optical scanning subsystem, two light detectors with associated amolifiers, analog divider, and adjustable nonlinear function generator, directly determines surface area, absolute depth, and point-to-point distance of three-dimensional object without physical contact with surface under observation.

Burcher, E. E.↗
NASA NTRS1975

Spectral response of the Viking lander camera: Preliminary evaluation

One of the objectives of the Viking lander imaging investigation is to obtain color and near-infrared multispectral panoramas of the Martian surface using six spectral channels in the 0.4 to 1.1 microns wavelength range. This data can be compared with data obtained by imaging a reference test chart to construct approximate spectral reflectance curves that can then be matched to laboratory standards to aid in identifying surface materials. Some channels exhibit appreciable out-of-band spectral responses, making data reduction and interpretation difficult. A preliminary evaluation of predicted multispectral data for eight geological materials reveals that fairly good reflectance estimates can be made for those materials which have monotonically increasing or decreasing reflectances. Reflectance estimates for materials with more complex reflectances often do not reveal important spectral features and sometimes provide misleading results.

Kelly, W. L., IV↗
NASA NTRS1975

Solid-state turn coordinator display

A solid state turn coordinator display which employs light emitting diodes (LED's) as the display medium was developed to demonstrate the feasibility of such displays for aircraft applications. The input to the display is supplied by a fluidic inertial rate sensor used in an aircraft wing leveler system. The display is composed of the LED radial display face and the electronics necessary to address and drive the individual lines of LED's. Three levels of brightness are provided to compensate for the different amounts of ambient light present in the cockpit.

Meredith, B. D.↗
NASA NTRS1975

Investigation of Facsimile Camera-spectrometer Capability in the 1.0 to 2.7 Micron Spectral Range

The capability of the facsimile camera augmented with a filter-spectrometer to provide scientifically valuable information in the 1.0 to 2.7 microns spectral range was investigated for a future planetary lander mission to Mars. A computer model was used to evaluate tradeoffs between signal-to-noise ratio, spatial and spectral resolution, and the number of spectral channels. Spectral absorption features resulting from water and chemical variations found in pyroxenes were used to represent scientific information of interest to biologists and geologists. Expected output data from a filter-spectrometer is illustrated which indicates that important information pertaining to water content and chemical composition can be obtained using six to eight spectral channels with 0.3 degree spatial resolution.

Kelly, W. L., IV↗
NASA NTRS1975

Spectrometer integrated with a facsimile camera

This invention integrates a spectrometer capability with the basic imagery function of facsimile cameras without significantly increasing mechanical or optical complexity, or interfering with the imaging function. The invention consists of a group of photodetectors arranged in a linear array in the focal plane of the facsimile camera with a separate narrow band interference filter centered over each photodetector. The interference filter photodetector array is on a line in the focal plane of the facsimile camera along the direction of image motion due to the rotation of the facsimile camera's vertical mirror. As the image of the picture element of interest travels down the interference filter photodetector array, the photodetector outputs are synchronously selected and sampled to provide spectral information on the single picture element.

Burcher, E. E.↗
NASA NTRS1974

Design and evaluation of a filter spectrometer concept for facsimile cameras

The facsimile camera is an optical-mechanical scanning device which was selected as the imaging system for the Viking '75 lander missions to Mars. A concept which uses an interference filter-photosensor array to integrate a spectrometric capability with the basic imagery function of this camera was proposed for possible application to future missions. This paper is concerned with the design and evaluation of critical electronic circuits and components that are required to implement this concept. The feasibility of obtaining spectroradiometric data is demonstrated, and the performance of a laboratory model is described in terms of spectral range, angular and spectral resolution, and noise-equivalent radiance.

Kelly, W. L., IV↗
NASA NTRS1974

A filter spectrometer concept for facsimile cameras

A concept which utilizes interference filters and photodetector arrays to integrate spectrometry with the basic imagery function of a facsimile camera is described and analyzed. The analysis considers spectral resolution, instantaneous field of view, spectral range, and signal-to-noise ratio. Specific performance predictions for the Martian environment, the Viking facsimile camera design parameters, and a signal-to-noise ratio for each spectral band equal to or greater than 256 indicate the feasibility of obtaining a spectral resolution of 0.01 micrometers with an instantaneous field of view of about 0.1 deg in the 0.425 micrometers to 1.025 micrometers range using silicon photodetectors. A spectral resolution of 0.05 micrometers with an instantaneous field of view of about 0.6 deg in the 1.0 to 2.7 micrometers range using lead sulfide photodetectors is also feasible.

Jobson, D. J.↗
NASA NTRS1973

Design and evaluation of controls for drift, video gain, and color balance in spaceborne facsimile cameras

The facsimile camera is an optical-mechanical scanning device which has become an attractive candidate as an imaging system for planetary landers and rovers. This paper presents electronic techniques which permit the acquisition and reconstruction of high quality images with this device, even under varying lighting conditions. These techniques include a control for low frequency noise and drift, an automatic gain control, a pulse-duration light modulation scheme, and a relative spectral gain control. Taken together, these techniques allow the reconstruction of radiometrically accurate and properly balanced color images from facsimile camera video data. These techniques have been incorporated into a facsimile camera and reproduction system, and experimental results are presented for each technique and for the complete system.

Katzberg, S. J.↗
NASA NTRS1973

Electro-optical device for monitoring wire size

Device recognizes variations in wire size and is being used during computer memory-plane fabrication. Decrease in wire diameter, due to stretching, permits removal of wire from memory-plant mold. Monitoring provides means of detecting imperfect wire and permits fabrication of computer memory plane to be stopped prior to its insertion into mold.

Burcher, E. E.↗
NASA NTRS1973

Investigation of responsivity and noise in a direct-coupled photodetector-preamplifier for facsimile cameras

The direct-coupled (DC) mode of detector operation is evaluated for use in a facsimile camera. Photodiode-preamplifier sensitivity is described in terms of photodiode responsivity and possible noise sources resulting from the photodiode and preamplifier. Responsivity and noise limitations are experimentally verified and used to predict photodiode-preamplifier sensitivity under a wide range of operating conditions. Results demonstrate that the DC mode offers advantages in sensitivity and reduced mechanical complexity for facsimile cameras over the more common technique of chopping the radiation and ac amplifying the resultant signal.

Kelly, W. L., IV↗