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At least 127 records · Page 7

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NASA NTRS1978

A parametric multiclass Bayes error estimator for the multispectral scanner spatial model performance evaluation

The author has identified the following significant results. The probability of correct classification of various populations in data was defined as the primary performance index. The multispectral data being of multiclass nature as well, required a Bayes error estimation procedure that was dependent on a set of class statistics alone. The classification error was expressed in terms of an N dimensional integral, where N was the dimensionality of the feature space. The multispectral scanner spatial model was represented by a linear shift, invariant multiple, port system where the N spectral bands comprised the input processes. The scanner characteristic function, the relationship governing the transformation of the input spatial, and hence, spectral correlation matrices through the systems, was developed.

Mobasseri, B. G.↗

NASA NTRS1979

Focusing laser scanner

Economical laser scanner assembled from commercially available components, modulates and scans focused laser beam over area up to 5.1 by 5.1 cm. Scanner gives resolution comparable to that of conventional television. Device is highly applicable to area of analog and digital storage and retrieval.

Callen, W. R.↗

NASA NTRS1978

Multispectral scanner system parameter study and analysis software system description, volume 2

The author has identified the following significant results. The integration of the available methods provided the analyst with the unified scanner analysis package (USAP), the flexibility and versatility of which was superior to many previous integrated techniques. The USAP consisted of three main subsystems; (1) a spatial path, (2) a spectral path, and (3) a set of analytic classification accuracy estimators which evaluated the system performance. The spatial path consisted of satellite and/or aircraft data, data correlation analyzer, scanner IFOV, and random noise model. The output of the spatial path was fed into the analytic classification and accuracy predictor. The spectral path consisted of laboratory and/or field spectral data, EXOSYS data retrieval, optimum spectral function calculation, data transformation, and statistics calculation. The output of the spectral path was fended into the stratified posterior performance estimator.

Landgrebe, D. A.↗

NASA NTRS1980

Infrared scanner concept verification test report

The test results from a concept verification test conducted to assess the use of an infrared scanner as a remote temperature sensing device for the space shuttle program are presented. The temperature and geometric resolution limits, atmospheric attenuation effects including conditions with fog and rain, and the problem of surface emissivity variations are included. It is concluded that the basic concept of using an infrared scanner to determine near freezing surface temperatures is feasible. The major problem identified is concerned with infrared reflections which result in significant errors if not controlled. Action taken to manage these errors result in design and operational constraints to control the viewing angle and surface emissivity.

Bachtel, F. D.↗

NASA NTRS1980

Assessment of satellite and aircraft multispectral scanner data for strip-mine monitoring

The application of LANDSAT multispectral scanner data to describe the mining and reclamation changes of a hilltop surface coal mine in the rugged, mountainous area of eastern Kentucky is presented. Original single band satellite imagery, computer enhanced single band imagery, and computer classified imagery are presented for four different data sets in order to demonstrate the land cover changes that can be detected. Data obtained with an 11 band multispectral scanner on board a C-47 aircraft at an altitude of 3000 meters are also presented. Comparing the satellite data with color, infrared aerial photography, and ground survey data shows that significant changes in the disrupted area can be detected from LANDSAT band 5 satellite imagery for mines with more than 100 acres of disturbed area. However, band-ratio (bands 5/6) imagery provides greater contrast than single band imagery and can provide a qualitative level 1 classification of the land cover that may be useful for monitoring either the disturbed mining area or the revegetation progress. However, if a quantitative, accurate classification of the barren or revegetated classes is required, it is necessary to perform a detailed, four band computer classification of the data.

Spisz, E. W.↗

NASA NTRS1980

Nimbus-7 coastal zone color scanner - System description and initial imagery

Initial imagery from the Nimbus-7 Coastal Zone Color Scanner (CZCS) shows subtle variations in water color. Organisms, especially phytoplankton, play a major influence on the variations in water color. Processing of the visual data is described, and in particular, the use of an algorithm to remove aerosol from the image is discussed. Data on the six spectral bands (433-12,500 nm) are presented and comparisons are made between the CZCS and the Landsat-1 multispectral scanner. The implications for management of fisheries is noted.

Hovis, W. A.↗

NASA NTRS1980

The remote-controlled spectrograph, area scanner, and spectropolarimeter for the Lick 3-m telescope

A Cassegrain spectrograph used in conjunction with an image-tube, image-dissector scanner (ITS) is discussed with reference to its design features and operation. The spectrograph has a remote control feature, and its parameters, such as slit width, decker position, filter selection, focus, and grating selection, can be easily changed by computer command or a hard-wired control box. The discussion also includes the area scanner modification which allows raster scanning and limited picture taking. Finally, the design of a two-channel polarization analyzer is presented which allows simultaneous sky and sky-plus-star observations and faint-object polarimetry.

Miller, J. S.↗

NASA NTRS1980

Simulated response of a multispectral scanner over wheat as a function of wavelength and view/illumination directions

Oblique viewing sensors are to be launched in the late 1980's on the Multispectral Resource Sampler, being developed by the U.S. Since the resulting oblique measurements will need to be better understood, the reflectance response with a view angle of wheat, excluding atmospheric effects but simulating the response of a multispectral scanner, is analyzed. Spectra were taken continuously in the wavelength range of 0.45 to 2.4 microns at more than 1200 view/illumination directions with a 20 C spectral radiometer, and data were acquired six meters above four wheat canopies, each at a different stage of growth. The study shows that the canopy reflective response is a function of the illumination angle, the scanner view angle, and the wavelength; and the variation is greater at low solar variations.

Vanderbilt, V. C.↗

NASA NTRS1981

Simulated response of a multispectral scanner over wheat as a function of wavelength and view/illumination direction

The reflectance response with view angle of wheat, was analyzed. The analyses, which assumes there are no atmospheric effects, and otherwise simulates the response of a multispectral scanner, is based upon spectra taken continuously in wavelength from 0.45 to 2.4 micrometers at more than 1200 view/illumination directions using an Exotech model 20C spectra radiometer. Data were acquired six meters above four wheat canopies, each at a different growth stage. The analysis shows that the canopy reflective response is a pronounced function of illumination angle, scanner view angle and wavelength. The variation is greater at low solar elevations compared to high solar elevations.

Bauer, M. E.↗

NASA NTRS1982

MSS D Multispectral Scanner System

The development and acceptance testing of the 4-band Multispectral Scanners to be flown on LANDSAT D and LANDSAT D Earth resources satellites are summarized. Emphasis is placed on the acceptance test phase of the program. Test history and acceptance test algorithms are discussed. Trend data of all the key performance parameters are included and discussed separately for each of the two multispectral scanner instruments. Anomalies encountered and their resolutions are included.

Lauletta, A. M.↗

NASA NTRS1982

The conical scanner evaluation system design

The software design for the conical scanner evaluation system is presented. The purpose of this system is to support the performance analysis of the LANDSAT-D conical scanners, which are infrared horizon detection attitude sensors designed for improved accuracy. The system consists of six functionally independent subsystems and five interface data bases. The system structure and interfaces of each of the subsystems is described and the content, format, and file structure of each of the data bases is specified. For each subsystem, the functional logic, the control parameters, the baseline structure, and each of the subroutines are described. The subroutine descriptions include a procedure definition and the input and output parameters.

Cumella, K. E.↗

NASA NTRS1983

LANDSAT-4 multispectral scanner (MSS) subsystem radiometric characterization

The multispectral band scanner (mass) and its spectral characteristics are described and methods are given for relating video digital levels on computer compatible tapes to radiance into the sensor. Topics covered include prelaunch calibration procedures and postlaunch radiometric processng. Examples of current data resident on the MSS image processing system are included. The MSS on LANDSAT 4 is compared with the scanners on earlier LANDSAT satellites.

Alford, W.↗

NASA NTRS1981

Multispectral scanner flight model (F-1) radiometric calibration and alignment handbook

This handbook on the calibration of the MSS-D flight model (F-1) provides both the relevant data and a summary description of how the data were obtained for the system radiometric calibration, system relative spectral response, and the filter response characteristics for all 24 channels of the four band MSS-D F-1 scanner. The calibration test procedure and resulting test data required to establish the reference light levels of the MSS-D internal calibration system are discussed. The final set of data ("nominal" calibration wedges for all 24 channels) for the internal calibration system is given. The system relative spectral response measurements for all 24 channels of MSS-D F-1 are included. These data are the spectral response of the complete scanner, which are the composite of the spectral responses of the scan mirror primary and secondary telescope mirrors, fiber optics, optical filters, and detectors. Unit level test data on the measurements of the individual channel optical transmission filters are provided. Measured performance is compared to specification values.

Source record↗

NASA NTRS1981

Multispectral scanner, thematic mapper, and beyond

The capabilities and functions of the Landsat D multispectral scanner (MSS) and thematic mapper (TM) are explored as a basis for improvements to satisfy increasing user demands. The MSS is an object-space line scanner for gathering data in four spectral bands ranging from 0.5-1.1 micron. In a 705 km near-polar sunsynchronous orbit, the MSS will generate 185 x 185 km imagery with 80 x 80 m ground resolution, mapping the entire earth every 16 days. Photomultiplier tubes are used for four of the bands and the other employs Si photodiodes. A calibration light source provides in orbit calibration during every reverse scan period of a pivotal on-board mirror. The TM collects data in seven bands from 0.45-12.5 microns, yielding a ground resolution of 30 x 30 m in six bands for reflected sunlight and 120 x 120 m for the 10.4-12.5 thermal bands. The addition of 16 Si detectors for 0.9-1.1 micron viewing for agricultural purposes, as well as higher resolution, is discussed.

Jones, C. R.↗

NASA NTRS1986

Optical Scanner for Linear Arrays

Optical scanner instantaneously reads contiguous lines forming scene or target in object plane. Reading active or passive and scans, continuous or discrete. Scans essentially linear with scan angle and symmetric about axial ray. Nominal focal error, resulting from curvature of scan, well within Rayleigh limit. Scanner specifically designed to be fully compatible with general requirements of linear arrays.

Finkel, M. W.↗

NASA NTRS1984

Rectification of single and multiple frames of satellite scanner imagery using points and edges as control

Rectification of single and overlapping multiple scanner frames produced by such satellite-borne scanners as the LANDSAT MSS was carried out using a newly developed comprehensive parametric model. Tests with both simulated and real image data demonstrate conclusively that this model in general is superior to the widely used polynomial model, and that the simultaneous rectification of overlapping frames using least squares techniques yields a high accuracy than sngle frame rectification due to the inclusion of tie points between the image frames. Used to control, edges or lines, whic are much more likely to be found in images, can replace conventional control points and can easily be implemented into the least squares approach. An efficient algorithm for findng corresponding points in image paris was developed which can be used for determining tie points between image frames and thus increase the ecnomy of the whole rectification procedure.

Paderes, F. C., Jr.↗

NASA NTRS1985

Validation of the ERBE scanner scene identification methodology: Analysis with Nimbus-7 ERB data

Maximum Likelihood Estimation (MLE) procedure for scene identification currently being utilized in the ERBE scanner data processing stream is applied to the Nimbus-7 ERB Scanner data for the month of June 1979. The Earth radiation budget parameters derived using MLE method show very good agreement with the values provided using sorting into angular bins (SAB) method. Results of the fields on different spatial scales are presented. A satellite zenith angle study indicates that the MLE procedure considerably improves the scene selection over the method of bispectral thresholds applied in the Nimbus-7 ERB data processing. Agreement with SAB results improved further when the observations were cut off at 75% in satellite zenith. Sampling constraints, however require that the cut-off angle should not be lower than 70%. Quantitative details about the reliability of the scene identification are also presented.

Vermury, S.↗

NASA NTRS1984

A low noise infrared spot scanner for testing detector arrays

A low noise spot scanner has been built for use in testing the performance of infrared detector arrays for NASA's IR detector technology development program and the University of California's MICRO program. The scanner provides a convenient low noise detector test environment and a wide range of test conditions including versatile temperature control of the detector, ambient background, and blackbody source temperature and control of spot size, color, and brightness.

Puetter, R. C.↗