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The astrometric application of the Wide Field Camera and the Planetary Camera is reviewed. It is shown that the digital image centering algorithms can yield a positional accuracy of 0.1 milli-arcsecond. Deconvolution of CCD's sensitivity, non-flatness of the filters, and crinkling of the CCD surface may limit the positional accuracy of 1 milli-arcsecond.
The theory, design, and results of optical fiber pulse dispersion measurements are considered. Both the hardware and software required to perform this type of measurement are described. Hardware includes a thermoelectrically cooled injection laser diode source, an 800 GHz gain bandwidth produce avalanche photodiode and an input mode scrambler. Software for a HP 9825 computer includes fast Fourier transform, inverse Fourier transform, and optimal compensation deconvolution. Test set construction details are also included. Test results include data collected on a 1 Km fiber, a 4 Km fiber, a fused spliced, eight 600 meter length fibers concatenated to form 4.8 Km, and up to nine optical connectors.
Previous models of microwave limb brightening have omitted the alignment of spicules along supergranule boundaries, have neglected the high temperature sheath around spicules, and have assumed an interspicular medium which was averaged over chromospheric network and nonnetwork regions. A model is presented here which includes these factors. Constraining the model to conform to results from earlier UV and optical studies in effect leaves two free parameters: the temperature at the core of the spicules and (at solar minimum) the interspicular chromospheric network density model of the lower transition zone. The absence of limb brightening at the short millimeter wavelengths implies a temperature at the core of the spicules less than approximately 6000 K. Differences between the model and certain deconvolved observations near 9 mm are expected as a consequence of an extension of emission beyond the optical limb, predicted by the model, which affects the accuracy of the deconvolution technique. Unlike models which assume homogeneous spicules in a random distribution, the model presented here does not require an abnormally high spicule area.
The detection of X-ray emission from Mrk 180, an elliptical galaxy which has a BL Lac object embedded in its core is reported. The X-ray observations were made by the Einstein and HEAO 1 satellites. In addition, new multiaperture UBVR photometric observations are presented which were used to separate the nonthermal optical emission from the galactic emission. Analysis of the Einstein data suggests that the continuous X-ray spectrum of Mrk 180 is a power law with an energy spectral index of -1.3. The deconvolution of the optical magnitudes is consistent with a nonthermal source having a spectral index of -1.2. The continuous spectrum of Mrk 180 is steep from the X-ray to the optical and flattens out in the radio.
Homomorphic deconvolution signal processing enhances information obtained in high-resolution soil-depth measurements by radar. Proposed technique is expected to increase accuracy with which soil-layer depths are gaged. Intended use with subsurface-interface radar sounding, in which subsurface features of soils are mapped.
The shape factor, parameter estimation, and deconvolution data analysis techniques were applied to the same set of Earth emitted radiation measurements to determine the effects of different techniques on the estimated radiation field. All three techniques are defined and their assumptions, advantages, and disadvantages are discussed. Their results are compared globally, zonally, regionally, and on a spatial spectrum basis. The standard deviations of the regional differences in the derived radiant exitance varied from 7.4 W-m/2 to 13.5 W-m/2.
The ultraviolet action spectrum for photosynthesis inhibition was determined to fall between that of the general DNA action spectrum and the generalized plant action spectrum. The characteristics of this action spectrum suggest that a combination of pronounced increase in effectiveness with decreasing wavelength, substantial specificity for the UV-B waveband, and very diminished response in the UV-A waveband result in large radiation amplification factors when the action spectra are used as weighting functions. Attempted determination of dose/response relationships for leaf disc inhibition provided inconclusive data from which to deconvolute an action spectrum.
Spatially resolved measurements of Saturn's absolute reflectivity in methane bands at 6190, 7250, and 8900 A and in nearby continuum regions are presented. Images were obtained through narrow-band interference filters with a 500 x 500-pixel charge-coupled device. Band/continuum ratios were measured to high accuracy by referencing to the ring brightness in each image. Several data processing techniques enhanced the quality of the observations. These are the use of the ring symmetry to find center position and orientation, accurate subtraction of ring light, and constrained image deconvolution. Uncertainty in the continuum absolute reflectivity is within 10%. Uncertainties in band/continuum ratios are from one to several percent. The Equatorial Zone was much brighter than any other latitude in the strong 8900 band image. Northern midlatitudes were brighter than southern midlatitudes. The latter observation indicates fewer high-altitude aerosols in the south, a possible result of atmospheric dynamics or seasonal sublimation of NH3 crystals. The data are tabulated and presented in a form suitable for quantitative scattering model analyses.
The accuracy of any physical measurement is limited by the instruments performing it. The proposed activities of this grant are related to the study of and application of mathematical techniques of deconvolution. Two techniques are being investigated: an iterative method and a function continuation Fourier method. This final status report describes the work performed during the period July 1 to December 31, 1982.
Airborne lidar oil spill experiments carried out to determine the practicability of the AOFSCE (absolute oil fluorescence spectral conversion efficiency) computational model are described. The results reveal that the model is suitable over a considerable range of oil film thicknesses provided the fluorescence efficiency of the oil does not approach the minimum detection sensitivity limitations of the lidar system. Separate airborne lidar experiments to demonstrate measurement of the water column Raman conversion efficiency are also conducted to ascertain the ultimate feasibility of converting such relative oil fluorescence to absolute values. Whereas the AOFSCE model is seen as highly promising, further airborne water column Raman conversion efficiency experiments with improved temporal or depth-resolved waveform calibration and software deconvolution techniques are thought necessary for a final determination of suitability.
An X-ray spectrum of a major fraction of the Vela supernova remnant has been obtained during scanning observations with the low energy proportional counters of the A-2 experiment, flown on HEAO 1. A deconvolution analysis of the data shows that the spectrum exhibits pronounced line emission near 0.6 keV due primarily to oxygen ions. Model fits using the Raymond-Smith hot plasma emission calculations indicate that the spectrum can be well described by a model involving two collisional equilibrium components with temperatures of 2.4 x 10 to the 6th and 1.9 x 10 to the 7th K, respectively. The abundances of oxygen and iron are found to be constrained to lie near their normal cosmic values.
Quasiperiodic X-ray, UV, microwave, and metric-wave variations after a solar flare on November 6, 1980 are reported and analyzed, based on observational data from SMM (HXRBS, UVSP, HXIS), GOES-2, the 100-m radiotelescope at Bonn, and the Nancay radioheliograph. The maxima of the 13 brightenings observed are listed and characterized; a comparison is made with a 'normal' flare at 17:26 UT on the same day. The HXIS and UVSP data are discussed in terms of the physical properties, X-ray flux, O V flux, and H-alpha flux. The variations are found to be mainly thermal and purely coronal, with no chromospheric (H-alpha) participation (in contrast to the 17:26 flare). Since strong X-ray emissions were observed which should have involved the chromosphere through magnetic-field-line heat conduction, it is proposed that the variations wre produced ina coronal plasmoid magnetically separate from the chromosphere. A mechanism for the evolution of such a plasmoid from the upper loops of a giant X-ray arch is discussed. An iterative HXIS-image-deconvolution process is presented in an appendix.
Two comparisons of available specular infrared measurements using identical or very similar coatings reveal that specular BRDF (bidirectional reflectance distribution function) measurements of rough coatings are comparable but that simple measured reflectances are not. This is seen as indicating that the diffuse component of the measured specular reflectance is significantly larger than that of the specular component. It is noted that the diffuse component of the measurement is a convolution of the intrinsic directional reflectivity of the surface with the instrument function and that because the value of that function increases at the wavelengths under consideration, the diffuse component is larger than would otherwise be expected. The BRDF normalization is found to cause a primitive deconvolution of the instrument function and to produce a quantity that is approximately equal to the mean intrinsic directional reflectivity very near the specular direction. The analysis and comparison of data reveal that nonspecular BRDF measurements at angles well outside the instrument function can be calibrated as well by an image of the source upon the detector as by reference to a known surface.
Charge-coupled device images of Uranus and Neptune taken in the 8900-A absorption band of methane are presented. The images have been digitally processed by means of nonlinear deconvolution techniques to partially remove the effects of atmospheric seeing. The restored Uranus images show strong limb brightening consistent with previous observations and theoretical models of the planet's atmosphere. The computer-processed images of Neptune show discrete cloud features similar to those reported previously by Smith, Reitsema, and Larson (1979). A time series of the restored Neptune images shows a continuous variation which may be due to the planet's rotation.
A restoration of the 37, 21, 18, 10.7, and 6.6 GHz satellite imagery from the scanning multichannel microwave radiometer (SMMR) aboard Nimbus-7 to 22.2 km resolution is attempted using a deconvolution method based upon nonlinear programming. The images are deconvolved with and without the aid of prescribed constraints, which force the processed image to abide by partial a priori knowledge of the high-resolution result. The restored microwave imagery may be utilized to examined the distribution of precipitating liquid water in marine rain systems.
Energy spectra of photons emitted from Bremsstrahlung (BR) of energetic electrons with matter, is obtained from the deconvolution of the electron energy spectra. It can be inferred that the scenario for the production of X-rays and gamma rays in solar flares may vary from event to event. However, it is possible in many cases to associated low energy events to impulsive acceleration, and the high energy phase of some events to stochastic acceleration. In both cases, flare particles seem to be strongly modulated by local energy losses. Electric field acceleration, associated to neutral current sheets is a suitable candidate for impulsive acceleration. Finally, that the predominant radiation process of this radiation is the inverse Compton effect due to the local flare photon field.
The construction of composition profiles from X-ray intensity bands was investigated. The intensity band-to-composition profile transformation utilizes a solution which can be easily evaluated. The technique can be applied to thin films and thick speciments for which the variation of lattice parameters, linear absorption coefficient, and reflectivity with composition are known. A deconvolution scheme with corrections for the instrumental broadening and ak-alfadoublet is discussed.
Morrison's iterative noise removal method is studied by characterizing its effect upon systems of differing noise level and response function. The nature of data acquired from a linear shift invariant instrument is discussed so as to define the relationship between the input signal, the instrument response function, and the output signal. Fourier analysis is introduced, along with several pertinent theorems, as a tool to more thorough understanding of the nature of and difficulties with deconvolution. In relation to such difficulties the necessity of a noise removal process is discussed. Morrison's iterative noise removal method and the restrictions upon its application are developed. The nature of permissible response functions is discussed, as is the choice of the response functions used.