Multispectral imaging and analysis system

Arrays of charge coupled devices or linear detector arrays simultaneously obtain spectral reflectance data of different wavelengths for a target area. Several accommodating a particular bandwidth, are individually associated with each array. Data from the arrays are read out in parallel and applied to a computer or microprocessor for processing. The microprocessor serves to analyze the data in real time and if possible, in accordance with hard-wired algorithms. The data are then displayed as an image on an appropriate display unit and also recorded for further use. The display system may be operationally connected to receive a terrain image such that the target area and the analyzed spectral reflectance data are superimposed and simultaneously displayed

Quantum optimal control of photoelectron spectra and angular distributions

Photoelectron spectra and photoelectron angular distributions obtained in photoionization reveal important information on e.g. charge transfer or hole coherence in the parent ion. Here we show that optimal control of the underlying quantum dynamics can be used to enhance desired features in the photoelectron spectra and angular distributions. To this end, we combine Krotov's method for optimal control theory with the time-dependent configuration interaction singles formalism and a splitting approach to calculate photoelectron spectra and angular distributions. The optimization target can account for specific desired properties in the photoelectron angular distribution alone, in the photoelectron spectrum, or in both. We demonstrate the method for hydrogen and then apply it to argon under strong XUV radiation, maximizing the difference of emission into the upper and lower hemispheres, in order to realize directed electron emission in the XUV regime

Study of the horizontal-to-vertical spectral ratio (HVSR) method for characterization of deep soils in the Mississippi Embayment

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Title from PDF of title page (University of Missouri--Columbia, viewed on December 22, 2009).Thesis advisor: Dr. Brent L. Rosenblad.Includes bibliographical references.M.S. University of Missouri--Columbia 2009.Dissertations, Academic -- University of Missouri--Columbia -- Civil engineering.Soil deposits can significantly influence the amplitude and frequency content of surface ground motions during earthquakes. Estimating the fundamental frequency (f0) of a site is often needed for improved planning and design for future earthquakes. A cost-effective method of obtaining an estimate of f0 is the Horizontal-to-Vertical Spectral Ratio (HVSR) method (also termed Nakamura's method), which utilizes ambient energy recorded in the horizontal and vertical directions from a single, three-component sensor. In addition to estimating the fundamental frequency, average shear wave velocity (VS,AVG) values have been estimated using the HVSR method and a simple approximate relationship relating VS,AVG to f0 and the depth to bedrock. This procedure was performed by Bodin et al. (2001) to develop a relationship between VS,AVG and soil depths in the Mississippi embayment. However, this relationship predicts average velocity values that are about 25% higher than values predicted by another relationship developed using a different method (Chen et al. 1996). Although this inconsistency is known, the relationship of Bodin et al. (2001) is often cited as the best information on the velocity structure in the embayment. In addition, Bodin et al. (2001) identified a second frequency peak of unknown origin in their HVSR plots. The objectives of this study are to answer these unresolved questions, specifically: (1) why the shear wave velocity relationships developed for the Mississippi embayment using the HVSR method are inconsistent with other findings, and (2) the origin of the second frequency peak observed in HVSR plots from the Mississippi embayment. To meet these objectives, the following three studies were performed: (1) a parametric study of site factors influencing the fundamental frequency and average velocity estimates from the HVSR method, (2) an investigation into the influence of the HVSR processing parameters using experimental data collected at eleven deep soil sites in the Mississippi embayment, and (3) comparison of experimental and simulated HVSR results for Mississippi embayment sites. With regard to the first objective, it was found that the HVSR method yielded reliable values of the fundamental site frequency for conditions of high velocity contrast between soil and rock and saturated soil conditions (conditions that are met in the Mississippi embayment). Also, it was shown that varying the HVSR processing parameters had a negligible impact on the HVSR frequency estimates. However, it was demonstrated that use of the approximate method to estimate VS,AVG systematically over-predicted the true VS,AVG values. With regard to the second objective, it was shown that the second frequency peak observed in the experimental HVSR plots can be attributed to either a higher-mode resonance of horizontally-polarized shear waves reflecting from the soil/bedrock boundary or local site resonance due to a shallow contrast in VS within the soil deposit. Based on the findings of this study it is recommended that the VS relationship for the sediments of the Mississippi embayment developed by Chen et al. (1996) should be preferred to the Bodin et al. (2001) relationship

Mapping of hydrothermal alternation zones and regional rock types using computer enhanced ERTS MSS images

A combination of digital computer processing and color compositing of ERTS MSS images has been used to map hydrothermal alternation zones and regional rock types in south-central Nevada. The technique is based on enhancement of subtle visible and near infrared reflectivity differences between mineralogically dissimilar rocks, especially unaltered and altered rocks. MSS spectral bands are ratioed, pixel by pixel, in the computer and subsequently stretched. These ratio values are used to produce a new black and white image which shows the subtle spectral reflectivity differences. Additional enhancement is achieved by preparing color composites of two or more stretched ratio images. The choice of MSS bands for rationing depends on the spectral reflectance properties of the rocks to be discriminated. Although this technique is in the initial stage of development and is untested in other areas, it already appears to have considerable potential for targeting mineral prospects and for regional geologic mapping