Recovering Enhanced Resolution Images And Digital Elevation Models From Compressed Image Sequences     

Gabriel Scarmana  John G. Fryer 《The Photogrammetric Record》2004,19(106):149-162

A device-independent algorithm for the estimation of an enhanced resolution image from a low-resolution compressed sequence is proposed. The algorithm utilises least squares matching to extract the interdependence of the low-resolution images. This algorithm also has the effect of attenuating compression artefacts. Improving the spatial resolution of the image sequence is not the only goal of the enhancement algorithm, as the enhanced images in turn lead to digital elevation models (DEMs) of improved accuracy.
Experimental results illustrate the algorithm's performance as a tool for digital photogrammetric applications. Stereoscopic sets of left and right images were taken of objects of known geometry and DEMs were created using both the original coarse images and compressed images enhanced by the algorithm.  相似文献   

The structure and the phyllosilicates (chemistry, crystallinity and texture) of Talas Ala-Tau (Tien Shan, Kyrgyz Republic): comparison with more recent subduction complexes     

Isabel Abad  Gabriel Gutirrez-Alonso  Fernando Nieto  Igor Gertner  Alex Becker  Ana Cabero 《Tectonophysics》2003,365(1-4):103

Geological mapping and structural analysis of the Talas Ala Tau (Tien Shan, Kyrgyz Republic) have revealed a complex structure composed of folds with axial-plane cleavage and thrust faults verging towards the NE. The main structures of the range correspond to minor Tertiary and Carboniferous–Permian deformation superimposed on the main deformation event that took place during the Baikalian orogeny. The pervasive axial-plane cleavage diminishes in penetrativity from the hinterland to the foreland in both the Uzunakhmat and Karagoin sheets. The main thrusts developed phyllonitic shear-related rocks on the hangingwall immediately above the thrust planes. A crystal-chemical study of the phyllosilicates growth during the Baikalian deformation event along a cross-section revealed changes in the crystallinity, composition and lattice parameters of them. The phyllosilicates present in the Talas Ala Tau rocks were crystallized in very low-grade metamorphic conditions, that is below 300 °C, as indicated by their Kübler Index (KI), which decreases from SW towards the NE. Detailed TEM study of the phyllosilicates reveals a clear textural difference at the lattice level between samples with higher or lower KI parameters. There is also a clear difference in crystal-chemical parameters (KI and b) and composition between the phyllosilicates growth in relation to the axial-plane cleavage and the ones belonging to the thrust-related phyllonites. The first ones are more affected by the ferrimuscovitic vector than the phyllosilicates of phyllonites, closer to the theoretical phengitic component. Huge ranges of values of phengitic content of micas at sample level are interpreted as the result of a decompression path from at least 8 kbar. We propose a subduction geodynamic environment for the regional deformation and the origin of the phyllosilicates, as they are similar to those obtained in more recent accretionary complexes.  相似文献   

Magnitude of Stokes’ drift in coastal waters     

Gabriel Godin 《Ocean Dynamics》1995,47(4):277-286

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Verknüpfung von Wasserbeschaffenheit und Wassermenge für das Grundwasser des Festgesteinsbereiches     

M. Schultze  H. Fischer  B. Gabriel 《洁净——土壤、空气、水》1990,18(6):673-681

Patterns of the typical groundwater quality for 13 hydrogeological units (lithofacies units) of the solid rock and for 5 stages of the contamination of groundwater by the agricultural production are derived from investigations carried out in six regions serving as examples and in evaluation of data series covering many years. The concentration values of the substances contained in water constituting the lower and upper limits of the typical width of variation are regarded as the quality of the groundwater reservoir (long retention time) and a fast runoff component of groundwater. On the basis of this model conception it is possible to determine one of the following four quantities from the other three quantities: groundwater quality, size of the groundwater reservoir, groundwater runoff with the shares of the slow component and of the fast one, removal of substances out of the root zone.  相似文献   

The characteristics of seismic signals produced by lahars and pyroclastic flows: Volcán de Colima,México     

Vyacheslav M. Zobin  Imelda Plascencia  Gabriel Reyes  Carlos Navarro 《Journal of Volcanology and Geothermal Research》2009,179(1-2):157-167

The general characteristics of seismic signals produced by pyroclastic flows (generated by either the collapse of a lava dome or an eruptive column) and lahars at Volcán de Colima, México are discussed. The paper concentrates on the 2004–2006 activity associated with and following the extrusion of andesitic block-lava in October–November 2004. It is shown that the duration of the broad-band seismic records of pyroclastic flows lasts a few minutes while the duration of seismic records of lahars continues for tens of minutes or hours. The spectra of seismic records produced by pyroclastic flows are characterized by lower peak frequencies (around 3–4 Hz) than for lahars (around 6–8 Hz). This difference in the frequency content together with the difference in the duration of seismic signals allows early diagnostic of the events in real time.  相似文献   

Major Elements in Lake Muhazi,Rwanda,East Africa     

Jean de la Paix MUPENZI  GE Jiwen  and Gabriel HABIYAREMYE 《《地质学报》英文版》2009,83(5):927-931

Abstract: The aim of this study undertaken at Lake Muhazi in Rwanda was to determine and analyze the major elements present in water. ?The presence of many major elements (Al, As, Ba, C, Ca, Cu, Fe, H+, K, Mg, Mn, N, P, S, Si, and Zn) was determined by spectroscopic technique. The concentrations of the elements were measured in water samples taken from three different locations of the lake from May to August 2008. The lake is polluted by water flow from mountain sides surrounding the lake. Other causes of pollution could be the use of agrochemicals in the sugar land, which surrounds the lake, and human activities near the lake. Finally, we proposed the strategies that can be applied in order to ensure good conservation of the environment and to prevent augmentation of heavy materials into the lake.  相似文献   

A three-dimensional biophysical model of Karenia brevis dynamics on the west Florida shelf: A look at physical transport and potential zooplankton grazing controls     

Scott P. Milroy  Dwight A. Dieterle  Ruoying He  Gary J. Kirkpatrick  Kristen M. Lester  Karen A. Steidinger  Gabriel A. Vargo  John J. Walsh  Robert H. Weisberg 《Continental Shelf Research》2008

The development of accurate predictive models of toxic dinoflagellate blooms is of great ecological importance, particularly in regions that are most susceptible to their detrimental effects. This is especially true along the west Florida shelf (WFS) and coast, where episodic bloom events of the toxic dinoflagellate Karenia brevis often wreak havoc on the valuable commercial fisheries and tourism industries of west Florida. In an effort to explain the dynamics at work within the maintenance and termination phases of a red tide, a simple three-dimensional coupled biophysical model was used in the analysis of the October 1999 red tide offshore Sarasota, Florida. Results of the numerical experiments indicate that: (1) measured and modeled flowfields were capable of transporting the observed offshore inoculum of K. brevis to within 16 km of the coastal boundary; (2) background concentrations (1000 cells L⁻¹) of K. brevis could grow to a red tide of over 2×10⁶ cells L⁻¹ in little more than a month, assuming an estuarine initiation site with negligible offshore advection, no grazing losses, negligible competition from other phytoplankton groups, and no nutrient limitation; (3) maximal grazing pressure could not prevent the initiation of a red tide or cause its termination, assuming no other losses to algal biomass and a zooplankton community ingestion rate similar to that of Acartia tonsa; and (4) the light-cued ascent behavior of K. brevis served as an aggregational mechanism, concentrating K. brevis at the 55 μE m⁻² s⁻¹ isolume when mean concentrations of K. brevis exceeded 100,000 cells L⁻¹. Further improvements in model fidelity will be accomplished by the future inclusion of phytoplankton competitors, disparate nutrient availability and limitation schemes, a more realistic rendering of the spectral light field and the attendant effects of photo-inhibition and compensation, and a mixed community of vertically-migrating proto- and metazoan grazers. These model refinements are currently under development and shall be used to aid progress toward an operational model of red tide forecasting along the WFS.  相似文献   

A stochastic model for daily subsurface CO₂ concentration and related soil respiration     

Edoardo Daly  A. Christopher Oishi  Amilcare Porporato  Gabriel G. Katul 《Advances in water resources》2008

Near-surface soil CO₂ gas-phase concentration (C) and concomitant incident rainfall (P_i) and through-fall (P_t) depths were collected at different locations in a temperate pine forest every 30 min during the 2005 and 2006 growing seasons (and then averaged to the daily timescale). At the daily scale, C temporal variations were well described by a sequence of monotonically decreasing functions interrupted by large positive jumps induced by rainfall events. A stochastic model was developed to link rainfall statistics responsible for these jumps to near-surface C dynamics. The model accounted for the effect of daily rainfall variability, both in terms of timing and amount of water, and permitted an analytical derivation of the C probability density function (pdf) using the parameters of the rainfall pdf. Given the observed positive correlation between daily C and soil CO₂ fluxes to the atmosphere (F_s), the effects of various rainfall regimes on the statistics of F_s can be deduced from the behavior of C under different climatic conditions. The predictions from this analytical model are consistent with flux measurements reported in manipulative experiments that varied rainfall amount and frequency.  相似文献   

Photometric and Polarimetric Observations of the Star SAO 124414     

N. D. Melikian  C. Magnan  M. A. Eritsian  A. A. Karapetian 《Astrophysics》2000,43(4):430-434

In the present work we give the results of photometric and polarimetric observations of the star SAO 124414 simultaneously in the BVR ranges of the spectrum. The observations were made over three years at Byurakan Astrophysical Observatory. Strong variations in the degree of light polarization in all three spectral ranges were recorded while the star's brightness was constant during the observations. It is confirmed that the recorded polarization has a stellar character. An analysis of the polarimetric measurements did not reveal periodicity in the variations of the degree of polarization.  相似文献   

Transient Effects in ISOPHOT Data: Status of Modelling and Correction Procedures     

J. A. Acosta-Pulido  C. Gabriel  H. O. Castañeda 《Experimental Astronomy》2000,10(2-3):333-346

The calibration of ISOPHOT observations is hampered in many cases by the transient response of the detectors. Here we outline thebehaviour observed in flight for the different ISOPHOT detectors. We also present some of the procedures which are currently used to correct transienteffects and their implementation in the ISOPHOT Interactive Analysis.  相似文献