Sökning: "spatial spectral analysis"

Visar resultat 6 - 10 av 78 avhandlingar innehållade orden spatial spectral analysis.

1. 6. Multi-spectral analysis of fine scale aurora

   Författare :Hanna Dahlgren; Göran Marklund; Nickolay Ivchenko; Fred Sigernes; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Plasma physics; Plasmafysik; Optics; Optik;

   Sammanfattning : The Aurora Borealis is the visible manifestation of the complex plasma interaction between the solar wind and the Earth's magnetosphere and ionosphere. Ground based and in situ measurements demonstrate a prevalence of dynamic fine structure within auroral displays, with spatial scales down to tens of metres and time variations occurring on a fraction of a second. LÄS MER

3. 7. Spatial Decompositions of a Fully-developed Turbulent Round Jet Sampled with Particle Image Velocimetry

   Författare :Maja Wänström; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; proper orthogonal decomposition; axisymmetric turbulent jet; PIV; spatial spectral analysis; equilibrium similarity;

   Sammanfattning : Spatial decompositions of the turbulence in a far, axisymmetric jet at exit Reynolds number of 20, 000 have been performed. Equilibrium similaritytheory applied to the two-point Reynolds stresses has shown that the turbulence statistics in the far, fully developed region of an axisymmetric jet should be independent of origin in the streamwise direction when evaluated on the similarity coordinates system. LÄS MER

4. 8. Hyperspectral Image Generation, Processing and Analysis

   Författare :Hamed Hamid Muhammed; Ewert Bengtsson; Tommy Lindell; Erkki Oja; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Bildanalys; hyperspectral imaging; colour filter mosaics; remote sensing; crop reflectance; surface water quality; disease severity; plant density; linear system of equations; waste water detection; chlorophyll a; suspended paticulate matter; weighted fixed neural networks; weighted incremental neural networks; camera spectrometer; Bildanalys; Image analysis; Bildanalys;

   Sammanfattning : Hyperspectral reflectance data are utilised in many applications, where measured data are processed and converted into physical, chemical and/or biological properties of the target objects and/or processes being studied. It has been proven that crop reflectance data can be used to detect, characterise and quantify disease severity and plant density. LÄS MER

5. 9. Numerical Methods for Wave Propagation : Analysis and Applications in Quantum Dynamics

   Författare :Emil Kieri; Sverker Holmgren; Vasile Gradinaru; Hans O. Karlsson; Tobias Jahnke; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; computational wave propagation; quantum dynamics; time-dependent Schrödinger equation; spectral methods; Gaussian beams; splitting methods; low-rank approximation; Scientific Computing; Beräkningsvetenskap;

   Sammanfattning : We study numerical methods for time-dependent partial differential equations describing wave propagation, primarily applied to problems in quantum dynamics governed by the time-dependent Schrödinger equation (TDSE). We consider both methods for spatial approximation and for time stepping. LÄS MER

7. 10. High Resolution Analysis of Halftone Prints : A Colorimetric and Multispectral Study

   Författare :Daniel Nyström; Björn Kruse; Markku Hauta- Kasari; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Color imaging; Multispectral imaging; Halftone print; Dot gain; Image analysis; Bildanalys;

   Sammanfattning : To reproduce color images in print, the continuous tone image is first transformed into a binary halftone image, producing various colors by discrete dots with varying area coverage. In halftone prints on paper, physical and optical dot gains generally occur, making the print look darker than expected, and making the modeling of halftone color reproduction a challenge. LÄS MER