Sökning: "phase-retrieval"

Visar resultat 6 - 10 av 15 avhandlingar innehållade ordet phase-retrieval.

1. 6. Non-Convex Methods for Compressed Sensing and Low-Rank Matrix Problems

   Författare :Daniele Gerosa; Matematik (naturvetenskapliga fakulteten); []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; compressed sensing; Low-rank Approximation; phase retrieval; Non-convex optimization;

   Sammanfattning : In this thesis we study functionals of the type \( \mathcal{K}_{f,A,\b}(\x)= \mathcal{Q}(f)(\x) + \|A\x - \b \| ^2 \), where \(A\) is a linear map, \(\b\) a measurements vector and \( \mathcal{Q} \) is a functional transform called \emph{quadratic envelope}; this object is a very close relative of the \emph{Lasry-Lions envelope} and its use is meant to regularize the functionals \(f\). Carlsson and Olsson investigated in earlier works the connections between the functionals \( \mathcal{K}_{f,A,\b}\) and their unregularized counterparts \(f(\x) + \|A\x - \b \| ^2 \). LÄS MER

3. 7. Coherent Diffractive Imaging with X-ray Lasers

   Författare :Max Felix Hantke; Filipe R. N. C. Maia; Janos Hajdu; Martin Svenda; Edgar Weckert; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; coherent diffractive X-ray imaging; lensless imaging; coherent X-ray diffractive imaging; flash diffractive imaging; single particle imaging; aerosol injection; electrospray injection; substrate-free sample delivery; carboxysome; phase retrieval; X-ray diffraction software; X-ray free-electron laser; XFEL; FEL; CXI; CDI; CXDI; FXI;

   Sammanfattning : The newly emerging technology of X-ray free-electron lasers (XFELs) has the potential to revolutionise molecular imaging. XFELs generate very intense X-ray pulses and predictions suggest that they may be used for structure determination to atomic resolution even for single molecules. LÄS MER

4. 8. Complex source modeling for electromagnetic dosimetry

   Författare :Markus Johansson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; optimization; phase-retrieval; source modeling; dosimetry; SAR;

   Sammanfattning : Electromagnetic modeling of complex sources is useful in dosimetry applications as well as for near-field to far-field transformations and antennadiagnostics. In order to determine whether exposure safety guidelines, such as the EU directive 2004/40/EC, are complied with, it is important to be able tomodel the field distribution from electromagnetic sources. LÄS MER

5. 9. Optical Memories and Processing in Time- and Frequency Domain

   Författare :Baozhu Luo; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Optical storage; photon echo; spectral hole burning; nonlinear optics; fiber amplifier; logical operation; phase retrieval; polarization holographic recording and retrieval; optical processing; Atomic and molecular physics; Atom- och molekylärfysik; Fysicumarkivet A:1998:Luo;

   Sammanfattning : Spectral hole burning and photon echoes are the techniques for frequency-selective optical memories, which have the potential to increase areal data storage density by a factor 10**7. They also have the capability to perform in-memory data processing. LÄS MER

7. 10. Dynamic and Static Diffractive Optics - some Examples

   Författare :Björn Löfving; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; subwavelength grating; spatial light modulator; phase retrieval; diffractive optics; ferroelectric liquid crystal; analog-to-digital conversion; optical switch; feedback generated hologram;

   Sammanfattning : Diffractive optics is a modern branch of optics, that exploits microstructures to manipulate the propagation of light. Fast computers and the progress in manufacturing technique of microelectronics have made possible a rapid development of diffractive optics during the past 10 years. LÄS MER