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| Identifier |
000350660 |
| Title |
Εφαρμογή τεχνικών αντιστροφής ABEL στην ολογραφική μικροσοκοπία |
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Author
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Αποστολόπουλος, Μιχάλης
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Thesis advisor
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Παπάζογλου, Δημήτρης
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Reviewer
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Ταρουδάκης, Μιχάλης
Ζχαράκης, Ιωάννης
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| Abstract |
We study the reconstruction in fine (micrometer) volume detail of the 3D distribution of the refractive index perturbations induced by the propagation of ultrafast laser pulses in transparent media. Our work is focused on recovering the volume distribution of the refractive index from the experimentally measured values of the perturbation of a probe wave-front that transverses the volume. The probe wave-front perturbation is experimentally reconstructed by use of in-line holographic techniques.
In order to recover the 3D distribution of the perturbation of the refractive index, we apply Abel inversion techniques. Any Abel inversion technique can be derived as a special case of the projection-slice theorem, a fundamental relation in the field of computed tomography. The most commonly used method for calculating the inverse Abel transform in imaging applications is the Fourier-Hankel technique. This method is based on a representation of the inverse Abel transform via the Hankel transform of the Fourier transform of the projection. However, this method magnifies experimental noise and becomes practically unusable in cases of excessively noisy images, or images with a large dynamic range.
In this work we compare the effectiveness of the Fourier-Hankel technique to Gaussian basis-set expansion Abel transform (BASEX) method. This method is based on expanding the projection in a basis set of functions that are analytical projections of known well-behaved functions. The 3D distribution can then be reconstructed as a linear combination of these well-behaved functions, which have a Gaussian-like shape, with the same expansion coefficients as the projection. The BASEX method is efficient and it requires less computational steps in progress and is particularly well suited for noisy images, or images with a large dynamic range.
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| Physical description |
81 σ. : πιν. ; 30 εκ. |
| Language |
Greek |
| Subject |
Ophthalmology |
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Vision Disorders |
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Όρασης διαταραχές |
| Issue date |
2008-12-15 |
| Collection
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School/Department--School of Medicine--Department of Medicine--Post-graduate theses
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Type of Work--Post-graduate theses
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| Notes |
Διατμηματικό μεταπτυχιακό πρόγραμμα σπουδών: "Οπτική και Όραση" |
| Views |
285 |
Εφαρμογή τεχνικών αντιστροφής ABEL στην ολογραφική μικροσοκοπία
