Results 201 to 210 of about 7,127 (246)
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Autofocusing‐based phase correction
Magnetic Resonance in Medicine, 2018PurposePhase artifacts due to B0 inhomogeneity can severely degrade the quality of MR images. The artifacts are particularly prominent in long‐TE scans and usually appear as ghosting and blur. We propose a retrospective phase correction method based on autofocusing.
Loktyushin, A. +3 more
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IEEE Transactions on Geoscience and Remote Sensing, 2023
The wavenumber domain algorithm is an ideal solution for high-resolution and highly squinted (HRHS) synthetic aperture radar (SAR) imaging in the case of an ideal straight trajectory.
Yuhui Deng +5 more
semanticscholar +1 more source
The wavenumber domain algorithm is an ideal solution for high-resolution and highly squinted (HRHS) synthetic aperture radar (SAR) imaging in the case of an ideal straight trajectory.
Yuhui Deng +5 more
semanticscholar +1 more source
Autofocusing in digital holography
SPIE Proceedings, 2013Digital holography allows the acquisition of 3D profiles of objects. Digitally captured holograms are reconstructed at the respective distances of the objects to reveal the phase and the intensity profiles. However, computing an object’s 3D profile with only a single reconstruction requires prior knowledge of the distance of the object from the ...
Meriç Özcan +2 more
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Volume holography-based abrupt autofocusing beam.
Applied Optics, 2023Volume holographic elements are excellent at shaping high-quality spatial and spectral modes. Many microscopy and laser-tissue interaction applications require precise delivery of optical energy at specific sites without affecting the peripheral regions.
S. Vyas, Yuan Luo
semanticscholar +1 more source
Multifocus autofocusing Airy beam
Journal of the Optical Society of America A, 2017We propose a multifocus autofocusing Airy beam (MAAB) by modifying the frequency spectrum of a symmetric Airy beam (SAB) with a Gaussian band elimination filter. Unlike the original SAB, there are four off-axis foci at the autofocusing plane of the MAAB. The MAAB has a better abruptly autofocusing property than the original SAB.
Fei Zi +3 more
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Sparse Aperture Autofocusing and Imaging Based on Fast Sparse Bayesian Learning From Gapped Data
IEEE Transactions on Geoscience and Remote Sensing, 2023Sparse aperture (SA) autofocusing and imaging is a hot research problem in the signal processing field and has been widely used. Under SA, the absence of echoes destroys the coherence between the pulses, which then affects the autofocusing accuracy of ...
Yuanyuan Wang +4 more
semanticscholar +1 more source
An autofocusing algorithm for digital holograms
SPIE Proceedings, 2012We propose an algorithm for the automatic estimation of the in-focus image and the recovery of the correct reconstruction distance for digital holograms. We tested the proposed approach applying it to stretched digital holograms. In fact, by stretching an hologram with a variable elongation parameter, it is possible to change the in-focus distance of ...
Ferraro P +5 more
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A survey on ISAR autofocusing techniques
2004 International Conference on Image Processing, 2004. ICIP '04., 2005Over many years of research, several ISAR autofocusing techniques have been proposed. Today, we can divide them into two main categories: parametric and non-parametric techniques. The prominent point processing and the phase gradient algorithm are two classical examples of non-parametric techniques, whereas the more recent image contrast and entropy ...
BERIZZI, FABRIZIO +4 more
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Three-Airy autofocusing beams*
Chinese Physics B, 2020We numerically and experimentally demonstrate that a three-Airy autofocusing beam can be generated by superposing three deformed two-dimensional (2D) Airy beams with a triangle symmetry. When the initial angle between two wings of the deformed 2D Airy beams increases, such a three-Airy autofocusing beam exhibits that the focusing length decreases and ...
Cibo Lou +4 more
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Observation of abruptly autofocusing waves
Optics Letters, 2011We report on the experimental observation of abruptly autofocusing waves. This interesting family of wave packets has been realized by using a radially symmetric Airy intensity distribution. As demonstrated in our experiments, these waves can exhibit unusual features, such as the ability to autofocus by following a parabolic trajectory toward their ...
Papazoglou, Dimitrios G. +3 more
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