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We present a method to calibrate a high-resolution wavefront-correcting device with a single, static camera, located in the focal plane; no moving of any component is needed. The method is based on a localized diversity and differential…

Instrumentation and Methods for Astrophysics · Physics 2015-06-17 Visa Korkiakoski , Niek Doelman , Johanan Codona , Matthew Kenworthy , Gilles Otten , Christoph U. Keller

High-throughput 2D and 3D scanning electron microscopy, which relies on automation and dependable control algorithms, requires high image quality with minimal human intervention. Classical focus and astigmatism correction algorithms attempt…

Instrumentation and Detectors · Physics 2023-05-10 Philipp Johannes Schubert , Rangoli Saxena , Joergen Kornfeld

Context. The QUBIC collaboration is building a bolometric interferometer dedicated to the detection of B-mode polarization fluctuations in the Cosmic Microwave Background. Aims. We introduce a self-calibration procedure related to those…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 M. -A. Bigot-Sazy , R. Charlassier , J. -Ch. Hamilton , J. Kaplan , G. Zahariade

Very long baseline interferometry (VLBI) achieves the highest angular resolution in astronomy. VLBI measures corrupted Fourier components, known as visibilities. Reconstructing on-sky images from these visibilities is a challenging inverse…

Instrumentation and Methods for Astrophysics · Physics 2025-11-25 Paul Tiede , William Moses , Valentin Churavy , Michael D. Johnson , Dominic Pesce , Lindy Blackburn , Peter Galison

Context: New generation low-frequency telescopes are exploring a new parameter space in terms of depth and resolution. The data taken with these interferometers, for example with the LOw Frequency ARray (LOFAR), are often calibrated in a…

Balanced steady-state free precession (bSSFP) imaging enables high scan efficiency in MRI, but differs from conventional sequences in terms of elevated sensitivity to main field inhomogeneity and nonstandard T2/T1-weighted tissue contrast.…

Image and Video Processing · Electrical Eng. & Systems 2021-08-12 Kübra Keskin , Uğur Yılmaz , Tolga Çukur

Phase microscopy is an invaluable tool in the biosciences and in clinical diagnostics. The sensitivity of current phase microscopy techniques is optimized for one specific mean phase value and varies significantly across a given sample.…

Optics · Physics 2019-08-30 Thomas Juffmann , Andrés de los Ríos Sommer , Sylvain Gigan

Interferometric phase (InPhase) imaging is an important part of many present-day coherent imaging technologies. Often in such imaging techniques, the acquired images, known as interferograms, suffer from two major degradations: 1) phase…

Signal Processing · Electrical Eng. & Systems 2019-11-25 Joshin P. Krishnan , Mário A. T. Figueiredo , José M. Bioucas-Dias

Direct imaging of exoplanets requires very high contrast levels, which are obtained using coronagraphs. But residual quasi-static aberrations create speckles in the focal plane downstream of the coronagraph which mask the planet. This…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 J. Mazoyer , P. Baudoz , R. Galicher , M. Mas , G. Rousset

Recent advances in the field of attosecond science hold the promise of tracking electronic processes at the shortest space and time scales. Imaging methods that combine attosecond temporal with nanometer spatial resolution are currently out…

Images of the linear polarization of synchrotron radiation around Active Galactic Nuclei (AGN) identify their projected magnetic field lines and provide key data for understanding the physics of accretion and outflow from supermassive black…

Instrumentation and Methods for Astrophysics · Physics 2016-09-21 Andrew A. Chael , Michael D. Johnson , Ramesh Narayan , Sheperd S. Doeleman , John F. C. Wardle , Katherine L. Bouman

This paper introduces a novel approach to the fine alignment of images in a burst captured by a handheld camera. In contrast to traditional techniques that estimate two-dimensional transformations between frame pairs or rely on discrete…

Computer Vision and Pattern Recognition · Computer Science 2023-12-11 Bruno Lecouat , Yann Dubois de Mont-Marin , Théo Bodrito , Julien Mairal , Jean Ponce

The spatial-frequency coverage of a radio interferometer is increased by combining samples acquired at different times and observing frequencies. However, astrophysical sources often contain complicated spatial structure that varies within…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 U. Rau

We proposed a novel approach to coherent imaging of dynamic samples. The inter-frame similarity of the sample's local structures is found to be a powerful constraint in phasing a sequence of diffraction patterns. We devised a new image…

Optics · Physics 2024-07-11 Pengju Sheng , Fucai Zhang

X-ray imaging is a fundamental tool of routine clinical diagnosis. Fluoroscopic imaging can further acquire X-ray images at video frame rates, thus enabling non-invasive in-vivo motion studies of joints, gastrointestinal tract, etc. For…

Image and Video Processing · Electrical Eng. & Systems 2018-10-22 Jacky C. K. Chow , Derek Lichti , Kathleen Ang , Gregor Kuntze , Gulshan Sharma , Janet Ronsky

Direction-dependent instrumental polarisation introduces wide-field polarimetric aberrations and limits the dynamic range of low-frequency interferometric images. We therefore provide a detailed two-dimensional analysis of the Giant…

Instrumentation and Methods for Astrophysics · Physics 2014-07-03 J. S. Farnes

We leverage the Sparsity Averaging Reweighted Analysis (SARA) approach for interferometric imaging, that is based on convex optimisation, for the super-resolution of Cyg A from observations at the frequencies 8.422GHz and 6.678GHz with the…

Instrumentation and Methods for Astrophysics · Physics 2018-05-15 Arwa Dabbech , Alexandru Onose , Abdullah Abdulaziz , Richard A. Perley , Oleg M. Smirnov , Yves Wiaux

Sample-induced aberrations and optical imperfections limit the resolution of fluorescence microscopy. Phase diversity is a powerful technique that leverages complementary phase information in sequentially acquired images with deliberately…

Conventional microwave imaging schemes, enabled by the ubiquity of coherent sources and detectors, have traditionally relied on frequency bandwidth to retrieve range information, while using mechanical or electronic beamsteering to obtain…

A lensless digital holography enables wide-field microscopic imaging without the limitations imposed by optical lens performance. However, conventional holographic imaging often relies on magnifying optical systems to compensate for the low…

Optics · Physics 2025-06-24 Byung Gyu Chae