English
Related papers

Related papers: Multi-frequency image reconstruction for radio-int…

200 papers

In ultrasound nondestructive testing, a widespread approach is to take synthetic aperture measurements from the surface of a specimen to detect and locate defects within it. Based on these measurements, imaging is usually performed using…

Signal Processing · Electrical Eng. & Systems 2020-12-09 Jan Kirchhof , Sebastian Semper , Christoph W. Wagner , Eduardo Pérez , Florian Römer , Giovanni Del Galdo

In recent years, deep learning has been successfully applied in various scientific domains. Following these promising results and performances, it has recently also started being evaluated in the domain of radio astronomy. In particular,…

In this paper, we propose a novel method for joint recovery of camera pose, object geometry and spatially-varying Bidirectional Reflectance Distribution Function (svBRDF) of 3D scenes that exceed object-scale and hence cannot be captured…

Computer Vision and Pattern Recognition · Computer Science 2023-06-07 Carolin Schmitt , Božidar Antić , Andrei Neculai , Joo Ho Lee , Andreas Geiger

A technique is described that is used to improve the detection of radio-frequency interference in astronomical radio observatories. It is applied on a two-dimensional interference mask after regular detection in the time-frequency domain…

Instrumentation and Methods for Astrophysics · Physics 2012-03-01 A. R. Offringa , J. J. van de Gronde , J. B. T. M. Roerdink

We present a new approach to multi-frequency synthesis in radio astronomy. Using Bayesian inference techniques, the new technique estimates the sky brightness and the spectral index simultaneously. In principle, the bandwidth of a wide-band…

Instrumentation and Methods for Astrophysics · Physics 2015-09-16 H. Junklewitz , M. A. Bell , T. Enßlin

Astronomical optical interferometers (OI) sample the Fourier transform of the intensity distribution of a source at the observation wavelength. Because of rapid atmospheric perturbations, the phases of the complex Fourier samples…

Instrumentation and Methods for Astrophysics · Physics 2015-03-06 Antony Schutz , André Ferrari , David Mary , Eric Thiébaut , Ferréol Soulez

Stein's unbiased risk estimator (SURE) has been shown to be an effective metric for determining optimal parameters for many applications. The topic of this article is focused on the use of SURE for determining parameters for blind…

Numerical Analysis · Mathematics 2022-03-01 Toby Sanders

Recovering images from optical interferometric observations is one of the major challenges in the field. Unlike the case of observations at radio wavelengths, in the optical the atmospheric turbulence changes the phases on a very short time…

Interferometers play an increasingly important role for spatially resolved observations. If employed at full potential, interferometry can probe an enormous dynamic range in spatial scale. Interpretation of the observed visibilities…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 C. Brinch , C. P. Dullemond

The new technique, multi-frequency imaging (MFI) is developed. In VLBI, Multi-Frequency Imaging (MFI) consists of multi-frequency synthesis (MFS) and multi-frequency analysis (MFA) of the VLBI data obtained from observations on various…

Astrophysics · Physics 2007-05-23 S. Likhachev

In this paper we propose a very efficient method to fuse the unregistered multi-focus microscopical images based on the speed-up robust features (SURF). Our method follows the pipeline of first registration and then fusion. However, instead…

Computer Vision and Pattern Recognition · Computer Science 2020-01-20 Yixiong Liang , Yuan Mao , Zhihong Tang , Meng Yan , Yuqian Zhao , Jianfeng Liu

Radio-frequency interference (RFI) is a major systematic limitation in radio astronomy, particularly for science cases requiring high sensitivity, such as 21 cm cosmology. Traditionally, RFI is dealt with by identifying its signature in the…

The development of new phased array systems in radio astronomy, as the low frequency array (LOFAR) and the square kilometre array (SKA), formed of a large number of small and flexible elementary antennas, has led to significant challenges.…

Modern image formation algorithms in radio interferometry rely on repeated applications of the operator {\Phi} modelling the measurement process and its adjoint {Phi^\dagger} to enforce consistency with the acquired data, specifically via…

Instrumentation and Methods for Astrophysics · Physics 2026-05-27 Arwa Dabbech , Yves Wiaux

Ultrasound images formed by delay-and-sum beamforming are plagued by artifacts that only clear up after compounding many transmissions. Some prior works pose imaging as an inverse problem. This approach can yield high image quality with few…

Signal Processing · Electrical Eng. & Systems 2024-07-03 Vincent van de Schaft , Oisín Nolan , Ruud J. G. van Sloun

Hyperspectral imaging systems based on multiple-beam interference (MBI), such as Fabry-Perot interferometry, are attracting interest due to their compact design, high throughput, and fine resolution. Unlike dispersive devices, which measure…

Signal Processing · Electrical Eng. & Systems 2024-10-30 Mohamad Jouni , Daniele Picone , Mauro Dalla Mura

Magnetic Resonance Imaging (MRI) has become an important technique in the clinic for the visualization, detection, and diagnosis of various diseases. However, one bottleneck limitation of MRI is the relatively slow data acquisition process.…

Image and Video Processing · Electrical Eng. & Systems 2022-11-28 Xue Liu , Juan Zou , Xiawu Zheng , Cheng Li , Hairong Zheng , Shanshan Wang

We present here three recipes for getting better images with optical interferometers. Two of them, Low- Frequencies Filling and Brute-Force Monte Carlo were used in our participation to the Interferometry Beauty Contest this year and can be…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 Florentin Millour , Martin Vannier , Anthony Meilland

Deep learning-based image reconstruction methods have achieved remarkable success in phase recovery and holographic imaging. However, the generalization of their image reconstruction performance to new types of samples never seen by the…

Computer Vision and Pattern Recognition · Computer Science 2022-08-17 Hanlong Chen , Luzhe Huang , Tairan Liu , Aydogan Ozcan
‹ Prev 1 4 5 6 7 8 10 Next ›