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X-ray Bragg coherent diffraction imaging has been demonstrated as a powerful three-dimensional (3D) microscopy approach for the investigation of sub-micrometer-scale crystalline particles. It is based on the measurement of a series of…

Radio interferometric imaging aims to estimate an unknown sky intensity image from degraded observations, acquired through an antenna array. In the theoretical case of a perfectly calibrated array, it has been shown that solving the…

Instrumentation and Methods for Astrophysics · Physics 2017-07-25 Audrey Repetti , Jasleen Birdi , Arwa Dabbech , Yves Wiaux

This paper proposes a method for estimating and detecting optical signals in practical photon-counting receivers. There are two important aspects of non-perfect photon-counting receivers, namely, (i) dead time which results in blocking…

Signal Processing · Electrical Eng. & Systems 2024-08-21 Chen Wang , Zhiyong Xu , Jingyuan Wang , Jianhua Li , Weifeng Mou , Huatao Zhu , Jiyong Zhao , Yang Su , Yimin Wang , Ailin Qi

For the sake of complete theoretical research of atmospheric refraction, the atmospheric refraction under the condition of lower angles of elevation is still worthy to be analyzed and explored. In some engineering applications, the objects…

Instrumentation and Methods for Astrophysics · Physics 2015-10-14 Yong Yu , Jian-Jun Cao , Zheng-Hong Tang , Hao Luo , Ming Zhao

In this study, we explore an approach aimed at enhancing the transmission or reflection coefficients of absorbing materials through the utilization of joint measurements of entangled photon states. On the one hand, through the…

Fourier transform (FT) spectroscopy is a versatile technique for studying the infrared (IR) optical response of solid-, liquid-, and gas-phase samples. In standard FT-IR spectrometers, a light beam passing through a Michelson interferometer…

Applied Physics · Physics 2021-03-12 Takashi Kuroda , Siti Chalimah , Yuanzhao Yao , Naoki Ikeda , Yoshimasa Sugimoto , Kazuaki Sakoda

A new generation of wide-field radio interferometers designed for 21-cm surveys is being built as drift scan instruments allowing them to observe large fractions of the sky. With large numbers of antennas and frequency channels the enormous…

Instrumentation and Methods for Astrophysics · Physics 2017-10-10 Philippe Berger , Niels Oppermann , Ue-Li Pen , J. Richard Shaw

When capturing images through the glass during rainy or snowy weather conditions, the resulting images often contain waterdrops adhered on the glass surface, and these waterdrops significantly degrade the image quality and performance of…

Computer Vision and Pattern Recognition · Computer Science 2024-04-01 Yunhao Li , Jing Wu , Lingzhe Zhao , Peidong Liu

We present a novel method for extrinsically calibrating a camera and a 2D Laser Rangefinder (LRF) whose beams are invisible from the camera image. We show that point-to-plane constraints from a single observation of a V-shaped calibration…

Computer Vision and Pattern Recognition · Computer Science 2018-09-05 Wenbo Dong , Volkan Isler

The development of compact indirect microwave holographic set-up by the implementation of low cost, specifically designed directive antennae as transmitter and receiver is proposed. Microwave holograms are recorded by 2D scanning over a…

Image and Video Processing · Electrical Eng. & Systems 2020-02-26 Vineeta Kumari , Aijaz Ahmed , Gyanendra Sheoran , Tirupathiraju Kanumuri , Chandra shakher

We summarise the mathematical foundation of the holographic method of measuring the reflector profile of an antenna or radio telescope. In particular, we treat the case, where the signal source is located at a finite distance from the…

Astrophysics · Physics 2016-11-18 J. W. M. Baars , R. Lucas , J. G. Mangum , J. A. Lopez-Perez

We address the estimation of the 6D pose of an unknown target spacecraft relative to a monocular camera, a key step towards the autonomous rendezvous and proximity operations required by future Active Debris Removal missions. We present a…

Computer Vision and Pattern Recognition · Computer Science 2024-06-12 Antoine Legrand , Renaud Detry , Christophe De Vleeschouwer

Continuous wavefront sensing on future space telescopes allows relaxation of stability requirements while still allowing on-orbit diffraction-limited optical performance. We consider the suitability of phase retrieval to continuously…

Instrumentation and Methods for Astrophysics · Physics 2023-09-14 Hyukmo Kang , Kyle Van Gorkom , Jess Johnson , Ole Singlestad , Aaron Goldtooth , Daewook Kim , Ewan S. Douglas

We present a new gravitational lens modelling technique designed to model high-resolution interferometric observations with large numbers of visibilities without the need to pre-average the data in time or frequency. We demonstrate the…

Instrumentation and Methods for Astrophysics · Physics 2021-01-06 Devon Powell , Simona Vegetti , John P. McKean , Cristiana Spingola , Francesca Rizzo , Hannah R. Stacey

This paper presents an uncalibrated deep neural network framework for the photometric stereo problem. For training models to solve the problem, existing neural network-based methods either require exact light directions or ground-truth…

Computer Vision and Pattern Recognition · Computer Science 2021-04-20 Berk Kaya , Suryansh Kumar , Carlos Oliveira , Vittorio Ferrari , Luc Van Gool

This paper presents a novel efficient method for spatial monitoring of the distribution of correlated field signals, such as temperature, humidity, etc. using unmanned aerial vehicles (UAVs). The spatial signal is compressed to its…

Signal Processing · Electrical Eng. & Systems 2024-11-27 Maryam Zahra , Homa Tajiani , Hadi Alasti

We present a novel high-definition (HD) snapshot diffractive spectral imaging system utilizing a diffractive filter array (DFA) to capture a single image that encodes both spatial and spectral information. This single diffractogram can be…

Accurate estimates of Instrument Spectral Response Functions (ISRFs) are crucial in order to have a good characterization of high resolution spectrometers. Spectrometers are composed of different optical elements that can induce errors in…

Numerical Analysis · Mathematics 2024-04-09 Jihanne El Haouari , Jean-Michel Gaucel , Christelle Pittet , Jean-Yves Tourneret , Herwig Wendt

Remote detection of the cardiac pulse has a number of applications in sports and medicine, and can be used to determine the physiological state of the subject. Previous approaches to estimate Heart Rate from video require the subject to…

Image and Video Processing · Electrical Eng. & Systems 2019-01-03 Arvind Subramaniam , Rajitha K

We address the problem of recovering the shape and spatially-varying reflectance of an object from multi-view images (and their camera poses) of an object illuminated by one unknown lighting condition. This enables the rendering of novel…

Computer Vision and Pattern Recognition · Computer Science 2021-12-23 Xiuming Zhang , Pratul P. Srinivasan , Boyang Deng , Paul Debevec , William T. Freeman , Jonathan T. Barron