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Neural Radiance Fields (NeRF) have emerged as a potent paradigm for representing scenes and synthesizing photo-realistic images. A main limitation of conventional NeRFs is that they often fail to produce high-quality renderings under novel…

Computer Vision and Pattern Recognition · Computer Science 2022-05-13 Jian Zhang , Yuanqing Zhang , Huan Fu , Xiaowei Zhou , Bowen Cai , Jinchi Huang , Rongfei Jia , Binqiang Zhao , Xing Tang

Lately a new approach to Extended Reality (XR), denoted as XR-RF, has been proposed which is realized by combining Radio Frequency (RF) Imaging and programmable wireless environments (PWEs). RF Imaging is a technique that aims to detect…

In high energy resolution X-ray spectroscopy beamlines of synchrotron radiation facilities, it is important to keep X-ray spectrometer operating in optimal conditions. The adjusting process is normally very time consuming due to the…

Accelerator Physics · Physics 2021-05-07 Fei Zhan

There are definite plans for the construction of X-ray free electron lasers (FEL), both at DESY, where the so-called XFEL is part of the design of the electron-positron linear collider TESLA, as well as at SLAC, where the so-called Linac…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Ringwald

In the coming years, strong gravitational lens discoveries are expected to increase in frequency by two orders of magnitude. Lens-modelling techniques are being developed to prepare for the coming massive influx of new lens data, and blind…

Astrophysics of Galaxies · Physics 2020-06-18 Philipp Denzel , Sampath Mukherjee , Jonathan P. Coles , Prasenjit Saha

In principle, diffractive optics, particularly Phase Fresnel Lenses (PFLs), offer the ability to construct large, diffraction-limited, and highly efficient X-ray/$\gamma$-ray telescopes, leading to dramatic improvement in angular resolution…

The advent of accelerator-driven free-electron lasers (FEL) has opened new avenues for high-resolution structure determination via diffraction methods that go far beyond conventional x-ray crystallography methods. These techniques rely on…

Random features (RFs) are a popular technique to scale up kernel methods in machine learning, replacing exact kernel evaluations with stochastic Monte Carlo estimates. They underpin models as diverse as efficient transformers (by…

Machine Learning · Statistics 2024-10-04 Isaac Reid , Stratis Markou , Krzysztof Choromanski , Richard E. Turner , Adrian Weller

A solution to the inversion problem of scattering would offer aberration-free diffraction-limited 3D images without the resolution and depth-of-field limitations of lens-based tomographic systems. Powerful algorithms are increasingly being…

Recent advances in grazing incidence X-ray optics using synchrotron radiation sources have stimulated the need for basic research in high quality mirror materials for novel applications. In this paper we communicate the results of the first…

Extensions of Neural Radiance Fields (NeRFs) to model dynamic scenes have enabled their near photo-realistic, free-viewpoint rendering. Although these methods have shown some potential in creating immersive experiences, two drawbacks limit…

Computer Vision and Pattern Recognition · Computer Science 2024-06-07 Xinhang Liu , Yu-Wing Tai , Chi-Keung Tang , Pedro Miraldo , Suhas Lohit , Moitreya Chatterjee

Accelerating neural radiance fields training is of substantial practical value, as the ray sampling strategy profoundly impacts network convergence. More efficient ray sampling can thus directly enhance existing NeRF models' training…

Computer Vision and Pattern Recognition · Computer Science 2023-08-31 Shilei Sun , Ming Liu , Zhongyi Fan , Yuxue Liu , Chengwei Lv , Liquan Dong , Lingqin Kong

Neural Radiance Fields (NeRF) have emerged as a powerful representation for the task of novel view synthesis due to their simplicity and state-of-the-art performance. Though NeRF can produce photorealistic renderings of unseen viewpoints…

Computer Vision and Pattern Recognition · Computer Science 2021-12-02 Michael Niemeyer , Jonathan T. Barron , Ben Mildenhall , Mehdi S. M. Sajjadi , Andreas Geiger , Noha Radwan

In planar metamaterial lenses, the focal point moves with the frequency. Here it is shown numerically that this movement can be controlled by properly engineering the dimensions of the metamaterial-based phase shifters that constitute the…

Optics · Physics 2013-03-01 W. J. Capecchi , N. Behdad , F. A. Volpe

The electromagnetic inverse problem has long been a research hotspot. This study aims to reverse radar view angles in synthetic aperture radar (SAR) images given a target model. Nonetheless, the scarcity of SAR data, combined with the…

Machine Learning · Computer Science 2024-01-03 Yanni Wang , Hecheng Jia , Shilei Fu , Huiping Lin , Feng Xu

We propose a correction to the conventional Rytov approximation (RA) and investigate its performance for predicting wave scattering under strong scattering conditions. An important motivation for the correction and investigation is to help…

Computational Physics · Physics 2022-11-30 Amartansh Dubey , Xudong Chen , Ross Murch

Comprehensive 3D scene understanding, both geometrically and semantically, is important for real-world applications such as robot perception. Most of the existing work has focused on developing data-driven discriminative models for scene…

Computer Vision and Pattern Recognition · Computer Science 2022-06-10 Mingtong Zhang , Shuhong Zheng , Zhipeng Bao , Martial Hebert , Yu-Xiong Wang

We report an extensive numerical study and supporting experimental results on the spectral characterization of optical aberrations in macroscopic fluidic lenses with tunable focal distance and aperture shape. Using a Shack-Hartmann…

Optics · Physics 2023-12-19 Graciana Puentes , Fernando Minotti

Relying on atomic scattering factors from evaluated databases, a new model for the reflectivity of x rays on solid surfaces has been developed for FLUKA v4-6.0. This model accounts for the variation of reflectivity as a function of the…

Modern x-ray free-electron lasers (XFELs) produce x-ray pulses of exceptional transverse coherence. This is due largely to the process of optical guiding by which the radiation is both refractively guided by the bunched electron beam and…

Accelerator Physics · Physics 2021-04-20 River R. Robles , Gabriel Marcus , Zhirong Huang
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