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Accurate and high-efficiency film metrology remains a key challenge in High-Volume Manufacturing (HVM), where conventional spectroscopic reflectometry and white light interferometry (WLI) are either limited by model dependence or…

In this paper, we propose a novel non-contact vibration measurement system that is competent in estimating linear and/or rotational motions of machine parts. The technique combines microwave radar, standard camera, and optical strobe to…

Signal Processing · Electrical Eng. & Systems 2020-06-02 Dibyendu Roy , Arijit Sinharay , Brojeshwar Bhowmick , Raj Rakshit , Tapas Chakravarty , Arpan Pal

Reflectometry is a technique that uses the light reflected by a sample to determine properties of the sample. Interferometric reflectometry uses interference between two beams, one of which is incident on ---and reflected back by--- a…

Optics · Physics 2019-10-10 Alexander Nahmad-Rohen , Wolfgang Langbein

A novel ultra-long distributed vibration sensing (DVS) system using forward transmission and coherent detection is proposed and experimentally demonstrated. In the proposed scheme, a pair of multi-span optical fibers are deployed for…

Signal Processing · Electrical Eng. & Systems 2019-07-19 Yaxi Yan , Changjian Guo , Xiong Wu , Ziqi Lin , Xian Zhou , Faisal Nadeem Khan , Alan Pak Tao Lau , Chao Lu

Herein, the concept of point of darkness based on polarized light phase difference and absorption of light is demonstrated by simulations using low refractive index and extinction coefficient semiconductor and dielectric, and high…

Optics · Physics 2022-02-17 Ilze Aulika , Martins Zubkins , Jelena Butikova , Juris Purans

Advanced gravitational wave interferometric detectors will operate at their design sensitivity with nearly 1MW of laser power stored in the arm cavities. Such large power may lead to the uncontrolled growth of acoustic modes in the test…

Instrumentation and Methods for Astrophysics · Physics 2015-10-07 Slawek Gras , Peter Fritschel , Lisa Barsotti , Matthew Evans

Mobile robots equipped with multiple light detection and ranging (LiDARs) and capable of recognizing their surroundings are increasing due to the minitualization and cost reduction of LiDAR. This paper proposes a target-less extrinsic…

Robotics · Computer Science 2024-09-16 Shun Niijima , Atsushi Suzuki , Ryoichi Tsuzaki , Masaya Kinoshita

Particle size measurement is crucial in various applications, be it sizing droplets in inkjet printing or respiratory events, tracking particulate ejection in hypersonic impacts, or detecting floating target markers in free surface flows.…

Fluid Dynamics · Physics 2023-10-04 Saini Jatin Rao , Shubham Sharma , Saptarshi Basu , Cameron Tropea

Sensing and manipulating targets hidden under scattering media are universal problems that take place in applications ranging from deep-tissue optical imaging to laser surgery. A major issue in these applications is the shallow light…

The measurements of size distribution of small particles (e.g. dusts, droplets, bubbles, etc.) are critical for a broad range of applications in environmental science, public health, industrial manufacturing, etc. Laser diffraction (LD), a…

Fluid Dynamics · Physics 2021-03-16 Santosh Kumar. S , Zilong He , Christopher Hogan , Steven Fredericks , Jiarong Hong

Empowered by deep learning, recent methods for material capture can estimate a spatially-varying reflectance from a single photograph. Such lightweight capture is in stark contrast with the tens or hundreds of pictures required by…

Graphics · Computer Science 2019-06-28 Valentin Deschaintre , Miika Aittala , Fredo Durand , George Drettakis , Adrien Bousseau

Optical Doppler shift demonstration experiments are not a simple task since the light source cannot usually be moved in a sufficiently smooth and uniform manner to keep the level of noise well below of that of the signal. For that reason…

Physics Education · Physics 2015-06-26 L. Bernal , L. Bilbao

The electron density is a key parameter to characterize any plasma. Most of the plasma applications and research in the area of low-temperature plasmas (LTPs) are based on the accurate estimations of plasma density and plasma temperature.…

We introduce a system and methods for the three-dimensional measurement of extended specular surfaces with high surface normal variations. Our system consists only of a mobile hand held device and exploits screen and front camera for…

Computer Vision and Pattern Recognition · Computer Science 2019-07-26 Florian Willomitzer , Chia-Kai Yeh , Vikas Gupta , William Spies , Florian Schiffers , Marc Walton , Oliver Cossairt

An improved phase retrieval method based Hilbert transform is introduced to quantitatively calculate the phase distribution from distorted fringe pattern. Also phase measurement deflectomety are widely used in specular type samples. The…

Instrumentation and Detectors · Physics 2016-09-21 Silin Na , Sanghoon Shin , Younghun Yu

Intelligent reflecting surface (IRS) is recognized as an enabler of future dual-function radar-communications (DFRC) by improving spectral efficiency, coverage, parameter estimation, and interference suppression. Prior studies on IRS-aided…

Information Theory · Computer Science 2023-08-11 Tong Wei , Linlong Wu , Kumar Vijay Mishra , M. R. Bhavani Shankar

Emitter localization is widely applied in the military and civilian _elds. In this paper, we tackle the problem of position estimation for multiple stationary emitters using Doppler frequency shifts and angles by moving receivers. The…

Signal Processing · Electrical Eng. & Systems 2021-12-07 Ziqiang Wang , Yimao Sun , Qun Wan , Lei Xie , Ning Liu

Multipath effects significantly influence the quality of microwave imaging in highly reflective environments, while the physical measurement aperture size constrains resolution. It is shown that by exploiting multipath reflections, improved…

Image and Video Processing · Electrical Eng. & Systems 2026-05-06 Quanfeng Wang , Mei Song Tong , Thomas F. Eibert

Reflection phase imaging provides label-free, high-resolution characterization of biological samples, typically using interferometric-based techniques. Here, we investigate reflection phase microscopy from intensity-only measurements under…

Quantitative Methods · Quantitative Biology 2019-12-18 Alex Matlock , Anne Sentenac , Patrick C. Chaumet , Ji Yi , Lei Tian

A novel interferometric method - SLIVER (Super Localization by Image inVERsion interferometry) - is proposed for estimating the separation of two incoherent point sources with a mean squared error that does not deteriorate as the sources…

Optics · Physics 2016-02-16 Ranjith Nair , Mankei Tsang
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