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We describe a high-speed interferometric method, using multiple angles of incidence and multiple wavelengths, to measure the absolute thickness, tilt, the local angle between the surfaces, and the refractive index of a fluctuating…

Optics · Physics 2020-08-26 Mengfei He , Sidney R. Nagel

Inverse scattering is the process of estimating the spatial distribution of the scattering potential of an object by measuring the scattered wavefields around it. In this paper, we consider reflection tomography of high contrast objects…

Signal Processing · Electrical Eng. & Systems 2020-12-17 Ajinkya Kadu , Hassan Mansour , Petros T. Boufounos

Describing the phenomenon of total internal reflection in terms of a reflection coefficient of unit magnitude, we found that, not only can propagating plane waves be total internally reflected at the planar interface of two dissimilar,…

Optics · Physics 2009-11-13 Akhlesh Lakhtakia , Tom G. Mackay

Near total reflection regime has been widely used in X-ray science, specifically in grazing incidence small angle X-ray scattering and in hard X-ray photoelectron spectroscopy. In this work, we introduce some practical aspects of using near…

Optical Deflectometric Tomography (ODT) provides an accurate characterization of transparent materials whose complex surfaces present a real challenge for manufacture and control. In ODT, the refractive index map (RIM) of a transparent…

Computer Vision and Pattern Recognition · Computer Science 2013-10-31 Adriana Gonzalez , Laurent Jacques , Christophe De Vleeschouwer , Philippe Antoine

We introduce a method based on the deflectometry principle for the reconstruction of specular objects exhibiting significant size and geometric complexity. A key feature of our approach is the deployment of an Automatic Virtual Environment…

Computer Vision and Pattern Recognition · Computer Science 2014-09-16 Jonathan Balzer , Daniel Acevedo-Feliz , Stefano Soatto , Sebastian Höfer , Markus Hadwiger , Jürgen Beyerer

Polarization is well known for its ability to decompose diffuse and specular reflections. However, the existing decomposition methods only focus on direct reflection and overlook multiple reflections, especially specular inter-reflection.…

Computer Vision and Pattern Recognition · Computer Science 2026-03-24 Ryota Maeda , Shinsaku Hiura

Is there a low-density region ('gap') between water and a hydrophobic surface? Previous X-ray/neutron reflectivity results have been inconsistent because the effect (if any) is sub-resolution for the surfaces studied. We have used X-ray…

Transparent objects are ubiquitous in daily life, making their perception and robotics manipulation important. However, they present a major challenge due to their distinct refractive and reflective properties when it comes to accurately…

Computer Vision and Pattern Recognition · Computer Science 2024-12-31 Hrishikesh Gupta , Stefan Thalhammer , Jean-Baptiste Weibel , Alexander Haberl , Markus Vincze

A smartphone camera can be used for measuring the width and distance of an object by taking its photograph. The focal length of the camera lens can be determined very accurately by finding the image width of an object on the camera sensor…

Physics Education · Physics 2021-11-15 Sanjoy Kumar Pal , Soumen sarkar , Surajit Chakrabarti

Schlieren imaging is a popular optical technique for visualizing flow in transparent media. In-water high-sensitivity flow visualization, using schlieren imaging, is usually performed with a large-footprint two-mirror z-configuration. Here,…

Fluid Dynamics · Physics 2026-04-06 Shubham Saxena , Manish Kumar

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

This paper presents a general refractive camera model and online co-estimation of odometry and the refractive index of unknown media. This enables operation in diverse and varying refractive fluids, given only the camera calibration in air.…

Robotics · Computer Science 2024-09-19 Mohit Singh , Kostas Alexis

We exploit the optical lever principle to detect minute fluctuations of a liquid-air interface. Waves propagating on the interface deflect a specularly reflected laser beam, inducing angular deviations captured by a dual-element photodiode.…

A non-invasive, in-situ calibration method for Total Internal Reflection Microscopy (TIRM) based on optical tweezing is presented which greatly expands the capabilities of this technique. We show that by making only simple modifications to…

An experimental apparatus measuring free-surface deformation of a centrifuged granular pile is developed. By horizontally rotating a quasi two-dimensional granular pile whose apex is located at the vertical rotation axis, the resultant…

Soft Condensed Matter · Physics 2021-09-22 T. i Irie , R. Yamaguchi , S. Watanabe , H. Katsuragi

The outer water buffer is an economic option to shield the external radiative backgrounds for liquid-scintillator neutrino detectors. However, the consequential total reflection of scintillation light at the media boundary introduces extra…

Instrumentation and Detectors · Physics 2022-09-23 Wei Dou , Benda Xu , Jianfeng Zhou , Zhe Wang , Shaomin Chen

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…

We analytically derive and experimentally demonstrate a method for the simultaneous measurement of deflection for large arrays of cantilevers. The Fresnel diffraction patterns of a cantilever independently reveals tilt, curvature, cubic and…

Instrumentation and Detectors · Physics 2013-07-18 Rodolfo I. Hermans , Joe M. Bailey , Gabriel Aeppli

Radiation pressure on a flat mirror submerged in a transparent liquid, depends not only on the refractive index n of the liquid, but also on the phase angle psi_0 of the Fresnel reflection coefficient of the mirror, which could be anywhere…

Optics · Physics 2012-05-10 Masud Mansuripur