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Related papers: A two-band approach to n$\lambda$ phase error corr…

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Depth cameras are emerging as a cornerstone modality with diverse applications that directly or indirectly rely on measured depth, including personal devices, robotics, and self-driving vehicles. Although time-of-flight (ToF) methods have…

Computer Vision and Pattern Recognition · Computer Science 2021-05-26 Seung-Hwan Baek , Noah Walsh , Ilya Chugunov , Zheng Shi , Felix Heide

Multi-spectral quantitative phase imaging (QPI) is an emerging imaging modality for wavelength dependent studies of several biological and industrial specimens. Simultaneous multi-spectral QPI is generally performed with color CCD cameras.…

Instrumentation and Detectors · Physics 2019-02-20 Azeem Ahmad , Anand Kumar , Vishesh Dubey , Ankit Butola , Balpreet Singh Ahluwalia , Dalip Singh Mehta

We introduce and experimentally implement Fourier-plane phase synchronization for optical microscopy, and demonstrate its performance with interferometric scattering microscopy. By combining a photothermal phase plate and laser beam…

This paper reviews two techniques that have been recently published for 3D profilometry and proposes one shot profilometry using iterative two-step temporal phase-unwrapping by combining the composite fringe projection and the iterative…

Instrumentation and Detectors · Physics 2016-05-24 Guangliang Du , Minmin Wang , Canlin Zhou , Shuchun Si , Hui Li , Zhenkun Lei , Yanjie Li

Microscopic fringe projection profilometry is a powerful 3D measurement technique with a theoretical measurement accuracy better than one micron provided that the measured targets can be imaged with good fringe visibility. However,…

Image and Video Processing · Electrical Eng. & Systems 2019-06-26 Yan Hu , Qian Chen , Yichao Liang , Shijie Feng , Tianyang Tao , Chao Zuo

Astrophysical time series often contain periodic signals. The large and growing volume of time series data from photometric surveys demands computationally efficient methods for detecting and characterizing such signals. The most efficient…

Instrumentation and Methods for Astrophysics · Physics 2021-02-09 John Hoffman , Jacob Vanderplas , Joel Hartman , Gaspar Bakos

This tutorial gives a general introduction to optical and infrared interferometry, specifically addressing two questions: `Can I use VLTI to observe my favourite object?' and `What will it tell me?' The observables measured by an…

Astrophysics · Physics 2007-05-23 Timothy R. Bedding

We review millimeter interferometric phase variations caused by variations in the precipitable water vapor content of the troposphere, and we discuss techniques proposed to correct for these variations. We present observations with the Very…

Astrophysics · Physics 2015-06-24 C. L. Carilli , M. A. Holdaway

This paper discusses a fast algorithm for analyzing the phases of a multi-tone phase calibration signal. The multi-tone method is superior to its single-tone counterpart. The PCal signal is a wide-band frequency comb derived from an…

Instrumentation and Methods for Astrophysics · Physics 2025-01-13 Jan Wagner , Sergei Pogrebenko

Large field-of-view (FOV) microscopic imaging with high lateral resolution (1-2 microns for high space-bandwidth product) plays a pivotal role in biomedicine and biophotonics, especially within the label-free regime, e.g., for whole slide…

We discuss the use of parametric phase-diverse phase retrieval as an in-situ high-fidelity wavefront measurement method to characterize and optimize the transmitted wavefront of a high-contrast coronagraphic instrument. We apply our method…

Instrumentation and Methods for Astrophysics · Physics 2019-03-06 Gregory R. Brady , Christopher Moriarty , Peter Petrone , Iva Laginja , Keira Brooks , Tom Comeau , Lucie Leboulleux , Remi Soummer

Phase microscopy is an invaluable tool in the biosciences and in clinical diagnostics. The sensitivity of current phase microscopy techniques is optimized for one specific mean phase value and varies significantly across a given sample.…

Optics · Physics 2019-08-30 Thomas Juffmann , Andrés de los Ríos Sommer , Sylvain Gigan

To achieve high data rates defined in 5G, the use of millimeter-waves and massive-MIMO are indispensable. To benefit from these technologies, an accurate estimation of the channel parameters is crucial. We propose a novel two-stage…

Signal Processing · Electrical Eng. & Systems 2020-07-15 Fazal-E-Asim , Felix Antreich , Charles C. Cavalcante , André L. F. de Almeida , Josef A. Nossek

Phase retrieval is one of the most challenging processes in many interferometry techniques. To promote the phase retrieval, Xu et. al [X. Xu, Y. Wang, Y. Xu, W. Jin. 2016] proposed a method based on dual-wavelength interferometry. However,…

Instrumentation and Detectors · Physics 2018-02-14 Minmin Wang , Canlin Zhou , Shuchun Si , XiaoLei Li , Zhenkun Lei , YanJie Li

Context: A turbulent atmosphere causes atmospheric piston variations leading to rapid changes in the optical path difference of an interferometer, which causes correlated flux losses. This leads to decreased sensitivity and accuracy in the…

Instrumentation and Methods for Astrophysics · Physics 2014-09-05 A. Müller , J. -U. Pott , A. Mérand , R. Abuter , F. Delplancke-Ströbele , Th. Henning , R. Köhler , Ch. Leinert , S. Morel , T. Phan Duc , E. Pozna , A. Ramirez , J. Sahlmann , C. Schmid

We propose and apply two methods to estimate pupil plane phase discontinuities for two realistic scenarios on VLT and Keck. The methods use both Phase Diversity and a form of image sharpening. For the case of VLT, we simulate the `low wind…

Long-baseline interferometry detects fringes created by superposition of two beams of light collected by two telescopes pointing into a common direction. The external path difference generated by pointing away from the zenith is commonly…

Astrophysics · Physics 2008-11-26 Richard J. Mathar

The implementation of fringe tracking for optical interferometers is inevitable when optimal exploitation of the instrumental capacities is desired. Fringe tracking allows continuous fringe observation, considerably increasing the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 J. Menu , G. Perrin , E. Choquet , S. Lacour

The number of phase wraps in 2D wrapped phase map can be completely eliminated, or greatly reduced by frequency shifting. But the wraps usually cannot be optimally reduced using the conventional fast Fourier transform (FFT) because the…

Instrumentation and Detectors · Physics 2017-10-11 Minmin Wang , Guangliang Du , Canlin Zhou , Shuchun Si , Zhenkun Lei , XiaoLei Li , YanJie Li

Atmospheric turbulence and precise measurement of the astrometric baseline vector between any two telescopes are two major challenges in implementing phase referenced interferometric astrometry and imaging. They limit the performance of a…

Instrumentation and Methods for Astrophysics · Physics 2018-03-14 N. Anugu , A. Amorim , P. Gordo , F. Eisenhauer , O. Pfuhl , M. Haug , E. Wiezorrek , J. Lima , G. Perrin , W. Brandner , C. Straubmeier , J. -B. Le Bouquin , P. J. V Garcia