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Light(Advanced Manufacturing) 2022年第1期3卷 98-113页

作者： Wolfgang Osten giancarlo pedrini Institute for Applied Optics ITO University Stuttgart Pfaffenwaldring 9 70569 StuttgartGermany

Holographic methods for non-destructive testing,shape measurement,and experimental stress analysis have shown to be versatile tools for the solution of many inspection *** main advantages are the non-contact nature,the non-destructive and areal working principle,the fast response,high sensitivity,resolution and *** contrast to conventional optical techniques such as classical interferometry,the holographic principle of wavefront storage and reconstruction makes it possible to investigate objects with rough ***,the response of various classes of products on operational or artificial load can be examined very *** paper looks back to the history of holographic metrology,honors the inventors of the main principles,discusses criteria for the selection of a proper inspection method,and shows exemplary ***,the main focus is on modern developments that are inspired by the rapid technological process in sensing technology and digitization,on current applications and future challenges.

关键词： Non-Destructive Testing Holography Stress Analysis Digital Holography Speckle Interferometry

Lensless light-field imaging through diffuser encoding

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Light(Science & Applications) 2020年第1期9卷 637-645页

作者： Zewei Cai Jiawei Chen giancarlo pedrini Wolfgang Osten Xiaoli Liu Xiang Peng Institut fur Technische Optik Universitat StuttgartPfaffenwaldring 970569 StuttgartGermany College of Physics and Optoelectronic Engineering Shenzhen University518060 GuangdongShenzhenChina

Microlens array-based light-field imaging has been one of the most commonly used and effective technologies to record high-dimensional optical signals for developing various potential high-performance applications in many ***,the use of a microlens array generally suffers from an intrinsic trade-off between the spatial and angular *** this paper,we concentrate on exploiting a diffuser to explore a novel modality for light-field *** demonstrate that the diffuser can efficiently angularly couple incident light rays into a detected image without needing any *** characterize and analyse this phenomenon,we establish a diffuser-encoding light-field transmission model,in which four-dimensional light fields are mapped into two-dimensional images via a transmission matrix describing the light propagation through the ***,a calibration strategy is designed to flexibly determine the transmission matrix,so that light rays can be computationally decoupled from a detected image with adjustable spatio-angular resolutions,which are unshackled from the resolution limitation of the *** proof-of-concept approach indicates the possibility of using scattering media for lensless four-dimensional light-field recording and processing,not just for two-or three-dimensional imaging.

关键词： scattering light field

Exploiting scattering media for exploring 3D objects

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Light(Science & Applications) 2016年第1期5卷 202-208页

作者： Alok Kumar Singh Dinesh N Naik giancarlo pedrini Mitsuo Takeda Wolfgang Osten Institut für Technische Optik(ITO)and Stuttgart Research Center of Photonic Engineering(SCoPE) University of StuttgartPfaffenwaldring 970569 StuttgartGermany School of Physics University of HyderabadHyderabad 500046India Center for Optical Research and Education(CORE) Utsunomiya UniversityYoto 7-1-2UtsunomiyaTochigi321-8585Japan

Scattering media,such as diffused glass and biological tissue,are usually treated as obstacles in *** cope with the random phase introduced by a turbid medium,most existing imaging techniques recourse to either phase compensation by optical means or phase recovery using iterative algorithms,and their applications are often limited to two-dimensional *** contrast,we utilize the scattering medium as an unconventional imaging lens and exploit its lens-like properties for lensless threedimensional(3D)imaging with diffraction-limited *** spatially incoherent lensless imaging technique is simple and capable of variable focusing with adjustable depths of focus that enables depth sensing of 3D objects that are concealed by the diffusing ***-field imaging with diffraction-limited resolution is verified experimentally by a single-shot recording of the 1951 USAF resolution test chart,and 3D imaging and depth sensing are demonstrated by shifting focus over axially separated objects.

关键词： intensity correlation technique lensless imaging scattering media 3D imaging

Phase imaging with an untrained neural network

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Light(Science & Applications) 2020年第1期9卷 1258-1264页

作者： Fei Wang Yaoming Bian Haichao Wang Meng Lyu giancarlo pedrini Wolfgang Osten George Barbastathis Guohai Situ Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences201800 ShanghaiChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences100049 BeijingChina Institut für Technische Optik Universität StuttgartPfaffenwaldring 970569 StuttgartGermany Department of Mechanical Engineering Massachusetts Institute of TechnologyCambridgeMA 02139-4301USA Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences310024 HangzhouChina

Most of the neural networks proposed so far for computational imaging(CI)in optics employ a supervised training strategy,and thus need a large training set to optimize their weights and *** aside the requirements of environmental and system stability during many hours of data acquisition,in many practical applications,it is unlikely to be possible to obtain sufficient numbers of ground-truth images for ***,we propose to overcome this limitation by incorporating into a conventional deep neural network a complete physical model that represents the process of image *** most significant advantage of the resulting physics-enhanced deep neural network(PhysenNet)is that it can be used without training beforehand,thus eliminating the need for tens of thousands of labeled *** take single-beam phase imaging as an example for *** experimentally show that one needs only to feed PhysenNet a single diffraction pattern of a phase object,and it can automatically optimize the network and eventually produce the object phase through the interplay between the neural network and the physical *** opens up a new paradigm of neural network design,in which the concept of incorporating a physical model into a neural network can be generalized to solve many other CI problems.

关键词： neural network eventually

Snap-shot topography measurement via dual-VCSEL and dual wavelength digital holographic interferometry

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Light(Advanced Manufacturing) 2021年第4期2卷 45-56页

作者： Daniel Claus Igor Alekseenko Martin Grabherr giancarlo pedrini Raimund Hibst Institut für Lasertechnologien in der Medizin und Meßtechnik Helmholzstraße 12UlmD-89081Germany Immanuel Kant Baltic Federal University A.Nevsky str.14Kaliningrad236016Russia Priolas GmbH Kellerhalde 24Ulm 89081Germany Instiut für Technische Optik Universität StuttgartPfaffenwaldring 970195StuttgartGermany

In this paper,we propose a dual-wavelength digital holographic interferometry method based on a compact dual vertical-cavity surface-emitting laser(VCSEL)*** source simultaneously emits light from two highly stabilized coherent light sources with slightly different wavelengths.A highly stabilized and adjustable current source enables the application of digital holographic dual-wavelength techniques to measure the shape of an object with height steps of a few *** wavelength drift over 12 h over the entire measurement range,which was evaluated using a wavemeter,was smaller than 1 *** addition to the low measurement uncertainty at large height jumps,the dual-wavelength digital holographic system distinguishes itself by its robustness to environmental disturbances such as air turbulence,heat load,and/or mechanical *** is enabled via a fiber-based almost common-path single-shot digital holographic acquisition of the information of the two different wavelengths using angular *** experimental setup and data evaluation are discussed,and we present measurements of non-cooperative objects with specular reflective and/or diffuse reflective surfaces having different colors.

关键词： reflective millimeter holographic

Resolution enhancement in digital holographic microscopy with structured illumination

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Chinese Optics Letters 2013年第9期11卷 28-32页

作者：马骏袁操今司徒国海 giancarlo pedrini Wolfgang Osten School of Electronic and Optical Engineering Nanjing University of Science and Technology Department of Physics Nanjing Normal University Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Institut fr Technische Optik Universitt StuttgartPfafenwaldring 9

We present a digital holographic microscope wherein the sample is illuminated by structured light to enable the capture of additional object spatial frequencies. Reconstructed images with increased spatial resolution are obtained by separating and synthesizing bandwidths of different frequency regions in the Fourier domain. The theoretical analysis and experimental results are presented.

关键词： Optics Physics