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Due to limited size and imperfect of the optical components in a spectrometer, aberration has inevitably been brought into two-dimensional multi-fiber spectrum image in LAMOST, which leads to obvious spacial variation of the point spread…

Instrumentation and Methods for Astrophysics · Physics 2020-10-28 Jiali Xu , Qian Yin , Ping Guo , Xin Zheng

Diffraction-limited imaging in epi-fluorescence microscopy remains a challenge when sample aberrations are present or when the region of interest rests deep within an inhomogeneous medium. Adaptive optics is an attractive solution albeit…

Phase-sensitive coherent imaging exploits changes in the phases of backscattered light to observe tiny alterations of scattering structures or variations of the refractive index. But moving scatterers or a fluctuating refractive index…

Phase aberrations, despite degrading ultrasound images, also encode valuable information about the spatial distribution of the speed of sound in tissue. In pulse-echo ultrasound, we can quantify them by exploiting speckle correlations.…

Medical Physics · Physics 2025-11-20 Naiara Korta Martiartu , Michael Jaeger

We consider blind ptychography, an imaging technique which aims to reconstruct an object of interest from a set of its diffraction patterns, each obtained by a local illumination. As the distribution of the light within the illuminated…

Numerical Analysis · Mathematics 2023-06-16 Oleh Melnyk

Spectroastrometry is a technique which has the potential to resolve flux distributions on scales of milliarcseconds. In this study, we examine the application of spectroastrometry to binary point sources which are spatially unresolved due…

Astrophysics · Physics 2009-11-10 John M. Porter , Rene D. Oudmaijer , Debbie Baines

Direct imaging of exoplanets requires very high contrast levels, which are obtained using coronagraphs. But residual quasi-static aberrations create speckles in the focal plane downstream of the coronagraph which mask the planet. This…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 J. Mazoyer , P. Baudoz , R. Galicher , M. Mas , G. Rousset

In the present work we discuss a possibility to build an instrument with two operation modes - spectral and imaging ones. The key element of such instrument is a dispersive and filtering unit consisting of two narrowband volume-phase…

Instrumentation and Methods for Astrophysics · Physics 2017-05-16 Eduard R. Muslimov , Sergei N. Fabrika , Gennady G. Valyavin

The presence of a scattering medium in the imaging path between an object and an observer is known to severely limit the visual acuity of the imaging system. We present an approach to circumvent the deleterious effects of scattering, by…

Some modified two-slit interference experiments were carried out showing an apparent paradox in wave-particle duality. In a typical such experiment, the screen, where the interference pattern is supposed to be formed, is replaced by a…

Quantum Physics · Physics 2023-04-05 Tabish Qureshi

Ptychography, a coherent diffraction imaging technique, has become an indispensable tool in materials characterization, biological imaging, and nanostructure analysis due to its capability for high-resolution, lensless reconstruction of…

We demonstrate a novel imaging approach and associated reconstruction algorithm for far-field coherent diffractive imaging, based on the measurement of a pair of laterally sheared diffraction patterns. The differential phase profile…

Optics · Physics 2018-05-23 G. S. M. Jansen , A. C. C. de Beurs , X. Liu , K. S. E. Eikema , S. Witte

I present a semiclassical analysis of a spatial-mode demultiplexing (SPADE) measurement scheme for far-field incoherent optical imaging under the effects of diffraction and photon shot noise. Building on previous results that assume two…

Optics · Physics 2018-02-28 Mankei Tsang

Optical quasar spectra can be used to trace variations of the fine-structure constant alpha. Controversial results that have been published in last years suggest that in addition to to wavelength calibration problems systematic errors might…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Nils Prause , Dieter Reimers

In photo injectors, the transverse emittance is one of the key measures of beam quality as it defines the possible performance of the whole facility. As such it is important to measure the emittance in photo injectors and ensure the…

Image deblurring is an ill-posed problem with multiple plausible solutions for a given input image. However, most existing methods produce a deterministic estimate of the clean image and are trained to minimize pixel-level distortion. These…

Computer Vision and Pattern Recognition · Computer Science 2021-12-30 Jay Whang , Mauricio Delbracio , Hossein Talebi , Chitwan Saharia , Alexandros G. Dimakis , Peyman Milanfar

In this letter, we study a nonlinear interferometric setup based on diffraction rather than beam combining. It consists of a nonlinear analogue of Young's double-slit experiment where a nonlinear material is placed exactly after one of the…

Optics · Physics 2023-07-19 Vassilis Paltoglou , Nikolaos K. Efremidis

Fibre-fed spectrographs now have throughputs equivalent to slit spectrographs. However, the sky subtraction accuracy that can be reached has often been pinpointed as one of the major issues associated with the use of fibres. Using technical…

Speckle photography can be used to monitor deformations of solid surfaces. The measuring characteristics, such as range or lateral resolution depend heavily on the optical recording and illumination set-up. This paper shows how, by the…

Optics · Physics 2014-01-30 Jose M. Diazdelacruz

Capturing more information, e.g. geometry and material, using optical cameras can greatly help the perception and understanding of complex scenes. This paper proposes a novel method to capture the spectral and light field information…

Image and Video Processing · Electrical Eng. & Systems 2018-02-27 Qian Huang , Yunqian Li , Linsen Chen , Xiaoming Zhong , Jinli Suo , Zhan Ma , Tao Yue , Xun Cao