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Sonography techniques use multiple transducer elements for tissue visualization. Signals detected at each element are sampled prior to digital beamforming. The required sampling rates are up to 4 times the Nyquist rate of the signal and…

Information Theory · Computer Science 2012-12-21 T. Chernyakova , Y. C. Eldar , R. Amit

We outline some basics of imaging using both fully-coherent and partially-coherent X-ray beams, with an emphasis on phase-contrast imaging. We open with some of the basic notions of X-ray imaging, including the vacuum wave equations and the…

Image and Video Processing · Electrical Eng. & Systems 2021-11-16 David M. Paganin , Daniele Pelliccia

Impressive pictures of moving Bose-Einstein condensates have been taken using phase-contrast imaging M. R. Andrews et al., Science 273, 84 (1996). We calculate the quantum backaction of this measurement technique. We find that…

Quantum Physics · Physics 2009-10-31 U. Leonhardt , T. Kiss , P. Piwnicki

Photoacoustic tomography is an emerging medical imaging technology whose primary aim is to map the high-contrast optical properties of biological tissues by leveraging high-resolution ultrasound measurements. Mathematically, this can be…

Analysis of PDEs · Mathematics 2025-02-14 Alessandro Felisi

Photoacoustic tomography (PAT) is a rapidly-evolving medical imaging modality that combines optical absorption contrast with ultrasound imaging depth. One challenge in PAT is image reconstruction with inadequate acoustic signals due to…

A new computational imaging method to reconstruct the complex wave-field is reported. Due to the existence of zero frequency component, the measured signal by amplitude modulation of pupil has a spectrum similar to the one of off-axis…

Optics · Physics 2021-11-09 Cheng Shen , An Pan , Mingshu Liang , Changhuei Yang

Photoacoustic (PA) imaging combines the high optical absorption contrast of optical imaging with the deep tissue penetration of ultrasound detection, offering great potential for functional imaging and disease diagnosis. However, current PA…

Optics · Physics 2026-01-29 Daohuai Jiang , Xuanxuan Ye , Hengrong Lan , Xianzeng Zhang , Fei Gao

Optical diffraction tomography is an indispensable tool for studying objects in three-dimensions due to its ability to accurately reconstruct scattering objects. Until now this technique has been limited to coherent light because spatial…

Schlieren flow visualizations of transverse oscillations of jets submitted to an acoustic perturbation are analyzed in this paper. The aim is to estimate the shape and the position of the median line of the jet. Two methods for image…

Classical Physics · Physics 2008-11-04 Patricio De La Cuadra , Christophe Vergez , Benoit Fabre

Coupled nonlinear systems under certain conditions exhibit phase synchronization, which may change for different frequency bands or with presence of additive system noise. In both cases, Fourier filtering is traditionally used to preprocess…

Data Analysis, Statistics and Probability · Physics 2009-11-11 Limei Xu , Zhi Chen , Kun Hu , H. Eugene Stanley , Plamen Ch. Ivanov

Temporal imaging systems are outstanding tools for single-shot observation of optical signals that have irregular and ultrafast dynamics. They allow long time windows to be recorded with femtosecond resolution, and do not rely on complex…

Wave-front sensing from focal plane multiple images is a promising technique for high-contrast imaging systems. However, the wave-front error of an optics system can be properly reconstructed only when it is very small. This paper presents…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Jiangpei Dou , Deqing Ren , Yongtian Zhu

We introduce optical polarization-insensitive high pass filters based on total internal reflection of light at the interface of two dielectric media (1D) and Bragg reflection of a multilayer stack (2D) in transmission mode. The wavevectors…

Optics · Physics 2019-11-26 Ali Pour Mohammad Qoli Vafa , Parisa Karimi , Amin Khavasi

Most reconstruction algorithms for photoacoustic imaging assume that the pressure field is measured by ultrasound sensors placed on a detection surface. However, such sensors do not measure pressure exactly due to their non-uniform…

Analysis of PDEs · Mathematics 2021-01-05 Sebastian Acosta

In Fourier ptychography, multiple low resolution images are captured and subsequently combined computationally into a high-resolution, large-field of view micrograph. A theoretical image-formation model based on the assumption of plane-wave…

Optics · Physics 2022-06-22 Tomas Aidukas , Lars Loetgering , Andrew Robert Harvey

In ultrabroadband terahertz electro-optic sampling, spectral filtering of the gate pulse can strongly reduce the quantum noise while the signal level is only weakly affected. The concept is tested for phase-matched electro-optic detection…

Optics · Physics 2016-04-25 Michael Porer , Jean-Michel Ménard , Rupert Huber

Fast camera imaging is used to study ion acoustic waves propagating azimuthally in a magnetized plasma column. The high speed image sequences are analyzed using Proper Orthogonal Decomposition and 2D Fourier Transform, allowing to evaluate…

Plasma Physics · Physics 2023-02-01 Simon Vincent , Vincent Dolique , Nicolas Plihon

The phase retrieval from multi-frequency intensity (power) observations is considered. The object to be reconstructed is complex-valued. A novel algorithm is presented that accomplishes both the object phase (absolute phase) retrieval and…

Signal Processing · Electrical Eng. & Systems 2018-02-07 Vladimir Katkovnik , Karen Egiazarian

On 3D imaging, light field cameras typically are of single shot, and however, they heavily suffer from low spatial resolution and depth accuracy. In this paper, by employing an optical projector to project a group of single high-frequency…

Image and Video Processing · Electrical Eng. & Systems 2024-04-11 Geyou Zhang , Ce Zhu , Kai Liu , Yipeng Liu

We introduce a framework for the reconstruction of the amplitude, phase and polarisation of an optical vector-field using calibration measurements acquired by an imaging device with an unknown linear transformation. By incorporating…