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Related papers: Compensation for the setup instability in ptychogr…

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Ptychography, a form of Coherent Diffractive Imaging, is used with short wavelengths (e.g. X-rays, electron beams) to achieve high-resolution image reconstructions. One of the limiting factors for the reconstruction quality is the accurate…

Image and Video Processing · Electrical Eng. & Systems 2018-04-02 P. Dwivedi , A. P. Konijnenberg , S. F. Pereira , H. P. Urbach

In SPECT image reconstruction, limited-angle (LA) conditions lead to a loss of frequency components, which distort the reconstructed tomographic image along directions corresponding to the non-collected projection angle range. Although…

Medical Physics · Physics 2025-07-16 Kensuke Hori , Fumio Hashimoto , Kazuya Koyama , Takeyuki Hashimoto

Medical ultrasound provides images which are the spatial map of the tissue echogenicity. Unfortunately, an ultrasound image is a low-quality version of the expected Tissue Reflectivity Function (TRF) mainly due to the non-ideal Point Spread…

Image and Video Processing · Electrical Eng. & Systems 2021-09-28 Sobhan Goudarzi , Hassan Rivaz

Modern technology for producing extremely bright and coherent X-ray laser pulses provides the possibility to acquire a large number of diffraction patterns from individual biological nanoparticles, including proteins, viruses, and DNA.…

Methodology · Statistics 2018-07-11 Stefan Engblom , Carl Nettelblad , Jing Liu

Machine learning methods for computational imaging require uncertainty estimation to be reliable in real settings. While Bayesian models offer a computationally tractable way of recovering uncertainty, they need large data volumes to be…

Machine Learning · Computer Science 2020-08-24 Francesco Tonolini , Jack Radford , Alex Turpin , Daniele Faccio , Roderick Murray-Smith

We use a spatial light modulator in a diffraction tomographic system to assess the accuracy of different refractive index reconstruction algorithms. Optical phase conjugation principles through complex media, allows us to quantify the error…

X-ray ptychography utilizes overlapping illuminations to reconstruct the object's phase and absorption signal with spatial resolutions much smaller than the focus size. Usually, the illumination overlap is chosen to be between 50% and 60%…

Materials Science · Physics 2022-07-29 Felix Wittwer , Peter Modregger

Imaging of scenes using light or other wave phenomena is subject to the diffraction limit. The spatial profile of a wave propagating between a scene and the imaging system is distorted by diffraction resulting in a loss of resolution that…

Image and Video Processing · Electrical Eng. & Systems 2020-07-20 Ji Hyun Nam , Andreas Velten

Measurements achieved with ptychographic imaging are a special case of diffraction measurements. They are generated by illuminating small parts of a sample with, e.g., a focused X-ray beam. By shifting the sample, a set of far-field…

Image reflection removal is crucial for restoring image quality. Distorted images can negatively impact tasks like object detection and image segmentation. In this paper, we present a novel approach for image reflection removal using a…

Computer Vision and Pattern Recognition · Computer Science 2024-12-16 Abdelrahman Elnenaey , Marwan Torki

Most existing MRI reconstruction methods perform tar-geted reconstruction of the entire MR image without tak-ing specific tissue regions into consideration. This may fail to emphasize the reconstruction accuracy on im-portant tissues for…

Image and Video Processing · Electrical Eng. & Systems 2023-09-06 Yu Guan , Chuanming Yu , Shiyu Lu , Zhuoxu Cui , Dong Liang , Qiegen Liu

Ptychography has rapidly grown in the fields of X-ray and electron imaging for its unprecedented ability to achieve nano or atomic scale resolution while simultaneously retrieving chemical or magnetic information from a sample. A…

Image and Video Processing · Electrical Eng. & Systems 2020-04-20 Mathew J. Cherukara , Tao Zhou , Youssef Nashed , Pablo Enfedaque , Alex Hexemer , Ross J. Harder , Martin V. Holt

Diffraction tomography is a widely used inverse scattering technique for quantitative imaging of weakly scattering media. In its conventional formulation, diffraction tomography assumes monochromatic plane wave illumination. This…

Numerical Analysis · Mathematics 2026-03-11 Peter Elbau , Noemi Naujoks , Otmar Scherzer

Precise calibration is a must for high reliance 3D computer vision algorithms. A challenging case is when the camera is behind a protective glass or transparent object: due to refraction, the image is heavily distorted; the pinhole camera…

Computer Vision and Pattern Recognition · Computer Science 2019-09-25 Szabolcs Pável , Csanád Sándor , Lehel Csató

Here the role and influence of aberrations in optical imaging systems employing partially coherent complex scalar fields is studied. Imaging systems require aberrations to yield contrast in the output image. For linear shift-invariant…

Optics · Physics 2015-06-30 Mario A. Beltran , Marcus J. Kitchen , T. Petersen , David M. Paganin

Purpose: Field monitoring measures field perturbations, which can be accounted for during image reconstructions. In certain field monitoring environments, significant phase deviations can arise far from isocenter due to the finite extent of…

Medical Physics · Physics 2023-01-25 Paul I. Dubovan , Kyle M. Gilbert , Corey A. Baron

Coherent imaging techniques such as ptychography offer powerful capabilities for 3D resolution of nanoscale structures. By application in grazing incidence, such techniques may achieve exceptional surface sensitivity as demonstrated by…

Despite its wide use in medicine, ultrasound imaging faces several challenges related to its poor signal-to-noise ratio and several sources of noise and artefacts. Enhancing ultrasound image quality involves balancing concurrent factors…

Computer Vision and Pattern Recognition · Computer Science 2024-10-28 Yuxin Zhang , Clément Huneau , Jérôme Idier , Diana Mateus

We experimentally demonstrate how to solve the phase problem of diffraction using multi-wave interference with standard diffraction experimental setups without the need for taking any auxiliary data. In particular, we show that the phases…

Optics · Physics 2021-05-04 M. Fally , Y. Tomita , A. Fimia , R. F. Madrigal , J. Guo , J. Kohlbrecher , J. Klepp

Recovering high-dimensional statistical structure from limited measurements is a fundamental challenge in hyperspectral imaging, where capturing full-resolution data is often infeasible due to sensor, bandwidth, or acquisition constraints.…

Image and Video Processing · Electrical Eng. & Systems 2025-08-01 Jonathan Monsalve , Kumar Vijay Mishra