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We present an alternative numerical reconstruction algorithm for direct tomographic reconstruction of a sample refractive indices from the measured intensities of its far-field coherent diffraction patterns. We formulate the well-known…

Computational Physics · Physics 2019-02-06 T. Ramos , Bastian E. Grønager , Martin Skovgaard Andersen , J. W. Andreasen

Ptychography in a reflection geometry shows great promise for non-destructive imaging of 3-dimensional nanostructures at the surface of a thick substrate. A major challenge to obtain high quality reflection-ptychographic images under…

We introduce a probabilistic approach to ptychographic reconstruction in computational imaging. Ptychography is an imaging method where the complex amplitude of an object is estimated from a sequence of diffraction measurements. We…

Applications · Statistics 2025-04-09 Hajime Ueda , Shun Katakami , Masato Okada

Magnetic Resonance Imaging (MRI) is a powerful, non-invasive diagnostic tool; however, its clinical applicability is constrained by prolonged acquisition times. Whilst present deep learning-based approaches have demonstrated potential in…

Image and Video Processing · Electrical Eng. & Systems 2024-09-24 Anurag Malyala , Zhenlin Zhang , Chengyan Wang , Chen Qin

We proposed a novel approach to coherent imaging of dynamic samples. The inter-frame similarity of the sample's local structures is found to be a powerful constraint in phasing a sequence of diffraction patterns. We devised a new image…

Optics · Physics 2024-07-11 Pengju Sheng , Fucai Zhang

By profiting from recent developments in detector technologies, making it possible to access a stream of detection events with few-ns time resolutions, a new ptychographic workflow is established. This methodological framework, referred to…

Applied Physics · Physics 2026-03-27 Hoelen L. Lalandec Robert , Arno Annys , Tamazouzt Chennit , Jo Verbeeck

Coherent X-ray diffraction microscopy is a method of imaging non-periodic isolated objects at resolutions only limited, in principle, by the largest scattering angles recorded. We demonstrate X-ray diffraction imaging with high resolution…

Diffusion models are able to produce AI-generated images that are almost indistinguishable from real ones. This raises concerns about their potential misuse and poses substantial challenges for detecting them. Many existing detectors rely…

Computer Vision and Pattern Recognition · Computer Science 2026-03-02 Xinyi Qi , Kai Ye , Chengchun Shi , Ying Yang , Hongyi Zhou , Jin Zhu

Ptychography is a lensless, computational imaging method that utilises diffraction patterns to determine the amplitude and phase of an object. In transmission ptychography, the diffraction patterns are recorded by a detector positioned…

Image and Video Processing · Electrical Eng. & Systems 2023-01-04 Kira A. M. Maathuis , Jacob Seifert , Allard P. Mosk

Generic 3D reconstruction from a single image is a difficult problem. A lot of data loss occurs in the projection. A domain based approach to reconstruction where we solve a smaller set of problems for a particular use case lead to greater…

Computer Vision and Pattern Recognition · Computer Science 2016-06-21 Atishay Jain

Most camera lens systems are designed in isolation, separately from downstream computer vision methods. Recently, joint optimization approaches that design lenses alongside other components of the image acquisition and processing pipeline…

Computer Vision and Pattern Recognition · Computer Science 2023-03-29 Geoffroi Côté , Fahim Mannan , Simon Thibault , Jean-François Lalonde , Felix Heide

Coherent diffractive imaging is a technique that recovers the sample image by numerically inverting its diffraction pattern. We propose a generalization of this method for the inversion of multi-wavelength data. Using this approach, we show…

Optics · Physics 2020-05-08 Erik Malm , Edwin Fohtung , Anders Mikkelsen

Automatic differentiation---the mechanical transformation of numeric computer programs to calculate derivatives efficiently and accurately---dates to the origin of the computer age. Reverse mode automatic differentiation both antedates and…

Machine Learning · Computer Science 2014-04-30 Atilim Gunes Baydin , Barak A. Pearlmutter

Coherent Diffraction Imaging (CDI), a technique where an object is reconstructed from a single (2D or 3D) diffraction pattern, recovers the lost diffraction phases without a priori knowledge of the extent (support) of the object, which…

Materials Science · Physics 2020-08-27 Vincent Favre-Nicolin , Steven Leake , Yuriy Chushkin

In this paper, we develop a novel phase retrieval approach to reconstruct x-ray differential phase shift induced by an object. A primary advantage of our approach is a higher-order accuracy over that with the conventional linear…

Medical Physics · Physics 2010-03-18 Wenxiang Cong , Ge Wang

Tomography is the three-dimensional reconstruction of an object from images taken at different angles. The term classical tomography is used, when the imaging beam travels in straight lines through the object. This assumption is valid for…

Quantitative Methods · Quantitative Biology 2016-10-10 Paul Müller , Mirjam Schürmann , Jochen Guck

This paper addresses the problem of reconstructing the surface shape of transparent objects. The difficulty of this problem originates from the viewpoint dependent appearance of a transparent object, which quickly makes reconstruction…

Image and Video Processing · Electrical Eng. & Systems 2021-05-24 Kai Han , Kwan-Yee K. Wong , Miaomiao Liu

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…

In this paper, we present a novel reconstruction method for diffuse optical spectroscopic imaging with a commonly used tissue model of optical absorption and scattering. It is based on linearization and group sparsity, which allows…

Numerical Analysis · Mathematics 2019-03-06 Habib Ammari , Bangti Jin , Wenlong Zhang

New lensless diffractive X-ray technic for micro-scale imaging of biological tissue is based on quantitative phase retrieval schemes. By incorporating refraction, this method yields improved contrast compared to purely absorption-based…

Numerical Analysis · Mathematics 2018-03-28 Victor Palamodov