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Lorentz transmission electron microscopy is a unique characterization technique that enables the simultaneous imaging of both the microstructure and functional properties of materials at high spatial resolution. The quantitative information…

Materials Science · Physics 2020-12-09 Tao Zhou , Mathew Cherukara , Charudatta Phatak

Ptychography is a computational imaging technique using multiple, overlapping, coherently illuminated snapshots to achieve nanometer resolution by solving a nonlinear phase-field recovery problem. Ptychography is vital for imaging of…

Image and Video Processing · Electrical Eng. & Systems 2021-12-10 Qiuchen Zhai , Brendt Wohlberg , Gregery T. Buzzard , Charles A. Bouman

Layered materials (LMs) are at the centre of an ever increasing research effort due to their potential use in a variety of applications. The presence of imperfections, such as bi- or multilayer areas, holes, grain boundaries, isotropic and…

Programmable electron-beam scanning offers new opportunities to improve dose efficiency and suppress scan-induced artifacts in scanning transmission electron microscopy. Here, we systematically benchmark the impact of non-raster…

Ptychography is now integrated as a tool in mainstream microscopy allowing quantitative and high-resolution imaging capabilities over a wide field of view. However, its ultimate performance is inevitably limited by the available coherent…

Computational Physics · Physics 2024-06-12 Wenhui Xu , Shoucong Ning , Pengju Sheng , Huixiang Lin , Angus I Kirkland , Yong Peng , Fucai Zhang

Learned data models based on sparsity are widely used in signal processing and imaging applications. A variety of methods for learning synthesis dictionaries, sparsifying transforms, etc., have been proposed in recent years, often imposing…

Machine Learning · Computer Science 2018-10-22 Saiprasad Ravishankar , Brendt Wohlberg

It has been argued that in atomic-resolution transmission electron microscopy (TEM) of sparse weakly scattering structures, such as small biological molecules, multiple electron scattering usually has only a small effect, while the…

Optics · Physics 2021-11-16 T. E. Gureyev , H. M. Quiney , A. Kozlov , D. M. Paganin , G. Schmalz , L. J. Allen

X-ray ptychography is one of the versatile techniques for nanometer resolution imaging. The magnitude of the diffraction patterns is recorded on a detector and the phase of the diffraction patterns is estimated using phase retrieval…

Image and Video Processing · Electrical Eng. & Systems 2021-05-21 Prasan Shedligeri , Florian Schiffers , Semih Barutcu , Pablo Ruiz , Aggelos K Katsaggelos , Oliver Cossairt

There is a clear need for developments in characterisation techniques that provide detailed information about structure-function relationships in biology. Using electron microscopy to achieve high resolution while maintaining a broad field…

Quantitative Methods · Quantitative Biology 2023-09-12 Chen Huang , Judy S. Kim , Angus I. Kirkland

In multi-contrast magnetic resonance imaging (MRI), compressed sensing theory can accelerate imaging by sampling fewer measurements within each contrast. The conventional optimization-based models suffer several limitations: strict…

Computer Vision and Pattern Recognition · Computer Science 2019-10-02 Liyan Sun , Zhiwen Fan , Yue Huang , Xinghao Ding , John Paisley

Polarized X-rays allow for imaging birefringent or dichroic properties of materials with nanometric resolution. To disentangle these properties from the electronic density, either a polarization analyzer or several measurements with…

We have demonstrated the capability of spectral multiplexing in multi-distance diffractive imaging, enabling the reconstruction of samples with diverse spectral responses. While previous methods like ptychography utilize redundancy in…

Optics · Physics 2024-05-31 Qijun You , Lingshuo Meng , Yun Gao , Qing Liao , Wei Cao , Peixiang Lu

Bilevel optimisation is used in inverse imaging problems for hyperparameter learning/identification and experimental design, for instance, to find optimal regularisation parameters and forward operators. However, computationally, the…

Optimization and Control · Mathematics 2025-08-06 Ensio Suonperä , Tuomo Valkonen

Variational formulations of reconstruction in computed tomography have the notable drawback of requiring repeated evaluations of both the forward Radon transform and either its adjoint or an approximate inverse transform which are…

Numerical Analysis · Mathematics 2017-05-23 Richard C. Barnard , Rick Archibald

When dealing with difficult inverse problems such as inverse rendering, using Monte Carlo estimated gradients to optimise parameters can slow down convergence due to variance. Averaging many gradient samples in each iteration reduces this…

Graphics · Computer Science 2023-09-28 Martin Balint , Karol Myszkowski , Hans-Peter Seidel , Gurprit Singh

Over the past decade, reflection matrix microscopy (RMM) and advanced image reconstruction algorithms have emerged to address the fundamental imaging depth limitations of optical microscopy in thick biological tissues and complex media. In…

Optics · Physics 2024-07-03 Sungsam Kang , Seokchan Yoon , Wonshik Choi

Design and reconstruction of 2d and 3d photonic structures are usually carried out by forward simulations combined with optimization or intuition. Reconstruction by means of layer-stripping has been applied in seismic processing as well as…

Optics · Physics 2011-05-19 Marte P. Hatlo Andresen , Harald E. Krogstad , Johannes Skaar

In many areas of imaging science, it is difficult to measure the phase of linear measurements. As such, one often wishes to reconstruct a signal from intensity measurements, that is, perform phase retrieval. In several applications the…

Information Theory · Computer Science 2015-06-16 Afonso S. Bandeira , Dustin G. Mixon

In this work, we demonstrate that the ptychographic phase problem can be solved in a live fashion during scanning, while data is still being collected. We propose a generally applicable modification of the widespread projection-based…

Image and Video Processing · Electrical Eng. & Systems 2023-09-20 Simon Welker , Tal Peer , Henry N. Chapman , Timo Gerkmann

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