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Ptychography is a computational method of microscopy that recovers high-resolution transmission images of samples from a series of diffraction patterns. While conventional phase retrieval algorithms can iteratively recover the images, they…

Image and Video Processing · Electrical Eng. & Systems 2024-10-24 Ryuma Nakahata , Shehtab Zaman , Mingyuan Zhang , Fake Lu , Kenneth Chiu

Conventional tomographic reconstruction algorithms assume that one has obtained pure projection images, involving no within-specimen diffraction effects nor multiple scattering. Advances in x-ray nanotomography are leading towards the…

Image and Video Processing · Electrical Eng. & Systems 2020-12-23 Ming Du , Youssef S. G. Nashed , Saugat Kandel , Doga Gursoy , Chris Jacobsen

Ptychography is a well-studied phase imaging method that makes non-invasive imaging possible at a nanometer scale. It has developed into a mainstream technique with various applications across a range of areas such as material science or…

Image and Video Processing · Electrical Eng. & Systems 2022-08-01 Semih Barutcu , Aggelos K. Katsaggelos , Doğa Gürsoy

In coherent X-ray diffraction microscopy the diffraction pattern generated by a sample illuminated with coherent x-rays is recorded, and a computer algorithm recovers the unmeasured phases to synthesize an image. By avoiding the use of a…

3D anomaly detection plays a crucial role in monitoring parts for localized inherent defects in precision manufacturing. Embedding-based and reconstruction-based approaches are among the most popular and successful methods. However, there…

Computer Vision and Pattern Recognition · Computer Science 2024-07-16 Zheyuan Zhou , Le Wang , Naiyu Fang , Zili Wang , Lemiao Qiu , Shuyou Zhang

One of the most prominent challenges in the field of diffractive imaging is the phase retrieval (PR) problem: In order to reconstruct an object from its diffraction pattern, the inverse Fourier transform must be computed. This is only…

Image and Video Processing · Electrical Eng. & Systems 2022-05-06 Simon Welker , Tal Peer , Henry N. Chapman , Timo Gerkmann

Generative models have demonstrated significant success in anomaly detection and segmentation over the past decade. Recently, diffusion models have emerged as a powerful alternative, outperforming previous approaches such as GANs and VAEs.…

Computer Vision and Pattern Recognition · Computer Science 2026-04-22 Mehrdad Moradi , Marco Grasso , Bianca Maria Colosimo , Kamran Paynabar

Most advanced unsupervised anomaly detection (UAD) methods rely on modeling feature representations of frozen encoder networks pre-trained on large-scale datasets, e.g. ImageNet. However, the features extracted from the encoders that are…

Computer Vision and Pattern Recognition · Computer Science 2023-10-25 Jia Guo , Shuai Lu , Lize Jia , Weihang Zhang , Huiqi Li

Ptychography is a scanning coherent diffractive imaging technique that enables imaging nanometer-scale features in extended samples. One main challenge is that widely used iterative image reconstruction methods often require significant…

Image and Video Processing · Electrical Eng. & Systems 2024-12-17 Canberk Ekmekci , Tekin Bicer , Zichao Wendy Di , Junjing Deng , Mujdat Cetin

Ptychography is an emerging imaging technique that is able to provide wavelength-limited spatial resolution from specimen with extended lateral dimensions. As a scanning microscopy method, a typical two-dimensional image requires a number…

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…

X-ray ptychography is a cutting edge imaging technique providing ultra-high spatial resolutions. In ptychography, phase retrieval, i.e., the recovery of a complex valued signal from intensity-only measurements, is enabled by exploiting a…

Image and Video Processing · Electrical Eng. & Systems 2022-09-14 Felix Wittwer , Peter Modregger

Ptychography is a popular imaging technique that combines diffractive imaging with scanning microscopy. The technique consists of a coherent beam that is scanned across an object in a series of overlapping positions, leading to reliable and…

Numerical Analysis · Mathematics 2024-08-08 Ricardo Parada , Samy Wu Fung , Stanley Osher

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

Ptychography is a lensless imaging technique, which considers reconstruction from a set of far-field diffraction patterns obtained by illuminating small overlapping regions of the specimen. In many cases, a distribution of light inside the…

Numerical Analysis · Mathematics 2022-10-05 Frank Filbir , Oleh Melnyk

Reconstruction-based approaches have achieved remarkable outcomes in anomaly detection. The exceptional image reconstruction capabilities of recently popular diffusion models have sparked research efforts to utilize them for enhanced…

Computer Vision and Pattern Recognition · Computer Science 2023-12-12 Haoyang He , Jiangning Zhang , Hongxu Chen , Xuhai Chen , Zhishan Li , Xu Chen , Yabiao Wang , Chengjie Wang , Lei Xie

This article presents a method to perform diffraction tomography in a standard microscope that includes an LED array for illumination. After acquiring a sequence of intensity-only images of a thick sample, a ptychography-based…

Optics · Physics 2015-10-30 Roarke Horstmeyer , Changhuei Yang

Ptychography is an attractive advance of coherent diffraction imaging (CDI), which can provide high lateral resolution and wide field of view. The theoretical resolution of ptychography is dose-limited, therefore making ptychography…

Biological Physics · Physics 2025-01-09 Huixiang Lin , Fucai Zhang

Electron ptychography has recently achieved unprecedented resolution, offering valuable insights across diverse material systems, including in three dimensions. However, high-quality ptychographic reconstruction is computationally expensive…

Materials Science · Physics 2025-08-07 Chia-Hao Lee , Steven E. Zeltmann , Dasol Yoon , Desheng Ma , David A. Muller

Diffusion models with transformer architectures have demonstrated promising capabilities in generating high-fidelity images and scalability for high resolution. However, iterative sampling process required for synthesis is very…

Computer Vision and Pattern Recognition · Computer Science 2025-04-16 Yeongmin Kim , Sotiris Anagnostidis , Yuming Du , Edgar Schönfeld , Jonas Kohler , Markos Georgopoulos , Albert Pumarola , Ali Thabet , Artsiom Sanakoyeu