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In this work we propose an efficient and accurate multi-scale optical simulation algorithm by applying a numerical version of slowly varying envelope approximation in FEM. Specifically, we employ the fast iterative method to quickly compute…

Optics · Physics 2024-12-03 Fan Xiao , Jingwei Wang , Zhongfei Xiong , Yuntian Chen

A large field-of-view fisheye camera allows for capturing a large area with minimal numbers of cameras when they are mounted on a high position facing downwards. This top-view omnidirectional setup greatly reduces the work and cost for…

Computer Vision and Pattern Recognition · Computer Science 2023-04-18 Jingrui Yu , Ana Cecilia Perez Grassi , Gangolf Hirtz

Sub-wavelength diffractive optics meta-optics present a multi-scale optical system, where the behavior of constituent sub-wavelength scatterers, or meta-atoms, need to be modelled by full-wave electromagnetic simulations, whereas the whole…

We developed a Bessel light sheet fluorescence microscopy (LSFM) system to enable high-speed, wide-field intra-vital imaging of zebrafish and other thick biological samples. This system uses air objectives for the convenient mounting of…

Optics · Physics 2023-11-07 Chuhui Wang , Jiaju Chen , Cuiyi Peng , Zhenglin Chen , Dongmei Yu , Peiwu Qin

Vascular segmentation extracts blood vessels from images and serves as the basis for diagnosing various diseases, like ophthalmic diseases. Ophthalmologists often require high-resolution segmentation results for analysis, which leads to…

Image and Video Processing · Electrical Eng. & Systems 2022-07-29 Yan Hu , Zhongxi Qiu , Dan Zeng , Li Jiang , Chen Lin , Jiang Liu

Dual-fisheye lens cameras have been increasingly used for 360-degree immersive imaging. However, the limited overlapping field of views and misalignment between the two lenses give rise to visible discontinuities in the stitching…

Computer Vision and Pattern Recognition · Computer Science 2017-08-31 Tuan Ho , Madhukar Budagavi

Object detection when provided image-level labels instead of instance-level labels (i.e., bounding boxes) during training is an important problem in computer vision, since large scale image datasets with instance-level labels are extremely…

Computer Vision and Pattern Recognition · Computer Science 2017-03-01 Ziang Yan , Jian Liang , Weishen Pan , Jin Li , Changshui Zhang

Scanning electron microscopy (SEM) is indispensable in diverse applications ranging from microelectronics to food processing because it provides large depth-of-field images with a resolution beyond the optical diffraction limit. However,…

In this paper, we deal with the problem of monocular depth estimation for fisheye cameras in a self-supervised manner. A known issue of self-supervised depth estimation is that it suffers in low-light/over-exposure conditions and in large…

Computer Vision and Pattern Recognition · Computer Science 2022-05-09 Qingan Yan , Pan Ji , Nitin Bansal , Yuxin Ma , Yuan Tian , Yi Xu

We present a ray-based finite element method (ray-FEM) by learning basis adaptive to the underlying high-frequency Helmholtz equation in smooth media. Based on the geometric optics ansatz of the wave field, we learn local dominant ray…

Numerical Analysis · Mathematics 2016-09-01 Jun Fang , Jianliang Qian , Leonardo Zepeda-Núñez , Hongkai Zhao

The emergence of far-field super-resolution microscopy has rejuvenated the possibility for nanoscale imaging. Approaches to far-field super-resolution that utilize point scanning often depends on spatially reducing the size of the focused…

Optics · Physics 2022-06-17 Ning Xu , Guoxuan Liu , Qiaofeng Tan

X-ray Free Electron Lasers (XFEL) are revolutionary photons sources, whose ultrashort, brilliant pulses are expected to allow single molecule diffraction experiments providing structural information on the atomic length scale. This ultimate…

Optics · Physics 2015-05-20 Andrea Fratalocchi , Giancarlo Ruocco

In this paper, we present a multi-class eye segmentation method that can run the hardware limitations for real-time inference. Our approach includes three major stages: get a grayscale image from the input, segment three distinct eye region…

Computer Vision and Pattern Recognition · Computer Science 2022-03-22 Van Thong Huynh , Soo-Hyung Kim , Guee-Sang Lee , Hyung-Jeong Yang

We prove sharp wavenumber-explicit error bounds for first- or second-family-N\'ed\'elec-element (a.k.a. edge-element) conforming discretisations, of arbitrary (fixed) order, of the variable-coefficient time-harmonic Maxwell equations posed…

Numerical Analysis · Mathematics 2026-01-09 Théophile Chaumont-Frelet , Jeffrey Galkowski , Euan A. Spence

Our vision is sharpest at the center of our gaze and becomes progressively blurry into the periphery. It is widely believed that this high foveal resolution evolved at the expense of peripheral acuity. But what if this sampling scheme is…

Neurons and Cognition · Quantitative Biology 2020-05-15 R. T. Pramod , Harish Katti , S. P. Arun

Accurate segmentation of live cell images has broad applications in clinical and research contexts. Deep learning methods have been able to perform cell segmentations with high accuracy; however developing machine learning models to do this…

Image and Video Processing · Electrical Eng. & Systems 2022-12-06 Mayur Bhandary , J. Patricio Reyes , Eylul Ertay , Aman Panda

A flexible multimode fiber is an exceptionally efficient tool for in vivo deep tissue imaging. Recent advances in compressive multimode fiber sensing allow for imaging with sub-diffraction spatial resolution and sub-Nyquist speed. At…

Optics · Physics 2024-07-17 Zhouping Lyu , Shih-Te Hung , Carlas S. Smith , Lyubov V. Amitonova

For many years, image over-segmentation into superpixels has been essential to computer vision pipelines, by creating homogeneous and identifiable regions of similar sizes. Such constrained segmentation problem would require a clear…

Computer Vision and Pattern Recognition · Computer Science 2025-09-24 Rémi Giraud , Michaël Clément

Foveated imaging provides a better tradeoff between situational awareness (field of view) and resolution and is critical in long-wavelength infrared regimes because of the size, weight, power, and cost of thermal sensors. We demonstrate…

Ultrashort light pulses are ubiquitous in modern research, but the electromagnetic field of the optical cycles is usually not easy to obtain as a function of time. Field-resolved pulse characterization requires either a nonlinear-optical…

Optics · Physics 2022-11-30 Yuya Morimoto , Bo-Han Chen , Peter Baum