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Shape recognition is the main challenging problem in computer vision. Different approaches and tools are used to solve this problem. Most existing approaches to object recognition are based on pixels. Pixel-based methods are dependent on…

Computer Vision and Pattern Recognition · Computer Science 2019-09-10 Narges Mirehi , Maryam Tahmasbi , Alireza Tavakoli Targhi

Omnidirectional cameras are widely used in such areas as robotics and virtual reality as they provide a wide field of view. Their images are often processed with classical methods, which might unfortunately lead to non-optimal solutions as…

Computer Vision and Pattern Recognition · Computer Science 2017-07-27 Renata Khasanova , Pascal Frossard

Memory-effect-based methods have been demonstrated to be feasible to observe hidden objects through thin scattering layers, even from a single-shot speckle pattern. However, most of the existing methods are performed with narrowband…

Image and Video Processing · Electrical Eng. & Systems 2018-09-20 Tengfei Wu , Chengfei Guo , Xiaopeng Shao

X-ray ptychography has revolutionised nanoscale phase contrast imaging at large-scale synchrotron sources in recent years. We present here the first successful demonstration of the technique in a small-scale laboratory setting. We conducted…

We describe and examine an algorithm for tomographic image reconstruction where prior knowledge about the solution is available in the form of training images. We first construct a nonnegative dictionary based on prototype elements from the…

Computer Vision and Pattern Recognition · Computer Science 2015-08-18 Sara Soltani , Martin S. Andersen , Per Christian Hansen

A pseudoscopic (inverted depth) image made with spiral diffracting elements intermediated by a pinhole is explained by its symmetry properties. The whole process is made under common white light illumination and allows the projection of…

Optics · Physics 2009-11-13 Jose J. Lunazzi , Noemi I. R. Rivera , Daniel S. F. Magalhaes

Entangled-photon coincidence imaging is a method to nonlocally image an object by transmitting a pair of entangled photons through the object and a reference optical system, respectively. The image of the object can be extracted from the…

Quantum Physics · Physics 2016-09-08 Jing Cheng , Shensheng Han

This paper proposes a non-computational method of counteracting the effect of image degradation introduced by the diffraction phenomenon in lensless microscopy. All the optical images (whether focused by lenses or not) are diffraction…

Optics · Physics 2021-04-08 Sanjeev Kumar , Manjunatha Mahadevappa , Pranab Kumar Dutta

We report the implementation of a fully on-chip, lensless microscopy technique termed optofluidic ptychography. This imaging modality complements the miniaturization provided by microfluidics and allows the integration of ptychographic…

Instrumentation and Detectors · Physics 2021-12-21 Pengming Song , Chengfei Guo , Shaowei Jiang , Tianbo Wang , Patrick Hu , Derek Hu , Zibang Zhang , Bin Feng , Guoan Zheng

On-invasive optical imaging techniques are essential diagnostic tools in many fields. Although various recent methods have been proposed to utilize and control light in multiple scattering media, non-invasive optical imaging through and…

We report a new coherent imaging technique, termed ptychographic structured modulation (PSM), for quantitative super-resolution microscopy. In this technique, we place a thin diffuser (i.e., a scattering lens) in between the sample and the…

Image and Video Processing · Electrical Eng. & Systems 2019-07-26 Pengming Song , Shaowei Jiang , He Zhang , Zichao Bian , Chengfei Guo , Kazunori Hoshino , Guoan Zheng

Homographies -- a mathematical formalism for relating image points across different camera viewpoints -- are at the foundations of geometric methods in computer vision and are used in geometric camera calibration, image registration, and…

Computer Vision and Pattern Recognition · Computer Science 2016-08-02 Graham D. Finlayson , Han Gong , Robert B. Fisher

We present a new algorithm for multi-region segmentation of 2D images with objects that may partially occlude each other. Our algorithm is based on the observation hat human performance on this task is based both on prior knowledge about…

Computer Vision and Pattern Recognition · Computer Science 2016-06-16 Yuka Kihara , Matvey Soloviev , Tsuhan Chen

Information multiplexing is important for biomedical imaging and chemical sensing. In this paper, we report a microscopy imaging technique, termed state-multiplexed Fourier ptychography (FP), for information multiplexing and coherent-state…

Optics · Physics 2014-05-12 Siyuan Dong , Radhika Shiradkar , Pariksheet Nanda , Guoan Zheng

Image vectorization is a process to convert a raster image into a scalable vector graphic format. Objective is to effectively remove the pixelization effect while representing boundaries of image by scaleable parameterized curves. We…

Computer Vision and Pattern Recognition · Computer Science 2024-09-11 Ho Law , Sung Ha Kang

Many optical microscopy techniques rely on structured illumination by way of a projected image (eg. structured illumination microscopy) or a tailored angular distribution of light (eg. ptychography). Electro-optical equipment such as…

Physics Education · Physics 2020-09-23 Antony Orth

We consider the inverse problem of determining an optical mask that produces a desired circuit pattern in photolithography. We set the problem as a shape design problem in which the unknown is a two-dimensional domain. The relationship…

Analysis of PDEs · Mathematics 2017-02-14 Luca Rondi , Fadil Santosa

Fourier Ptychographic Microscopy (FPM) is a computational imaging method that is able to super-resolve features beyond the diffraction-limit set by the objective lens of a traditional microscope. This is accomplished by using synthetic…

Signal Processing · Electrical Eng. & Systems 2019-04-09 Michael Kellman , Emrah Bostan , Michael Chen , Laura Waller

Reflectometry is a technique that uses the light reflected by a sample to determine properties of the sample. Interferometric reflectometry uses interference between two beams, one of which is incident on ---and reflected back by--- a…

Optics · Physics 2019-10-10 Alexander Nahmad-Rohen , Wolfgang Langbein

We propose a new technique for estimating spatially varying parametric materials from a single image of an object with unknown shape in unknown illumination. Our method uses a low-order parametric reflectance model, and incorporates strong…

Graphics · Computer Science 2019-12-30 Kevin Karsch , David Forsyth