The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Bahram Javidi - One of the best experts on this subject based on the ideXlab platform.
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optical encryption using Photon Counting polarimetric imaging
Optics Express, 2015Co-Authors: David Maluenda, Artur Carnicer, R Martinezherrero, I Juvells, Bahram JavidiAbstract:We present a polarimetric-based optical encoder for image encryption and verification. A system for generating random polarized vector keys based on a Mach-Zehnder configuration combined with translucent liquid crystal displays in each path of the interferometer is developed. Polarization information of the encrypted signal is retrieved by taking advantage of the information provided by the Stokes parameters. Moreover, Photon-Counting model is used in the encryption process which provides data sparseness and nonlinear transformation to enhance security. An authorized user with access to the polarization keys and the optical design variables can retrieve and validate the Photon-Counting plain-text. Optical experimental results demonstrate the feasibility of the encryption method.
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Three-dimensional Photon Counting double-random-phase encryption
Optics letters, 2013Co-Authors: Myungjin Cho, Bahram JavidiAbstract:In this Letter, we present a three-dimensional (3D) Photon Counting double-random-phase encryption (DRPE) technique using passive integral imaging. A 3D Photon Counting DRPE can encrypt a 3D scene and provides more security and authentications due to Photon Counting Poisson nonlinear transformation on the encrypted image. In addition, 3D imaging allows verification of the 3D object at different depths. Preliminary results and performance evaluation have been presented.
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Three-Dimensional Photon Counting Axially Distributed Image Sensing
Journal of Display Technology, 2013Co-Authors: Myungjin Cho, Bahram JavidiAbstract:In this paper, we present a 3D Photon Counting axially distributed image sensing system using statistical approaches, such as a maximum-likelihood estimation and total variation maximum a posteriori expectation maximization, to enhance the visual quality of 2D Photon Counting images and obtain better 3D reconstructed images. Conventional Photon Counting integral imaging is implemented by using a lens array, moving an image sensor in lateral (horizontal and vertical) directions, or using an image sensor array to obtain elemental images. To avoid lateral movement of the image sensor, axially distributed sensing is applied to Photon Counting imaging. A single image sensor is moved along its optical axis to pickup multi-view 2D images with slightly different perspectives which are used for 3D visualization. Axially distributed sensing (ADS) with proper statistical processing can remedy the effect of partial occlusion of the 3D scene. We show that our method can improve the visual quality of 2D Photon Counting images computationally and obtain the enhanced 3D reconstructed images.
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3D Photon Counting integral imaging with unknown sensor positions
Journal of the Optical Society of America. A Optics image science and vision, 2012Co-Authors: Xiao Xiao, Bahram JavidiAbstract:Photon Counting techniques have been introduced with integral imaging for three-dimensional (3D) imaging applications. The previous reports in this area assumed a priori knowledge of exact sensor positions for 3D image reconstruction, which may be difficult to satisfy in certain applications. In this paper, we extend the Photon Counting 3D imaging system to situations where sensor positions are unknown. To estimate sensor positions in Photon Counting integral imaging, scene details of Photon Counting images are needed for image correspondences matching. Therefore, an iterative method based on the total variation maximum a posteriori expectation maximization (MAP-EM) algorithm is used to restore Photon Counting images. Experimental results are presented to show the feasibility of the method. To the best of our knowledge, this is the first report on 3D Photon Counting integral imaging with unknown sensor positions.
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Three dimensional Photon Counting imaging
2012 11th Euro-American Workshop on Information Optics, 2012Co-Authors: Xiao Xiao, Myungjin Cho, Bahram JavidiAbstract:In this paper, we overview an iterative method based on total variation constraint and Bayesian framework to restore Photon Counting images. A 3D Photon Counting integral imaging using moving array-lens technique (MALT) is also introduced to improve the visualization of a reconstructed 3D scene. Experimental results verify the feasibility of these methods to enhance the visual quality under Photon starved conditions.
Martin J. Willemink - One of the best experts on this subject based on the ideXlab platform.
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Spectral Photon-Counting CT in cardiovascular imaging.
Journal of cardiovascular computed tomography, 2020Co-Authors: Veit Sandfort, Mats Persson, Amir Pourmorteza, Peter B. Noël, Dominik Fleischmann, Martin J. WilleminkAbstract:Photon-Counting computed tomography (PCCT) is an emerging technology promising to substantially improve cardiovascular imaging. Recent engineering and manufacturing advances by several vendors are expected to imminently launch this new technology into clinical reality. Photon-Counting detectors (PCDs) have multiple potential advantages over conventional energy integrating detectors (EIDs) such as the absence of electronic noise, multi-energy capability, and increased spatial resolution. These developments will have different timescales for implementation and will affect different clinical scopes. We describe the technical aspects of PCCT, explain the current developments, and finally discuss potential advantages of PCCT in cardiovascular imaging.
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Photon-Counting CT: Technical Principles and Clinical Prospects.
Radiology, 2018Co-Authors: Martin J. Willemink, Mats Persson, Amir Pourmorteza, Norbert J. Pelc, Dominik FleischmannAbstract:Photon-Counting CT is an emerging technology with the potential to dramatically change clinical CT. Photon-Counting CT uses new energy-resolving x-ray detectors, with mechanisms that differ substantially from those of conventional energy-integrating detectors. Photon-Counting CT detectors count the number of incoming Photons and measure Photon energy. This technique results in higher contrast-to-noise ratio, improved spatial resolution, and optimized spectral imaging. Photon-Counting CT can reduce radiation exposure, reconstruct images at a higher resolution, correct beam-hardening artifacts, optimize the use of contrast agents, and create opportunities for quantitative imaging relative to current CT technology. In this review, the authors will explain the technical principles of Photon-Counting CT in nonmathematical terms for radiologists and clinicians. Following a general overview of the current status of Photon-Counting CT, they will explain potential clinical applications of this technology.
Dominik Fleischmann - One of the best experts on this subject based on the ideXlab platform.
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Spectral Photon-Counting CT in cardiovascular imaging.
Journal of cardiovascular computed tomography, 2020Co-Authors: Veit Sandfort, Mats Persson, Amir Pourmorteza, Peter B. Noël, Dominik Fleischmann, Martin J. WilleminkAbstract:Photon-Counting computed tomography (PCCT) is an emerging technology promising to substantially improve cardiovascular imaging. Recent engineering and manufacturing advances by several vendors are expected to imminently launch this new technology into clinical reality. Photon-Counting detectors (PCDs) have multiple potential advantages over conventional energy integrating detectors (EIDs) such as the absence of electronic noise, multi-energy capability, and increased spatial resolution. These developments will have different timescales for implementation and will affect different clinical scopes. We describe the technical aspects of PCCT, explain the current developments, and finally discuss potential advantages of PCCT in cardiovascular imaging.
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Photon-Counting CT: Technical Principles and Clinical Prospects.
Radiology, 2018Co-Authors: Martin J. Willemink, Mats Persson, Amir Pourmorteza, Norbert J. Pelc, Dominik FleischmannAbstract:Photon-Counting CT is an emerging technology with the potential to dramatically change clinical CT. Photon-Counting CT uses new energy-resolving x-ray detectors, with mechanisms that differ substantially from those of conventional energy-integrating detectors. Photon-Counting CT detectors count the number of incoming Photons and measure Photon energy. This technique results in higher contrast-to-noise ratio, improved spatial resolution, and optimized spectral imaging. Photon-Counting CT can reduce radiation exposure, reconstruct images at a higher resolution, correct beam-hardening artifacts, optimize the use of contrast agents, and create opportunities for quantitative imaging relative to current CT technology. In this review, the authors will explain the technical principles of Photon-Counting CT in nonmathematical terms for radiologists and clinicians. Following a general overview of the current status of Photon-Counting CT, they will explain potential clinical applications of this technology.
Felix K Kopp - One of the best experts on this subject based on the ideXlab platform.
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spectral Photon Counting ct initial experience with dual contrast agent k edge colonography
Radiology, 2017Co-Authors: Daniela Muenzel, Daniel Barness, Ewald Roessl, Ira Blevis, Matthias Bartels, Alexander A Fingerle, Stefan Ruschke, Philippe Coulon, Heiner Daerr, Felix K KoppAbstract:This report describes experimental spectral Photon-Counting CT colonographic results from a preclinical spectral Photon-Counting CT system, which displays the possible clinical path toward full use of spectral Photon-Counting CT systems; clinical introduction of such a system may provide improved diagnostic imaging.
Nicolas Gisin - One of the best experts on this subject based on the ideXlab platform.
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Photon Counting otdr advantages and limitations
Journal of Lightwave Technology, 2010Co-Authors: Patrick Eraerds, Matthieu Legre, Jun Zhang, Hugo Zbinden, Nicolas GisinAbstract:In this paper, we provide a detailed insight into Photon-Counting optical time-domain reflectometer (?-OTDR) operation, ranging from Geiger-mode operation of avalanche photodiodes (APD), analysis of different APD bias schemes, to the discussion of OTDR perspectives. Our results demonstrate that an InGaAs/InP APD-based ?-OTDR has the potential of outperforming the dynamic range of a conventional state-of-the-art OTDR by 10 dB, as well as the two-point resolution by a factor of 20. Considering the trace acquisition speed of ?-OTDRs, we find that a combination of rapid gating for high Photon flux and free running mode for low Photon flux is the most efficient solution. Concerning dead zones, our results are less promising. Without additional measures, e.g., an optical shutter, the Photon Counting approach is not competitive.
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Photon Counting otdr advantages and limitations
arXiv: Quantum Physics, 2010Co-Authors: Patrick Eraerds, Matthieu Legre, Jun Zhang, Hugo Zbinden, Nicolas GisinAbstract:We give detailed insight into Photon Counting OTDR (nu-OTDR) operation, ranging from Geiger mode operation of avalanche photodiodes (APD), analysis of different APD bias schemes, to the discussion of OTDR perspectives. Our results demonstrate that an InGaAs/InP APD based nu-OTDR has the potential of outperforming the dynamic range of a conventional state-of-the-art OTDR by 10 dB as well as the 2-point resolution by a factor of 20. Considering the trace acquisition speed of nu-OTDRs, we find that a combination of rapid gating for high Photon flux and free running mode for low Photon flux is the most efficient solution. Concerning dead zones, our results are less promising. Without additional measures, e.g. an optical shutter, the Photon Counting approach is not competitive.