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POSTDETECTION PULSE INTEGRATION EFFICIENCY OF A SCANNING LIDAR

APPLIED OPTICS 1988年第17期27卷 3638-3644页

作者： WANG, JY The author is with General Dynamics Convair Division P.O. Box 85357 San Diego California 92138.

Probability of detection and postdetection integration efficiency are formulated and calculated for pulses that are partially correlated. For high probabilities of detection, substantial gain may be obtained for a coh... 详细信息

关键词： Coherent receivers Coherent systems image processing algorithms Laser ranging Laser speckle Lidar

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Evaluation of image quality and patient exposure in fluoroscopy using a phantom: Is there any clinical relevance

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EUROPEAN JOURNAL OF RADIOLOGY 2021年 138卷 109607-109607页

作者： Tsalafoutas, I. A. Tsapaki, V Triantopoulou, I Hamad Med Corp OHS Dept Radiat Safety Sect Doha Qatar Konstantopoulio Hosp Med Phys Unit Athens 14233 Greece

Objective: To investigate the impact of X-ray preset acquisition protocol settings on fluoroscopy image quality (IQ) and radiation exposure. Materials & Methods: A quality control (QC) phantom was imaged with a modern digital C-arm system, using various preset fluoroscopy protocols. IQ was assessed using human observers and in-house software for automated evaluation, based on contrast-to-noise ratios of details and their background. Patient radiation exposure was evaluated using the displayed Incident Air-Kerma and Kerma-Area Product values. Results: Protocol selection affects radiation exposure by a factor of about 3. IQ evaluation showed that acquisition protocols produce images with quite different characteristics. The visual IQ evaluation method was time consuming and cumbersome. The automated method, utilized the visual IQ evaluation results for calibration of detection thresholds. However, it failed to reproduce these results for all images and details types. In some images, digital image processing created artifacts which affected the pixel value distributions around details in a way that could be handled only by the human vision. Conclusion: Manufacturers provide many preset protocols designated for specific clinical uses, which have large impact on IQ characteristics and radiation exposure. However, protocol settings' selection rationale is essentially a "black box" for the end user. Though QC phantoms are currently used for IQ evaluation, they are not appropriate for drawing firm conclusions concerning the expected performance of each protocol in clinical practice. Currently, there is no consensus on the optimum technical characteristics of preset protocols for specific procedures. More work is needed in this area.

关键词： Digital fluoroscopy image quality image artifacts image processing algorithms Radiation exposure

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Circumventing LoS Blocking in Beam-Steered Optical-Wireless Systems with Real-Time Tracking and Handover

Circumventing LoS Blocking in Beam-Steered Optical-Wireless ...

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Optical Fiber Communication (OFC) Conference

作者： Ketema Mekonnen Quan Pham Frans Huijskens Eduward Tangdiongga Ali Mefleh Ton Koonen Institute for Photonic Integration Eindhoven University of Technology Eindhoven The Netherlands KPN CTO Technology Roadmap & Architecture The Hague The Netherlands

This paper demonstrates a real-time user tracking and handover mechanism for indoor ultrahigh-speed beam-steered optical-wireless systems implementing a low-cost camera. This allows us to tackle LoS blocking by switch... 详细信息

ISBN: (数字)9781943580712

ISBN: (纸本)9781728167626

关键词： Beam steering image processing image processing algorithms Laser materials processing Tunable diode lasers Tunable lasers

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Automated System for Crack Detection Using Infrared Thermographic Testing

Automated System for Crack Detection Using Infrared Thermogr...

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17th World Conference on Non-Destructive Testing

作者： Stanislav TARMAN Václav MATZ STARMANS electronics s.r.o.V Zahradach 24/836 Prague 8180 00

The objective of this study was the development of the automated system for crack detection on square steel bars used in the automotive industry for axle and shaft *** automated system for thermographic crack detection uses brief pulsed eddy currents to heat steel components under ***,if present,will disturb the current flow and so generate changes in the temperature profile in the crack *** changes of temperature are visualized using an infrared *** image acquired by the infrared camera is evaluated through an image processing *** advantages afforded by the system are its inspection times,its excellent flaw detection sensitivity and its ability to detect hidden,subsurface *** automated system consists of four IR cameras (each side of steel bar is evaluated at a time),coil,high frequency generator,and control place with *** system is a part of the inspection line where the subsurface and surface cracks are *** the crack is present,the cracked place is automatically *** components without cracks are then deposited apart from defective *** system is fully automated and its ability is to evaluate four meter blocks within 20 *** is the real reason for using this system in real industrial applications.

关键词： Thermographic testing image processing algorithms Crack detection

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Multi-User Localization and Upstream Signaling for Indoor OWC System using a Camera Technology

Multi-User Localization and Upstream Signaling for Indoor OW...

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Optical Fiber Communication (OFC) Conference

作者： N. Q. Pham K. A. Mekonnen E. Tangdiongga A. Mefleh A. M. J. Koonen Eindhoven University of Technology Eindhoven Netherlands Institute for Photonic Integration Eindhoven University of Technology Eindhoven The Netherlands KPN CTO Technology Roadmap & Architecture The Hague The Netherlands

We present upstream signaling and localization for an indoor beam-steered OWC system using vision-based technology. We demonstrate a 1.2kbps upstream signaling and localization system which enables to identify a large... 详细信息

ISBN: (数字)9781943580712

ISBN: (纸本)9781728167626

关键词： image processing algorithms Light beams Light intensity Optical signals Optical wireless communication Tunable lasers

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Experimental Demonstration of a Flicker-Free Scheme for Optical Camera Communication

Experimental Demonstration of a Flicker-Free Scheme for Opti...

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Asia Communications and Photonics Conference and Exhibition (ACP)

作者： Zhongwei Jiang Jing He Jin Shi Yi Liu Qi Tang Hunan University Changsha China Shenzhen Institute of Information Technology Shenzhen China

In this paper, a flicker-free scheme based on Manchester modulation is proposed and demonstration for OCC. Experimental results show that the BER performance is not affected by ISO under the visible image.

ISBN: (纸本)9781943580705

关键词： Bit error rate image processing image processing algorithms image sensors Modulation Visible light

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Large scale Si3N4 Integrated Circuit for High-resolution Interferometric imaging

Large scale Si3N4 Integrated Circuit for High-resolution Int...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Yichi Zhang Rijuta Ravichandran Yujia Zhang S. J. Ben Yoo Department of Electrical and Computer Engineering University of California Davis CA USA

We design, fabricate and characterize a 4-layer 110mm×44mm Si 3 N 4 PIC with long routing waveguides and arrayed waveguides gratings based on a wafer-scale integration process for a high-resolution interferometr... 详细信息

ISBN: (纸本)9781957171258

关键词： Array waveguide devices Detector arrays image processing algorithms image quality Interferometric imaging Waveguide gratings

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Improved edge detection of regions enriched with gold nanorods inside biological phantom

Improved edge detection of regions enriched with gold nanoro...

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Conference on Lasers and Electro-Optics Europe

作者： Yossef Danan Moshe Sinvani Zeev Zalevsky Faculty of Engineering Bar-Ilan University Ramat-Gan 52900 Israel

ISBN: (纸本)9781509067374

The ability to resect a tumor completely is a key merit in preventing recurrence of the disease. In order to achieve more complete tumor resection the surgeon must clearly identify the tumor margins. This identification is even more crucial when the tumor growth is adjacent or in neurological structures, and therefore it is dangerous to remove extra tissue [1], [2].

关键词： Edge detection image processing algorithms Nanorods Spatial resolution Thermal imaging Tissue

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Mid-infrared imaging system based on polarizers for detecting marine targets covered in sun glint

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Optics express 2016年第15期24卷 16396-409页

作者： Huijie Zhao Zheng Ji Ying Zhang Xiaofeng Sun Pengfei Song Yansong Li School of Instrumentation Science & Opto-electronics Engineering Beihang University 37 Xueyuan Road Haidian Beijing 100191 China China Academy of Space Technology 104 Youyi Road Haidian Beijing 100094 China

When a marine target is detected by a mid-infrared detector on a sunny day, the target's information could be lost if it is located in sun glint. Therefore, we developed a new mid-infrared imaging system capable of effectively detecting marine targets in regions of strong sun glint, which is presented in this report. Firstly, the theory of the analysis methods employed in different detection scenarios is briefly described to establish whether one or two polarizers should be utilized to suppress further the p-polarized component of sun glint. Secondly, for the case in which a second polarizer is employed, the formula for the optimum angle between the two polarizers is given. Then, the results of our field experiment are presented, demonstrating that the developed system can significantly reduce sun glint and can enhance the contrast of target images. A commonly used image processing algorithm proved capable of identifying a target in sun glint, confirming the effectiveness of our proposed mid-infrared polarization imaging system.

关键词： Analytical techniques image detection systems image processing image processing algorithms Polarimetric imaging Wire grid polarizers

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Toward omnidirectional and automated imaging system for measuring oceanic whitecap coverage

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Journal of the Optical Society of America. A, Optics, image science, and vision 2016年第8期33卷 1589-97页

作者： Raied S Al-Lashi School of Food Science and Nutrition Faculty of Mathematics and Physical Sciences University of Leeds Leeds UK (R.Al-lashi@leeds.ac.uk)

Accurate measurements of oceanic whitecap coverage from whitecap images are required for better understanding air-gas transfer and aerosol production processes. However, this is a challenging task because whitecap patches are formed immediately after a wave breaks and are spread over a wide area. The main challenges in designing whitecaps imaging instrument are the small field of view of the camera lens, processing huge numbers of images, recording data over long time periods, and deployment difficulties in stormy conditions. This paper describes the hardware design of a novel high-resolution optical instrument for imaging oceanic whitecaps and the automated algorithm processing the collected images. The instrument was successfully deployed in 2013 as part of the HiWINGS campaign in the North Atlantic Ocean. The instrument uses a fish-eye camera lens to image the whitecaps in a wide angle of view (180°).

关键词： Camera calibration image processing image processing algorithms image quality Imaging techniques Solar radiation

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