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Numerical Investigation of Influence of the Martensite Volume Fraction on DP Steels Fracture Behavior on the Basis of Digital Material Representation Model

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METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE 2014年第13期45A卷 5852-5865页

作者： Perzynski, Konrad Madej, Lukasz Wang, Jinfeng Kuziak, Roman Hodgson, Peter D. AGH Univ Sci & Technol PL-30059 Krakow Poland Deakin Univ Inst Frontier Mat Geelong Vic 3217 Australia Inst Ferrous Met PL-44100 Gliwice Poland

Development of the methodology for creating reliable digital material representation (DMR) models of dual-phase steels and investigation of influence of the martensite volume fraction on fracture behavior under tensile load are the main goals of the paper. First, an approach based on image processing algorithms for creating a DMR is described. Then, obtained digital microstructures are used as input for the numerical model of deformation, which takes into account mechanisms of ductile fracture. Ferrite and martensite material model parameters are evaluated on the basis of micropillar compression tests. Finally, the model is used to investigate the impact of the martensite volume fraction on the DP steel behavior under plastic deformation. Results of calculations are presented and discussed in the paper.

关键词： Basis data processing Steels Dual phase steels Volume fraction TENSILE LOADING MARTENSITE image processing algorithm

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Design of a multichannel, multiresolution smart imaging system

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APPLIED OPTICS 2012年第20期51卷 4810-4817页

作者： Belay, Gebirie Y. Meuret, Youri Ottevaere, Heidi Veelaert, Peter Thienpont, Hugo Vrije Univ Brussel Fac Engn Dept Appl Phys & Photon TONA Brussels Photon TeamB PHOT B-1050 Brussels Belgium Univ Ghent B-9000 Ghent Belgium

This paper presents the design of a multichannel imaging system where the different optical channels have a different angular resolution and field-of-view. Such an imaging system is able to resolve fine details in a small region of interest through the channel that has the highest angular resolution (0.0096 degrees) while controlling the surrounding region through the channel that has the widest field-of-view (2 x 40 degrees). An interesting feature of such a multichannel, multiresolution imaging system is that various image processing algorithms can be applied at different segments of the image sensor. We have designed a three channel imaging system where each optical channel consists of four aspheric lens surfaces. These three imaging channels share a single image sensor with a resolution of 1440 x 960 and a 10 mu m pixel size. All imaging channels have diffraction-limited performance ensuring good overall image quality. (C) 2012 Optical Society of America

关键词： image processing algorithm Imaging systems ANGULAR RESOLUTION OPTICAL CHANNEL Sensors (image) image quality region of interest

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A method for detection of randomly placed objects for robotic handling

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CIRP JOURNAL OF MANUFACTURING SCIENCE AND TECHNOLOGY 2016年第0期14卷 20-27页

作者： Tsarouchi, Panagiota Matthaiakis, Stereos-Alexandros Michalos, George Makris, Sotiris Chryssolouris, George Univ Patras Dept Mech Engn & Aeronaut Lab Mfg Syst & Automat Patras 26500 Greece

The image based systems still have open issues in order to meet the latest manufacturing requirements for simplicity, low cost as well as the limited maintenance requirements. In this direction, there is a method proposed for the recognition of 3D randomly placed objects for eventual robotic handling. The method includes a 2D vision system and is combined with data from computer-aided design (CAD) files for the generation of 3D coordinates. It is generic and can be used for the identification of multiple randomly placed objects. The method has been implemented in a software tool using MATLAB and has been applied to a consumer goods case for the recognition of shaver handles. (C) 2016 The Authors. This is an open access article under the CC BY-NC-ND license (hup://***/by-787791/4.01).

关键词： Object recognition image processing algorithm Robot Sensor Measurement

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A KNOWLEDGE-BASED SYSTEM FOR HIGHWAY NETWORK EXTRACTION

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 1988年第5期26卷 525-531页

作者： WANG, FJ NEWKIRK, R Faculty of Environmental Studies University of Waterloo Waterloo ONT Canada Fac. of Environ. Studies Waterloo Univ. Ont. Canada

A knowledge-based system has been set up to extract highway networks automatically from Landsat thematic mapper (TM) imagery. The system was developed using image processing algorithms and some artificial intelligence techniques. It inputs raw TM data and outputs an interpreted image clearly identifying highway and road networks. The main algorithms in the system are discussed in detail, results are presented, and features of the system are examined. Landsat TM images of study areas in Toronto, Canada, are presented by way of illustration.

关键词： road network Freeway Landsat Thematic mapper image processing algorithm thulium ILLUSTRATIONS

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Spatiotemporal characterization of 3D fracture behavior of carbon-fiber-reinforced polymer composites

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COMPOSITE STRUCTURES 2018年 203卷 30-37页

作者： Pei, Shenli Wang, Kaifeng Li, Yang Zeng, Danielle Su, Xuming Li, Jingjing Yang, Hui Xiao, Xianghui Penn State Univ Dept Ind & Mfg Engn State Coll PA 16802 USA Ford Motor Co Res & Innovat Ctr Dearborn MI 48124 USA Argonne Natl Lab Adv Photon Source Argonne IL 60439 USA

This study proposed a spatiotemporal algorithm to quantitatively characterize the in-situ 3D fracture behavior of carbon-fiber-reinforced polymer (CFRP) composites at microscale. In-situ micro X-ray computed tomography (mu XCT) integrated with a tensile stage was applied to capture the 3D fracture evolution of the CFRP composites, where the initiation and propagation of fracture features (e.g., fiber tip-end crack and fiber/matrix debonding) were identified. After the reconstruction of the 3D material microstructure, the proposed spatiotemporal algorithm thereafter extracted the fracture features by employing multiple image processing techniques for quantitative analysis. A similar distribution of the 3D strain obtained from the volumetric digital image correlation demonstrated the feasibility of the developed spatiotemporal algorithm. Moreover, this algorithm provided in-depth and quantitative analysis of fracture features, which provided insights into the microscale failure mechanism and thus shed light on the improvement of failure criteria for CFRP composites with complex microstructures.

关键词： Carbon fiber reinforced polymer composite Micro X-ray computed tomography Fracture feature image processing algorithm

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Flight Results of Vision-Based Navigation for Autonomous Spacecraft Inspection of Unknown Objects

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JOURNAL OF SPACECRAFT AND ROCKETS 2014年第6期51卷 2016-2026页

作者： Fourie, Dehann Tweddle, Brent E. Ulrich, Steve Saenz-Otero, Alvar MIT Dept Aeronaut & Astronaut Cambridge MA 02139 USA

This paper describes a vision-based relative navigation and control strategy for inspecting an unknown, noncooperative, and possibly spinning object in space using a visual-inertial system that is designed to minimize the computational requirements while maintaining a safe relative distance. The proposed spacecraft inspection system relies solely on a calibrated stereo camera and a three-axis gyroscope to maintain a safe inspection distance while following a circular trajectory around the object. The navigation system is based on image processing algorithms, which extract the relative position and velocity between the inspector and the object, and a simple control approach is used to ensure that the desired range and bearing are maintained throughout the inspection maneuver. The hardware implementation details of the system are provided. Computer simulation results and experiments conducted aboard the International Space Station during Expedition 34 are reported to demonstrate the performance and applicability of the proposed hardware, and related navigation and control systems to inspect an unknown spacecraft.

关键词： Bearings control systems Unknown control strategy Stereo cameras International space stations navigation Spacecraft image processing algorithm Navigation systems

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Experimental study on water-exit of cylinder

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OCEAN ENGINEERING 2024年 293卷

作者： Yun, Honglu Liu, Qingbo Zeng, Zheng Lian, Lian Shanghai Jiao Tong Univ Sch Oceanog Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ State Key Lab Ocean Engn Shanghai 200240 Peoples R China

In this paper, the hydrodynamic characteristics of the cylinder water-exit are studied by high-speed camera experiments. The characteristics of cylindrical motion trajectory, velocity and acceleration are analyzed by image processing algorithm. The emission voltage (i.e. initial velocity) and emission depth are important influencing factors. Based on different emission voltage and depth, the hydrodynamic coefficient is compared and analyzed. The results show that the new research method has good adaptability to the experimental study of cylindrical water-exit. The emission voltage directly affects the initial velocity of the cylinder, which in turn affects the force changes during the water exit process. The increase in emission depth exacerbates the uncertainty of the moment when the cylinder exits the water, thereby affecting the changes in the wake and motion stability during the cylinder water exit process.

关键词： Water-exit Hydrodynamic characteristics image processing algorithm

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Optical through-turbulence imaging configuration: experimental validation

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OPTICS LETTERS 2010年第4期35卷 453-455页

作者： Grossman, Elnatan Tzioni, Rami Gur, Aviram Gur, Eran Zalevsky, Zeev Bar Ilan Univ Sch Engn IL-52900 Ramat Gan Israel Shenkar Coll Engn & Design Fac Engn IL-52526 Ramat Gan Israel

In this Letter the authors present a field experimental validation of an imaging system that, when combined with a special image-processing algorithm, allows obtaining an improved imaging quality through turbulence perturbation. The system includes simultaneous capturing of three differently focused images and performing an iterative Gerchberg-Saxton based processing for phase retrieval. After the phase is retrieved the intensity of the object is reconstructed by numerical free-space propagation of the extracted complex field to the estimated position of the object. (C) 2010 Optical Society of America

关键词： image processing algorithm Imaging systems optical Imaging free-space propagation experimental fields estimated position Phase

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Reflective scanning imaging based on a fast terahertz photodetector

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OPTICS COMMUNICATIONS 2018年 427卷 170-174页

作者： Qiu, Fucheng Tan, Zhiyong Fu, Zhanglong Wan, Wenjian Li, Mengqi Wang, Chang Cao, Juncheng Chinese Acad Sci Shanghai Inst Microsyst & Informat Technol Key Lab Terahertz Solid State Technol 865 Changning Rd Shanghai 200050 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

The fast detection of terahertz radiation is recognized as a key technology of terahertz imaging systems. We realize a terahertz imaging system employing a terahertz quantum-well photodetector (QWP) and a terahertz quantum cascade laser (QCL). The detector can rapidly detect the 4.3THz light generated from a pulsed electrically-pump terahertz QCL, which is used as the terahertz source of the imaging system. The object is placed on a rotary scanning platform to realize fast scanning. A practical detection method of the terahertz pulse signal is employed to extract the amplitude information from the terahertz signal and improve the signal-to-noise ratio (SNR) of the system. The electrical and optical performances of the fast terahertz QWP are characterized, and the results show that the terahertz QWP can completely meet the fast detection requirement of the terahertz imaging system. The terahertz images of some invisible objects are obtained with a high contrast within 5 s. The imaging system owns a resolution of 0.3 mm and a circular imaging region with a diameter of 100 mm. An image processing algorithm is applied in this system to solve the noise problem and improve the quality of the images. The imaging results indicate that terahertz QWP has a good application prospect in nondestructive inspection applications and the research of the fast physical or chemistry process.

关键词： Terahertz quantum-well photodetectors Fast imaging system Pulse signal detection method Invisible objects image processing algorithm

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A high-throughput imaging system to quantitatively analyze the growth dynamics of plant seedlings

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INTEGRATIVE BIOLOGY 2012年第8期4卷 945-952页

作者： Men, Yongfan Yu, Qiang Chen, Zitian Wang, Jianbin Huang, Yanyi Guo, Hongwei Peking Univ Coll Life Sci Biodynam Opt Imaging Ctr Beijing 100871 Peoples R China Peking Univ Coll Engn Beijing 100871 Peoples R China Peking Univ Coll Life Sci State Key Lab Prot & Plant Gene Res Beijing 100871 Peoples R China Peking Univ Coll Chem & Mol Engn Beijing 100871 Peoples R China

Most current methods for analyzing the growth rate of plant seedlings are limited to low-throughput experimental configurations. We have developed an automatic system to investigate the dynamics of the growth of hypocotyls using Arabidopsis as model. This system is able to capture time-lapse infrared images of 24 seedlings automatically, with a spatial resolution of 2 mm per pixel and temporal interval of 5 min. Seedling length is rapidly calculated using automated geometric image-processing algorithms. With this high-throughput platform, we have investigated the genotype dependent difference of growth patterns, as well as the response to plant hormone - ethylene. Our analyses suggest that cytoskeleton function is not required in ethylene-induced hypocotyl inhibition. This novel integrative method can be applied to large-scale dynamic screening of plants, as well as any other image-based biological studies related to dynamic growth.

关键词： hypocotyls dynamics pixel Seedling Growth patterns Spatial resolution automation system Imaging systems image processing algorithm Arabidopsis

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