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A correlative classifiers approach based on particle filter and sample set for tracking occluded target

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Applied Mathematics(A Journal of Chinese Universities) 2017年第3期32卷 294-312页

作者： LI Kang HE Fa-zhi yu hai-ping CHEN Xiao School of Computer Science Wuhan University Wuhan 430072 China School of Computer Science and Information Engineering Hubei University Wuhan 430062 China The State Key Laboratory of Software Engineering Wuhan University Wuhan 430072 China

Target tracking is one of the most important issues in computer vision and has been applied in many fields of science, engineering and industry. Because of the occlusion during tracking, typical approaches with single classifier learn much of occluding background information which results in the decrease of tracking performance, and eventually lead to the failure of the tracking algorithm. This paper presents a new correlative classifiers approach to address the above problem. Our idea is to derive a group of correlative classifiers based on sample set method. Then we propose strategy to establish the classifiers and to query the suitable classifiers for the next frame tracking. In order to deal with nonlinear problem, particle filter is adopted and integrated with sample set method. For choosing the target from candidate particles, we define a similarity measurement between particles and sample set. The proposed sample set method includes the following steps. First, we cropped positive samples set around the target and negative samples set far away from the target. Second, we extracted average Haar-like feature from these samples and calculate their statistical characteristic which represents the target model. Third, we define the similarity measurement based on the statistical characteristic of these two sets to judge the similarity between candidate particles and target model. Finally, we choose the largest similarity score particle as the target in the new frame. A number of experiments show the robustness and efficiency of the proposed approach when compared with other state-of-the-art trackers.

关键词： visual tracking sample set method online learning particle filter

Effect of hydrogen content and stress state on room-temperature mechanical properties of Ti-6Al-4V alloy

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Transactions of Nonferrous Metals Society of China 2009年第S02期19卷 423-428页

作者： yuAN Bao-guo LI Chun-feng yu hai-ping SUN Dong-li School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

This work aims to investigate the effects of hydrogen content(in the range of 0%-0.5%,mass fraction)and stress state (tension and compression)on the room-temperature mechanical properties of Ti-6Al-4V alloy through mechanical properties tests. The effects of hydrogen content on microstructure evolution of Ti-6Al-4V alloy is also examined by optical microscopy,X-ray diffractometry,transmission electron microscopy and scanning electron *** results show that hydrogen content and stress state have important effects on the room-temperature mechanical properties of Ti-6Al-4V *** strength and ultimate elongation decrease with increasing the hydrogen content,while compressive strength and ultimate reduction are improved after *** reason is that the intergranular deformation dominates at the state of *** atoms in solid solution and hydrides at grain boundaries increase with increasing the hydrogen content and they can promote the initiation and propagation of cracks along grain *** the intragranular deformation dominates at the state of *** plastic beta phase and hydrides increase with increasing the hydrogen content and they improve the ultimate reduction and compressive strength.

关键词： Ti-6Al-4V alloy hydrogen content stress state mechanical properties

Investigations on Flanging of Aluminum Alloy Tube Under Pulsed Magnetic Force

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Journal of Iron and Steel Research International 2012年第S1期19卷 438-441页

作者： yu hai-ping JIANG Hong-wei LI Chun-feng National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology

In this work,the magnetic pulse forming process was used to flange the AA 3003-O aluminum alloy tube to improve the flanging formability *** results show that there are critical discharge energy values for the flanging dies with varied slope *** mechanism of magnetic pulse flanging process is the bulging in contrast to the expanding of the quasi-static *** the flanging with 90 slope degree,the limited hoop strain at the outer fringe could be up to 0.54 without rapture,to which the limit of simple tension limit is improved by 85%in *** 180 degree flanging at tube end can be achieved by one time magnetic pulse forming.

关键词： magnetic pulse forming flanging forming limit aluminum alloy tube

Numerical and Experimental Investigation of Electromagnetic Free Bulging of AZ31 Magnesium Alloy Sheet

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Journal of Iron and Steel Research International 2012年第S1期19卷 451-454页

作者： XU Jun-rui yu hai-ping LI Chun-feng National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology

The electromagnetic free bulging experiment and the coupled-field numerical simulation of the EMF process were carried out to determine the possibility to improve the formability of magnesium alloy AZ31 sheets(1 mm thick)at room *** data were examined using strain *** numerical simulation for the electromagnetic sheet free bulging is performed by means of ANSYS FEA *** with quasi-static FLD results,increase in the major and minor principal strains of approximately 87%and 39%were achieved,*** effects of various process parameters on electromagnetic bulging of AZ31 magnesium alloy sheets were evaluated. Three-dimensional(3D)FE model is established to predict the electromagnetic bulging of the *** simulation results agreed well with experimental observations.

关键词： Electromagnetic sheet forming AZ31 magnesium alloy formability numerical simulation

Interface Microstructure of Al-Fe Tubes Joint by Magnetic Pulse Welding

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Journal of Iron and Steel Research International 2012年第S1期19卷 442-445页

作者： XU Zhi-dan yu hai-ping LI Chun-feng HAN yu-jie National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology The Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology

Magnetic Pulse Welding(MPW)is a very high speed process which produces solid-state *** this work, Welding interface microstructure of Al/Fe tubes by MPW and its influence factors were *** equipment with a capacitor of 100 μF was used under different voltages range from 8 kV to 15 *** and TEM observation were carried out to investigate microstructure of the welding *** results show that the dissimilar tubes(Al/Fe)could be welded with the optimum tapered angle of about 4 *** welding interface in Al/Fe joints exhibits a characteristic wavy morphology with wavelength of about I00 μm.A new layer exists between base tubes consisting of AI and Fe *** grained microstructure is founded near the welding *** results obtain in this work provide the fundamentals for the investigation of MPW mechanism of dissimilar tubes.

关键词： magnetic pulse welding dissimilar material ultrafine grained microstructure

The Research on Micro Electronic-Magnetic Forming of Sheet Metal

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Journal of Iron and Steel Research International 2012年第S1期19卷 434-437页

作者： ZHAO Qing-juan GUO Bin WANG Chun-ju SHAN De-bin yu hai-ping LI Chun-feng School of Materials Science and Engineering Harbin Institute of Technology

Micro channel of T2 copper were molding through electronic-magnetic forming *** scanning confocal microscope and contourgraph were used to measure the section profile and sheet *** effects of voltage,shape of channel and discharge cycles on laws of metal flow were *** showed that forming depth of micro channel and thinning of sheet thickness increased as the increasing of the ***-filling capacity of components formed by two molds with different structures had been increased when the voltage was *** with semicircle structure facilitate the material flow and the forming depth of parts was relative *** structure was better than taper structure in mold-filling capacity.A number of small pulse discharges can improve the forming quality and deformation,but local thinning in sheet metal leads to non-uniform distribution of thickness.

关键词： electromagnetic forming array microstructure foil board micro forming micro channel

Interface Microstructure of Al-Fe Tubes Joint by Magnetic Pulse Welding

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Interface Microstructure of Al-Fe Tubes Joint by Magnetic Pu...

第七届冶金与材料电磁过程国际会议（EPM2012）

Magnetic Pulse Welding（MPW） is a very high speed process which produces solid-state *** this work,Welding interface microstructure of Al/Fe tubes by MPW and its influence factors were *** equipment with a capacitor of 100 μF was used under different voltages range from 8 kV to 15 *** and TEM observation were carried out to investigate microstructure of the welding *** results show that the dissimilar tubes（Al/Fe） could be welded with the optimum tapered angle of about 4 *** welding interface in Al/Fe joints exhibits a characteristic wavy morphology with wavelength of about 100 μm.A new layer exists between base tubes consisting of Al and Fe *** grained microstructure is founded near the welding *** results obtain in this work provide the fundamentals for the investigation of MPW mechanism of dissimilar tubes.

关键词： magnetic pulse welding dissimilar material ultrafine grained microstructure

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异种金属板材磁脉冲连接技术研究进展

塑性工程学报 2023年第6期30卷 37-57页

作者：姜爔于海平哈尔滨工业大学材料科学与工程学院黑龙江哈尔滨150001 哈尔滨工业大学金属精密热加工国家级重点实验室黑龙江哈尔滨150001

面向现代工业发展,磁脉冲连接技术作为对环境友好的室温异种材料连接技术,能满足轻量化及复合性能的需求,具有极大的发展潜力和应用前景。磁脉冲连接技术自开始发展至今,主要应用在管-管及管-棒的连接。对板材磁脉冲技术原理、适用范围... 详细信息

面向现代工业发展,磁脉冲连接技术作为对环境友好的室温异种材料连接技术,能满足轻量化及复合性能的需求,具有极大的发展潜力和应用前景。磁脉冲连接技术自开始发展至今,主要应用在管-管及管-棒的连接。对板材磁脉冲技术原理、适用范围、工艺参数的制定、板材在连接过程中的变形行为、连接接头的宏观和微观形貌、接头性能的评价及板材磁脉冲设备和工作线圈进行了总结和分析。在此基础之上,提出了当前板材磁脉冲连接技术需要解决的问题,并对未来板材磁脉冲技术的发展进行了展望。

关键词：磁脉冲连接板材工艺参数连接界面接头性能

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基于冲击屈曲能量准则的磁脉冲缩径塑性失稳判据

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塑性工程学报 2008年第5期15卷 121-126页

作者：于海平李春峰哈尔滨工业大学材料科学与工程学院哈尔滨150001

磁脉冲成形是利用磁压力对金属坯料进行塑性加工的高能、高速率加工方法,与常规成形工艺相比有诸多优点,为高强度、难成形材料开辟了新的成形加工途径。而瞬时近似正弦衰减的脉冲磁压力和不均匀起皱变形,使圆管磁脉冲缩径压缩失稳判据... 详细信息

磁脉冲成形是利用磁压力对金属坯料进行塑性加工的高能、高速率加工方法,与常规成形工艺相比有诸多优点,为高强度、难成形材料开辟了新的成形加工途径。而瞬时近似正弦衰减的脉冲磁压力和不均匀起皱变形,使圆管磁脉冲缩径压缩失稳判据研究非常棘手。文章选择王仁提出的冲击屈曲能量准则进行此塑性屈曲判据研究。首先,应用该能量准则确定冲击载荷作用下圆管产生塑性屈曲的临界冲击能量;然后,通过使临界冲击能量与磁压力脉冲第一波对工件变形和运动做功相等,建立圆管产生径向塑性压缩失稳的临界判据。研究表明,产生径向屈曲塑性变形的临界放电电压随径厚比增加而提高,其试验值与判据确定的理论值吻合较好。应用该判据能够预测使圆管产生失稳屈曲的临界放电电压(能量),使均匀径向塑性变形的定量分析成为可能。

关键词：冲击屈曲能量准则塑性失稳判据磁脉冲缩径放电电压(能量)