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Video tracking method for three-dimen-sional measurement of a free-swimming fish

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Science China(Physics,Mechanics & Astronomy) 2007年第6期50卷 779-786页

作者： wu guanhao ZENG LiJiang State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentsTsinghua UniversityBeijing 100084China

A video system for tracking a free-swimming fish two-dimensionally is introduced in this paper. The tracking is accomplished by simultaneously taking images from the ventral view and the lateral view of the fish with two CCD cameras mounted on two computer-controlled and mutually orthogonal translation stages. By processing the images recorded during tracking,three-dimensional kinematic parameters of the tail and pectoral fin of the fish in forward,backward and turning swimming modes are obtained.

关键词： fish tracking kinematics tail pectoral fin

Measuring the kinematics of a free-flying hawk-moth(Macroglossum stellatarum)by a comb-fringe projection method

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Acta Mechanica Sinica 2010年第1期26卷 67-71页

作者： guanhao wu Li jiang Zeng State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision Instruments Tsinghua University 100084 Beijing China

We describe a 2D fringe projection method that involves projecting two groups of sharp comb fringes onto a free-flying hawk-moth from different directions and recording the images of distorted fringes by two high speed cameras from two orthogonal views. By calculating the 3D coordinates of the points on the hawk-moth and three-dimensional reconstruction of the wing, the flight trajectory, body attitude and wing kinematics including flapping angle, elevation angle, torsion angle, and camber deformation are obtained.

关键词： Fringe projection Kinematics Measurement Hawk-moth

Hybrid undulatory kinematics of a robotic Mackerel(Scomber scombrus):Theoretical modeling and experimental investigation

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Science China(Technological Sciences) 2012年第10期55卷 2941-2952页

作者： WEN Li WANG TianMiao wu guanhao LIANG JianHong Museum of Comparative Zoology Harvard University26 Oxford StreetCambridgeMA 02138USA Robotic Institute in School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentsTsinghua UniversityBeijing 100084China

Fishes that use undulatory locomotion occasionally change their inherent kinematics in terms of some natural *** special locomotion pattern was vividly dubbed "hybrid kinematics" by biologists *** this paper,we employed a physical model with body shape of a Mackerel(Scomber scombrus),to use the three most typical undulatory kinematics:anguillform,carangiform and thunniform,to investigate the hydrodynamic performance of the so-called "hybrid kinematics" biological *** models of both kinematics and hydrodynamics of the physical model swimming were *** on this model,the instantaneous force produced by fish undulatory body and flapping tail were calculated *** also quantitatively measured the hydrodynamic variables of the robotic model swimming with the three undulatory kinematics on an experimental *** results of both theoretical model and experiment showed that the robot with thunniform kinematics not only reaches a higher speed but also is more efficient during steady swimming ***,anguilliform kinematics won the speed race during the initial ***,the digital particle image velocimetry(DPIV) results showed some difference of the wake flow generated by the robotic swimmer among the three undulatory *** findings may possibly shed light on the motion control of a biomimetic robotic fish and provide certain evidence of why the "hybrid kinematics" exists within the typical undulatory locomotion patterns.

关键词： hybrid kinematics robotic fish digital partial image velocimetry(DPIV) self-propulsive

Dual-comb spectroscopy resolved three-degreeof-freedom sensing

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Photonics Research 2021年第2期9卷 243-251页

作者： SIYU ZHOU VUNAM LE SHILIN XIONG YUETANG YANG KAI NI QIAN ZHOU guanhao wu State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China Division of Advanced Manufacturing Graduate School at ShenzhenTsinghua UniversityShenzhen 518055China

Precise and fast determination of position and orientation, which is normally achieved by distance and angle measurements, has broad applications in academia and industry. We propose a dynamic three-degree-of-freedom measurement technique based on dual-comb interferometry and a self-designed grating-corner-cube(GCC) combined sensor. Benefiting from its unique combination of diffraction and reflection characteristics, the absolute distance, pitch, and yaw of the GCC sensor can be determined simultaneously by resolving the phase spectra of the corresponding diffracted beams. We experimentally demonstrate that the method exhibits a ranging precision(Allan deviation) of 13.7 nm and an angular precision of 0.088 arcsec, alongside a 1 ms reaction time. The proposed technique is capable of precise and fast measurement of distances and two-dimensional angles over long stand-off distances. A system with such an overall performance may be potentially applied to space missions,including in tight formation-flying satellites, for spacecraft rendezvous and docking, and for antenna measurement as well as the precise manufacture of components including lithography machines and aircraftmanufacturing devices.

关键词： precise freedom absolute

基于线阵APD探测器的脉冲式一维非扫描激光雷达系统

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红外与激光工程 2012年第1期41卷 96-100页

作者：郑睿童吴冠豪清华大学精密仪器系精密测试技术及仪器国家重点实验室北京100084

介绍了非扫描激光雷达的原理,描述了研制的基于线阵APD雪崩光电二极管的一维非扫描激光雷达系统。该系统使用线阵APD作为探测器,红外脉冲式纳秒激光器作为探测光源,利用飞行时间法实现了目标的一维距离图像的非扫描测量。系统使用了APD... 详细信息

介绍了非扫描激光雷达的原理,描述了研制的基于线阵APD雪崩光电二极管的一维非扫描激光雷达系统。该系统使用线阵APD作为探测器,红外脉冲式纳秒激光器作为探测光源,利用飞行时间法实现了目标的一维距离图像的非扫描测量。系统使用了APD多通道并行前置放大电路,并利用模拟开关控制高速继电器进行多通道轮询切换,实现了APD阵列的多通道驱动,并有效地降低了通道间的串扰。进行了多组6～18 m的一维距离成像实验,结果表明系统的距离分辨率优于10 cm,各通道的平均测距标准偏差约为8.6 cm。该系统的设计为将来的面阵APD二维非扫描激光雷达的研制奠定了基础。

关键词：非扫描激光雷达线阵APD 脉冲式激光测距

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用于精密位移测量的微型光栅传感器开发

光子学报 2021年第9期50卷 1-11页

作者：魏正杰张迪吴冠豪清华大学精密仪器系精密测试技术及仪器国家重点实验室北京100084

基于双光栅干涉扫描原理,通过复用透射光栅实现干涉扫描型光栅位移传感器的小型化开发。开发了适用于精密位移测量的光栅传感器原理样机。传感器的电路系统包括信号转换放大电路模块和置于传感器D-SUB接口外壳内的信号处理电路模块。通... 详细信息

基于双光栅干涉扫描原理,通过复用透射光栅实现干涉扫描型光栅位移传感器的小型化开发。开发了适用于精密位移测量的光栅传感器原理样机。传感器的电路系统包括信号转换放大电路模块和置于传感器D-SUB接口外壳内的信号处理电路模块。通过15 pin接口输出四路电平为2.5±0.5 V的模拟差分信号,差分信号接口可用于高倍细分而达到高分辨率,具备RS422接口适配能力,可以提高传感器远距离传输的抗干扰能力。以电容传感器为基准,光栅位移传感器原理样机实现了±30 nm的重复性精度,满足10 mm/s的测量速度需求,10 s短时位移稳定性达到5 nm,6 h的长时间稳定性达到70 nm。

关键词：编码器光栅位移测量稳定性高精度仪器

工程专业混合式教学设计与实践研究--以清华大学“光电仪器设计”课程为例

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电化教育研究 2020年第5期41卷 104-111页

作者：张冲吴冠豪清华大学教育研究院北京100084 清华大学精仪系北京100084

工程专业的混合式教学有其自身的特点。文章首先阐述了工程专业混合式教学"混合"的内涵;其次基于工程人才培养目标特点,围绕学习活动、教学资源、教学评价三个方面对混合式教学进行了设计;最后,结合清华大学"光电仪器设计"课程教学改革... 详细信息

工程专业的混合式教学有其自身的特点。文章首先阐述了工程专业混合式教学"混合"的内涵;其次基于工程人才培养目标特点,围绕学习活动、教学资源、教学评价三个方面对混合式教学进行了设计;最后,结合清华大学"光电仪器设计"课程教学改革案例,在教学实践中实施并验证了混合式教学效果。

关键词：工程专业混合式教学工程人才教学设计教学实践

用于高反表面测量的分块平滑自适应条纹投影方法

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红外与激光工程 2023年第5期52卷 316-329页

作者：何信欣刘斌王春柳吴冠豪天津理工大学电气工程与自动化学院天津市复杂系统控制理论及应用重点实验室天津300384 清华大学精密仪器系精密测试技术及仪器国家重点实验室北京100084

条纹投影轮廓术用于测量高反表面时,相机成像会出现饱和区域,区域内相位信息难以提取,进而造成三维重建错误。为此,文中提出了一种分块平滑自适应条纹投影方法。首先,通过投影少量均匀灰度图,对饱和区域进行分块,根据各块的饱和程度,计... 详细信息

条纹投影轮廓术用于测量高反表面时,相机成像会出现饱和区域,区域内相位信息难以提取,进而造成三维重建错误。为此,文中提出了一种分块平滑自适应条纹投影方法。首先,通过投影少量均匀灰度图,对饱和区域进行分块,根据各块的饱和程度,计算相应的初始投影强度。随后,在不饱和情况下,投射亮暗两种强度的条纹图,通过在饱和区域融合两者相位信息,实现相机到投影仪的坐标匹配,获取初始映射投影强度;然后,对初始映射投影强度进行多项式拟合,构建平滑的投影强度曲线,用于逐像素获取最佳投影强度值,同步填补了因相机与投影机分辨率差异引起的映射孔洞,最终生成自适应条纹。最后,将生成的自适应条纹投射至被测物体,进行了相位解算和三维重建。实验结果表明:所提方法只需投影少量灰度图就能生成高动态范围的自适应条纹,实现了饱和区域相位信息的完整提取。相比于现有改进方法,面形三维重建的标准偏差分别减少了40%和28.6%,有效地提高了高反表面形貌测量精度。

关键词：自适应条纹投影三维测量最佳投影强度多项式拟合孔洞填补

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基于光学频率梳的表面形貌测量方法

激光与光电子学进展 2023年第3期60卷 199-210页

作者：吴冠豪施立恒李尔格清华大学精密仪器系精密测试技术及仪器国家重点实验室北京100084

表面形貌检测是工业生产和科学研究所需的关键技术之一,高精度和高效率是该领域一直以来的发展方向。光学频率梳有着独特宽光谱、窄线宽和稳定频率的特性,展现了优越的计量潜力,在表面形貌测量领域有着重要的应用并取得了重要的进展。... 详细信息

表面形貌检测是工业生产和科学研究所需的关键技术之一,高精度和高效率是该领域一直以来的发展方向。光学频率梳有着独特宽光谱、窄线宽和稳定频率的特性,展现了优越的计量潜力,在表面形貌测量领域有着重要的应用并取得了重要的进展。首先介绍了光学频率梳的定义;根据不同的技术路线,分类回顾了光学频率梳在形貌测量中的研究现状及特点;最后,对基于光频梳的形貌测量技术进行了展望。

关键词：光学频率梳形貌检测干涉显微轮廓术