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Application and evaluation of optical distance measurements in geometrical quality testing of microgears

Albert ALBERS, Duotai PAN, Leif MARXEN, Claudia BECKE,

《机械工程前沿（英文）》 2010年第5卷第3期页码 261-269 doi: 10.1007/s11465-010-0100-3

摘要： Microgears are increasingly important in industry. Compared to normal gears, the quality assurance of microgears needs more accurately measured data and simple but feasible measurement methods because of their dimension particula

关键词： microgear optical distance measurement profile deviation CWL sensor micromechanical technology (MMT)

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Development of surface reconstruction algorithms for optical interferometric measurement

Dongxu WU, Fengzhou FANG

《机械工程前沿（英文）》 2021年第16卷第1期页码 1-31 doi: 10.1007/s11465-020-0602-6

摘要： Optical interferometry is a powerful tool for measuring and characterizing areal surface topography in precision manufacturing. A variety of instruments based on optical interferometry have been developed to meet the measurement needs in various applications, but the existing techniques are simply not enough to meet the ever-increasing requirements in terms of accuracy, speed, robustness, and dynamic range, especially in on-line or on-machine conditions. This paper provides an in-depth perspective of surface topography reconstruction for optical interferometric measurements. Principles, configurations, and applications of typical optical interferometers with different capabilities and limitations are presented. Theoretical background and recent advances of fringe analysis algorithms, including coherence peak sensing and phase-shifting algorithm, are summarized. The new developments in measurement accuracy and repeatability, noise resistance, self-calibration ability, and computational efficiency are discussed. This paper also presents the new challenges that optical interferometry techniques are facing in surface topography measurement. To address these challenges, advanced techniques in image stitching, on-machine measurement, intelligent sampling, parallel computing, and deep learning are explored to improve the functional performance of optical interferometry in future manufacturing metrology.

关键词： surface topography measurement optical interferometry coherence envelope phase-shifting algorithm

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A 14-year measurement of toxic elements in atmospheric particulates in Hong Kong from 1995 to 2008

Wei NIE,Tao WANG,Aijun DING,Xuehua ZHOU,Wenxing WANG

《环境科学与工程前沿（英文）》 2014年第8卷第4期页码 553-560 doi: 10.1007/s11783-013-0523-2

摘要： Toxic elements in the atmosphere can enter and accumulate in the human body, seriously impacting human health. In this study, we analyzed a 14-year (1995–2008) measurement of three toxic elements (As, Cd and Cr) in PM in Hong Kong, China. The pollution of these toxic elements in Hong Kong was not serious. The trend analysis showed that As and Cr in PM increased at a statistically significant level ( <0.05) during the 14-year period, while the Cd in PM did not change significantly. Typical seasonal variations were observed for all three toxic elements, largely in relation to the Asian monsoon. Hourly 10-day backward trajectories were computed and categorised into four groups. The continental air masses showed much higher concentrations of the three toxic elements than the marine air masses. The abundances of As and Cd in the PM were much higher in the continental air masses than those in the marine air masses, while the abundances of Cr showed an opposite pattern. The trends of the three toxic elements in East China’s air mass were consistent with those in the overall data set of Hong Kong. Examination of the toxic element data recorded at urban sites and a roadside site also indicated a large contribution of external air masses to particulate As and Cd in Hong Kong. These results suggest that the long-range transport from the mainland of China is the dominant contributor to particulate As and Cd, while both local and long-distance sources determine the particulate Cr in Hong Kong.

关键词： toxic elements increasing trends seasonal variations air masses long-distance sources

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A low cost wearable optical-based goniometer for human joint monitoring

Chee Kian LIM, Zhiqiang LUO, I-Ming CHEN, Song Huat YEO

《机械工程前沿（英文）》 2011年第6卷第1期页码 13-22 doi: 10.1007/s11465-011-0201-7

摘要：

Widely used in the fields of physical and occupational therapy, goniometers are indispensible when it comes to angular measurement of the human joint. In both fields, there is a need to measure the range of motion associated with various joints and muscle groups. For example, a goniometer may be used to help determine the current status of the range of motion in bend the arm at the elbow, bending the knee, or bending at the waist. The device can help to establish the range of motion at the beginning of the treatment series, and also allow the therapist to monitor progress during subsequent sessions. Most commonly found are the mechanical goniometers which are inexpensive but bulky. As the parts are mechanically linked, accuracy and resolution are largely limited. On the other hand, electronic and optical fiber-based goniometers promise better performance over its mechanical counterpart but due to higher cost and setup requirements does not make it an attractive proposition as well. In this paper, we present a reliable and non-intrusive design of an optical-based goniometer for human joint measurement. This device will allow continuous and long-term monitoring of human joint motion in everyday setting. The proposed device was benchmarked against mechanical goniometer and optical based motion capture system to validate its performance. From the empirical results, it has been proven that this design can be use as a robust and effective wearable joint monitoring device.

关键词： optical goniometer human-joint measurement

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Improved directional-distance filter

JIN Lianghai, LI Dehua

《机械工程前沿（英文）》 2008年第3卷第2期页码 205-211 doi: 10.1007/s11465-008-0025-2

摘要： This paper proposes a new spatial-distance weighting function. By combining the weighting function and the traditional directional-distance filter (DDF) in a novel way, a new vector filter - the adaptive distance-weighted directional-distance filter (ADWDDF) - is presented. The experimental results show that the proposed solution provides better filtering performance and preserves better image chromaticity and edge or detail information compared with the traditional DDF and some other typical vector filters.

关键词： information distance-weighted directional-distance ADWDDF traditional DDF spatial-distance weighting

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基于LMS自适应时延估计法的微地形测距系统研究

刘爱军,周知进,卜英勇,龙迎春

《中国工程科学》 2009年第11卷第8期页码 79-82

摘要：

根据单波束超声波测距原理，向模拟海底钴结壳微地形的水池表面发射超声波，应用自适应滤波方法可以估计超声回波信号的时延，使最小均方误差（LMS）后的回波信号与参考信号之间方差达到最小值，此刻的延时量就是渡越时间t，从而求出探头与目标之间的距离。通过计算机仿真和试验结果表明,将最小均方误差自适应时延法应用于海底微地形高程数据的测量,获得测距精度高，能够适用于海底微地形的探测。

关键词：海底钴结壳微地形测距 LMS 单波束测距自适应滤波法

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优化光学亚像素定位精度极限——揭示小PSF的像素相位效应 Article

战海洋, 邢飞, 宝竞宇, 孙婷, 陈真真, 尤政, 袁利

《工程（英文）》 2023年第27卷第8期页码 140-149 doi: 10.1016/j.eng.2023.03.009

摘要：

Subpixel localization techniques for estimating the positions of point-like images captured by pixelated image sensors have been widely used in diverse optical measurement fields. With unavoidable imaging noise, there is a precision limit when estimating the target positions on image sensors, which depends on the detected photon count, noise, point spread function (PSF) radius, and PSF’s intra-pixel position. Previous studies have clearly reported the effects of the first three parameters on the precision limit but have neglected the intra-pixel position information. Here, we develop a localization precision limit analysis framework for revealing the effect of the intra-pixel position of small PSFs. To accurately estimate the precision limit in practical applications, we provide effective PSF (ePSF) modeling approaches and apply the Cramér-Rao lower bound. Based on the characteristics of small PSFs, we first derive simplified equations for finding the best precision limit and the best intra-pixel region for an arbitrary small PSF; we then verify these equations on real PSFs. Next, we use the typical Gaussian PSF to perform a further analysis and find that the final optimum of the precision limit is achieved at the pixel boundaries when the Gaussian radius is as small as possible, indicating that the optimum is ultimately limited by light diffraction. Finally, we apply the maximum likelihood method. Its combination with ePSF modeling allows us to successfully reach the precision limit in experiments, making the above theoretical analysis effective. This work provides a new perspective on combining image sensor position control with PSF engineering to make full use of information theory, thereby paving the way for thoroughly understanding and achieving the final optimum of the precision limit in optical localization.

关键词： Optical measurement Subpixel localization Precision limit optimization Small point spread functions Centroiding Star sensors

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位移测量光栅干涉仪综述 Special Feature on Precision Measurement and Inst

Peng-cheng HU, Di CHANG, Jiu-bin TAN, Rui-tao YANG, Hong-xing YANG, Hai-jin FU

《信息与电子工程前沿（英文）》 2019年第20卷第5期页码 631-654 doi: 10.1631/FITEE.1800708

摘要：光栅干涉仪是测量精密位移的常用方法。和激光干涉仪相比，光栅干涉仪对空气折射率不敏感且易于实现多自由度测量结构，因此被广泛研究、应用。从光学测量原理角度看，光栅干涉仪历经零差干涉、外差干涉和空间分离式外差干涉3个阶段。与前两者相比，空间分离式外差光栅干涉仪具有能消除光学混叠引起纳米级周期非线性误差的特性，可以获得更高位移测量精度。与此同时，各式各样光栅干涉仪结构被提出，以提高光学细分数、增加量程、提升适用性或实现多自由度位置姿态测量。本文详细总结了近年来增量式位移测量光栅干涉仪的发展，并简述其测量误差相关的研究。

关键词：光栅干涉仪；光学编码器；位移测量；精密测量

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New method of fault diagnosis of rotating machinery based on distance of information entropy

Houjun SU, Tielin SHI, Fei CHEN, Shuhong HUANG

《机械工程前沿（英文）》 2011年第6卷第2期页码 249-253 doi: 10.1007/s11465-011-0124-3

摘要：

This paper introduces the basic conception of information fusion and some fusion diagnosis methods commonly used nowadays in rotating machinery. From the thought of the information fusion, a new quantitative feature index monitoring and diagnosing the vibration fault of rotating machinery, which is called distance of information entropy, is put forward on the basis of the singular spectrum entropy in time domain, power spectrum entropy in frequency domain, wavelet energy spectrum entropy, and wavelet space feature entropy in time-frequency domain. The mathematic deduction suggests that the conception of distance of information entropy is accordant with the maximum subordination principle in the fuzzy theory. Through calculation it has been proved that this method can effectively distinguish different fault types. Then, the accuracy of rotor fault diagnosis can be improved through the curve chart of the distance of information entropy at multi-speed.

关键词： rotating machinery information fusion fault diagnosis Information entropy distance of the information entropy

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density measurement for plastic injection molding via ultrasonic technology

《机械工程前沿（英文）》 2022年第17卷第4期 doi: 10.1007/s11465-022-0714-2

摘要： Density variation during the injection molding process directly reflects the state of plastic melt and contains valuable information for process monitoring and optimization. Therefore, in-situ density measurement is of great interest and has significant application value. The existing methods, such as pressure−volume−temperature (PVT) method, have the shortages of time-delay and high cost of sensors. This study is the first to propose an in-situ density measurement method using ultrasonic technology. The analyses of the time-domain and frequency-domain signals are combined in the proposed method. The ultrasonic velocity is obtained from the time-domain signals, and the acoustic impedance is computed through a full-spectral analysis of the frequency-domain signals. Experiments with different process conditions are conducted, including different melt temperature, injection speed, material, and mold structure. Results show that the proposed method has good agreement with the PVT method. The proposed method has the advantages of in-situ measurement, non-destructive, high accuracy, low cost, and is of great application value for the injection molding industry.

关键词： ultrasonic measurement melt density in-situ measurement injection molding

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三峡升船机塔柱混凝土施工测量技术

罗琛,晏春波

《中国工程科学》 2013年第15卷第9期页码 97-101

摘要：

针对三峡垂直升船机高薄壁塔柱结构混凝土形体及内置埋件施工精度指标要求，对三峡升船机塔柱混凝土及内置埋件施工测量中的平面、高程基准传递及埋件定位测量方法进行了研究。分别将天顶仪投点、电磁波测距及中心带照准标志的圆柱螺帽型定位装置施工测量技术运用于混凝土结构尺寸控制测量以及内置埋件定位测量。通过对实测数据的统计与分析，证明三峡升船机塔柱混凝土施工测量技术方案具有可靠性和可行性。

关键词：施工测量天顶仪投点电磁波测距套管空间定位测量三峡升船机

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立体偏转测量系统几何参数的性能分析与评价 Article

徐永佳, 高峰, 蒋向前

《工程（英文）》 2018年第4卷第6期页码 806-815 doi: 10.1016/j.eng.2018.10.007

摘要：

本文提出了一种新颖的几何参数分析方法，以提高立体偏转系统的测量精度。立体偏转测量可用于获得自由曲面的三维形貌信息。基于立体偏转测量的测量系统通常由条纹显示屏、主相机和参考相机组成。立体偏转测量系统组件的布置对于实现高精度测量十分重要。本文分析和评估了立体偏转测量系统的4个几何参数：主相机与被测物体表面之间的距离、主相机光线与被测表面法线之间的角度、条纹显示屏与被测物体之间的距离，以及主相机和参考相机之间的角度。本文通过模拟和实验数据对这些几何参数对测量精度的影响进行了验证。实验结果证实了这些参数对测量精度的影响。基于本文所提出的分析方法，一个立体偏转系统被搭建并且被用于测量一个标准的凹面镜。通过与凹面镜的给定表面参数进行比较，该系统的全局测量精度可达154.2 nm。

关键词：光学测量误差分析立体偏转测量三维形貌测量性能评估模拟

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Design and calibration of a new high-definition three-dimensional laparoscopic system

Jia TANG,Li-qiang WANG,Bo YUAN,Hong JIANG,Qi-ming ZHU

《信息与电子工程前沿（英文）》 2015年第16卷第1期页码 79-84 doi: 10.1631/FITEE.1400149

摘要： We present a high-definition (HD) 3D laparoscopic system including a dual channel optical system, two cameras, a camera control unit (CCU), and an HD 3D monitor. This laparoscopic system is capable of outputting dual high-definition videos and providing vivid 3D images. A modified pinhole camera model is used for camera calibration and a new method of depth measurement to improve precision. The average error of depth measurement measured by experiment (about 1.13 mm) was small in proportion to the large range in distance of the system (10-150 mm). The new method is applicable to any calibrated binocular vision system.

关键词： Dual optical channels Three dimensional Camera calibration Pinhole model Depth measurement Laparoscopic system

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Efficient utilization of wind power: Long-distance transmission or local consumption?

Yuanzhang SUN, Xiyuan MA, Jian XU, Yi BAO, Siyang LIAO

《机械工程前沿（英文）》 2017年第12卷第3期页码 440-455 doi: 10.1007/s11465-017-0440-3

摘要：

Excess wind power produced in wind-intensive areas is normally delivered to remote load centers via long-distance transmission lines. This paper presents a comparison between long-distance transmission, which has gained popularity, and local energy consumption, in which a fraction of the generated wind power can be locally consumed by energy-intensive industries. First, the challenges and solutions to the long-distance transmission and local consumption of wind power are presented. Then, the two approaches to the utilization of wind power are compared in terms of system security, reliability, cost, and capability to utilize wind energy. Finally, the economic feasibility and technical feasibility of the local consumption of wind power are demonstrated by a large and isolated industrial power system, or supermicrogrid, in China. The coal-fired generators together with the short-term interruptible electrolytic aluminum load in the supermicrogrid are able to compensate for the intermittency of wind power. In the long term, the transfer of high-energy-consumption industries to wind-rich areas and their local consumption of the available wind power are beneficial.

关键词： wind power long-distance transmission local consumption supermicrogrid

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Precision glass molding: Toward an optimal fabrication of optical lenses

Liangchi ZHANG,Weidong LIU

《机械工程前沿（英文）》 2017年第12卷第1期页码 3-17 doi: 10.1007/s11465-017-0408-3

摘要：

It is costly and time consuming to use machining processes, such as grinding, polishing and lapping, to produce optical glass lenses with complex features. Precision glass molding (PGM) has thus been developed to realize an efficient manufacture of such optical components in a single step. However, PGM faces various technical challenges. For example, a PGM process must be carried out within the super-cooled region of optical glass above its glass transition temperature, in which the material has an unstable non-equilibrium structure. Within a narrow window of allowable temperature variation, the glass viscosity can change from 10⁵ to 10¹² Pa·s due to the kinetic fragility of the super-cooled liquid. This makes a PGM process sensitive to its molding temperature. In addition, because of the structural relaxation in this temperature window, the atomic structure that governs the material properties is strongly dependent on time and thermal history. Such complexity often leads to residual stresses and shape distortion in a lens molded, causing unexpected changes in density and refractive index. This review will discuss some of the central issues in PGM processes and provide a method based on a manufacturing chain consideration from mold material selection, property and deformation characterization of optical glass to process optimization. The realization of such optimization is a necessary step for the Industry 4.0 of PGM.

关键词： precision glass molding optical lens constitutive modeling optimization manufacturing chain Industry 4.0