To professionally plan and manage the development and evolution of the Internet of Things(IoT),researchers have proposed several IoT performance measurement solutions.IoT performance measurement solutions can be very ...To professionally plan and manage the development and evolution of the Internet of Things(IoT),researchers have proposed several IoT performance measurement solutions.IoT performance measurement solutions can be very valuable for managing the development and evolution of IoT systems,as they provide insights into performance issues,resource optimization,predictive maintenance,security,reliability,and user experience.However,there are several issues that can impact the accuracy and reliability of IoT performance measurements,including lack of standardization,complexity of IoT systems,scalability,data privacy,and security.While previous studies proposed several IoT measurement solutions in the literature,they did not evaluate any individual one to figure out their respective measurement strengths and weaknesses.This study provides a novel scheme for the evaluation of proposed IoT measurement solutions using a metrology-coverage evaluation based on evaluation theory,metrology principles,and software measurement best practices.This evaluation approach was employed for 12 IoT measure categories and 158 IoT measurement solutions identified in a Systematic Literature Review(SLR)from 2010 to 2021.The metrology coverage of these IoT measurement solutions was analyzed from four perspectives:across IoT categories,within each study,improvement over time,and implications for IoT practitioners and researchers.The criteria in this metrology-coverage evaluation allowed for the identification of strengths and weaknesses in the theoretical and empirical definitions of the proposed IoT measurement solutions.We found that the metrological coverage varies significantly across IoT measurement solution categories and did not show improvement over the 2010–2021 timeframe.Detailed findings can help practitioners understand the limitations of the proposed measurement solutions and choose those with stronger designs.These evaluation results can also be used by researchers to improve current IoT measurement solution designs and suggest new solutions with a stronger metrology base.展开更多
Based on the development of the non-contact measurement system of free-formsurface, NURBS reconstruction of measurement points of freeform surface is effectively realized bymodifying the objective function and recursi...Based on the development of the non-contact measurement system of free-formsurface, NURBS reconstruction of measurement points of freeform surface is effectively realized bymodifying the objective function and recursive procedure and calculating the optimum number ofcontrol points. The reconstruction precision is evaluated through Ja-cobi's transformation method.The feasibility of the measurement system and effectiveness of the reconstruction algorithm aboveare proved by experiment.展开更多
We present a quantitative measurement of the horizontal component of the microwave magnetic field of a coplanar waveguide using a quantum diamond probe in fiber format.The measurement results are compared in detail wi...We present a quantitative measurement of the horizontal component of the microwave magnetic field of a coplanar waveguide using a quantum diamond probe in fiber format.The measurement results are compared in detail with simulation,showing a good consistence.Further simulation shows fiber diamond probe brings negligible disturbance to the field under measurement compared to bulk diamond.This method will find important applications ranging from electromagnetic compatibility test and failure analysis of high frequency and high complexity integrated circuits.展开更多
Non-contact measurements of machining temperatures were performed with optical pyrometer when drilling particle(B4C) reinforced metal matrix composites(MMCs) with different drills. The effect of particle content, ...Non-contact measurements of machining temperatures were performed with optical pyrometer when drilling particle(B4C) reinforced metal matrix composites(MMCs) with different drills. The effect of particle content, cutting speed, feed rate and tool material on the maximum drilling temperature was investigated. The drilling parameters were optimized based on multiple performance characteristics in terms of the maximum cutting temperature and tool wear. According to the results, the most influential control factors on the cutting temperatures are found to be particle fraction, feed rate and interaction between the cutting speed and particle content, respectively. The influences of the cutting speed and drill material on the drilling temperature are found to be relatively lower for the used range of parameters. Minimum cutting temperatures are obtained with lower particle fraction and cutting speed, with relatively higher feed rates and carbide tools. The results reveal that optimal combination of the drilling parameters can be used to obtain both minimum cutting temperature and tool wear.展开更多
The slug rivet is widely used in wing assembly due to its longer fatigue life and better sealing performance compared with other connection technologies.As a countersink with dual-angle is widely adopted for this type...The slug rivet is widely used in wing assembly due to its longer fatigue life and better sealing performance compared with other connection technologies.As a countersink with dual-angle is widely adopted for this type of connection,the countersink diameter and depth are key factors that affect assembly quality.Therefore,it is of great importance to efficiently inspect the countersink quality to ensure high accuracy.However,contact measurements are susceptible to the loss of accuracy due to cutting debris and lube build-up,while the hole-scanning method using laser profilometry is time consuming and complex.In this paper,a non-contact method for countersink diameter and depth measurement based on a machine vision system is proposed.The countersink diameter can be directly measured by the machine vision system,while the countersink depth is determined through the countersink diameter indirectly.First,by means of image processing technology together with an improved edge detection algorithm,the countersink diameter can be obtained.Then,a 3D microscope is employed to measure the countersink depth,which helps to model the countersink.As a result,once the countersink diameter is measured,so is the depth.The experimentation demonstrated that this method has strong feasibility and enables time saving,which is conducive to improve the riveting efficiency.展开更多
Tubes are used widely in aerospace vehicles, and their accurate assembly can directly affect the assembling reliability and the quality of products. It is important to measure the processed tube's endpoints and then ...Tubes are used widely in aerospace vehicles, and their accurate assembly can directly affect the assembling reliability and the quality of products. It is important to measure the processed tube's endpoints and then fix any geometric errors correspondingly. However, the traditional tube inspection method is time-consuming and complex operations. Therefore, a new measurement method for a tube's endpoints based on machine vision is proposed. First, reflected light on tube's surface can be removed by using photometric linearization. Then, based on the optimization model for the tube's endpoint measurements and the principle of stereo matching, the global coordinates and the relative distance of the tube's endpoint are obtained. To confirm the feasibility, ll tubes are processed to remove the reflected light and then the endpoint's positions of tubes are measured. The experiment results show that the measurement repeatability accuracy is 0.167 mm, and the absolute accuracy is 0.328 ram. The measurement takes less than 1 min. The proposed method based on machine vision can measure the tube's endpoints without any surface treatment or any tools and can realize on line measurement.展开更多
A precise aperture measuring system of small deep holes with capacitance sensors is presented. Based on the working principle of non-contact capacitance sensors, influence of the edge effect of gauge head is studied, ...A precise aperture measuring system of small deep holes with capacitance sensors is presented. Based on the working principle of non-contact capacitance sensors, influence of the edge effect of gauge head is studied, and one capacitance sensor for measuring the aperture of the small blind holes or through holes is introduced. The system is composed of one positioning device, one aperture measuring capacitance sensor, one measuring circuit, and software. This system employs visual CCD and two-dimensional mic...展开更多
Aiming at the shortcomings of traditional contact measurement methods such as low measurement efficiency,high cost and low accuracy,a non-contact optical measurement method based on the laser displacement sensor is pr...Aiming at the shortcomings of traditional contact measurement methods such as low measurement efficiency,high cost and low accuracy,a non-contact optical measurement method based on the laser displacement sensor is proposed.According to the relevant regulations of the coaxiality error evaluation standard and the structural characteristics of the compound gear shaft,we have designed and built a set of supporting software system as well as a hardware test platform.In this paper,the distance difference threshold and scale threshold methods are used to eliminate outlier data.The least squares circle is selected to calculate the center of the circle and the minimum containment cylinder axis method is used as the reference axis of the composite gear shaft.Compensated by the standard step shaft calibration,the coaxiality error of the composite gear shaft can be measured to be within 0.01 mm in less than two minutes.The range value of the multi-section measurement test is 0.065 mm.The average coaxiality error is∅0.476 mm.展开更多
The configuration principles and functions of the non-contact three-dimensional (3D) body measurement system (BMS) developed by the Textile/Clothing Technology Corporation ([TC]^2) are described in this paper. T...The configuration principles and functions of the non-contact three-dimensional (3D) body measurement system (BMS) developed by the Textile/Clothing Technology Corporation ([TC]^2) are described in this paper. The advantages of this new system, compared with traditional contact body measurement instruments ( Martin instruments ) are discussed by selecting 40 female undergraduates of Donghna University as the scan objects. In the experiments both the Martin instruments and [TC]^2 BMS were used respectively. According to the data of different position (Bust Circumference, Full Waist, Full Hips, Bust Height, Front Waist Height and Back Waist Height) obtained from both of the methods we can get the correlation coefficient which is close to 1, indicating that the results of both methods have comparability. Finally some suggestions for the further applications of the non-contact BMS in the apparel development of China are given.展开更多
This paper introduces a new method of measuring the three-dimensional drape shape of fabrics with structural light. First, we apply parallel annular structural light to form light and shade alternating contour stripes...This paper introduces a new method of measuring the three-dimensional drape shape of fabrics with structural light. First, we apply parallel annular structural light to form light and shade alternating contour stripes on the surface of fabrics. We then collect the images of contour stripes using Charge Coupled Device (CCD). Subsequently, we process the images to identify the contour stripes and edges of fabrics, and obtain the fabric contour lines of curved surfaces. Finally, we apply three-dimensional curved surface modeling method based on a network of polar coordinates, and reconstruct the three-dimensional drape shape of fabrics. Experiments show that our method is effective in testing and reconstructing three-dimensional drape shape of fabrics.展开更多
In software engineering, software measures are often proposed without precise identification of the measurable concepts they attempt to quantify: consequently, the numbers obtained are challenging to reproduce in diff...In software engineering, software measures are often proposed without precise identification of the measurable concepts they attempt to quantify: consequently, the numbers obtained are challenging to reproduce in different measurement contexts and to interpret, either as base measures or in combination as derived measures. The lack of consistency when using base measures in data collection can affect both data preparation and data analysis. This paper analyzes the similarities and differences across three different views of measurement methods (ISO International Vocabulary on Metrology, ISO 15939, and ISO 25021), and uses a process proposed for the design of software measurement methods to analyze two examples of such methods selected from the literature.展开更多
The velocity of warhead fragment is key criteria to determine its mutilation efficiency.We have designed an optoelectronic system to accurately measure the average velocity of warhead fragments.The apparatus including...The velocity of warhead fragment is key criteria to determine its mutilation efficiency.We have designed an optoelectronic system to accurately measure the average velocity of warhead fragments.The apparatus including two parallel laser screens spaced apart at a known fixed distance for providing time measurement start and stop signals.The large effective screen area is formed by laser source,retro-reflector and large area photo-diode with a central hole.Whenever a moving fragment interrupts two optical screen,the corresponding photometers senses the event,due to partial obscuration of the incident energy.Experiments have been performed to measure velocity of the different kinds of projectiles and fragments within various size and velocity ranges,including 7.62 mm bullet shooting experiments,prefabricated steel-ball exploding experiments.They were proved that the system is adequate to measure the velocity of larger than 5 mm,less than 1 000 m/s in the range,when fixed trajectory,test the velocity of the projectile average relative deviation is less than 4.21%.The system can perform satisfactorily with a lot of advantages such as larger effective light screen area,quick response speed,low uncertainty,strong repetition and reliability,etc.展开更多
Complex surface shape measurement has been a focus topic in the CAD/CAM field. A popular method for measuring dimensional information is using a 3D coordinate measuring machine (CMM)with a touch trigger probe. The mea...Complex surface shape measurement has been a focus topic in the CAD/CAM field. A popular method for measuring dimensional information is using a 3D coordinate measuring machine (CMM)with a touch trigger probe. The measurement set up with CMM, however, is a time consuming task and the accuracy of the measurement deteriorates as the speed of measurement increase. Non-contact measurement is favored since high speed measurement can be achieved and problems with vibration and friction can be eliminated. Although much research has been conducted in non-contact measurement using image capturing and processing schemes, accuracy is poor and measurement is limited. Some optical technologies developed provide a good accuracy but the dynamic range and versatility is very limited. A novel fiber-optic sensor used for the inspection of complex internal contours is presented in this paper, which is able to measure a surface shape in a non-contact manner with high accuracy and high speed, and is compact and flexible to be incorporated into a CMM. Modulation functions for tilted surface shape measurement, based on the Gaussian distribution of the emitting beam from single-mode fiber (SMF), were derived for specular reflection. The feasibility of the proposed measurement principle was verified by simulations.展开更多
In this paper, we present the complex permittivity measurement of low-loss substrates based on a microstrip-line-excited split-ring resonator (SRR). Permittivity of an unknown substrate is calculated based on the chan...In this paper, we present the complex permittivity measurement of low-loss substrates based on a microstrip-line-excited split-ring resonator (SRR). Permittivity of an unknown substrate is calculated based on the change in oscillation frequency of SRR caused by the material-under-test (MUT) above the SRR. Theoretical analysis and results of the simulations and experiments demonstrate the microstrip-line-excited SRR can be used to effectively improve measurement sensitivity. Simple equations for measurement of low-loss substrates using SRR are proposed and experimentally verified.展开更多
Form error measurement is a critical exercise in providing measures for the quality control in the precision manufacturing industry.Coordinate measuring machine (CMM) is one of the automated systems used in the accu...Form error measurement is a critical exercise in providing measures for the quality control in the precision manufacturing industry.Coordinate measuring machine (CMM) is one of the automated systems used in the accurate and precise dimensional measurements and geometrical form.This paper aims to study the effect of dynamic original unforeseeable errors at different undulations per revolution (UPR) of standard artifact measurement using selected two types of CMM touchtriggering stylus.Stylus-type and stylus-speed parameters were adopted and utilized throughout the course of experiment.The results are analyzed using fast Fourier transformation to obtain foreseeable geometrical errors due to CMM machine structure and stylus scanning speeds.The results of experiment successfully indicate that the number of UPR plays an important role in determining the CMM accuracy level of the roundness measurement result.Some specific error equations for stylus system and machine structure responses have been postulated and analysed to empirically predict the accuracy of PRISMOBridge-CMM-type at National Institute for Standards (NIS) in egypt.展开更多
A novel hybrid instrument of contact and non-contact measurement with large range is developed, and both measurement systems are based on a Linnik interference microscope and on white-light interference measuring tech...A novel hybrid instrument of contact and non-contact measurement with large range is developed, and both measurement systems are based on a Linnik interference microscope and on white-light interference measuring techniques. The ambiguity presented in conventional monochromatic interferometers is not present in the contact and non-contact measurement, and they have a virtually unlimited unambiguous range. For the contact measurement, the vertical measuring range is ±5 mm with a resolution of 1 nm and the horizontal measuring range is ±25 mm in x-range and y-range with a resolution of 1.25 μm; for the non-contact measurement, the vertical measuring range is ~5 mm with a resolution of 1 nm and the horizontal resolution better than 0.5 urn.展开更多
Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome t...Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy.展开更多
With the rapid development of China’s economy and society,under the existing economic system,measurement work is of great significance to promote market development and improve people’s living standards.The quality ...With the rapid development of China’s economy and society,under the existing economic system,measurement work is of great significance to promote market development and improve people’s living standards.The quality evaluation of testing work is an important means to ensure the accuracy of measurement.Based on the analysis of several factors affecting the quality of measurement work,this paper takes the ionizing radiation monitoring quality as an example,and makes a concrete exposition on the evaluation and analysis of the quality of metrological verification work.展开更多
基金supported by the University of South Africa under Grant No.409000.
文摘To professionally plan and manage the development and evolution of the Internet of Things(IoT),researchers have proposed several IoT performance measurement solutions.IoT performance measurement solutions can be very valuable for managing the development and evolution of IoT systems,as they provide insights into performance issues,resource optimization,predictive maintenance,security,reliability,and user experience.However,there are several issues that can impact the accuracy and reliability of IoT performance measurements,including lack of standardization,complexity of IoT systems,scalability,data privacy,and security.While previous studies proposed several IoT measurement solutions in the literature,they did not evaluate any individual one to figure out their respective measurement strengths and weaknesses.This study provides a novel scheme for the evaluation of proposed IoT measurement solutions using a metrology-coverage evaluation based on evaluation theory,metrology principles,and software measurement best practices.This evaluation approach was employed for 12 IoT measure categories and 158 IoT measurement solutions identified in a Systematic Literature Review(SLR)from 2010 to 2021.The metrology coverage of these IoT measurement solutions was analyzed from four perspectives:across IoT categories,within each study,improvement over time,and implications for IoT practitioners and researchers.The criteria in this metrology-coverage evaluation allowed for the identification of strengths and weaknesses in the theoretical and empirical definitions of the proposed IoT measurement solutions.We found that the metrological coverage varies significantly across IoT measurement solution categories and did not show improvement over the 2010–2021 timeframe.Detailed findings can help practitioners understand the limitations of the proposed measurement solutions and choose those with stronger designs.These evaluation results can also be used by researchers to improve current IoT measurement solution designs and suggest new solutions with a stronger metrology base.
基金This project is supported by Provincial Natural Science Foundation of Zhejiang of China (No.599026).
文摘Based on the development of the non-contact measurement system of free-formsurface, NURBS reconstruction of measurement points of freeform surface is effectively realized bymodifying the objective function and recursive procedure and calculating the optimum number ofcontrol points. The reconstruction precision is evaluated through Ja-cobi's transformation method.The feasibility of the measurement system and effectiveness of the reconstruction algorithm aboveare proved by experiment.
基金Project supported by the National Key Research and Development Program of China (Grant No.2021YFB2012600)。
文摘We present a quantitative measurement of the horizontal component of the microwave magnetic field of a coplanar waveguide using a quantum diamond probe in fiber format.The measurement results are compared in detail with simulation,showing a good consistence.Further simulation shows fiber diamond probe brings negligible disturbance to the field under measurement compared to bulk diamond.This method will find important applications ranging from electromagnetic compatibility test and failure analysis of high frequency and high complexity integrated circuits.
文摘Non-contact measurements of machining temperatures were performed with optical pyrometer when drilling particle(B4C) reinforced metal matrix composites(MMCs) with different drills. The effect of particle content, cutting speed, feed rate and tool material on the maximum drilling temperature was investigated. The drilling parameters were optimized based on multiple performance characteristics in terms of the maximum cutting temperature and tool wear. According to the results, the most influential control factors on the cutting temperatures are found to be particle fraction, feed rate and interaction between the cutting speed and particle content, respectively. The influences of the cutting speed and drill material on the drilling temperature are found to be relatively lower for the used range of parameters. Minimum cutting temperatures are obtained with lower particle fraction and cutting speed, with relatively higher feed rates and carbide tools. The results reveal that optimal combination of the drilling parameters can be used to obtain both minimum cutting temperature and tool wear.
文摘The slug rivet is widely used in wing assembly due to its longer fatigue life and better sealing performance compared with other connection technologies.As a countersink with dual-angle is widely adopted for this type of connection,the countersink diameter and depth are key factors that affect assembly quality.Therefore,it is of great importance to efficiently inspect the countersink quality to ensure high accuracy.However,contact measurements are susceptible to the loss of accuracy due to cutting debris and lube build-up,while the hole-scanning method using laser profilometry is time consuming and complex.In this paper,a non-contact method for countersink diameter and depth measurement based on a machine vision system is proposed.The countersink diameter can be directly measured by the machine vision system,while the countersink depth is determined through the countersink diameter indirectly.First,by means of image processing technology together with an improved edge detection algorithm,the countersink diameter can be obtained.Then,a 3D microscope is employed to measure the countersink depth,which helps to model the countersink.As a result,once the countersink diameter is measured,so is the depth.The experimentation demonstrated that this method has strong feasibility and enables time saving,which is conducive to improve the riveting efficiency.
基金Supported by National Natural Science Foundation of China(Grant No51305031)
文摘Tubes are used widely in aerospace vehicles, and their accurate assembly can directly affect the assembling reliability and the quality of products. It is important to measure the processed tube's endpoints and then fix any geometric errors correspondingly. However, the traditional tube inspection method is time-consuming and complex operations. Therefore, a new measurement method for a tube's endpoints based on machine vision is proposed. First, reflected light on tube's surface can be removed by using photometric linearization. Then, based on the optimization model for the tube's endpoint measurements and the principle of stereo matching, the global coordinates and the relative distance of the tube's endpoint are obtained. To confirm the feasibility, ll tubes are processed to remove the reflected light and then the endpoint's positions of tubes are measured. The experiment results show that the measurement repeatability accuracy is 0.167 mm, and the absolute accuracy is 0.328 ram. The measurement takes less than 1 min. The proposed method based on machine vision can measure the tube's endpoints without any surface treatment or any tools and can realize on line measurement.
文摘A precise aperture measuring system of small deep holes with capacitance sensors is presented. Based on the working principle of non-contact capacitance sensors, influence of the edge effect of gauge head is studied, and one capacitance sensor for measuring the aperture of the small blind holes or through holes is introduced. The system is composed of one positioning device, one aperture measuring capacitance sensor, one measuring circuit, and software. This system employs visual CCD and two-dimensional mic...
基金supported by the National Natural Science Foundation of China(No.51975293)Aeronautical Science Foundation of China (No. 2019ZD052010)
文摘Aiming at the shortcomings of traditional contact measurement methods such as low measurement efficiency,high cost and low accuracy,a non-contact optical measurement method based on the laser displacement sensor is proposed.According to the relevant regulations of the coaxiality error evaluation standard and the structural characteristics of the compound gear shaft,we have designed and built a set of supporting software system as well as a hardware test platform.In this paper,the distance difference threshold and scale threshold methods are used to eliminate outlier data.The least squares circle is selected to calculate the center of the circle and the minimum containment cylinder axis method is used as the reference axis of the composite gear shaft.Compensated by the standard step shaft calibration,the coaxiality error of the composite gear shaft can be measured to be within 0.01 mm in less than two minutes.The range value of the multi-section measurement test is 0.065 mm.The average coaxiality error is∅0.476 mm.
文摘The configuration principles and functions of the non-contact three-dimensional (3D) body measurement system (BMS) developed by the Textile/Clothing Technology Corporation ([TC]^2) are described in this paper. The advantages of this new system, compared with traditional contact body measurement instruments ( Martin instruments ) are discussed by selecting 40 female undergraduates of Donghna University as the scan objects. In the experiments both the Martin instruments and [TC]^2 BMS were used respectively. According to the data of different position (Bust Circumference, Full Waist, Full Hips, Bust Height, Front Waist Height and Back Waist Height) obtained from both of the methods we can get the correlation coefficient which is close to 1, indicating that the results of both methods have comparability. Finally some suggestions for the further applications of the non-contact BMS in the apparel development of China are given.
基金National Natural Science Foundation of China (50275139) Natural Science Foundation of Zhejiang (01388-G)
文摘This paper introduces a new method of measuring the three-dimensional drape shape of fabrics with structural light. First, we apply parallel annular structural light to form light and shade alternating contour stripes on the surface of fabrics. We then collect the images of contour stripes using Charge Coupled Device (CCD). Subsequently, we process the images to identify the contour stripes and edges of fabrics, and obtain the fabric contour lines of curved surfaces. Finally, we apply three-dimensional curved surface modeling method based on a network of polar coordinates, and reconstruct the three-dimensional drape shape of fabrics. Experiments show that our method is effective in testing and reconstructing three-dimensional drape shape of fabrics.
文摘In software engineering, software measures are often proposed without precise identification of the measurable concepts they attempt to quantify: consequently, the numbers obtained are challenging to reproduce in different measurement contexts and to interpret, either as base measures or in combination as derived measures. The lack of consistency when using base measures in data collection can affect both data preparation and data analysis. This paper analyzes the similarities and differences across three different views of measurement methods (ISO International Vocabulary on Metrology, ISO 15939, and ISO 25021), and uses a process proposed for the design of software measurement methods to analyze two examples of such methods selected from the literature.
基金supported by the Science and Technology on Electronic Test & Measurement Laboratory,China(No.9140C1204041009)Science and Technology on Electronic Test & Measurement Laboratory Fund for Young Scholars,China
文摘The velocity of warhead fragment is key criteria to determine its mutilation efficiency.We have designed an optoelectronic system to accurately measure the average velocity of warhead fragments.The apparatus including two parallel laser screens spaced apart at a known fixed distance for providing time measurement start and stop signals.The large effective screen area is formed by laser source,retro-reflector and large area photo-diode with a central hole.Whenever a moving fragment interrupts two optical screen,the corresponding photometers senses the event,due to partial obscuration of the incident energy.Experiments have been performed to measure velocity of the different kinds of projectiles and fragments within various size and velocity ranges,including 7.62 mm bullet shooting experiments,prefabricated steel-ball exploding experiments.They were proved that the system is adequate to measure the velocity of larger than 5 mm,less than 1 000 m/s in the range,when fixed trajectory,test the velocity of the projectile average relative deviation is less than 4.21%.The system can perform satisfactorily with a lot of advantages such as larger effective light screen area,quick response speed,low uncertainty,strong repetition and reliability,etc.
文摘Complex surface shape measurement has been a focus topic in the CAD/CAM field. A popular method for measuring dimensional information is using a 3D coordinate measuring machine (CMM)with a touch trigger probe. The measurement set up with CMM, however, is a time consuming task and the accuracy of the measurement deteriorates as the speed of measurement increase. Non-contact measurement is favored since high speed measurement can be achieved and problems with vibration and friction can be eliminated. Although much research has been conducted in non-contact measurement using image capturing and processing schemes, accuracy is poor and measurement is limited. Some optical technologies developed provide a good accuracy but the dynamic range and versatility is very limited. A novel fiber-optic sensor used for the inspection of complex internal contours is presented in this paper, which is able to measure a surface shape in a non-contact manner with high accuracy and high speed, and is compact and flexible to be incorporated into a CMM. Modulation functions for tilted surface shape measurement, based on the Gaussian distribution of the emitting beam from single-mode fiber (SMF), were derived for specular reflection. The feasibility of the proposed measurement principle was verified by simulations.
文摘In this paper, we present the complex permittivity measurement of low-loss substrates based on a microstrip-line-excited split-ring resonator (SRR). Permittivity of an unknown substrate is calculated based on the change in oscillation frequency of SRR caused by the material-under-test (MUT) above the SRR. Theoretical analysis and results of the simulations and experiments demonstrate the microstrip-line-excited SRR can be used to effectively improve measurement sensitivity. Simple equations for measurement of low-loss substrates using SRR are proposed and experimentally verified.
文摘Form error measurement is a critical exercise in providing measures for the quality control in the precision manufacturing industry.Coordinate measuring machine (CMM) is one of the automated systems used in the accurate and precise dimensional measurements and geometrical form.This paper aims to study the effect of dynamic original unforeseeable errors at different undulations per revolution (UPR) of standard artifact measurement using selected two types of CMM touchtriggering stylus.Stylus-type and stylus-speed parameters were adopted and utilized throughout the course of experiment.The results are analyzed using fast Fourier transformation to obtain foreseeable geometrical errors due to CMM machine structure and stylus scanning speeds.The results of experiment successfully indicate that the number of UPR plays an important role in determining the CMM accuracy level of the roundness measurement result.Some specific error equations for stylus system and machine structure responses have been postulated and analysed to empirically predict the accuracy of PRISMOBridge-CMM-type at National Institute for Standards (NIS) in egypt.
基金Supported by The Special Coordination Fund(SCF)for Pro-moting Science and Technology commissioned by the Ministry of Education,Culture,Sports,Science and Technology(MEXT)of Japan
文摘AIM: To verify the performance of a lesion size measurement system through a clinical study.
基金Supported by the National Natural Science Foundation of China (50605018)
文摘A novel hybrid instrument of contact and non-contact measurement with large range is developed, and both measurement systems are based on a Linnik interference microscope and on white-light interference measuring techniques. The ambiguity presented in conventional monochromatic interferometers is not present in the contact and non-contact measurement, and they have a virtually unlimited unambiguous range. For the contact measurement, the vertical measuring range is ±5 mm with a resolution of 1 nm and the horizontal measuring range is ±25 mm in x-range and y-range with a resolution of 1.25 μm; for the non-contact measurement, the vertical measuring range is ~5 mm with a resolution of 1 nm and the horizontal resolution better than 0.5 urn.
基金State Administration of Science,Technology and Industry for the National Defense(No.JSJL2014206B001)。
文摘Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy.
文摘With the rapid development of China’s economy and society,under the existing economic system,measurement work is of great significance to promote market development and improve people’s living standards.The quality evaluation of testing work is an important means to ensure the accuracy of measurement.Based on the analysis of several factors affecting the quality of measurement work,this paper takes the ionizing radiation monitoring quality as an example,and makes a concrete exposition on the evaluation and analysis of the quality of metrological verification work.