Huijie Zhao, Mingyi Xing, Hongzhi Jiang, Yang Xu, Xiaochun Diao, Chenghao Liu
In the modern industrial manufacturing, how to effectively obtain the three-dimensional data of the parts profile is the key component for precision test and subsequent analysis. A light-duty design scheme for optical vision probe, which can be installed with a PH10T motorized probe head in CMM, is discussed in this paper. The optical probe can overcome several defects of the traditional measurement mode of CMM, such as poor efficiency and sparse point cloud. Therefore, the problem of 3D measurement and quality analysis for complicated parts can be solved. To splice data in different fields of view, a registration method using a new designed artifact is proposed. Experiments demonstrated the feasibility of the designed non-contact CMM integrated with optical 3D probe for precise 3D shape measurement. The measurement uncertainty of the optical probe can reach 0.012mm within the measuring volume width 200mm and the measurement uncertainty of the global 3D measurement is less than 0.03mm in 1500mm.
{"title":"A new non-contact coordinate measuring machine equipped with light-duty optical probe based on fringe projection profilometry","authors":"Huijie Zhao, Mingyi Xing, Hongzhi Jiang, Yang Xu, Xiaochun Diao, Chenghao Liu","doi":"10.1117/12.2512223","DOIUrl":"https://doi.org/10.1117/12.2512223","url":null,"abstract":"In the modern industrial manufacturing, how to effectively obtain the three-dimensional data of the parts profile is the key component for precision test and subsequent analysis. A light-duty design scheme for optical vision probe, which can be installed with a PH10T motorized probe head in CMM, is discussed in this paper. The optical probe can overcome several defects of the traditional measurement mode of CMM, such as poor efficiency and sparse point cloud. Therefore, the problem of 3D measurement and quality analysis for complicated parts can be solved. To splice data in different fields of view, a registration method using a new designed artifact is proposed. Experiments demonstrated the feasibility of the designed non-contact CMM integrated with optical 3D probe for precise 3D shape measurement. The measurement uncertainty of the optical probe can reach 0.012mm within the measuring volume width 200mm and the measurement uncertainty of the global 3D measurement is less than 0.03mm in 1500mm.","PeriodicalId":115119,"journal":{"name":"International Symposium on Precision Engineering Measurement and Instrumentation","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116772513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guodong Liu, Qi Luo, Bingguo Liu, Binghui Lu, P. Guo
This article designed an embedded smart camera based on the ZYNQ-7000 development board, which has an ARM+FPGA architecture. The system functions are divided into three parts: image acquisit ion, image processing and image display, each of them adopting a modular design. The image acquisition part adopts OV7725 camera. The image processing section uses the VIVADO HLS development kit to design hardware IP-based image processing algorithms. Compared with the traditional HDL-based IP core design method, HLS method that use C/C++ to design IP reduces the development difficulty and shortens the development cycle. Hardware IP implemented through HLS includes image preprocessing, spot-based centroid positioning algorithm, edge detection and corner detection. For complex image processing algorithms, it is still used software to implement, while preprocessing are accomplished through hardware IP. The VDMA channel realizes high-speed data interaction between hardware and software. The image display part is based on the embedded Linux system, OpenCV, and cross -platform C++ graphical user interface development framework QT to implement the GUI interface. The entire embedded smart camera system finally achieves accelerat ion processing based on hardware IP, such as spot location, sobel edge detection, and corner detection.
{"title":"Embedded intelligent camera algorithm based on hardware IP","authors":"Guodong Liu, Qi Luo, Bingguo Liu, Binghui Lu, P. Guo","doi":"10.1117/12.2512216","DOIUrl":"https://doi.org/10.1117/12.2512216","url":null,"abstract":"This article designed an embedded smart camera based on the ZYNQ-7000 development board, which has an ARM+FPGA architecture. The system functions are divided into three parts: image acquisit ion, image processing and image display, each of them adopting a modular design. The image acquisition part adopts OV7725 camera. The image processing section uses the VIVADO HLS development kit to design hardware IP-based image processing algorithms. Compared with the traditional HDL-based IP core design method, HLS method that use C/C++ to design IP reduces the development difficulty and shortens the development cycle. Hardware IP implemented through HLS includes image preprocessing, spot-based centroid positioning algorithm, edge detection and corner detection. For complex image processing algorithms, it is still used software to implement, while preprocessing are accomplished through hardware IP. The VDMA channel realizes high-speed data interaction between hardware and software. The image display part is based on the embedded Linux system, OpenCV, and cross -platform C++ graphical user interface development framework QT to implement the GUI interface. The entire embedded smart camera system finally achieves accelerat ion processing based on hardware IP, such as spot location, sobel edge detection, and corner detection.","PeriodicalId":115119,"journal":{"name":"International Symposium on Precision Engineering Measurement and Instrumentation","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125035657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This topic mainly studies the navigation parameters obtained by image processing technology to achieve omnidirectional mobile AGV autonomous navigation. The camera is mounted on the bottom of the body of the AGV and captures the black tape path on the ground. Image preprocessing is performed, including image graying, improved CANNY algorithm edge detection, morphological processing, and so on. Then the Hough transform is used to detect the path of the preprocessed image. Finally, a straight line is selected to obtain the effective edge line, and the navigation deviation parameters are extracted. Experimental results show that the effectiveness of the guidance techniques in this paper has achieved the expected results.
{"title":"Research on omnidirectional motion of AGV based on vision guidance","authors":"Jianhua Bao, Zai Luo, Dong Li","doi":"10.1117/12.2512102","DOIUrl":"https://doi.org/10.1117/12.2512102","url":null,"abstract":"This topic mainly studies the navigation parameters obtained by image processing technology to achieve omnidirectional mobile AGV autonomous navigation. The camera is mounted on the bottom of the body of the AGV and captures the black tape path on the ground. Image preprocessing is performed, including image graying, improved CANNY algorithm edge detection, morphological processing, and so on. Then the Hough transform is used to detect the path of the preprocessed image. Finally, a straight line is selected to obtain the effective edge line, and the navigation deviation parameters are extracted. Experimental results show that the effectiveness of the guidance techniques in this paper has achieved the expected results.","PeriodicalId":115119,"journal":{"name":"International Symposium on Precision Engineering Measurement and Instrumentation","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114438033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Liang Yu, G. Molnár, S. Bütefisch, C. Werner, R. Meeß, H. Danzebrink, J. Flügge
Quantitative determination of dimensional properties like length, diameter, height, etc. is essential in research, development and in production process control. To meet these requirements, the widely used approach is the coordinate measurement technique. The equipments - the coordinate measuring machines (CMMs) – using the mentioned technique cover a wide measurement range from meter to nanometer. Below a newly developed equipment for the micro scale is presented. The system – the micro coordinate measuring machines (μCMM) - consists of a probing system, voice coil based actuators and an integrated interferometric measurement system. The key component - in addition to the probing system – is the positioning stage, since the characteristics of the position acquisition and control directly influences the achievable accuracy of the complete measurement system. In contrast to a standard interferometer the presented system utilizes a 2D CMOS image sensor to capture the measurement signal. To drive the stage, a commercial voice coil actuator is used: the scanning range of the introduced system covers about 15 mm, and can be easily extended. The applied probing system uses a ruby ball stylus probe. It is a measuring probe, which means that it provides a signal corresponding to the occurring deflections of the probe ball for all three spatial directions. The probe achieves nanometer resolution.
{"title":"Micro Coordinate Measurement Machine (μCMM) using voice coil actuator with interferometric position feedback","authors":"Liang Yu, G. Molnár, S. Bütefisch, C. Werner, R. Meeß, H. Danzebrink, J. Flügge","doi":"10.1117/12.2511527","DOIUrl":"https://doi.org/10.1117/12.2511527","url":null,"abstract":"Quantitative determination of dimensional properties like length, diameter, height, etc. is essential in research, development and in production process control. To meet these requirements, the widely used approach is the coordinate measurement technique. The equipments - the coordinate measuring machines (CMMs) – using the mentioned technique cover a wide measurement range from meter to nanometer. Below a newly developed equipment for the micro scale is presented. The system – the micro coordinate measuring machines (μCMM) - consists of a probing system, voice coil based actuators and an integrated interferometric measurement system. The key component - in addition to the probing system – is the positioning stage, since the characteristics of the position acquisition and control directly influences the achievable accuracy of the complete measurement system. In contrast to a standard interferometer the presented system utilizes a 2D CMOS image sensor to capture the measurement signal. To drive the stage, a commercial voice coil actuator is used: the scanning range of the introduced system covers about 15 mm, and can be easily extended. The applied probing system uses a ruby ball stylus probe. It is a measuring probe, which means that it provides a signal corresponding to the occurring deflections of the probe ball for all three spatial directions. The probe achieves nanometer resolution.","PeriodicalId":115119,"journal":{"name":"International Symposium on Precision Engineering Measurement and Instrumentation","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116614737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lei Yang, F. Ji, Yuzhong Zhang, Mengjie Xu, Jingjing Chen, R. Lu
The surface laser speckle image is obtained by the reflected and scattered light beams from a rough surface illuminated by laser. Based on the fractal theory, Double Blanket Model (DBM) is proposed to analyze laser speckle images. The dimension of the space surface is regarded as the characteristic parameter in DBM method. Laser speckle images are preprocessed to remove interference and noise from the environment at first. The size and direction of optimum window are researched. The DBM characteristic parameter is calculated under the optimum window. The relationships are researched between DBM characteristic parameter and surface roughness Ra. The results show that the surface roughness contained in the surface speckle images has a good monotonic relationship with DBM characteristic parameter. To obtain roughness value through a laser speckle image, the fitting function relationship between Ra and DBM characteristic parameter is established, and the fitting function stability is analyzed by experiments. The experiment results show that surface roughness measurement based on DBM method of laser speckle is feasible and applicable to on-line high-precision roughness detection, which has some advantages such as non-contact, high accuracy, fast, remote measurement and simple equipment.
{"title":"Characterization of surface roughness by double blanket model from laser speckle images","authors":"Lei Yang, F. Ji, Yuzhong Zhang, Mengjie Xu, Jingjing Chen, R. Lu","doi":"10.1117/12.2512212","DOIUrl":"https://doi.org/10.1117/12.2512212","url":null,"abstract":"The surface laser speckle image is obtained by the reflected and scattered light beams from a rough surface illuminated by laser. Based on the fractal theory, Double Blanket Model (DBM) is proposed to analyze laser speckle images. The dimension of the space surface is regarded as the characteristic parameter in DBM method. Laser speckle images are preprocessed to remove interference and noise from the environment at first. The size and direction of optimum window are researched. The DBM characteristic parameter is calculated under the optimum window. The relationships are researched between DBM characteristic parameter and surface roughness Ra. The results show that the surface roughness contained in the surface speckle images has a good monotonic relationship with DBM characteristic parameter. To obtain roughness value through a laser speckle image, the fitting function relationship between Ra and DBM characteristic parameter is established, and the fitting function stability is analyzed by experiments. The experiment results show that surface roughness measurement based on DBM method of laser speckle is feasible and applicable to on-line high-precision roughness detection, which has some advantages such as non-contact, high accuracy, fast, remote measurement and simple equipment.","PeriodicalId":115119,"journal":{"name":"International Symposium on Precision Engineering Measurement and Instrumentation","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128468227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
During proposal and development of a new non-contact nano-probe based on tunneling effect, analysis of the bias electric field (BEF) distribution is a key step for modeling and characterization of the probe. However, the BEF between the spherical electrode serving as the probing ball and the surface to be measured has combined features of macro- and micro- dimensions, which makes the modeling of it a far tricky problem. In this paper, a modeling finite difference method (FDM) based on non-uniform grids generation according to the structural features of the BEF is proposed, and the field distribution is solved with high accuracy. The maximum relative calculation error is within 15% compared with calculation results for a bias electric field with regular boundary with analytical electric image method.
{"title":"Bias electric field distribution analysis based on finite difference method with non-uniform grids for a non-contact tunneling current probe","authors":"Xing Bian, Junning Cui, Yesheng Lu, Jiubin Tan","doi":"10.1117/12.2512440","DOIUrl":"https://doi.org/10.1117/12.2512440","url":null,"abstract":"During proposal and development of a new non-contact nano-probe based on tunneling effect, analysis of the bias electric field (BEF) distribution is a key step for modeling and characterization of the probe. However, the BEF between the spherical electrode serving as the probing ball and the surface to be measured has combined features of macro- and micro- dimensions, which makes the modeling of it a far tricky problem. In this paper, a modeling finite difference method (FDM) based on non-uniform grids generation according to the structural features of the BEF is proposed, and the field distribution is solved with high accuracy. The maximum relative calculation error is within 15% compared with calculation results for a bias electric field with regular boundary with analytical electric image method.","PeriodicalId":115119,"journal":{"name":"International Symposium on Precision Engineering Measurement and Instrumentation","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128588274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Junzhong Li, Lei Wang, Bo Zhao, Guo-ru Zhao, Jing Wang, Zhen Zhang, Jiamin Chen, Shitong Wang
Whether velocity sensor can accurately acquire payload vibration information has become the most important factor that restricts vibration isolation performance. In order to get accurate sensor parameters, DC excitation method is used to measure the central frequency, damping ratio and sensitivity of inertial velocity sensor. The influence of different currents on the measurement accuracy of sensors such as response voltage, central frequency, damping ratio and sensitivity is analyzed, and the optimal current value is determined, which provides a powerful guarantee for obtaining accurate sensor parameters. Finally, the GS-11D sensor is used to carry out the experiment. The experimental results show that the relative error of the central frequency, damping ratio and sensitivity of the DC excitation method can meet the application requirements.
{"title":"Parameter identification of inertial velocity sensor for low-frequency vibration measurement","authors":"Junzhong Li, Lei Wang, Bo Zhao, Guo-ru Zhao, Jing Wang, Zhen Zhang, Jiamin Chen, Shitong Wang","doi":"10.1117/12.2512105","DOIUrl":"https://doi.org/10.1117/12.2512105","url":null,"abstract":"Whether velocity sensor can accurately acquire payload vibration information has become the most important factor that restricts vibration isolation performance. In order to get accurate sensor parameters, DC excitation method is used to measure the central frequency, damping ratio and sensitivity of inertial velocity sensor. The influence of different currents on the measurement accuracy of sensors such as response voltage, central frequency, damping ratio and sensitivity is analyzed, and the optimal current value is determined, which provides a powerful guarantee for obtaining accurate sensor parameters. Finally, the GS-11D sensor is used to carry out the experiment. The experimental results show that the relative error of the central frequency, damping ratio and sensitivity of the DC excitation method can meet the application requirements.","PeriodicalId":115119,"journal":{"name":"International Symposium on Precision Engineering Measurement and Instrumentation","volume":"11053 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129692486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a novel randomly encoded hybrid grating (REHG) interferometric wavefront sensor with the features of high-precision, high-resolution, high-dynamic-range and anti-vibration is proposed. The REHG consists of a randomly encoded binary amplitude grating and a phase chessboard. The far filed Fraunhofer diffractions only contain ±1 orders in two orthogonal directions. Different from the cross grating lateral shearing interferometer (CGLSI), there is no need of order selection mask for quadriwave lateral shearing interference. Without the influence of periodical Talbot effect, a continuously variable shear ratio can be obtained with the REHG, which makes it possible to control the dynamic range and measurement sensitivity of the wavefront sensor. A high-precision calibration method for shear ratio based on the shearing wavefront feature extraction and the generalized wavefront retrieval algorithm are employed to ensure the accuracy of the wavefront measurement results. The REHG wavefront sensor can work in collimated beam and convergent beam modes. Due to self-referenced and common-path characteristics, the REHG wavefront sensor can applied to different application fields in situ. Compared to the ZYGO interferometer, the results of the optical aberration and spherical surface measured by the REHG are highly precise and also show good repeatability. By applying two REHG wavefront sensors with different shear ratio, a wideband sensitivity-enhanced interferometric microscopy with real-time visualization can retrofit existing bright-field microscopes into quantitative phase microscopes.
{"title":"Research and application of a novel randomly encoded hybrid grating interferometric wavefront sensor","authors":"Yongying Yang, Rui Zhang, Zijian Liang, Pin Cao","doi":"10.1117/12.2510892","DOIUrl":"https://doi.org/10.1117/12.2510892","url":null,"abstract":"In this paper, a novel randomly encoded hybrid grating (REHG) interferometric wavefront sensor with the features of high-precision, high-resolution, high-dynamic-range and anti-vibration is proposed. The REHG consists of a randomly encoded binary amplitude grating and a phase chessboard. The far filed Fraunhofer diffractions only contain ±1 orders in two orthogonal directions. Different from the cross grating lateral shearing interferometer (CGLSI), there is no need of order selection mask for quadriwave lateral shearing interference. Without the influence of periodical Talbot effect, a continuously variable shear ratio can be obtained with the REHG, which makes it possible to control the dynamic range and measurement sensitivity of the wavefront sensor. A high-precision calibration method for shear ratio based on the shearing wavefront feature extraction and the generalized wavefront retrieval algorithm are employed to ensure the accuracy of the wavefront measurement results. The REHG wavefront sensor can work in collimated beam and convergent beam modes. Due to self-referenced and common-path characteristics, the REHG wavefront sensor can applied to different application fields in situ. Compared to the ZYGO interferometer, the results of the optical aberration and spherical surface measured by the REHG are highly precise and also show good repeatability. By applying two REHG wavefront sensors with different shear ratio, a wideband sensitivity-enhanced interferometric microscopy with real-time visualization can retrofit existing bright-field microscopes into quantitative phase microscopes.","PeriodicalId":115119,"journal":{"name":"International Symposium on Precision Engineering Measurement and Instrumentation","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129141977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Lei, Ruijun Li, Zhen-Xin Chang, Liansheng Zhang, K. Fan
Low-frequency vibration is a harmful factor that affects the accuracy of precision machining and high precision measurement. Low-frequency micro-vibration cannot be completely eliminated by air-floating platforms. Therefore, lowfrequency vibration must be measured with high-precision before being suppressed actively. A low-cost high-sensitivity low-frequency optical accelerometer is proposed. This optical accelerometer mainly consists of three components: a seismic mass, a leaf spring, and a displacement sensor (four-quadrant photodetector). When vibration is detected, the seismic mass moves up and down due to the effect of inertia, which is amplified by using an optical lever and measured by the four-quadrant photodetector. Then, the acceleration can be calculated. The resonant frequencies and elastic coefficients of various seismic structures are simulated by ANSYS software to attain the optimal detection of lowfrequency low-amplitude vibration. The accelerometer is calibrated using a homemade vibration calibration system, and the calibration experimental results demonstrate that the sensitivity of the optical accelerometer is 4.92 V (m·s−2 ) −1 , the measurement range of the accelerometer is 0.0095–2.58 m·s−2 , and the operating frequencies range from 5 Hz to 15 Hz. The efficacy of the optical accelerometer in measuring low-frequency and low-amplitude dynamic responses is verified.
低频振动是影响精密加工和高精度测量精度的有害因素。气浮平台不能完全消除低频微振动。因此，在主动抑制低频振动之前，必须对低频振动进行高精度测量。提出了一种低成本、高灵敏度的低频光学加速度计。该光学加速度计主要由三部分组成:地震质量、钢板弹簧和位移传感器(四象限光电探测器)。当检测到振动时，由于惯性的影响，地震质量上下移动，使用光学杠杆放大并由四象限光电探测器测量。然后，可以计算出加速度。利用ANSYS软件对不同抗震结构的共振频率和弹性系数进行模拟，实现低频低幅振动的最优检测。标定实验结果表明，该光学加速度计的灵敏度为4.92 V (m·s−2)−1，测量范围为0.0095 ~ 2.58 m·s−2，工作频率为5 Hz ~ 15 Hz。验证了光学加速度计在测量低频和低幅值动态响应方面的有效性。
{"title":"Design of optical accelerometer using four-quadrant photodetector","authors":"Y. Lei, Ruijun Li, Zhen-Xin Chang, Liansheng Zhang, K. Fan","doi":"10.1117/12.2517411","DOIUrl":"https://doi.org/10.1117/12.2517411","url":null,"abstract":"Low-frequency vibration is a harmful factor that affects the accuracy of precision machining and high precision measurement. Low-frequency micro-vibration cannot be completely eliminated by air-floating platforms. Therefore, lowfrequency vibration must be measured with high-precision before being suppressed actively. A low-cost high-sensitivity low-frequency optical accelerometer is proposed. This optical accelerometer mainly consists of three components: a seismic mass, a leaf spring, and a displacement sensor (four-quadrant photodetector). When vibration is detected, the seismic mass moves up and down due to the effect of inertia, which is amplified by using an optical lever and measured by the four-quadrant photodetector. Then, the acceleration can be calculated. The resonant frequencies and elastic coefficients of various seismic structures are simulated by ANSYS software to attain the optimal detection of lowfrequency low-amplitude vibration. The accelerometer is calibrated using a homemade vibration calibration system, and the calibration experimental results demonstrate that the sensitivity of the optical accelerometer is 4.92 V (m·s−2 ) −1 , the measurement range of the accelerometer is 0.0095–2.58 m·s−2 , and the operating frequencies range from 5 Hz to 15 Hz. The efficacy of the optical accelerometer in measuring low-frequency and low-amplitude dynamic responses is verified.","PeriodicalId":115119,"journal":{"name":"International Symposium on Precision Engineering Measurement and Instrumentation","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124127855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wavefront modulation devices are of great significance in optical information processing systems. These devices capable of phase modulation are used in a variety of optical applications: wavefront correction, optical metrology, adaptive optics, aberration compensation, etc. The liquid crystal spatial light modulators (LC-SLMs) and deformable mirrors (DMs) have been regarded as the promising device for their flexibility and programmability on wavefront modulations. This paper presents applications of LC-SLMs and DMs when they are used as aberration compensators in testing of aspheric and freeform. Besides, a pixel-wise method based on analysis of the phase maps obtained by a Fizeau interferometer for calibrating the phase modulation characteristics of the LC-SLM is proposed. A PLUTO-VIS-020 LC-SLM produced by the Holoeye Company is employed in the calibrating experiment. A Zygo interferometer based on Fizeau interference theory is also employed. The experimental results demonstrate that the phase modulation characteristics of LC-SLM and a specific lookup table (LUT) for every pixel of the LC-SLM aperture can be obtained by utilizing the proposed method with convenience and high efficiency. The device calibrated in this paper provides a high phase shift up to 6π at 632.8nm wavelength and has a linearized phase distribution. It coincides well with the average modulation curve offered in the manual of the device. This paper provides a simple and accurate method for pixel-wise phase modulation characteristics calibration.
{"title":"Applications of wavefront modulation devices in aspheric and freeform measurement","authors":"Q. Hao, Yan Ning, Yao Hu","doi":"10.1117/12.2511949","DOIUrl":"https://doi.org/10.1117/12.2511949","url":null,"abstract":"Wavefront modulation devices are of great significance in optical information processing systems. These devices capable of phase modulation are used in a variety of optical applications: wavefront correction, optical metrology, adaptive optics, aberration compensation, etc. The liquid crystal spatial light modulators (LC-SLMs) and deformable mirrors (DMs) have been regarded as the promising device for their flexibility and programmability on wavefront modulations. This paper presents applications of LC-SLMs and DMs when they are used as aberration compensators in testing of aspheric and freeform. Besides, a pixel-wise method based on analysis of the phase maps obtained by a Fizeau interferometer for calibrating the phase modulation characteristics of the LC-SLM is proposed. A PLUTO-VIS-020 LC-SLM produced by the Holoeye Company is employed in the calibrating experiment. A Zygo interferometer based on Fizeau interference theory is also employed. The experimental results demonstrate that the phase modulation characteristics of LC-SLM and a specific lookup table (LUT) for every pixel of the LC-SLM aperture can be obtained by utilizing the proposed method with convenience and high efficiency. The device calibrated in this paper provides a high phase shift up to 6π at 632.8nm wavelength and has a linearized phase distribution. It coincides well with the average modulation curve offered in the manual of the device. This paper provides a simple and accurate method for pixel-wise phase modulation characteristics calibration.","PeriodicalId":115119,"journal":{"name":"International Symposium on Precision Engineering Measurement and Instrumentation","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126297169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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