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On-Orbit Infrared Radiometric calibration and Land Surface Temperature Inversion of FY-3C MERSI

Advances in Astronautics Science and Technology 2022年第4期5卷 397-406页

作者： Qichang, Zhao Yiquan, Wu Jiancheng, Dang Yong, Yang Xinhua, Niu Xiuqing, Hu Nanjing University of Aeronautics and Astronautics Nanjing 211106 China Shanghai Institute of Satellite Engineering Shanghai 201109 China Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai 200083 China National Satellite Meteorological Center Beijing 100081 China

In this paper, the spectral characteristics, performance of spaceborne radiation source, in orbit infrared radiometric calibration method and radiance data generation process of the Medium Resolution Spectral Imager (MERSI) of FY-3C satellite are introduced. The land surface temperature of typical areas is inversed using the radiometric calibration data. The nonlinear radiometric calibration method for the long wavelength infrared channel with wide spectrum is discussed, the cold space and on-board radiometer count values are obtained independently in each scanning cycle of the instrument, and the infrared channel in orbit calibration calculation is carried out. According to the infrared radiation calibration results, the single channel method is used to retrieve the land surface temperature. The calibration and inversion results provide an important basis for FY-3C/MERSI in orbit performance evaluation. © 2022, Chinese Society of Astronautics.

关键词： calibration algorithm FY-3 Infrared radiometric Land surface temperature Medium resolution spectral imager

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LMS-FIR Based Digital Background calibration for the Four-channel Time-Interleaved ADC 12

LMS-FIR Based Digital Background Calibration for the Four-ch...

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2017 IEEE 12th International Conference on ASIC

作者： Yongsheng Wang Shanshan Li Ruoyang Wang Xiaowei Liu Department of Microelectronics Harbin Institute of Technology

ISBN: (纸本)9781509066261;9781509066254

The backstage calibration method based on LMS-FIR and interpolation filter for a four-channel time-interleaved analog-to-digital converter(TI-ADC) is presented in this *** analysis is made for the mismatch between sub-channels of multi-channel TI-ADC,such as offset mismatch,gain mismatch,and sampling *** the LMS calibration algorithm can reduce the performance loss caused by the mismatch *** proposed four-channel TI-ADC is designed in a 90 nm CMOS *** pre-corrected input is 12.55 MHz and sampling frequency is 200 MHz with mismatch errors,SNDR is 44.0 d B,the effective number of bit(ENOB) is 7.0 bit,and SFDR is 53.4 d *** correction,the spurious performance is significantly reduced and the overall noise reduction is decreased,the SNDR is 65.6 d B and ENOB is 10.6 *** calibration effect is obvious with ENOB inproved by 3.6 bit and the spurious performance decreased by 30.7 d BFS.

关键词： TI-ADC LMS-FIR calibration algorithm

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Dynamic Accuracy Analysis of a 5PSS/UPU Parallel Mechanism Based on Rigid-Flexible Coupled Modeling

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Chinese Journal of Mechanical Engineering 2022年第2期35卷 77-90页

作者： Yanbiao Li Zesheng Wang Chaoqun Chen Taotao Xu Bo Chen College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China Key Laboratory of E&M Ministry of Education&Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310023China

In order to improve the low output accuracy caused by the elastic deformations of the branch chains,a finite element-based dynamic accuracy analysis method for parallel mechanisms is proposed in this ***,taking a 5-prismatic-spherical-spherical(PSS)/universal-prismatic-universal(UPU)parallel mechanism as an example,the error model is established by a closed vector chain method,while its influence on the dynamic accuracy of the parallel mechanism is analyzed through numerical *** to the structural and error characteristics of the parallel mechanism,a vector calibration algorithm is proposed to reduce the position and pose errors along the whole motion ***,considering the elastic deformation of the rod,the rigid-flexible coupling dynamic equations of each component are established by combining the finite element method with the Lagrange *** elastodynamic model of the whole machine is obtained based on the constraint condition of each moving part,and the correctness of the model is verified by ***,the effect of component flexibility on the dimensionless root mean square error of the displacement,velocity and acceleration of the moving platform is investigated by using a Newmark method,and the mapping relationship of these dimensionless root mean square errors to dynamic accuracy is further *** research work provides a theoretical basis for the design of the parameter size of the prototype.

关键词： Parallel mechanism Geometric error calibration algorithm Elastodynamic model Dynamic accuracy

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High precision ultrasonic on-machine measurement

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MEASUREMENT 2006年第5期39卷 407-414页

作者： Pfeifer, T Benz, M Engelmann, B Hafner, P Rhein Westfal TH Aachen Lab Machine Tools & Prod Engn WZL D-52056 Aachen Germany

The integration of metrology into the manufacturing process is getting more and more important for production technology. The measurement directly on machine tools is especially improving manufacturing strategies. So far optical or tactile measuring systems are state-of-the-art for dimensional measurements in process metrology. However, the wall thickness of structures with inner cavities cannot be measured with these systems. Due to these deficits, an ultrasonic system has been integrated into the periphery of a machine tool. Both the extensive signal processing of the acoustic echoes and the developed software tool "mu-sonic" are discussed in the paper. The objective of this article is to illustrate the potential of the ultrasonic in-line measurement. Finally, a practical application for the individual machining of gas cylinders and initial results are presented. (C) 2006 Published by Elsevier Ltd.

关键词： ultrasonic measurement machine integrated calibration algorithm measurement uncertainty

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Concurrent Dual-Band Receiver Based on the Multi-Port Correlator for Wireless Applications

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS 2018年第6期65卷 759-763页

作者： Zhang, Weiwei Hasan, Abul Ghannouchi, Fadhel M. Helaoui, Mohamed Li, Xiang Wu, Yongle Meng, Linglong Liu, Yuanan Beijing Univ Posts & Telecommun Sch Elect Engn Beijing Key Lab Work Safety Intelligent Monitorin Beijing 100876 Peoples R China Univ Calgary Schulich Sch Engn Dept Elect & Comp Engn Intelligent RF Radio Lab Calgary AB T2N 1N4 Canada

A concurrent dual-band receiver based on a single multiport correlator is proposed in this brief to down-convert dual-band radio frequency signals. The system configuration, output power, as well as its spectrum analysis are discussed, and then a generalized baseband signal recovery theory is put forward. Next, the calibration algorithm based on real-valued time-delay neural network, which can take the system impairments and signal distortions into consideration, is proposed to retrieve two baseband signals, simultaneously. Finally, the six-port receiver is tested under the common modulated signals, and the measured error vector magnitudes between the transmitted and the received signals are all less than 2%.

关键词： Concurrent dual band receiver multiport correlator calibration algorithm

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Study of the metrological characteristics of the hydrostatic pressure sensor

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SENSOR REVIEW 2019年第5期39卷 665-669页

作者： Nadezhdin, Igor S. Goryunov, Aleksey G. Svinolupov, Yuri G. Zadorozhnaya, Olga J. Tomsk Polytech Univ Sch Nucl Sci & Engn Tomsk Russia JSC Manotom Tomsk Russia JSC NEVZ Ceram Novosibirsk Russia

Purpose The purpose of this paper is to develop a digital hydrostatic pressure sensor with the required metrological and operational characteristics. The developed sensor is designed to control hydrostatic pressure in wells during various geophysical works and studies. Design/methodology/approach To obtain the required metrological and operational characteristics of the sensor, a method was developed and applied to reduce the measurement error based on the calibration algorithm and the sensor model. Findings By using the developed calibration algorithm and the mathematical model of the sensor, it was possible to compensate for the measurement errors of the hydrostatic pressure sensor. Originality/value In the course of this research, tests of the developed sensor were carried and the maximum/minimum of measurement result errors was determined.

关键词： Temperature Sensor calibration algorithm Error Hydrostatic pressure

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Validation of optical properties quantification with a dual-step technique for biological tissue analysis

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JOURNAL OF BIOMEDICAL OPTICS 2018年第9期23卷 1-14页

作者： Sorgato, Veronica Berger, Michel Emain, Charlotte Vever-Bizet, Christine Dinten, Jean-Marc Bourg-Heckly, Genevieve Planat-Chretien, Anne CEA LETI Minatec Campus Grenoble France UPMC Univ Paris 06 Sorbonne Univ CNRS UMR 8237 Paris France

To approach wide-field optical properties quantification in real heterogeneous biological tissue, we developed a Dual-Step setup that couples a punctual diffuse reflectance spectroscopy (DRS) technique with multispectral imaging (MSI). The setup achieves wide-field optical properties assessment through an initial estimation of scattering with DRS, which is used to estimate absorption with MSI. The absolute quantification of optical properties is based on the ACA-Pro algorithm that has been adapted both for DRS and for MSI. This paper validates the Dual-Step system not only on homogeneous Intralipid phantoms but also on a heterogeneous gelatine phantom with different scattering and absorbing properties. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： quantification optical properties multispectral imaging diffuse reflectance spectroscopy calibration algorithm

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Distributed temperature sensing in OPGW with multiple optical fibres

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2019年第8期13卷 1219-1223页

作者： Carvalho, Renatto, V do Couto Bonfim, Marlio Jose Ussuna, Daniel A. Toledo, Luiz F. R. B. Martins, Rafael Filho, Vitoldo S. Lactec Dept Mat Engn Curitiba Parana Brazil Univ Fed Parana Dept Elect Engn Curitiba Parana Brazil Companhia Paranaense Energia Eletr COPEL Substn Project Div Curitiba Parana Brazil

The ampacity of a material is defined as its maximum electrical current capacity. In an overhead transmission line, it is related to the maximum sag that does not compromise its safe operation. As the sag depends on the conductor's temperature, with this parameter it is possible to estimate its ampacity, increasing the efficiency of the electrical system via real-time energy dispatch management. With the Brillouin backscattering phenomena, the distributed temperature measurement in the fibre inside the optical ground wire (OPGW) or optical phase conductor is possible. However, it is common for overhead power transmission lines to be composed by more than one optical fibre. A calibration algorithm was developed to enable the application of a distributed temperature sensing equipment to monitor the temperature of an OPGW with more than two different fibres. The 230 kV Ibipora-Londrina Transmission Line was used as a case study, being approximately 20 km long and composed of three different fibres spliced in series along with its extension. Through comparison with calibrated sensors, the technique and algorithm were validated. It was possible to characterize the system and perform the temperature monitoring with a spatial resolution of 1 m and amplitude error of less than 6 degrees C.

关键词： optical cables temperature sensors refractive index fibre optic sensors temperature measurement calibration overhead line conductors power overhead lines distributed sensors Brillouin spectra OPGW multiple optical fibres maximum electrical current capacity overhead transmission line maximum sag thermal expansion electrical system real-time energy dispatch management Brillouin backscattering phenomena strain gradients distributed temperature measurement optical phase conductor overhead power transmission lines distributed temperature sensing equipment temperature monitoring refractive index fluctuation Ibipora-Londrina transmission line conductor temperature cables optical ground wire calibration algorithm calibrated sensors voltage 230 0 kV

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Research on localisation algorithm of large irregular workpiece for industrial robot

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INTERNATIONAL JOURNAL OF COMPUTING SCIENCE AND MATHEMATICS 2022年第1期15卷 30-42页

作者： Zheng, Zhen Wu, Shilin Huang, Qinxia Yang, Jun Wuhan Text Univ Sch Mech Engn & Automat Wuhan 430200 Peoples R China

Aiming at the problem of large irregular workpiece positioning difficulty and large error, a new workpiece positioning method is presented. The research object of this paper is a large porous irregular workpiece with holes as the processing location of the workpiece. For this porous workpiece, a special calibration tool is designed and an appropriate calibration algorithm is selected to complete the calibration of the tool. And a relative calibration method is designed. This method uses a small number of holes on the workpiece as the calibration point, and combines the data of the 3D model of the workpiece to calculate the poses of all the holes of the workpiece. Using the robot teaching method, take the pose data of part of the hole on the workpiece, and calculate the calibration error by combining the hole pose obtained above. The experimental results show that the deviation meets the calibration requirements.

关键词： industrial robots large irregular workpieces calibration of tools workpiece positioning calibration algorithm

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Geometric Wide-Angle Camera calibration: A Review and Comparative Study

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SENSORS 2024年第20期24卷 6595页

作者： Huai, Jianzhu Shao, Yuxin Jozkow, Grzegorz Wang, Binliang Chen, Dezhong He, Yijia Yilmaz, Alper Wuhan Univ Lab Informat Engn Surveying Mapping & Remote Sensi 129 Luoyu Rd Wuhan 430079 Peoples R China Wroclaw Univ Environm & Life Sci Inst Geodesy & Geoinformat PL-50375 Wroclaw Poland Wuhan Univ GNSS Res Ctr 129 Luoyu Rd Wuhan 430079 Peoples R China Chinese Acad Sci Inst Automat 95 Zhongguancun East Rd Beijing 100190 Peoples R China Ohio State Univ Dept Civil Environm & Geodet Engn Columbus OH 43210 USA

Wide-angle cameras are widely used in photogrammetry and autonomous systems which rely on the accurate metric measurements derived from images. To find the geometric relationship between incoming rays and image pixels, geometric camera calibration (GCC) has been actively developed. Aiming to provide practical calibration guidelines, this work surveys the existing GCC tools and evaluates the representative ones for wide-angle cameras. The survey covers the camera models, calibration targets, and algorithms used in these tools, highlighting their properties and the trends in GCC development. The evaluation compares six target-based GCC tools, namely BabelCalib, Basalt, Camodocal, Kalibr, the MATLAB calibrator, and the OpenCV-based ROS calibrator, with simulated and real data for wide-angle cameras described by four parametric projection models. These tests reveal the strengths and weaknesses of these camera models, as well as the repeatability of these GCC tools. In view of the survey and evaluation, future research directions of wide-angle GCC are also discussed.

关键词： geometric camera calibration calibration tool camera model calibration target calibration algorithm

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