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2014 Vol. 35, No. 3
Published: 2014-05-22
 
193 Disseminating the International Temperature Scale above 961.78 ℃ in the “Fixed point-Pyrometer” Method
LU Xiao-feng, YUAN Zun-dong, WANG Jing-hui, BAI Cheng-yu, DONG Wei, HAO Xiao-peng, WANG Tie-jun
DOI: 10.3969/j.issn.1000-1158.2014.03.01
The high-temperature primary standard system was gradually improved through the continuing research work at the National Institute of Metrology (NIM) in China. Based on the developed primary standard pyrometer, an improved scheme, the “fixed-point blackbody pyrometer” assembly, was applied to realize and disseminate the International Temperature Scale of 1990 (ITS-90) above the silver point. The new scheme can correct the drifts of the pyrometer and extend the highest temperature range from 2 200 ℃ to 2 474 ℃. The expanded uncertainties of the scale were 0.08~0.62 ℃ between the temperature range  961.78~2 474 ℃.The uncertainties of the temperature scale are strongly supported by the international comparison of the high temperature fixed points’ ITS-90 values among China, the U K and Spain in 2009. The new method could be not only applied in the highest level calibration of the precise pyrometers, but also in the calibration of the 900 nm infrared thermometers.
2014 Vol. 35 (3): 193-197 [Abstract] ( 602 ) HTML (1 KB)  PDF (2082 KB)  ( 1067 )
198 Geometric Error Measurement and Identification for Rotary Table Using Double Ballbar
CHEN Jian-xiong, LIN Shu-wen, HAN Guo-qiang
DOI: 10.3969/j.issn.1000-1158.2014.03.02
The derivations of the center of the ball installed on the rotary table are measured by double ballbar with circular paths in the error sensitive directions.  Hence, there are nine results measured from three mounting positions of the ball at the same rotation angle, to form four axis location and six motion errors identification model using homogeneous transformation.  In addition, the condition number is applied to select the optimum installation parameters of the ballbar.  Finally, the measurement and verification experiments are conducted on the four-axis machining center.  All the elements of the geometric error can be identified by the proposed method from the measured results with high accuracy and measuring effectively.  Then, comparing the predicted value from the identified errors with the measured results by ballbar, it shows that the absolute residual error is less than 0. 003 mm.
2014 Vol. 35 (3): 198-203 [Abstract] ( 775 ) HTML (1 KB)  PDF (3527 KB)  ( 1420 )
204 Multi-sensor Global Calibration Technology of Vision Sensor  in Car Body-in-white Visual Measurement System
LIU Yue, LIN Jia-rui, LIU Tao, LIU Chang-jie, YE Sheng-hua
DOI: 10.3969/j.issn.1000-1158.2014.03.03
A novel global calibration method for the multi-sensor vision measurement system in industrial field is proposed to solve the problem of multiple sensors of different types,large distribution space and complicated position relations in the car body-in-white vision measurement system. Based on the indirect coordinates transformation,two precise 3D targets are designed as the intermediary in coordinates transformation,and field calibration data is acquired by a laser tracker. On the basis of the unit quaternion global calibration model,the optimized transformation parameters can be established in order to unify the stationary sensor coordinates and flexible sensors coordinates to the global coordinate system. The method has been applied in the inline measurement station of a company successfully. Only the calibration of transformation relation between the sensor coordinates and the global coordinates is needed in the application filed. Therefore,the complex environmental restriction is reduced in multi-sensor global calibration. Meanwhile,the environment adaptability is improved and the calibration process is simplified. The maximum deviation of the vision measurement system is ±0.2 mm, which meets the accuracy requirements of the manufacture dimension changes control of car body-in-white.
2014 Vol. 35 (3): 204-209 [Abstract] ( 822 ) HTML (1 KB)  PDF (2402 KB)  ( 1235 )
210 Calibration on Measurement System for the Refractive Index of Air Based on Edlén Formula
CUI Jian-jun, LIU Xiang-bin, KANG Yan-hui, ZHANG Heng, LI Jian-shuang
DOI: 10.3969/j.issn.1000-1158.2014.03.04
To verify the performance of refractive index of air measurement system, which has a great influence for accuracy of laser interferometer, one kind of calibration approach is presented for the refractive index of air measurement system of laser interferometer. One special calibration setup is designed which consists of temperature, air pressure and humidity sensors and it is based on Edlén formula to measure the refractive index of air indirectly.Experiment shows that the temperature  uncertainty is less than 0.02 ℃ in (5~40)℃, uncertainty of air pressure is 18 Pa in (60~110) kPa and uncertainty of air humidity is 2.0% RH in (10~90) %RH. The relative expend uncertainty of whole system for refractive index of air is 1×10-7, where cover factor k=2.
2014 Vol. 35 (3): 210-215 [Abstract] ( 896 ) HTML (1 KB)  PDF (2474 KB)  ( 2097 )
216 Calibration and Analysis for Probing Size Error  of Industrial CT
WANG Yi-xu, SHI Yu-shu, GAO Si-tian, LI Dong-sheng, LI Wei, LI Qi, SONG Xu
DOI: 10.3969/j.issn.1000-1158.2014.03.05

 According to the needs of calibrating the probing size error, a method based on the standard balls for the calibration of industrial CT probing size error  is proposed and factors which cause the probing size  error are detailly analyzed. Firstly, it calibrates the diameter by the length-measuring machine of National Institute of Metrology, then calibrates the industrial CT probing  size error by these balls. The experimental results show that these standard balls can be calibrated accurately, and high quality image with lower artifacts can be acquired. And this kind of standards can meet the calibration needs of probing  size error of industrial CT system. Error sources in imaging process, which influence the probing  size error are discussed and analyzed. It is of great significance to establish calibration and traceability method for industrial CT system.
2014 Vol. 35 (3): 216-220 [Abstract] ( 812 ) HTML (1 KB)  PDF (1636 KB)  ( 1958 )
221 Study on the Influence Rule of Different Imaging Distance to Distortion Coefficients
PAN Hui, WANG Min, XU Jian-liang, LIU Xiao-hui, XU Si-xiang
DOI: 10.3969/j.issn.1000-1158.2014.03.06
Based on the approach to estimate the image distortion coefficients through a set of collinear pints,the influence of the distance between the object plane and the lens plane on the image distortion coefficients is studied. Combined with the experimental result,the change rule of the distortion coefficients is explored. Then,the influence of the distortion coefficients (under various distances between the object plane and the lens plane) on the correction of the same gauge block is experimentally researched. The experimental results show that the correction results of gauge block image are different under different parameters of distortion coefficients. Only when the chosen distance in the distortion parameters is the same as the real imaging distance,the correction precision is the highest,and the measured accuracy of the gauge is also the highest.
2014 Vol. 35 (3): 221-225 [Abstract] ( 781 ) HTML (1 KB)  PDF (1205 KB)  ( 1588 )
226 Road Luminance Test System Designer Based on CCD
JI Shuang-shuang, YU Lian-zhi, YOU Yuan
DOI: 10.3969/j.issn.1000-1158.2014.03.07
Based on the imaging property of CCD, a method for design of CCD imaging luminance for road luminance test was proposed. It is analyzing the relationship between the gray-level of the image pixel and the luminance of the measurement point and find a road lighting practical demarcation installment. To improve the measurement accuracy,  the influential factors of the calibration environment in a quantitative study is analyzed. With the aid of the MATLAB software  between the digital picture element grey level and brightness mathematical model is given ,  the Songjiang Road in Yancheng city is measured. The relative error of the test results and the reference value is within 15% indicting that the new designed method is effective to improve the road lighting test accuracy and reduce the measuring error.
2014 Vol. 35 (3): 226-229 [Abstract] ( 596 ) HTML (1 KB)  PDF (440 KB)  ( 1202 )
230 A Particle Swarm Optimization Static Calibration Method of Micro-electro-mechanical System Accelerometer Based on Ellipsoidal Restriction
JIN Mei, ZHANG Kang-ning, JIN Ju,YU Guo-hui, LI Wen-chao
DOI: 10.3969/j.issn.1000-1158.2014.03.08
The  particle swarm optimization static calibration method of micro-electro-mechanical system accelerometer based on ellipsoidal restriction is studied. According to the output mathematical model of the micro-electro-mechanical system accelerometer, the standard particle swarm optimization algorithm is taken to estimate scale factors, bias, and installation errors in the output mathematical model. The experimental results show that the method can eliminate the random errors in the sampling process effectively. With the introduction of particle swarm optimization algorithm, the outputs of the micro-electro-mechanical system accelerometer can reflect their true values.
2014 Vol. 35 (3): 230-235 [Abstract] ( 575 ) HTML (1 KB)  PDF (428 KB)  ( 837 )
236 A Permanent Magnet Angular Acceleration Sensor and Its Calibration Method Research
WU Wen-tao, FENG Hao, ZHAO Hao
DOI: 10.3969/j.issn.1000-1158.2014.03.09
A new permanent magnet angular acceleration sensor based on the principle of electromagnetic induction is described, and its mechanical structure and principle are introduced.A new method of calibration angular acceleration sensor based on mechanical torsion pendulum institutions is put forward and proved.The experiments show that the calibration method works well and it can objectively reflect the relationship between the un-voltage input and voltage output of the sensor, and can ensure the accuracy of the result. The experiment proves the feasibility of the permanent magnet angular acceleration sensor and its calibration method, and the sensitivity of sensor is about 6.562 μV/(rad·s-2).
2014 Vol. 35 (3): 236-241 [Abstract] ( 698 ) HTML (1 KB)  PDF (2223 KB)  ( 1143 )
242 Signal Processing Methods of Coriolis Mass Flowmeter for Measurement of the Frequent Starting and Stopping Flow
LIU Cui, XU Ke-jun,HOU Qi-li, XIONG Wen-jun, FANG Min
DOI: 10.3969/j.issn.1000-1158.2014.03.10
According to the characteristic of the frequent starting and stopping flow, a mutation-signal mode of Coriolis mass sensor is proposed to describe the change patterns of signal parameters with the sudden change of flow. The exiting DTFT algorithm with negative frequency contribution is evaluated using this model, and its errors are analyzed in the batch applications. On the basis of these studies, this algorithm is improved to apply to processing of the mutation signal. The algorithm is implemented in real time in a DSP-based digital Coriolis mass flow transmitter developed, and water flow calibrations consisting of starting-stopping flow method and steady-flow method are performed for the transmitter. The experimental results show that the method has both fast dynamic response and highed measurement accuracy.
2014 Vol. 35 (3): 242-247 [Abstract] ( 580 ) HTML (1 KB)  PDF (778 KB)  ( 940 )
248 Coolant Flow Measurement of Aircraft Liquid Cooling System Based on Differential Pressure Method
FENG Wei-zhong
DOI: 10.3969/j.issn.1000-1158.2014.03.11
The coolant flow in the aircraft liquid cooling system is usually regarded as an important parameter of the assessment of the system performance. With the aid of utilizing the diameter-variable ducts in the liquid cooling system as a throttling element, the coolant flow can be measured by using the differential pressure method. By applying data fitting to the experimental findings obtained from the groud calibration system, the characteristic curves of the coolant flow versus differential pressure for different temperature and pressure values were obtained. Furthermore, the formulate for the correction of calculated coolant flow were gained through linear interpolation. The flight test results indicate that the method is feasible for the measurement of the coolant flow of the aircraft liquid cooling system and, therefore, the problem of inconvenient refitting of flowmeter for the liquid cooling system has been solved.
2014 Vol. 35 (3): 248-151 [Abstract] ( 634 ) HTML (1 KB)  PDF (348 KB)  ( 879 )
252 The Application of Two Dimensional Principal Component Analysis in the Detection of Myocardial Infarction ECG Signals
GE Ding-fei, XU Ai-qun
DOI: 10.3969/j.issn.1000-1158.2014.03.12
The joint energy percentage(EP) search method based on two dimensional principal component analysis is introduced to extract global features from 12-lead high resolution electrocardiogram(ECG) for the purpose of classification. Four types of classes are collected from PTB clinical diagnostic database, which corresponding patient’s statuses are health control, myocardial infarction(MI) in early stage, MI in acute stage and MI in recover stage, respectively. The experimental results show that the information can be fused efficiently using the proposed method, which are from 12-lead ECG and the details contained in high frequency components of ECG. The average classification accuracy can be increased by 10.43% compared with that of conventional principal component analysis. The ECG signal can be represented with lower dimensions compared with that of independent EP criterion, and an average classification accuracy of 99.46% can be achieved.
2014 Vol. 35 (3): 252-257 [Abstract] ( 505 ) HTML (1 KB)  PDF (795 KB)  ( 970 )
258 The Evaluation Method of Effective Bits of A/D Converters Based on Sinusoidal Distortion Measurement
LIANG Zhi-guo
DOI: 10.3969/j.issn.1000-1158.2014.03.13
Aiming at the measurement of effective bits of A/D converters, a method based on sinusoidal distortion measurement is presented, and the calculation formula is given out.One can realize the calibration of effective bits of A/D converters without complicated sinusoidal curve-fitting.When A/D bit varying from 3 bits to 24 bits, and sampling rate to frequency ratio is varied, by using a group of simulation, the measurement method is compared with the sine wave curve-fitting method.The results show that, the sinusoidal curve-fitting method fit for more cases, but the method is more simple and easy.Through a group of experiments, both the feasibility and correctness of the method in this paper are proved.
2014 Vol. 35 (3): 258-262 [Abstract] ( 520 ) HTML (1 KB)  PDF (1008 KB)  ( 857 )
263 Development of Transfer Standard for Digital Modulation Quality Parameters
FANG Hong, BIAN Xin, ZHOU Xin, LIU Ke, ZHAO Hai-ning
DOI: 10.3969/j.issn.1000-1158.2014.03.14
In order to develop transfer standard of digital modulation quality parameters, a new method is proposed to set the modulation errors of the output digital modulation signal from vector signal generator accurately based on constellation diagram designing.Theoretical derivation, implementation and measurement points for comparison are presented.Stability of the developed transfer standard is verified by the statistics of the experimental data.
2014 Vol. 35 (3): 263-267 [Abstract] ( 425 ) HTML (1 KB)  PDF (1587 KB)  ( 860 )
268 Impact of Time Domain Window-adding for the Ramp Filter on Image Reconstruction
QIAO Zhi-wei
DOI: 10.3969/j.issn.1000-1158.2014.03.15
The time domain window-adding method for the unit impulse response of the ramp filter is proposed. the unit impulse response of the ramp filter should be symmetrical and its length should be odd number to ensure that it is strict zero-phase. There are many windows to truncate the unit impulse response, for example, rectangle window, triangle window, Hanning window, Hamming windows, Blackman window etc. The simulation experiment demonstrates that the rectangle window is the best and the triangle window is the worst, for the triangle window depresses the first side petal overly. The precision of the CT images reconstructed by the others windows is in-between. The rectangle window should be used when the unit impulse response of the ramp filter is been truncated.
2014 Vol. 35 (3): 268-271 [Abstract] ( 501 ) HTML (1 KB)  PDF (637 KB)  ( 750 )
272 A Measurement Method of Frequency Response Characteristics Test Based on Chirp Signal at Low SNR
WEI Lie-jiang, LI Xu-fang, WANG Lin, DONG Wan-yu, MENG Li
DOI: 10.3969/j.issn.1000-1158.2014.03.16
A method using band-pass filter and wavelet packet transform to pre-treat signal and then using FFT analysis and treatment to get frequency response diagrams is described. This method is better to solve the problems that frequency characteristic test of the system is under low SNR, and reduce hardware requirements of acquisition system in the test. The research show that when SNR is very low and even negative 20 dB value, the amplitude-frequency characteristic that accuracy is not less than 1dB and phase frequency response curve that accuracy is not less than 3°can be obtained for frequency bands that is below the cutoff frequency, which fully meet the system performance evaluation and controller design application requirements.
2014 Vol. 35 (3): 272-275 [Abstract] ( 592 ) HTML (1 KB)  PDF (4429 KB)  ( 967 )
276 Error Analysis of Two-way Optical Fiber Time Transfer
FU Yong-jie, CAI Ying
DOI: 10.3969/j.issn.1000-1158.2014.03.17
The basic principle and system composition of two-way optical fiber time transfer (TWOFTT) method is described. The factors influencing the synchronous precision are deduced through analysis of signal transfer link. Asymmetry error of signal two-way transfer link, optical device processing error and time interval measurement error are analyzed. The magnitude of each error factor is calculated through theoretical analysis. The methods for reducing every error are proposed. The time synchronization precision of TWOFTT system can reach subnanosecond magnitude through theoretical analysis and calculation.
2014 Vol. 35 (3): 276-280 [Abstract] ( 735 ) HTML (1 KB)  PDF (791 KB)  ( 2035 )
281 Design of Magnetic Shield for Cesium Fountain Clock
LIU Kun, FANG Fang, CHEN Wei-liang, LIU Nian-feng, SUO Rui, LI Tian-chu
DOI: 10.3969/j.issn.1000-1158.2014.03.18
The high quality magnetic shielding system is one of the most important components of cesium fountain clock.Firstly,  the three parameters for magnetic shielding performance evaluation were defined, i.e.uniform range, the starting position of uniform range and shielding factor.And then, the results for different configurations of three layer cylindrical magnetic shield sets using finite element calculation are presented.In particular, effects on shielding of radial and axial spacing between shield layers, the length of sleeves weld on the end cap and the connection geometry between end caps and shield cylinders are examined.From the calculation results, the performance of optimal configuration of three layer shield sets is compared with the four layer ones used in NIM5 cesium fountain clock.This is important in design and assemble the magnetic shielding for the next generation cesium fountain clock to improve the accuracy.
2014 Vol. 35 (3): 281-285 [Abstract] ( 581 ) HTML (1 KB)  PDF (3569 KB)  ( 1338 )
286 Research on Cesium Frequency Standard Comparison Method
ZHANG Ai-min, YANG Zhi-qiang, ZHANG Yue, MA Xiu-lan
DOI: 10.3969/j.issn.1000-1158.2014.03.19
The national comparison of Cesium frequency standard was finished in  2012, the pilot laboratory is National Institute of Metrology(NIM), a Rubidium frequency standard is used as a transfer standard. 8 laboratories got satisfied result among the 9 participating laboratories. The basic situation, the technic program of the comparison were introduced, the comparison method and the evaluation of the uncertainty were studied, and the particularity of time and frequency comparison was proposed  and at last the comparison results was analysed.
2014 Vol. 35 (3): 286- [Abstract] ( 655 ) HTML (1 KB)  PDF (685 KB)  ( 933 )
291 Extract Bone Trabecular of Hematoxylin-eosin Staining Dyeing Pathological Section by Visual Model
YE Han-xiao1, JIN Hong-ting1, YUAN Xin2, JIANG Yi-fa1
DOI: 10.3969/j.issn.1000-1158.2014.03.20
To extract trabecular bone of hematoxylin-eosin staining staining bone tissue pathological slices,for quantitative detection of trabecular bone area,create a polar diffusion model,to let computer extract any hematoxylin-eosin staining dyeing bone slice trabecular bone,divide the boundary of the trabecular bone with bone cells and bone cortex.Extract a pixel’s RGB values of background,use RGB color value of all pixels with the background pixels to calculate 3d euclidean distance,get threshold,to achieve image binarization segmentation,by area filling get trabecular bone.Results show that the visual model can get the boundary of the region of interest well.Measurement accuracy and speed are significantly improved.Results of measurement relative to the conventional software the robustness improve over 95%,reduce human-computer interaction,to reduce the blindness of testing.
2014 Vol. 35 (3): 291-295 [Abstract] ( 677 ) HTML (1 KB)  PDF (1395 KB)  ( 1975 )
296 Study and Preliminary Results of the 4πγ Well-type NaI(Tl) Crystal Detector
ZHANG Ming1, YANG Yuan-di1, LIU Hao-ran1,2
DOI: 10.3969/j.issn.1000-1158.2014.03.21
A 4πγ well-type NaI(Tl) crystal counting device for gamma-ray detection at NIM is introduced. By analyzing the detected gamma spectrum of 60Co, it is found that the sum-peak counting effect is inevitable for nuclei with complex decay scheme using 4πγ well-type NaI(Tl) crystal. Further, a series of test experiments are carried out to investigate the performance of detector by changing the depth of 60Co source in the well. The results reveal that the sum-peak counting rate increases as the source moved to the bottom of the well, and the efficiency for full-energy peak has a slight reduction for the increasing sum-peak effect. Besides, the efficiency is reasonable lower at the mouth of the well-type NaI(Tl) crystal for the smaller solid angle coverage. Moreover, the energy calibration is also effected by the variation of source position.
2014 Vol. 35 (3): 296-299 [Abstract] ( 476 ) HTML (1 KB)  PDF (597 KB)  ( 1084 )
300 Uncertainty Evaluation Based on Quantile Function and Bootstrap
SONG Ming-shun, ZHANG Jun-liang, FANG Xing-hua
DOI: 10.3969/j.issn.1000-1158.2014.03.22
 Maximum entropy is one of the chief methods in the evaluation of measurement uncertainty based on probability distribution, and the higher moments it depended on  a larger sample of measurement data. However, measurement in calibration and testing laboratories is generally a small sample survey, so evaluation of measurement uncertainty based on the maximum entropy method for small samples lacks a certain degree of reliability. A method for uncertainty evaluation based on quantile function and probability weighting moment is put forward as the constraint condition of maximum information entropy method. By this way, the high order moment is fell down for a moment, the probability distribution is solved with the combination of genetic algorithm, and the complicated calculation problem arising from quantile interval estimation of asymmetric distribution is managed about with Bootstrap distribution estimation for expanded uncertainty and coverage interval.
2014 Vol. 35 (3): 300-304 [Abstract] ( 638 ) HTML (1 KB)  PDF (302 KB)  ( 973 )
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