Identification and location technology of refueling taper sleeve based on deep learningHu, Guoxing; Liu, Haoguang
doi: 10.1117/12.3007578pmid: N/A
In the process of aerial refueling test flight and autonomous aerial refueling, it is necessary to measure the high-precision motion parameters of the Taper sleeve relative to the oil-receiving probe to provide data for the docking process. In this paper, aiming at the problems of intelligent identification and tracking of aerial refueling targets and high-precision stereo vision positioning, a multi-layer convolutional neural network with visual characteristics was constructed by deep learning theory, and the recognition results of Taper sleeve were corrected by using frame regression algorithm, so as to improve the Taper sleeve positioning accuracy from three dimensions: identification and tracking, optical calibration and measurement and solution. In this paper, combined with the test and flight verification, the solution accuracy is better than 0.09%, the identification success rate is better than 98%, and the Taper sleeve positioning accuracy is better than2cm+0.15%*L, which accords with the positioning accuracy of the refueling taper sleeve in the flight test.
Distributed temperature profile in flip chip measured by optical-frequency-domain reflectometry with telecom fiberLi, Shuwang; Yang, Xiaofeng; Xiao, Qingzhong; Zhu, Jianyuan; Wang, Jinjie
doi: 10.1117/12.3007683pmid: N/A
The electromigration problem in flip chip becomes one of the focuses of the microelectronic device durability. Temperature is a key parameter for the electromigration life evaluation, due to the occurrence of material structure defect will be accelerated with the rise of temperature. But it is difficult to measure the temperature inside the flip chip packaging structure of large-scale integrated circuits directly with traditional test means. In this paper, a distributed temperature profile test method in interconnect solder joints flip chip has been present, which is measured by the optical-frequency-domain reflectometry (OFDR) with telecom single model fiber. The most distinguishing feature of this method is that the thin flexible optical fiber can directly penetrate into the flip chip from the position of the interconnection solder joint to realize the distributed sensing of the temperature field of the solder joint inside the chip. The modulated linear sweep light directly injected into optical fiber and transmitted forward, and a certain interference pattern formed by back Rayleigh scattering is generated. When the temperature environment of the optical fiber changed, the interference pattern formed by back Rayleigh scattering will change accordingly, which will cause the wavelength shift of the interference pattern, that is similar to the fiber grating effect. Thus, the distributed temperature change can be demodulated from the wavelength shift. The experimental results show that this method can realize the distributed measurement of the internal temperature of flip chip directly, and provides a novel solution for more accurate evaluation of electromigration effect.
Angle measurement system based on Risley prisms and normal tracing methodTang, Yi; Peng, Chuanqian; Cao, Mengjun; Fan, Junliang; Huang, Junyu; Gong, Hengxiang
doi: 10.1117/12.2692496pmid: N/A
Because of factors such as aberration, processing defects, and beam symmetry loss, the three important performances of traditional autocollimators in terms of measuring range, measurement accuracy and working distance cannot be improved at the same time. In this paper, the Risley prisms normal tracing angle measurement system is built according to the method of "normal tracing", and the angle measurement is realized by tracing the normal angle change of the mirror to be measured. When using this method for angle measurement, by rotating the Risley prisms, the measurement beam is incident on the mirror surface in the near-specular normal direction and reflected, so as to realize the trace measurement of the normal direction of the reflective mirror. The experiment shows that when the normal tracing method is used for angle measurement, the system error related to distance in the autocollimator system is greatly reduced. Within the precision range allowed by the experimental environment, the measured data of the normal tracing angle measurement system based on Risley prisms does not show obvious systematic error characteristics.
Application of distributed optical fiber temperature sensing technology in cable safety monitoringDu, Rui; Yang, Xiaojun; Yang, Yong; Fu, Chaoshuai; Tian, Chang; Wang, Xiaoping; Luo, Shihui
doi: 10.1117/12.3005924pmid: N/A
In order to monitor the safety of the whole cable in real time and effectively, this study introduces and adopts distributed optical fiber temperature sensing (DTS) technology as the method of cable safety monitoring. A variety of statistical results are used as the basis for judging the running state. Not only does the whole system have no blind zone of safety monitoring, but also provides accurate alarm information and fast response, which enables managers to deal with faults timely and avoid heavy losses. Therefore, the DTS technology has a high promotion value in the field of cable safety monitoring.
Evaluation of initial alignment algorithm for dynamic base of fiber optic gyro inertial navigation systemMa, Xianglu; Yao, Xiaoshan; Meng, Hao; Yi, Fan
doi: 10.1117/12.3005201pmid: N/A
Fiber optic gyro inertial navigation system (FOGINS), as a kind of navigation equipment with high accuracy, wide dynamic range, and simple mechanical structure, is widely used in moving platforms such as vehicles, aircraft, and ships. For some motion platforms, such as vehicles and aircraft, the FOGINS can be provided with a stationary state so as to realize the initial alignment under static base conditions. However, some motion platforms, such as ships and floating balloons, are always in a swaying state and cannot provide a stationary state for the FOGINS. In such special motion platforms, only the dynamic base initial alignment technique can be implemented. This paper proposes a moving base simulation method, through the simulation, and observed the mainstream initial algorithm effect under different conditions, and categorized to make the relevant analysis, provides a number of engineering guidance strategy, through these strategies, can effectively avoid huge errors of initial alignment, which affect the subsequent positioning accuracy.
Research on technology of dissolved gas analysis in oil based on T-type resonant photoacoustic cellWang, Guangzhen; Yuan, Shuai; Du, Jinchao; Fu, Dehui; Du, Fei
doi: 10.1117/12.3007673pmid: N/A
Aiming at the need of detecting trace dissolved characteristic gases in transformer oil, technology of dissolved gas analysis (DGA) in oil based on a T-type photoacoustic (PA) cell with a small capacity was proposed. The capacity of the T-type PA cell was reduced to 30 mL by optimizing the parameters. This resulted in a significant reduction in sampling volume of transformer oil. A laser photoacoustic spectroscopy (PAS) system for DGA in oil was built combined with headspace degassing method. The T-type resonant PA cell was used to enhance PA signals. The second-harmonic wavelength modulation spectroscopy (2f-WMS) technology was used for detection of escaped gases. The experimental results show that the detection limit of acetylene (C2H2) gas dissolved in oil is 0.5 μL/L when the oil volume is 50 mL. The technical scheme has the advantages of small oil extraction volume, high precision and fast response speed.
Experimental study of optical parametric oscillator cascaded Cr2+:ZnS laserYu, Xinchen; Wang, Yuchen; Li, Xiao; Jiang, Yiguang; Jiang, Benxue; Dong, Zhaofeng; Hou, Jing
doi: 10.1117/12.3007284pmid: N/A
Broadband and multi-wavelength laser is an emerging research direction with promising future applications. The optical parametric oscillator has the characteristic of wide tunable wavelength and the zinc sulfide polycrystal doped with Cr2+ ions have a wide absorption spectrum. Combining the advantages of both output and input, a unique cascade structure using optical parametric oscillator as pump source is constructed for Cr2+:ZnS laser resonator. The output advantages of the cascade laser are studied by analyzing the characteristics of the continuous wave and pulse laser output from the experimental device. The experimental system successfully outputs a laser with a wavelength of 2330 nm and an average power of over 510 mW. The experimental system realizes the laser output of four wavelengths over 2000 nm in the three spectral regions of near infrared, short wave infrared and medium wave infrared. The experimental results provide a new idea and reference for differential absorption measurement and multi-component material measurement in toxic gas molecular detection and optical measurement.
Error analysis and comparison of wavelength tuning phase shifting interferometry of transparent optical flatsChang, Lin; Gao, Jiehua; Yu, Yingjie
doi: 10.1117/12.3007413pmid: N/A
Wavelength-tuning phase-shifting interferometry has advantages over conventional hardware phase-shifting for the simultaneous detection of all surfaces of the transparent parallel flats. The Fourier transform and its derivative methods can be used to characterize the signal based on the optical path difference and the phase-shifting value of the corresponding interferometric harmonic signals on each measured surface and to solve for the phase accordingly. Therefore, considering the influence of the sampling length and the choice of the window function in the Fourier transform on the measurement results, based on the established multi-surface interference model, an adequate simulation analysis is carried out, and the corresponding explanations and discussions are given subsequently. In practical measurements, the appropriate window function and sampling length should be selected according to the corresponding measurement conditions, so that reliable measurements can be guaranteed.
A highly sensitive optical fiber sensor based on magnetic ion imprinting technologyYang, Tianyu; Feng, Yue; Shen, Tao
doi: 10.1117/12.3007853pmid: N/A
In view of the high cost, slow response and insufficient detection limit of traditional detection methods, this paperproposes a high sensitive fiber sensor based on magnetic ion imprinting technology for the detection of lowconcentration of Cd2+. First, the evanescent field and waist cone diameter are analyzed by beam propagation method(BPM), and the sensing unit is prepared. Second, -Fe2O3@MAA(M-IIP) magnetic ion printing nanomaterials wereprepared by solid-liquid separation and combined the magnetic blomaterial with the sensing unit by silanlation. Finally, the sensor enables a low-concentration detection of Cd2+. The detection sensitivity was up to 2691.5nm/Min the rangeof 0-1 M. The limit of detection (LOD) reached 0.45 nM and the response time was 37s at the lowest concentration. At the same time, the sensor also has good results in terms of structural compactness and production cost.