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Issue 11 ， 2019
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Direct determination of relative wavelength response of DFB lasers in sinusoidal scanning wavelength modulation spectra based on current scanning wavelength response function
Abstract：In order to identify a method suitable for describing the Relative Wavelength Response (RWR) in the sine wave scanning wavelength modulation spectrum, and to improve the accuracy of the sinusoidal scanning measurement of gas concentration, existing methods for describing the RWR of the laser are discussed. First, several existing methods for describing the wavelength response of a laser for sinusoidal scanning are analyzed. Then, the RWR simulated by the different methods and the residuals of the measured l Keywords：sine wave scanning;wavelength response;wavelength modulation;concentration error- 117
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Published：2020-08-13 -
Design of deep-sea optical imaging system with wide field of view and ultra-high resolution
Abstract：In order to meet the needs of deep-sea imaging devices in China, a whole deep-sea wide-field-of-view optical imaging system was designed based on the aberration characteristics of an underwater optical system. According to the operating environment of the deep-sea system, the optical parameters and structural forms were analyzed. A sample optical design characterized by miniaturization, low cost, and high performance was completed using common glass and spherical lens. The energy utilization of the optical Keywords：optical design;underwater imaging;wide field of view;optical properties of seawater- 198
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Published：2020-08-13 -
Ultraviolet detection and positioning method for unmanned aerial vehicle patrol of power line discharge
Abstract：As discharge failures caused by problems such as pollution and cracking of transmission facilities have constantly threatened the safety of the transmission network, in this paper, discharge ultraviolet detection technology was first studied. Then, the Photomultiplier Tube (PMT) was used as the detector to design the discharge ultraviolet detection scheme. An ultraviolet detection and localization method for the Unmanned Aerial Vehicle (UAV) inspection of power line discharge was proposed. The PMT was drive Keywords：ultra-violet detection;power line discharge;unmanned aearial vehicle;positioning- 121
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Published：2020-08-13 -
Sensing characteristics of long period fiber grating functionalized with graphite oxide
Abstract：A graphene oxide-functionalized long period fiber grating (GO-LPFG)-based fiber optic sensor is proposed. The surface of the LPFG was hydroxylated by sodium hydroxide solution, and GO was fixed on the grating surface by hydrogen bonding to form a GO modification LPFG sensor. The responses of the GO-LPFG to external refractive index and temperature were studied experimentally. The experimental results show that the average refractive index sensitivity of the GO-LPFG is 1.09 times higher than that of uncoated Keywords：optical fiber sensing;long period fiber grating;graphene oxide;sensitivity- 97
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Published：2020-08-13 -
Large-range and high-resolution temperature measurement system for satellite-borne infrared detector
Abstract：In order to realize the high temperature resolution measurement for the satellite-borne infrared detector to further realize the stability of temperature control, the imaging quality of a remote sensing infrared camera is improved. Aiming at the shortcoming that the traditional temperature measuring system cannot take into account wide range and high-resolution characteristics, the temperature measurement system for the infrared detector is designed, and wide range and high-resolution temperature measurements are realized by subdividing the whole temperature area and the automatic switching function of the temperature zone. The experimental results show that the infrared detector temperature measurement system can measure the wide range of 70-260 K with measurement resolution as high as 7.6 mK/code compared with the previous temperature measurement system for improved magnitude, and to meet the requirements of satellite-borne infrared detector temperature measurement.Keywords：infrared detector;temperature measurement;high resolution;automatic switching- 116
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Published：2020-08-13 -
Measurement and calibration of optical axis changes for multi-function astronomical theodolite
Abstract：Telescopic Optical Axis Change (OAC) is the main source of systematic errors in astrometry. Real-time determination and calibration of OAC are the foundation for obtaining high-quality astrometric data. The determination and analysis of the influence of OAC on time and latitude measurements should be performed to meet the requirements of high-quality astrometric results. First, the influence of OAC on time and latitude measurements were analyzed. The method of determining OAC for multifunction astronomical Keywords：astrometry;multi-function astronomical theodolite;optical axis change;real-time measurement- 110
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Published：2020-08-13 -
Experiments and simulation of X-ray optical Wolter-I focusing mirror
Abstract：In order to investigate the optical performance of the Wolter-I X-ray mirror shell and to grasp the focusing and testing methods of focusing mirror, the performance of single-layer Wolter-I X-ray focusing mirror was studied. The defocusing, focusing, and off-axis conditions of single-layer focusing lens were experimentally tested in the 100-m vacuum X-ray calibration facility at the Institute of High Energy Physics, Chinese Academy of Sciences. Optical performance parameters such as focal length, focal spot Keywords：X-ray optics;Einstein probe;Wolter optics;x-ray focus mirror- 129
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Published：2020-08-13 -
Optical property characterization of optical blocking filters used in space X-ray survey
Abstract：In order to satisfy the requirements of space X-ray surveys at home and abroad, some X-ray filters could be used in space project were manufactured. First, the transmission properties were characterized by UV-V is spectrometer and X-ray source of synchrotron radiation. The relationship between the optical properties and geographic structure of X-ray filters was studied. The results indicate that in the ultraviolet, visible, and infrared bands, the transmission decreased as the thickness of the Al layer increased. The transmission of filters, whose Al layers are deposited on one side of polyimide, is lower than that whose Al layers are deposited on both sides of polyimide. The transmission is less than 10-4 while the thickness of Al layers is 120 nm. In the X-ray band, the transmission is determined by the whole thickness of polyimide and the whole thickness of Al. The proposed filters can satisfy the present requirements of space X-ray surveys.Keywords：X-ray;filter;space survey;optical properties- 74
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Published：2020-08-13
Modern Applied Optics
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Sensing Characteristics of Long Period Fiber Grating Functionalized with Graphite Oxide
Abstract：A graphene oxide-functionalized long period fiber grating (GO-LPFG)-based fiber optic sensor is proposed. The surface of the LPFG was hydroxylated by sodium hydroxide solution, and GO was fixed on the grating surface by hydrogen bonding to form a GO modification LPFG sensor. The responses of the GO-LPFG to external refractive index and temperature were studied experimentally. The experimental results show that the average refractive index sensitivity of the GO-LPFG is 1.09 times higher than that of uncoated LPFG，and the temperature sensitivity slightly declines. With the decrease of grating diameter, the average refractive index sensitivity of GO-LPFG was further improved. The average wavelength and coupling intensity refractive index sensitivities of the GO-LPFG with a diameter of 108 μm in the refractive index range of 1.333-1.448 are ~38.99 nm/RIU and ~57.33 dB/RIU, respectively. These increased by 1.45, 2.17 and 3.80, 3.42 times, respectively, compared with those of bare LPFG and GO-LPFG with diameter of 125 μm. The proposed GO-LPFG sensor has potential applications in detecting various viral antigen proteins with high molecular weight and biological pathogens in biofields.Keywords：optical fiber sensing;long period fiber grating;graphene oxide;sensitivity- 74
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Published：2020-08-13 -
Measurement and Calibration of Optical Axis Changes for Multi-function Astronomical Theodolite
Abstract：Objective: Telescopic optical axis change (OAC) is the biggest source of systematic error of astrometry. Real-time determination and calibration of OAC are the foundation of obtaining high-quality astrometric data. Determination and analysis the influence of OAC on time and latitude measurements should be done to meet the requirement of high-quality astrometric results. Method: First, the influences of OAC on time and latitude measurements are analyzed. The method of determining OAC for Multi-function Astronomical Theodolite is introduced. Then we determine the OAC in real time and analyze the results. Result: Experimental results indicate that the influence of OAC on latitude measurement can reach to 2.5" when the zenith distance is 550, and the precision of latitude measurement can reach 0.36" from 1.37" after the calibration of OCA, the precision of time-measuring can reach 0.023s from 0.033s after the calibration of OCA. Conclusion: The precision of latitude and time measurements is significantly improved and can satisfy the requirements of high-quality astrometry after the measurement and calibration of OAC in real time.Keywords：astrometry;multi-function astronomical theodolite;optical axis change;real-time measurement- 92
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- 11
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Published：2020-08-13 -
Optical property characterization of X-ray filters used in X-ray space survey
Abstract：In order to satisfy the requirements of space X-ray survey at home and abroad, Some X-ray filters could be used in space project were manufactured by ourselves. First, the transmission properties were characterized by UV-Vis spectrometer and X-ray source of synchrotron radiation. The relationship between optical properties and geographic structure of X-ray filters was studied. The results indicate that: In ultraviolet, visible and infrared bands, the transmission gets lower while the thickness of Al layer gets thicker. The transmission of filters whose Al layers is deposited on one side of polyimide is lower than the transmission of filters whose Al layers are deposited on both side of polyimide. The transmission is lower than 10-4 while the thickness of Al layers is 120 nm. In X-ray band, the transmission is just decided by the whole thickness of polyimide and the whole thickness of Al. The filters manufactured by ourselves could satisfy the requirements of space X-ray survey at present.Keywords：X-ray;filter;space survey;optical properties- 52
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Published：2020-08-13 -
Adhesive Mounting Deformation of Ultra-thin Quartz Workpiece in Precision Machining
Abstract：Ultra-thin optical workpieces get significantly deformed when mounted on pressure plates owing to their high aspect ratio and low stiffness, thereby affecting the accuracy in determining the final surface figure. In this study, we mounted a Ф50 mm×1 mm fused silica workpiece using different methods and in a specific curing sequence. The deformation mechanism was analyzed using finite element simulation. The results show that the mounting deformation of the ultra-thin workpiece is asymmetric and irregular and is caused by the curing sequence of the adhesive used instead of the profile of the adhesive surface. With the aim of reducing the effect of the adhesive curing sequence, a mounting method is developed to reduce the mounting deformation from 1.88 μm to 0.51 μm. A flatness of PV 0.46 μm for the fused silica workpiece is achieved post pitch polishing and demounting, and the deterioration is effectively restrained. This study helps to understand the mechanism of mounting deformation and guides the fabrication of ultra-thin optical workpieces.Keywords：ultra-thin optical workpiece;adhesive mounting;surface figure deformation;finite element simulation- 71
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- 11
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Published：2020-08-13 -
Correlation filter tracking algorithm based on double model
Abstract：For the correlation filtering tracking algorithm is not robust enough and cannot adapt to scale changes due to the boundary effect, an improved correlation filtering tracking algorithm based on double model is proposed. Methods: The target tracking consists of position prediction and scale prediction. In the stage of the position prediction, the samples were enhanced to make the samples more consistent with the actual scene.Then the solution is obtained by using the alternating?direction?method?of?multipliers(ADMM), and the estimated target position is achieved. For scale prediction, a multi-scale pyramid was constructed in order to train the scale filter, and then the target scale is acquired. The final tracking result is decided by target position and scale together. Finally, an occlusion criterion is introduced to determine whether the model is updated or not. Results: Comparing with the classical correlation filtering tracking algorithm, the proposed algorithm boosts the tracking success rate by 18% and tracking accuracy by 11%. Conclusion: Our algorithm in this paper could track the target stably even when the target is occluded and its scale changes.Keywords：object tracking;correlation filtering;sample enhancement;Alternating Direction Method of Multipliers(ADMM)- 102
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- 11
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Published：2020-08-13 -
Three-dimensional depth segmentation technique utilizing discontinuities of wrapped phase sequence
Abstract：To segment objects with abrupt change surface positioned at different depth, this paper presented a flexible technique for 3D depth segmentation. The system consisted of one projector, one camera, and the objects for segmentation. The first step was to establish the system for segmentation. The second step was to cast the phase-shifted gratings onto the object surface. The gratings, which were modulated by the 3D information of the objects, were then captured by the camera and sent to the computer for further processing. The wrapped phase sequence could then be calculated by changing the sequence of the phase-shifted patterns and using the least squares algorithm. By applying the neighbor pixel difference algorithm to the wrapped phase maps, the edges for segmentation could be retrieved further. Finally, these edges could be optimized and sent for segmentation. The simulation result shows that the method can effectively segment the complex objects with size 900 × 900 pixels, with the corresponding error reaching only two pixels. The experimental result shows that the approach can segment objects with similar color precisely. The proposed method has the advantages of low cost, high precision, and can perform the task of 3D depth segmentation.Keywords：image segmentation;three-dimensional depth segmentation;wrapped phase- 65
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Published：2020-08-13
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Control system of electrostatic levitation based on high-speed vision
Abstract：Electrostatic levitation is one of the most important methods used to study the properties of materials without having to collide them against the wall of a chamber. A dynamic, ground electrostatic levitation control system model is designed and built using two Graphics Processing Units (GPUs) to process the image sequence and calculate the position of the material. In addition, a real-time detection algorithm is proposed for quick real-time visual detection of the targets. The melting experiment of the mat Keywords：electrostatic levitation;high-speed vision;real-time control- 75
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Published：2020-08-13 -
Estimation of hydrazine propellant leakage for LEO satellite
Abstract：The propulsion system of a satellite is influenced by the in-flight environment in space. Consequently, to investigate the leakage of propellant from a monopropellant hydrazine propulsion system, a Low Earth Orbit (LEO) satellite is sampled over its devised life. Details regarding orbit shifting, inclination, solar shining angle, and Local Time of Descending Node (LTDN) are discussed. The cause of leakage is attributed to acceleration in the pitch velocity of the satellite when it has no attitude control. A Keywords：LEO satellite;hydrazine propellant;leakage;estimation;telemetry- 145
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Published：2020-08-13 -
Parameter design and optimization of a flight attitude simulator system based on PILCO framework
Abstract：Proportional-integral-derivative (PID) controllers are widely used in flight control systems. However, it is often very cumbersome to adjust the parameters of a PID controller. In this study, we use Probabilistic Inference for Learning Control (PILCO) to optimize the parameters of a PID controller. As the first step, we develop a probabilistic dynamics model of the flight control system using input and output data. Next, the existing PID controller is evaluated using the policy evaluation method. Finally, the evaluated PID controller is optimized by policy update. The sampling frequency of the system is 100 Hz and the data acquisition time per round is 8 s. The optimized PID controller can achieve stable control post 10 rounds of offline training. Through PILCO optimization, the flight attitude simulator performed robustly in a fixed-point experiment, indicating that PILCO has tremendous potential in solving nonlinear control and parameter optimization problems.Keywords：aircraft control;Probabilistic Inference for Learning Control(PILCO);reinforcement learning;parameter optimization- 113
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Published：2020-08-13 -
Accuracy analysis and testing for secondary mirror adjusting mechanism in large space telescope
Abstract：To obtain images of high quality from a large space telescope in orbit, an adjustment mechanism for a secondary mirror was developed based on the 6-Prismatic-Spherical-Spherical (6-PSS) parallel mechanism, and the accuracy of the adjustment mechanism was tested. First, the composition and precision requirements for the optical system of the adjustment mechanism for a secondary mirror was analyzed. Next, the error model of the mechanism was established based on its inverse kinematics analysis. Finally, the i Keywords：large space telescope;secondary mirror adjusting mechanism;error model;accuracy analysis;accuracy testing- 209
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Published：2020-08-13 -
Control of bearing preload during assembly of space servomechanism
Abstract：Productized bearings can be applied to servomechanisms in space with different loads by adjusting the bearing preload, and this can helps reduce cost and improve succession. Firstly, in accordance with the relationship between preload and friction torque, the factors influencing preload in the bearing assembling process were identified and an equation was developed. Subsequently, the bearing′s interference fit was simplified to a thick-walled-cylinder model and the relevant equations were deduced. Further, Keywords：space servomechanism;preload control;productized bearing;assembling process- 102
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Published：2020-08-13 -
Backstepping sliding mode neural network control system for hypersonic vehicle
Abstract：Strong coupling between the elastic body and the propulsion system in a hypersonic vehicle is caused by its integrated pneumatic layout and strong nonlinearity uncertainty, and obvious time-varying characteristics of aerodynamics, when the vehicle spans a large airspace and is flying at high speed. To eliminate the influence of this coupling, we propose a backstepping sliding mode control scheme based on a recurrent cerebellar model articulation controller (RCMAC). The input-output feedback linearization ap Keywords：aerocraft control and navigation technology;hypersonic vehicle;backstepping;recurrent cerebella mode articulation controller;sliding mode control;uncertainty- 158
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Published：2020-08-13 -
Adhesive mounting deformation of ultra-thin quartz workpiece in polishing
Abstract：Ultra-thin optical workpieces get significantly deformed when mounted on pressure plates owing to their high aspect ratio and low stiffness, thereby affecting the accuracy in determining the final surface figure. In this study, we mounted a Ф50 mm×1 mm fused silica workpiece using different methods and in a specific curing sequence. The deformation mechanism was analyzed using finite element simulation. The results show that the mounting deformation of the ultra-thin workpiece is asymmetric and irregular an Keywords：ultra-thin optical workpiece;adhesive mounting;surface figure deformation;finite element simulation- 78
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- 18
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Published：2020-08-13 -
High-sensitive tactile sensor with triaxial force decoupling measurements
Abstract：Traditional capacitive tactile sensors have much lower sensitivity in the direction of shear force than in that in the normal direction owing to the existence of coupling measurement of signals. To resolve this issue, a highly sensitive tactile sensor, with triaxial force decoupling measurements was designed based on multilayer capacitor structure. The sensor comprised of measuring units for both the shear force and normal directions. The measuring unit for the shear force direction adopted differential fin Keywords：tactile sensor;multi-layer capacitor structure design;decoupling measurements;highly sensitivity- 101
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Published：2020-08-13 -
Energy optimization and experimental for a permanent magnet-biased redial magnetic bearing
Abstract：To address the requirement for low power of a magnetically suspended flywheel, the energy optimization of permanent magnet-biased radial magnetic bearing is studied. The magnetic circuit and working principles are introduced, based on the current stiffness and displacement stiffness mathematical models of a magnetic bearing, and the energy optimization factorσ of a magnetic bearing is obtained. The objective function of the power consumption of the magnetic bearing is then established, followed by optimizat Keywords：permanent magnet-biased magnetic bearing;energy optimization;equivalent magnetic circuit;finite element method;bias magnetic flux- 109
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- 13
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Published：2020-08-13
Micro/Nano Technology and Fine Mechanics
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Autonomous driving semantic segmentation with convolution neural networks
Abstract：Semantic image segmentation is an essential part of modern autonomous driving systems because accurate understanding of the scene around the car is the key to navigation and motion planning. The existing advanced convolutional neural network-based semantic segmentation model DeepLab v3+ can not use attention information, which leads to rough segmentation boundary. To improve the semantic image segmentation accuracy for autonomous driving scenario, this paper proposed a segmentation model that combined the l Keywords：autonomous driving;semantic image segmentation;convolutional neural networks;DeepLab v3+- 247
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Published：2020-08-13 -
Gaussian decay and adaptive compensation dehazing algorithm combined with scene depth estimation
Abstract：In order to solve the problem of large sky or white area failure in a dark channel prior algorithm, a Gaussian decay and adaptive compensation dehazing algorithm combined with scene depth estimation was proposed. Firstly, estimating the scene depth by an approximately positive correlation between the arithmetic mean of the RGB channel scattering intensities and the haze concentration. Then, combined with the edge information of the scene depth, a Gaussian filter is constructed using the difference between a Keywords：Gaussian attenuation;adaptive compensation;scene depth;edge detection- 99
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Published：2020-08-13 -
Correlation filter tracking algorithm based on double model
Abstract：For the correlation filtering tracking algorithm is not robust enough and cannot adapt to scale changes due to the boundary effect, an improved correlation filtering tracking algorithm based on double model was proposed. The target tracking consisted of position prediction and scale prediction. In the position prediction stage, the samples were enhanced to make them more consistent with the actual scene. Then, the solution was obtained using the alternating direction method of multipliers, and the estimated Keywords：object tracking;correlation filtering;sample enhancement;Alternating Direction Method of Multipliers(ADMM)- 111
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- 18
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- 3
Published：2020-08-13 -
Three-dimensional depth segmentation technique utilizing discontinuities of wrapped phase sequence
Abstract：To segment objects with abrupt change surface positioned at different depth, this paper presented a flexible technique for 3D depth segmentation. The system consisted of one projector, one camera, and the objects for segmentation. The first step was to establish the system for segmentation. The second step was to cast the phase-shifted gratings onto the object surface. The gratings, which were modulated by the 3D information of the objects, were then captured by the camera and sent to the computer for furth Keywords：image segmentation;three-dimensional depth segmentation;wrapped phase- 113
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- 18
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Published：2020-08-13 -
Star identification algorithm based on similar triangle principle
Abstract：The star identification algorithm is a key technology for star sensors. Traditional star identification algorithms, such as triangle algorithm, polygon algorithm, and other improved algorithms mainly consider the star diagonal distance as an identification feature. The accuracy of the calculated star diagonal distance is dependent on the calibration accuracy of the focus length of the charge-coupled device (CCD) camera. These identification algorithms cannot work properly if the calibration accuracy is insu Keywords：star identification;similar triangle;relative magnitude;star sensor- 109
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Published：2020-08-13 -
High-order statistics integration method for automatic building extraction of remote sensing images
Abstract：To address the poor performance of building extraction caused by low discrimination between the building target and background environment in remote sensing images, a high-order statistics integrated encoder-decoder network method was proposed to improve the accuracy of automatic building extraction. First, the deep encoder-decoder network was used to extract the low-order semantic features of building targets. Then, the polynomial kernels were used to achieve the high-order description of intermediate feat Keywords：remote sensing;building extraction;high-order statistics;encoder-decoder network;semantic segmentation- 114
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Published：2020-08-13 -
Extraction for HHT features of pressure vibration signals of oil pulsating flow with different particle concentration
Abstract：Particle concentration has any effect on turbulence characteristics of the oil, by using Hilbert-Huang method, the pressure signal of oil pulsating flow with different particle concentration was analyzed, and the law of particle concentration effect on vibration characteristics of pressure signal was discussed. Using empirical mode function, Hilbert transform and envelope demodulation method, the Hilbert spectrum and energy characteristics of oil pressure signal was obtained, analyzes the energy distributio Keywords：pulsating flow;Hilbert-Huang transform;pressure vibration signals;extraction feature;particle concentration- 128
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Published：2020-08-13
Information Sciences
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