Journals >Infrared and Laser Engineering
Contents
2015
Volume: 44 Issue 7
45 Article(s)
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[in Chinese]
Organic light-emitting device based on LSMO
Guan Yunxia, Chen Lijia, Chen Ping, and Niu Lianbin
Organic Light Emitting Device(OLED) has been a promising new research area that has received a lot of attention in the recent. In this paper,the OLED was fabricated using spin LSMO substrate. The electrode was made of La1-xSrxMnO3(LSMO) thin films by RF magnetron sputtering with SrTiO3 (100) substrate. In order to incrOrganic Light Emitting Device(OLED) has been a promising new research area that has received a lot of attention in the recent. In this paper,the OLED was fabricated using spin LSMO substrate. The electrode was made of La1-xSrxMnO3(LSMO) thin films by RF magnetron sputtering with SrTiO3 (100) substrate. In order to increase light transmittance ratio of LSMO film, the substrate was double-sided polished. The structure was LSMO/NPB/Alq3/CsF/Mg:Ag. Light was emitted at above 14 V. The brightness of device was the most at 25 V. The characteristic brightness, voltage and current of these devices were investigated with the magnetic field. The brightness of device was improved 10% with 150 mT. The photovoltaic character was little affected by the magnetic field in the device using LSMO substrate. This phenomenon was related on the ratio of single exciton and triplet exciton in the emissive layer. it would then be possible to preferentially form triplets or singlets by controlling the spin polarizations of the injected carriers. As Alq3 belonged to singlet materials, the brightness of device was improved..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2105 (2015)
Growth and properties of ZnO/ZnFe2O4 nanoparticles
Gao Xian, Jia Huimin, Fang Xuan, Liu He, Tang Jilong, Fang Dan, Wang Shuangpeng, Zhao Haifeng, Li Jinhua, Fang Fang, Chu Xueying, Wang Fei, Wang Xiaohua, Xu Li, Ma Xiaohui, and Wei Zhipeng
ZnO/ZnFe2O4 nanoparticles were synthesized by hydrothermal and annealed method. X-ray diffraction(XRD), scanning electron microscopy(SEM) and photoluminescence(PL) spectroscopy were used to characterize the synthesized and annealed ZnO/ZnFe2O4 nanoparticles. The results indicate that the synthesized nanoparticles are mZnO/ZnFe2O4 nanoparticles were synthesized by hydrothermal and annealed method. X-ray diffraction(XRD), scanning electron microscopy(SEM) and photoluminescence(PL) spectroscopy were used to characterize the synthesized and annealed ZnO/ZnFe2O4 nanoparticles. The results indicate that the synthesized nanoparticles are mainly composed of hexagon wurtzite ZnO and cubic ZnFe2O4, and the crystal quality is improved by annealing treatment. It is observed that the intrinsic photoluminescence attributed to the recombination of photogenerated carriers of ZnO was obviously weakened after annealing process, which confirms that a ZnO/ZnFe2O4 heterojunction was formed which could improve the separation of photogenerated carriers. Photocatalytic test′s results show the photocatalytic activity of the annealed ZnO/ZnFe2O4 nanoparticles is better than the synthesized, and the photocatalytic degradation ratio of MO is 50.48% under 3 hours′ UV-illumination. The magnetic properties of the annealed ZnO/ZnFe2O4 were also investigated, the synthesized nanoparticles were paramagnetic at room temperature, and the annealed nanoparticles were ferromagnetic. In conclusion, the annealed ZnO/ZnFe2O4 nanoparticles may have a great potential in the magnetic photocatalytic fields..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2110 (2015)
Sensing mechanism of anatase TiO2 (101) surface adsorption of CO2 molecules
Yang Ying, and Feng Qing
Exploration and application of the gas sensitive sensor material of metal oxide optics is a hot issue. The adsorption energy, adsorption distance, density of states and optical properties were studied from the plane wave ultra-soft pseudo-potential technology based on the density function theory(DFT). The results throuExploration and application of the gas sensitive sensor material of metal oxide optics is a hot issue. The adsorption energy, adsorption distance, density of states and optical properties were studied from the plane wave ultra-soft pseudo-potential technology based on the density function theory(DFT). The results through simulation calculation of CO2 adsorbed on the anatase TiO2 (101) surface show that only containing oxygen vacancy surface can stably adsorb CO2 molecules; the higher of oxygen vacancy concentration, the more obvious adsorption effect. The adsorption energy is positive value when CO2 molecules horizontal adsorption on surface, the best adsorption model is CO2 molecules horizontal O-terminal dsorption on surface with two oxygen vacancies. Compared with the density of states, a new peak appears nearby the fermi level because of surface with oxygen vacancies and 2p electrons of CO2 molecules doping in surface. The transition probability, optical gas sensitive features, absorption coefficient and reflectivity can be improved in the low-energy scope of visible light..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2116 (2015)
A new design of seed source used in optical streak camera
Wang Qiaoli, Bai Yonglin, Zhu Bingli, Wang Bo, Gou Yongsheng, and Jin Jing
A new technique to generate high frequency repeated sine synchronous scan seed source was introduced, based on the method of phase locked loop and direct digital synthesize technique. Phase locked loop was used to realize synchronous track of sine scan signal and trigger light impulse. Modulation of frequency, phase, aA new technique to generate high frequency repeated sine synchronous scan seed source was introduced, based on the method of phase locked loop and direct digital synthesize technique. Phase locked loop was used to realize synchronous track of sine scan signal and trigger light impulse. Modulation of frequency, phase, and amplitude was achieved by direct digital synthesize technique. Delay of scan time was achieved by phase modulation, while different scanning rate was achieved by amplification modulation. The circuit system can obtain stable sine synchronous scan seed signal with frequency as high as 250 MHz, and jitter lower than 10 ps. The design is confirmed to meet the expectation, and fulfill the high precision requirements of streak camera on seed source for frequency, amplitude and time jitter..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2122 (2015)
Mid infrared laser power stabilizer
Sun Quanshe, Chen Kunfeng, and Shi Xueshun
In order to accurately measure spectral response rate of mid infrared photoelectric detectors, the power stability of mid infrared laser must be improved. A novel method of stabilizing laser power was proposed using the technique of light feedback based on Bragg diffraction principle of the acousto-optic modulator in tIn order to accurately measure spectral response rate of mid infrared photoelectric detectors, the power stability of mid infrared laser must be improved. A novel method of stabilizing laser power was proposed using the technique of light feedback based on Bragg diffraction principle of the acousto-optic modulator in this paper. The optical path design, control electrocircuit and arithmetic were discussed particularly, on this basis, a mid infrared laser power stabilizers was fabricated. Using this power stabilizers, the power stability of He-Ne laser at a wavelength of 3.39 μm was compared. The experimental result shows that this method can improve the power stability of the infrared laser from 8% to 0.4%, and meet spectral responsivity of the infrared detector parameters..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2127 (2015)
Research and design of astigmatism-free for C-T imaging spectrometer under non-parallel grating illumination
Hao Aihua, and Hu Bingliang
Czerny-Turner(C-T)spectrometer usually been used monochromators and spectral radiometers due to its compact structure and spherical mirrors. However, astigmatism greatly confines C-T spectrometer used in imaging spectrometers. Astigmatism-free methods were analyzed theoretically and verified experimentally under non-paCzerny-Turner(C-T)spectrometer usually been used monochromators and spectral radiometers due to its compact structure and spherical mirrors. However, astigmatism greatly confines C-T spectrometer used in imaging spectrometers. Astigmatism-free methods were analyzed theoretically and verified experimentally under non-parallel grating illumination. As a result, astigmatism of C-T spectrometer can be corrected under convergent or divergent grating illumination. When the cosine square ratio of grating incidence to difference angle was more than 1, divergent illumination can correct astigmatism. Conversely, when it was less than 1, convergent illumination can correct astigmatism..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2132 (2015)
[in Chinese]
Analysis and optimization of angle measurement accuracy of strap-down laser semi-active guidance seeker
Gao Siyuan, Liu Hui, Zhu Mingchao, Zhang Xin, and Bai Yang
In order to reduce the cost of the laser guidance weapons system and improve its accuracy, the strap-down laser guided seeker was designed. The precision of angle measurement which affecting the attack precision was studied. First, the method of gain controlling affecting the precision of angle measurement was analyzedIn order to reduce the cost of the laser guidance weapons system and improve its accuracy, the strap-down laser guided seeker was designed. The precision of angle measurement which affecting the attack precision was studied. First, the method of gain controlling affecting the precision of angle measurement was analyzed. Second, the four channel variable gain amplifier was calibrated and the least squares fitting curve of the gain was got. Then, the method of gain compensation and its error under the discrete control were discussed. Finally, the error of light spot between uncompensated and compensated in different amplified mode by simulation was got. Experimental results indicate that the system error is decreased by 5.6 mrad. The precision of angle measurement reach to 2 mrad in the linear field of view. It can satisfy the system requirements by semi-active laser guidance weapons system..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2169 (2015)
Expeditions calibration algorithm of visual tracking and measurement system with field coordinate system for moving target
Zheng Xuehan, Wei Zhenzhong, and Zhang Guangjun
Expeditious calibration of vision measurement system with field coordinate system is fundamental and crucial, especially for movable visual tracking and measurement system. The calibrating principle of coordinate transformation was elaborated based on their characteristic, and mathematical model of the algorithm was prExpeditious calibration of vision measurement system with field coordinate system is fundamental and crucial, especially for movable visual tracking and measurement system. The calibrating principle of coordinate transformation was elaborated based on their characteristic, and mathematical model of the algorithm was proposed to calibrate the visual measurement system with field coordinate system. Two control points that parallel the axis in field coordinate were used as target. The calibrating results were computed based on azimuth and pitch angle of the visual measurement system when the line-of-sight collimated the control points. Simulation analysis and real data experiment results show that the angle error is 0.03°, and length error is 0.52%. The proposed algorithm is practical, convenient and wieldy to movable vision measurement coordinate system expeditious calibration..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2175 (2015)
Cylindrical grating angle measurement technology based on genetic algorithm
Lao Dabao, Zhou Weihu, Li Wanhong, Shi Dong, and Lin Xinlong
High precision angle measuring unit, which is the key to ensure accuracy and performance of rotary equipments, is extensively applied in measuring and tracking apparatuses. In regard to large-scale coordinate measuring instruments, angle measurement is the bottleneck to enhance instruments′ coordinate measurement accurHigh precision angle measuring unit, which is the key to ensure accuracy and performance of rotary equipments, is extensively applied in measuring and tracking apparatuses. In regard to large-scale coordinate measuring instruments, angle measurement is the bottleneck to enhance instruments′ coordinate measurement accuracy by comparing with distance measurement. High accuracy cylindrical grating and four reading heads were adopted to build angle measuring unit for precise one-dimension turntable platform, then the influence on angle measuring accuracy by sensor itself, installation and axis shafting were analyzed in detail. Angle measuring error was calibrated by standard device and analyzed with harmonic method. A parameter optimization method based on genetic algorithm was proposed to develop error compensating model, by which angle measurement error was compensated. The experimental results show that cylindrical grating angle measuring error is reduced to ±0.7″ after compensation, which demonstrates that the compensation method is effective to improve accuracy obviously..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2182 (2015)
Numerical analysis of small particle measurement based on the theory of laser scattering
Shi Zhenhua, Lin Guanyu, Wang Shurong, Yu Lei, and Cao Diansheng
According to the accuracy, stability and fast property of algorithms, the numerical algorithms of the classical Mie scattering and Rayleigh scattering were presented in this paper. Compared the numerical results acquired from the Mie scattering theory and Rayleigh scattering theory by using Matlab with Wiscombe′s numerAccording to the accuracy, stability and fast property of algorithms, the numerical algorithms of the classical Mie scattering and Rayleigh scattering were presented in this paper. Compared the numerical results acquired from the Mie scattering theory and Rayleigh scattering theory by using Matlab with Wiscombe′s numerical results, the results acquired from Matlab programs were also accurate. According to Matlab numerical results, the forward light scattering distribution in a certain angle can be determined by Rayleigh scattering theory when the size parameter x is less than 0.3. The size distribution can also be determined. The algorithm of Rayleigh scattering theory is more efficient than the corresponding algorithm acquired from Mie scattering theory. This simplified method can provide theoretical support for online measuring micro particles when some test objects(the relative refractive index, particle type) are determined..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2189 (2015)
Design of high-precision variable star chart background star map simulator
Sun Gaofei, Zhang Guoyu, Liu Shi, Wang Qi, Gao Yujun, Wang Lingyun, and Wang Haojun
In order to meet the star sensor ground calibration and testing, a set of high-precision variable star chart background star map simulator was designed, the precision angular distance between the star of this system was required better than 10". Static targets with high precision was made as the standard source coIn order to meet the star sensor ground calibration and testing, a set of high-precision variable star chart background star map simulator was designed, the precision angular distance between the star of this system was required better than 10". Static targets with high precision was made as the standard source core device of star map simulator, matching with a brightness controlled lighting system to fulfill star point and background simulation in the same time, designing collimating optical system that males parallel light outgoing analog star chart and background, a star map was displayed at the pupil of star sensor, to achieve background controllable and high accuracy star chart position simulation. Finally, a method to improve the accuracy of the simulation star point was brought out, star point position accuracy was measured by using theodolite matching with the brightness tested of the background by light meter test. The experiments results show that, the star map simulation accuracy of the simulator is better than 10", can achieve the background brightness adjustment 26 times, and be used for high-precision star sensor ground calibration and accuracy testing..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2195 (2015)
Lightweight pointing mechanism and its pointing error analysis based on ultrasonic motor
Tian Mi, He Zhiping, Chen Kai, Lv Gang, and Wang Jianyu
In the lunar exploration project, in order to achieve multi-target spectrum detection based on space applications, designing a lightweight and highly reliable two-dimensional pointing mechanism is needed. Currently, the ultrasonic motor as a driving source and the precise potentiometer as a position sensor, are gradualIn the lunar exploration project, in order to achieve multi-target spectrum detection based on space applications, designing a lightweight and highly reliable two-dimensional pointing mechanism is needed. Currently, the ultrasonic motor as a driving source and the precise potentiometer as a position sensor, are gradually applied in precise instruments and positioning technologies due to their excellent performance. Based on this, a two-dimensional pointing mechanism consisting of ultrasonic motor, precise potentiometer and scanning mirror was designed. Besides, in order to validate feasibility of the two-dimensional pointing mechanism in space applications, one-dimensional pointing mechanism model was designed and assembled as the engineering prototype, and functional test was conducted based on the closed-loop control circuit and pointing control mechanism. In order to meet the demand of accuracy test, laboratory test platform was built, several pointing experiments were carried out to measure and solutions to improve accuracy were put forward through error analysis of the test results..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2200 (2015)
Sub-aperture stitching testing technology based on maximum likelihood estimation algorithm
Yan Gongjing, and Zhang Xianzhong
As an important part of the optical system, the accuracy of the plane mirror is an influence factor to system imaging. Subaperture stitching testing is a usual way to test plane mirror in large aperture, while the stitching algorithm is the key in the stitching technology. The plane sub-aperture stitching algorithm wasAs an important part of the optical system, the accuracy of the plane mirror is an influence factor to system imaging. Subaperture stitching testing is a usual way to test plane mirror in large aperture, while the stitching algorithm is the key in the stitching technology. The plane sub-aperture stitching algorithm was studied in the paper and a reasonable stitching algorithms and mathematical models was established based on maximum likelihood estimation and orthogonalization Zernike polynomial fitting. Stitching to plane mirror in large aperture can be accomplished with the above stitching model. Stitching program was also written and stitching testing was carried on with a Φ100 mm interferometer on a Φ120 mm plane mirror. Comparing the stitching result with the full aperture testing result, it shows that the stitching map is in consistent with the full aperture testing map. The difference of RMS between them is 0.002λ, verifying the reliability and accuracy of the algorithm..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2206 (2015)
[in Chinese]
Design of 5-Gbps full differential optical receiver pre-amplifier
Sun Yang, Huang Qijun, Wang Hao, Chang Sheng, and He Jin
Optical fiber communication has been adopted widely in big-data era, which can satisfy the long-distance and high-capacity needs with characteristics of fast speed, wide bandwidth and high reliability. As the front end of optical receiver, optical receiver pre-amplifier determines the performance of the whole receiver Optical fiber communication has been adopted widely in big-data era, which can satisfy the long-distance and high-capacity needs with characteristics of fast speed, wide bandwidth and high reliability. As the front end of optical receiver, optical receiver pre-amplifier determines the performance of the whole receiver system. Based on SMIC 0.13 μm CMOS technology, a 5Gbps optical receiver pre-amplifier was completed in this work. At first, the full differential structure can eliminate the common-mode noise and reduce the input-referred noise. Then, in order to suppress the defect of large photodiode capacitance, Regulated Cascade(RGC) structure with low input impedance was exploited. The output buffer was realized with Common-Mode Logic structure that can balance the gain and bandwidth. The simulation results show the gain of 62 dBΩ and bandwidth of 4.7 GHz. Meanwhile, the amplifier has a input-referred noise of 30.1 pA/ sqrt(Hz). The eye diagram is clear and the opening is enough big, which can meet the communication demand of 5 Gbps balance detector system..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2137 (2015)
Design, fabrication and encapsulation of sensing head for Fiber Optic Current Transducer
Li Jianzhong, Li Zeren, Tian Jianhua, and Lei Jiangbo
The error of commercial Fiber Optic Current Transducer(FOCT) must be less than 0.2%, the sensing head is a key factor for high-accuracy current sensing. The topology, operational principle and difficulties of fiber optic current transducer were introduced, and the sensing head affecting the performance of fiber optic cThe error of commercial Fiber Optic Current Transducer(FOCT) must be less than 0.2%, the sensing head is a key factor for high-accuracy current sensing. The topology, operational principle and difficulties of fiber optic current transducer were introduced, and the sensing head affecting the performance of fiber optic current transducer was analyzed. The design, fabrication and encapsulation of sensing head were studied. The improved sensing head that can avoid all kinds of negative effects was manufactured by using suitable material and method, which has excellent environment adaptability, reliability and stability. The experimental results show that the measurement precision of fiber optic current transducer is improved by using the improved sensing head, and the FOCT can satisfy the accuracy requirements of the 0.2 S class measuring electronic transducer, meeting the requirements of digital substation..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2143 (2015)
Laser frequency drift noise reduction in fiber-optic system based on Φ-OTDR through a novel location algorithm
Zhang Xi, Cao Qiaoyuan, Li Qin, Zhong Xiang, and Li Lijing
In the distributed fiber-optic disturbance sensor system based-on Φ-OTDR, the frequency drift of laser directly results in low signal to noise ratio(SNR) of the system and further influences system location. In order to reduce the disturbance location error induced by laser frequency drift, a location algorithm was proIn the distributed fiber-optic disturbance sensor system based-on Φ-OTDR, the frequency drift of laser directly results in low signal to noise ratio(SNR) of the system and further influences system location. In order to reduce the disturbance location error induced by laser frequency drift, a location algorithm was proposed through analyzing the error mechanics, which combines spectrum analysis with characteristic frequency selection. The characteristic frequency for location was achieved by comparing the SNR of the system owing to different frequency. Laboratory tests were established and the results indicate that the algorithm is efficient to disturbance location for the location and the performance of system has been enhanced..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2150 (2015)
Technical research of adaptive fiber coupler array based on SPGD algorithm
Li Feng, Geng Chao, Li Xinyang, Luo Wen, and Qiu Qi
Adaptive fiber coupler(AFC) is a new kind of fiber-based adaptive-optics device which can achieve high and steady efficiency in coupling laser beam from space into fibers. Analysis on the feasibility of adopting AFC array as receiver in free space laser communications was studied. Simulation research on the closed-loopAdaptive fiber coupler(AFC) is a new kind of fiber-based adaptive-optics device which can achieve high and steady efficiency in coupling laser beam from space into fibers. Analysis on the feasibility of adopting AFC array as receiver in free space laser communications was studied. Simulation research on the closed-loop control process of AFC array with different number of sub-units using SPGD algorithm under different turbulence conditions was achieved. Simulation results show that: (1) adopting AFC array as receiver can realize high and stable coupling efficiency and alleviate the effects of atmospheric turbulences; (2) coupling efficiency and the algorithm convergence rate promote as the number of the array increases, where the equivalent aperture of the receiver is certain..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2156 (2015)
Weighted centroid localization algorithm based on multilateral localization error of received signal strength indicator
Cui Fayi, and Shao Guanlan
In order to optimize the localization algorithm and improve the accuracy of positioning in Wireless Sensor Network(WSN), a kind of weighted centroid localization algorithm based on multilateral localization error was proposed. After analyzing the transmission model of wireless signal, a model of distance measurement waIn order to optimize the localization algorithm and improve the accuracy of positioning in Wireless Sensor Network(WSN), a kind of weighted centroid localization algorithm based on multilateral localization error was proposed. After analyzing the transmission model of wireless signal, a model of distance measurement was established on account of logarithm fit about the relationship between Received Signal Strength Indicator(RSSI) and distance. Then the multilateral localization algorithm and location estimation model of solving unknown node′s coordinates were introduced. After the orientation of several sets of data, the reciprocal of positioning error was used as a weight in the process of calculation to improve usual centroid algorithm and the influence of selection of reference point number to the error was discussed. The experimental result shows that when compared with traditional centroid algorithm, the improved weighted centroid algorithm has better localization precision, when choosing four or five reference nodes, the experiment can achieve better location performance..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2162 (2015)
[in Chinese]
Study on atmospheric transmittance of thermal infrared remote sensing(II): application of atmospheric transmittance model
Gong Shaoqi, Sun Haibo, Wang Shaofeng, Guo Wenzhe, and Li Yunmei
Atmospheric transmittance is an important parameter in the thermal infrared remote sensing. For the atmospheric transmittance models in the previous paper, taking the transmittance model of the infrared camera(IRS) onboard chinese environment and disaster monitoring satellite(HJ-1B)as an example, the radiance at top atAtmospheric transmittance is an important parameter in the thermal infrared remote sensing. For the atmospheric transmittance models in the previous paper, taking the transmittance model of the infrared camera(IRS) onboard chinese environment and disaster monitoring satellite(HJ-1B)as an example, the radiance at top atmosphere over waters was simulated, a series of error were brought to the variables in the atmospheric transmittance model, and the temperature from the simulated radiance was retrieved. Given that, the sensitivity of aerosol model, water vapor, visibility and view zenith affecting on retrieved temperature was analyzed. The atmospheric transmittance model was applied to 4 HJ/IRS thermal infrared images and the water surface temperature on April 17, 21, 22 and 25, 2009 was retrieved in lake Taihu, China. The results show that the atmospheric transmittance model within different aerosol models for any channel produce various errors during the temperature retrieving from the remote sensed radiance, that the error is the largest for the advective fog model and is the lowest for the tropospheric model, that the retrieved error of temperature displays the linear trend with the error of variables in the atmospheric transmittance models, the water vapor is the most susceptible for the temperature retrieving, the second for the view zenith and the third for visibility. When the atmospheric transmittance model is applied to HJ/IRS thermal infrared images for retrieving the water surface temperature, the error on April 17 is a little high which the root mean square error(RMSE)and the mean relative error(MRE)are 1.127℃ and 5.75% respectively, while the RMSE on other 3 days is below 1℃ and their MRE is less than 5%. This illustrates that the atmospheric transmittance model have the perfect application accuracy in the thermal infrared remote sensing..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2013 (2015)
Cold strap design of long linear IRFPA dewar
Fan Guangyu, Fan Cui, Li Jun, and Gong Haimei
A design scheme of flexible cold strap according to the requirement of long linear IRFPA packaging was presented in this paper, the characteristics of long linear IRFPA and linear pulse tube cooler were summarized, design ideas and design methods based on the mechanical and thermal requirements of cold strap were propoA design scheme of flexible cold strap according to the requirement of long linear IRFPA packaging was presented in this paper, the characteristics of long linear IRFPA and linear pulse tube cooler were summarized, design ideas and design methods based on the mechanical and thermal requirements of cold strap were proposed. For typical butting substrate size and working temperature, used partial flexible cold strap scheme was used, which was optimized by FEM tool, design requirements was achieved. Test dewar was made according to the design result, temperature difference of cold strap, flatness and temperature uniformity of butting substrate were verified. The test dewar has passed vibration testing. The test results show that the design scheme is correct and feasible..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2021 (2015)
Analysis of imaging features and tracking performance of seeker after decoys jamming
Guo Bingtao, Wang Xiaorui, Wang Xiaobing, Yuan Hongxue, and Yang Hongjian
The main factors that affect the imaging characteristic of infrared imaging seeker and the jamming principle of infrared decoys on the imaging characteristic of infrared imaging seeker were analyzed based on signal transfer and conversion mechanism of infrared imaging seeker. Then, with the end-to-end imaging modeling The main factors that affect the imaging characteristic of infrared imaging seeker and the jamming principle of infrared decoys on the imaging characteristic of infrared imaging seeker were analyzed based on signal transfer and conversion mechanism of infrared imaging seeker. Then, with the end-to-end imaging modeling ideas, and considering the impact of infrared decoys on the radiative properties of target surface and the auto gain characteristics of infrared imaging seeker, the imaging characteristics quantitative model of infrared imaging seeker was established. Furthermore, on the basis of theoretical analysis mentioned above, the real-time simulation of the output images and tracking features of infrared imaging seeker after infrared decoys jamming was carried out by computer 3D scene simulation technology, and the tracking performance of the infrared imaging seeker was studied based on the simulation results. The results show that the jamming effect of infrared decoys on the tracking performance of infrared imaging seeker varies with the launching direction of infrared decoys. The infrared decoys show the greatest jamming effect when the launching angle of infrared decoys are about 75°-95°、190°-215° or 250°-280°, while infrared decoys show the least jamming effect when the launching angles of infrared decoys are about10°-40°, 150°-170° or 315°- 325°..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2027 (2015)
Effects of cloud on air target IR detection
Fang Yiqiang, Chen Wei, Sun Xiaojun, Ma Donghui, Cheng Zhengdong, and Zhang Faqiang
Cloud is an important factor for the difficulty in air target detection and recognition. Based on the IR radiation of target and cloud, the effects of cloud on the target IR detection were analyzed. Firstly, according to the 4 different position relationships of target and cloud, the models for calculating the radiatioCloud is an important factor for the difficulty in air target detection and recognition. Based on the IR radiation of target and cloud, the effects of cloud on the target IR detection were analyzed. Firstly, according to the 4 different position relationships of target and cloud, the models for calculating the radiation difference of target and cloud that received by the detector were established, and then the calculations of the parameters in the model were discussed. Lastly, the simulation calculation was done as an example based on the model, and the results were analyzed. The results show that：in the band of 8-14 μm, the radiation difference of target and cloud has bigger value near the wavelength of 9 μm and direction angle of 50°, and smaller value appears at the longer wavelength and larger direction angle. The conclusion can provide the basis for the design of IR detection system..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2034 (2015)
Effect of reflected background radiation by skin on infrared characteristics of subsonic aircraft (II): application
Huang Wei, and Ji Honghu
The effect of background radiation, such as the sunshine, the atmosphere and the ground on the total infrared radiation signature of a subsonic aircraft was studied by using the infrared radiation signature computation model under typical background environment. The influence of the background radiation on the infraredThe effect of background radiation, such as the sunshine, the atmosphere and the ground on the total infrared radiation signature of a subsonic aircraft was studied by using the infrared radiation signature computation model under typical background environment. The influence of the background radiation on the infrared suppression of low emissivity was analyzed. The results show that the sunshine radiation has a great effect on the front detection region of the aircraft in the 3-5 μm waveband; the atmosphere and ground radiation has a more obvious effect on the front and side detection region of the aircraft in the 8-14 μm waveband; the impact is different when the detection orientation and season changes; the infrared radiation suppression effect of low emissivity is reduced or even failed because of the background infrared radiation reflected from the skin..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2039 (2015)
Research on column channel gain non-uniformity of simulate detector
Xu Honglie, Chen Qian, Liu Ning, and Yang Chunhua
Assumed that the response to the blackbody radiation of the same temperature are equal for each pixel, each column of the infrared detector should have the same gain. But in practice, due to the defects of the production process and the material components of the focal plane array, the response of each pixel is not ideAssumed that the response to the blackbody radiation of the same temperature are equal for each pixel, each column of the infrared detector should have the same gain. But in practice, due to the defects of the production process and the material components of the focal plane array, the response of each pixel is not identical, meanwhile the channel gain of each column is not the same. The column channel gain non-uniformity of the readout circuit of the IRFPA was mainly studied. A lot of actual data was used for column channel output response curve fitting. Then, according to the data, the model of the polynomial curve simulate detector with column channel gain non-uniformity was deduced, and the precision analysis of the fitting curve was did, where a hypothesis testing method was used to verify whether the polynomial model was fit for the column gain of actual detector in global. Finally, a good simulation to the gain non-uniformity of each column was achieved..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2044 (2015)
Quantitative identification of coating thickness and debonding defects of TBC by pulse phase technology
Chen Lin, Yang Li, Fan Chunli, Shi Hongchen, and Zhao Xiaolong
In order to promote quantitative detection of thermal barrier coating by pulse phase, the pulse phase nondestructive testing model of thermal barrier coating in axisymmetric cylindrical coordinates was established. Temperature field was solved by using a finite volume method in the heat pulse excitation. And the phase In order to promote quantitative detection of thermal barrier coating by pulse phase, the pulse phase nondestructive testing model of thermal barrier coating in axisymmetric cylindrical coordinates was established. Temperature field was solved by using a finite volume method in the heat pulse excitation. And the phase of the model was accepted by FFT. The impacts of different factors on the phase were analysised. Based on this, quantitative detection of coating thickness and position of the bonding defect of thermal barrier coating were researched in axisymmetric cylindrical coordinates by using the method of LM. The impacts of different factors on quantitative detection were analysised. The research results show that the recognition accuracy of results are high in different initial assumption and different modulation time when there is no measurement error, the effect of initial assumption and modulation time on quantitative recognition is little, the recognition accuracy of results are high in different uniform temperature measurement error, uniform temperature error would not change the result of recognition, the accuracy of the identification results would decrease with the increase of the random temperature error, but there is still a high recognition accuracy under large random temperature error, the effectiveness of the quantitative identification method was proved..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2050 (2015)
Infrared lock-in excitation technology based on digital power control
Tao Shengjie, Yang Zhengwei, Tian Gan, and Zhang Wei
To improve the integration level and performance of modulated heat excitation source, a new digital power control technology was developed for application of lock-in thermography in NDT. Silicon controlled rectifier(SiCR) was used as a power output controlling unit, and a relationship between SiCR′s control angle and oTo improve the integration level and performance of modulated heat excitation source, a new digital power control technology was developed for application of lock-in thermography in NDT. Silicon controlled rectifier(SiCR) was used as a power output controlling unit, and a relationship between SiCR′s control angle and output power was also obtained. Taking the sinusoidal signal as the excitation source, the changing rule of control angle over time was achieved by using numerical calculation while the control algorithm and implementation method of the conduction angle were designed based on digital micro processing circuit. The experimental platform was thus built up and the comparison experiments were carried out. The results show that the present approach can gain higher precision of power control, better fidelity of thermal waveform and preferable equipment in structure and size. Moreover, its electromagnetic safety can meet the relevant requirement. Therefore, better results can be expected by using this method in the infrared lock-in thermography..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2057 (2015)
Design of fusion system based on infrared moving target segmentation
Sun Bin, Chang Benkang, Zhang Junju, Wang Guiyuan, and Li Yingjie
In order to improve the fusion image quality and target detection performance of infrared and visible image fusion system, an image fusion reconnaissance system was designed which used moving target of infrared video and visual to moniter the scene. This system realized the infrared image segmentation algorithm based oIn order to improve the fusion image quality and target detection performance of infrared and visible image fusion system, an image fusion reconnaissance system was designed which used moving target of infrared video and visual to moniter the scene. This system realized the infrared image segmentation algorithm based on human visual characteristics and weighted fusion algorithm based on target′s characteristics in the hardware platform. Also, the system contained the circuit of infrared moving object segmentation and fusion processing circuit. Firstly, image segmentation circuit to extract the moving target of infrared video was designed by FPGA. Secondly, the image which only contained moving target was input to fusion processing circuit consisting of DSP. Last, a series of fusion images which had the characteristic of target form prominent and background details clear were furnished. Through the experiment, this system can both improve the target detection performance and processing speed. The image fusion evaluation increased more than 90%, and some indexes increased more than 7 times..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2064 (2015)
[in Chinese]
Optimization of the number of quantum wells in the active region for 2 μm laser diode
An Ning, Liu Guojun, Li Zhanguo, Li Hui, Xi Wenxing, Wei Zhipeng, and Ma Xiaohui
In order to find the appropriate quantum well number, the electrical and optical characteristics of InGaAsSb/AlGaAsSb laser diode with various QW numbers and contents were investigated using LASTIP simulation program. In the case of single QW, the total number of carriers injected into the QW will be small and the radiIn order to find the appropriate quantum well number, the electrical and optical characteristics of InGaAsSb/AlGaAsSb laser diode with various QW numbers and contents were investigated using LASTIP simulation program. In the case of single QW, the total number of carriers injected into the QW will be small and the radiative recombination will be poor. When the number of QWs was increased into larger than 4, however, the optical performance started to degrade because of the uneven distribution of carrier concentration and the higher electron concentration in the p-side, which increased in the internal loss in the active region. Taking into account of the effect of QWs number on the epitaxy layers quality, the optimized number of InGaAsSb/AlGaAsSb 2 μm LDs was 2-3. The obtained results are beneficial to the design of the high performance 2 μm Sb-containing LDs..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 1969 (2015)
Power stabilization system of medium wave infrared laser based on acousto-optic modulator
Gao Miao, Shao Xiaopeng, Wang Lin, Shi Xueshun, Sun Haoyang, Ding Zhongkui, Sun Hualiang, Zhang Yanjie, and Liu Yulong
To suppress the fluctuation of medium wave infrared laser output power, a kind of power stabilization system was developed by the method of acousto-optic feedback, which consists of acousto-optic modulator, detector, micro-current amplifier and feedback control circuit. According to the experimental results, this systeTo suppress the fluctuation of medium wave infrared laser output power, a kind of power stabilization system was developed by the method of acousto-optic feedback, which consists of acousto-optic modulator, detector, micro-current amplifier and feedback control circuit. According to the experimental results, this system has the ability to suppress the power fluctuation in the range of ± 0.08% and to meet the stable output power requirement of cryogenic radiometer. Different mode can be set easily in software to obtain the different output power of the laser, and the adjust progress will be finished within 2 s by using the incremental PID control algorithm. This function gives users great convenience and solves the problem that one laser can only supply one output power. This system has the advantage of good practicability and innovation..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 1975 (2015)
Analysis of impact factors of output characteristics for optically pumped THz lasers
Li Ting, Guo Xiaoyang, Meng Qinglong, and Zhang Bin
Designing stable and reliable THz lasers as well as reducing dimension of THz lasers have always been a hot research spot in THz field. Based on the rate equations, the model of optically pumped THz lasers has been built up. The effects of the operating temperature, the pressure in cavity, the dimension of cavity and tDesigning stable and reliable THz lasers as well as reducing dimension of THz lasers have always been a hot research spot in THz field. Based on the rate equations, the model of optically pumped THz lasers has been built up. The effects of the operating temperature, the pressure in cavity, the dimension of cavity and the stability of pump laser on the output characteristics of optically pumped THz lasers have been simulated and analyzed. The results show that it is necessary to realize the reliable temperature control since the output of THz laser becomes more and more sensible for the higher pump power. In order to reduce the dimension of THz lasers, the output power of THz lasers could be ensured by appropriately increasing the pressure of working gas in THz cavity. THz output characteristics are more sensitive to the fluctuation of pump power and the drift of pump frequency for the lower power of pump laser. Consequently, the stability of pump laser should be controlled, especially for the stability of pump frequency..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 1980 (2015)
Simulation of actively Q-switched pulse parameters in Nd:YVO4 and Nd:YAG
Dong Xiaolong, Gao Lanlan, Zhang Fan, Jiao Shi, and Ji Guandong
Using Q-switched rate equations, the relationship among the optimum reflectivity, maximum pulse energy, largest peak power, pulse width and the dimensionless variable z was analyzed, and the influence of the condition of different cavity roundtrip dissipative loss, cavity gain and inversion reduction factor on activelyUsing Q-switched rate equations, the relationship among the optimum reflectivity, maximum pulse energy, largest peak power, pulse width and the dimensionless variable z was analyzed, and the influence of the condition of different cavity roundtrip dissipative loss, cavity gain and inversion reduction factor on actively Q-switched pulse parameters in Nd:YVO4 and Nd:YAG was also analyzed, respectively. The modeling results indicate that the optimum reflectivity and pulse width decrease with the increase of cavity roundtrip dissipative loss, and the maximum pulse energy and largest peak power decrease with the increase of inversion reduction factor which affects maximum pulse energy and largest peak power greatly. One can make the Q-switched pulse parameters embodied through the certain value of z..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 1986 (2015)
Design of semiconductor laser quick temperature control system
Xia Jinbao, Liu Zhaojun, Zhang Sasa, and Qiu Gang
Temperature was one of the parameters influencing the characteristic of the semiconductor laser. To realize the temperature control quickly and stably，the temperature controlling hardware and algorithm were researched. The system was based on the Micro Control Unit(MCU) MSP430. The driver circuit was used, adjusting ciTemperature was one of the parameters influencing the characteristic of the semiconductor laser. To realize the temperature control quickly and stably，the temperature controlling hardware and algorithm were researched. The system was based on the Micro Control Unit(MCU) MSP430. The driver circuit was used, adjusting circuit voltage adaptively was in conjunction with output style of pulse width modulation. The self-adjusting temperature algorithm was also designed by the model of the mechanical temperature balance and experiment in high-low temperature test-box. According to the experiment result, the stability time from the temperature -40-+50 ℃ to the setting temperature 23 ℃ were respectively 2 min 30 s and 1 min 30 s, respectively. The control precise was 0.2 ℃. By the analysis of power stability experiment result, the laser power stability is improved from 5% before temperature control to less than 1% after temperature control. The laser power stability density is safe for the eye. The schematic design of system has significance for the small power and quick stability laser system..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 1991 (2015)
Development of high power direct output semiconductor laser processing system
Hu Xiaodong, Xu Yuanfei, Yao Jianhua, and Yu Chengsong
Semiconductor lasers and their industrial applications are research focus in laser field, the development of domestic high power semiconductor lasers has made great progress, but the research on automated processing equipment based on domestic high power semiconductor direct output lasers is few. A laser processing equSemiconductor lasers and their industrial applications are research focus in laser field, the development of domestic high power semiconductor lasers has made great progress, but the research on automated processing equipment based on domestic high power semiconductor direct output lasers is few. A laser processing equipment was developed which was based on domestic high power direct output semiconductor lasers. DSP-based embedded control system was also developed for laser processing measurement and control, and fuzzy control algorithm was designed for closed-loop temperature control, and a desirable temperature control effect was acheved. Wideband laser transformation hardening experiments on this platform show that, the consistency of depth and hardness of the transformation hardening layer are better in the temperature control mode contrast to that in the constant power mode..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 1996 (2015)
Ultrafast laser-induced changes in titanium
Yang Chengjuan, Tian Yanling, Cui Liangyu, and Zhang Dawei
In order to realize the qualitative control of the ultrafast laser-induced changes trend and the quantitative control of the ultrafast laser-induced changes range in titanium, respectively, comparative ablation experiments by femtosecond, and picosecond-pulsed laser with different pulse durations were carried out on tiIn order to realize the qualitative control of the ultrafast laser-induced changes trend and the quantitative control of the ultrafast laser-induced changes range in titanium, respectively, comparative ablation experiments by femtosecond, and picosecond-pulsed laser with different pulse durations were carried out on titanium. Then the influence of laser pulse duration varying on final surface morphology, ablation depth, chemical composition and microstructural state of the ablated titanium were analyzed by laser scanning confocal microscopy, X-ray photoelectron spectroscopy and transmission electron microscopy, respectively. It is found that, as the laser pulse duration increases from femtosecond to picosecond scale, surface morphology quality of ablated titanium gets worse, chemical composition of final ablation products is more complex and also the microstructural state has a higher degree of amorphization. Finally, it is deduced that the occurrence of all above experimental results can be attributed to the more serious thermal and mechanical damages in material resulted from the enhanced heat accumulation effect in titanium with the pulse duration increasing..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2002 (2015)
Land-based facilities vibration monitoring system based on laser Doppler effect
Feng Qingqi, Liu Gang, Zhou Mingxi, and Feng Chao
Several vibration monitoring methods were compared. The basic principle of laser Doppler vibration monitoring was elaborated. A new kind of laser Doppler vibration monitoring system(LDVMS) that used for the small-size land-based facilities of launch site was designed. High precision PDV100-type LDVMS was used in the exSeveral vibration monitoring methods were compared. The basic principle of laser Doppler vibration monitoring was elaborated. A new kind of laser Doppler vibration monitoring system(LDVMS) that used for the small-size land-based facilities of launch site was designed. High precision PDV100-type LDVMS was used in the experiment. The electrodynamic loudspeaker, which was selected to simulate the frequency character of the small-size land-based facilities of launch site, its amplitude and vibration frequency were investigated as two important characteristic parameters. The analysis of experiment results show that the relative error of the vibration frequency is less than 0.4%, the amplitude can reach 1 μm order of magnitude. The character of the designed LDVMS satisfies the need of launch site..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2008 (2015)
[in Chinese]
Optical design of the off-axis three-mirror anastigmatic collimator with long focal length and wide field
Yang Yufei, and Yan Changxiang
For the application demand of high image quality collimator with large diameter, long focal length and wide field, an off-axis three-mirror configuration for the light collimator was proposed. Based on the coaxial three-mirror configuration theories, the computation of the initial structure of the system was dervied, aFor the application demand of high image quality collimator with large diameter, long focal length and wide field, an off-axis three-mirror configuration for the light collimator was proposed. Based on the coaxial three-mirror configuration theories, the computation of the initial structure of the system was dervied, and a method of optimizing the off-axis amount was put forward by using the ZPL language of zemax software. A wide field off-axis three-mirror light tubes was designed, with focal length of 10 m, F-number of 28.57. Results show that the modulation transfer function of this system is near the diffraction limit, within the field 2°×1°, the full field wave-front aberration is less than λ/200(λ=632.8 nm), the total length of the system is less than f ′/3, providing a possibility design of long focal length, large diameter, and wide field of view light collimator..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2070 (2015)
Application and analysis of wave front coding technology on TMC system
Guo Xiaohu, Zhao Yuejin, and Wu Yijian
Temperature difference and satellite vibration lead to in-orbit space camera defocused and deteriorated image quality. The wave front coding technology can extend the depth of focus without changing the optical system structure, which makes MTF insensitive for defocus. The wave front coding technology was applied to TMTemperature difference and satellite vibration lead to in-orbit space camera defocused and deteriorated image quality. The wave front coding technology can extend the depth of focus without changing the optical system structure, which makes MTF insensitive for defocus. The wave front coding technology was applied to TMC system. Optimized to the best surface type, the phase mask plate was placed in the exit pupil. The imaging characteristics of the original system and wave front coding system were analyzed and evaluated. And the phase parameter which was related to the extended ratio of depth of focus and image quality was aslo analyzed. Theory and simulation results show that the application of wave front coding technology on TMC system can be easy to extend the depth of focus. It is concluded that the wave front coding technology has high practical value to solve the imaging defocused..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2075 (2015)
Ground attitude simulation light source technology
Wang Lingyun, Wang Bo, Zhang Guoyu, Sun Gaofei, Su Shi, and Liu Shi
The solar sensor and the infrared earth sensor are important equipments for controlling the satellite′s attitude; they must be tested in the ground before the satellite launch. The system includes one solar simulating light which′s made up of four slits and two earth simulating lights which is simulated for an earth anThe solar sensor and the infrared earth sensor are important equipments for controlling the satellite′s attitude; they must be tested in the ground before the satellite launch. The system includes one solar simulating light which′s made up of four slits and two earth simulating lights which is simulated for an earth angle of 15.6° of earth synchronous orbit height. In this paper, the overall structure and the components of the ground attitude simulation lights were described. To design the system, infrared optical technique was used and the germanium collimating lens was designed, meanwhile the installation institutions of the ground attitude simulation light source was designed in order to connect the simulation light source to the real satellite safely for ensuring the requirements of the star products. The earth simulation light can simulate the earth chord width of 15.6° and the speed of the satellite is 10-120 rpm. The earth chord width and speed were tested through experiment, which show that the earth angle error is less than 0. 04° and speed phase-locked error is no more than 1 ms..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2080 (2015)
Optical design of small-sized camera in visible for micro-satellite
Chen Yonghe, Chen Hongda, and Fu Yutian
Micro-satellite was greatly developed in the past 20 years due to its advantages of small-size, light weight, short developing period, low cost, etc. Now, micro-satellite plays a great role in many realms, such as navigation, communication, earth observation, science research and technology experiments, which make it tMicro-satellite was greatly developed in the past 20 years due to its advantages of small-size, light weight, short developing period, low cost, etc. Now, micro-satellite plays a great role in many realms, such as navigation, communication, earth observation, science research and technology experiments, which make it to be an important part of space technology. To miniaturize, micro-satellite has to be equipped with small-size instruments. A small-sized camera worked in visible band was introduced, which can be installed on micro-satellite. Technical parameters of the camera were as follows： effective focal length was 210 mm, optical aperture was 56 mm, spatial resolution was 33 μrad, field of view was 7.8°×7.8°, or 16 M pixels in all. In the design phase, different optical structures were compared, and a catadioptric system was adopt. Fused silica and low density flint glass materials were used to balance chromatic aberration. Total length of optical system was 110 mm, and the ratio between total length and effective focal length was less than 0.53. The weight of all lenses was under 370 g..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2087 (2015)
Research on achieving zero optical path difference interferometer based on infrared static wedge
Zhang Rui, Wang Zhibin, Wang Yaoli, and Li Kewu
Existing static wedge interferometer can not achieve zero optical path difference, thereby affecting the accuracy and speed of spectral inversion. Therefore, a method of achieving zero optical path difference by improving the wedge structure was put forward. By improving the structure of the inclined surface, the wedgeExisting static wedge interferometer can not achieve zero optical path difference, thereby affecting the accuracy and speed of spectral inversion. Therefore, a method of achieving zero optical path difference by improving the wedge structure was put forward. By improving the structure of the inclined surface, the wedge can be achieved on the incident light interference signal which contains zero optical path difference. By deducing and analyzing the optical path difference of the arbitrary wedge position, and the formula of spectral inversion was deduced. Using Zinc Selenide(ZnSe) materials design and processing of the wedge, interference signal and the optical path difference was simulated, and the process of spectral inversion was simulated. The wedge was analyzed by experiments which used 10.64 μm laser. Result shows that the interference signal clarity, optical path difference can reach 1 450 μm, and the relative error of experiment is 0.1%..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2093 (2015)
Research on large radio telescope structure scheme
Liu Yan, Qian Hongliang, and Fan Feng
Aiming at the 110 m fully-steerable radio telescope(which is called QTT for short ) to be built in the future, in order to improve the main reflector precision, the traditional structural concepts were analyzed based on the best fit paraboloid. It is the uneven deformation of the reflector that results in the lower preAiming at the 110 m fully-steerable radio telescope(which is called QTT for short ) to be built in the future, in order to improve the main reflector precision, the traditional structural concepts were analyzed based on the best fit paraboloid. It is the uneven deformation of the reflector that results in the lower precision. It is mainly due to the following three aspects: the concentrated loads exist on the main reflecting surface, the back frame supporting system is unreasonable and the back frame structure has a poor performance. Based on this, the catching points of the secondary reflector supporting legs were changed, the space truss structure combining cones and quadrangular pyramids were adopted as the back frame structure design, and a kind of polar symmetry umbrella structure was proposed as the supporting system for the back frame structure. Finally the introduced scheme for the fully-steerable radio telescope significantly improved the main reflector precision, its maximal RMS was reduced to 0.306 mm. Compared with the fully-steerable radio telescope GBT which has the largest diameter in the world, the reflective surface area of QTT increases 10%, the surface precision improves 12.6% and the total weight decreases 40%. The QTT performance reaches the international advanced level..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2097 (2015)
[in Chinese]
Research for resources scheduling of relay satellite system with hybrid links based on fusion algorithm of genetic and ant colony
Deng Boyu, Zhao Shanghong, Hou Rui, Zhao Weihu, Zhao Jing, and Zhang Xiwen
According the defects that genetic algorithm easily falling into local optimum and ant colony optimization is little initial pheromone information, the fusion algorithm of genetic and ant colony was proposed for the resources scheduling problem. The definition of ant colony optimization pheromone was improved. The ideaAccording the defects that genetic algorithm easily falling into local optimum and ant colony optimization is little initial pheromone information, the fusion algorithm of genetic and ant colony was proposed for the resources scheduling problem. The definition of ant colony optimization pheromone was improved. The idea of coding based on the serial number of time windows was used. The restrictive condition and the objective function of the resources scheduling was given and the mathematical model was established. The optimization characteristics of fusion algorithm, standard genetic algorithm and modified ant colony algorithm were analyzed by simulation. The result shows that it is quite good to solve the relay satellite scheduling problem by using the fusion algorithm..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2211 (2015)
Comparison of hyperspectal and imagery characteristics of freezing stress and normal wheat
Duan Yunsheng, Zhang Dongyan, Huang Linsheng, and Zhao Jinling
Freezing stress is one of the meteorological disasters causing significant loss of agricultural production in China, and easily leads to serious threat for national crop security. Image processing technique was used to extract the coverage characteristics of freezing stress and normal wheat, while hyperspectral remote Freezing stress is one of the meteorological disasters causing significant loss of agricultural production in China, and easily leads to serious threat for national crop security. Image processing technique was used to extract the coverage characteristics of freezing stress and normal wheat, while hyperspectral remote sensing technology was utilized to explore spectral changes of freezing stress and normal wheat and determine the sensitive recognition bands. The results indicated that the green and red bands in visible ranges are identification bands of freezing stress, especially in the green peak and red valley location; near-infrared bands are sensitive range to detect freezing stress. In conclusion, spectral analysis combination with image processing technology is feasible for analyzing and extracting freeze injury characteristics of wheat in the field..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2218 (2015)
A multi-subregions decision tree land cover classification approach using Landsat8 image
Li Feng, Liang Handong, Mi Xiaonan, and Wei Aixia
Coal fires burning caused serious environmental, economic and safety catastrophe in Wuda district, North China. The land cover change research helped to evaluate the extent of coal fire damage. The image data of Landsat8 satellite offered the possibility of detecting and studying land cover/use in coal fire area. Five Coal fires burning caused serious environmental, economic and safety catastrophe in Wuda district, North China. The land cover change research helped to evaluate the extent of coal fire damage. The image data of Landsat8 satellite offered the possibility of detecting and studying land cover/use in coal fire area. Five subregions were divided from one Wuda image based on topographic, landform and land surface radiation characteristics. Corresponding to each subregion, five different decision tree models with different parameters were respectively constructed based on a general sole decision tree for the whole research area, which was built by spectral characteristics analysis, height, slope and infrared information. By contrasting with a general sole decision tree and other four common classification methods applied to the whole area, land cover accuracy of multi-subregions decision tree classification approach derived higher overall accuracy(87.63%) and Kappa coefficient(0.86) because subregions decreased land-cover confusions. In particular, the accuracy of building and coal ash classification mapping showed a marked increase..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2224 (2015)
Estimating 6 DOF pose transformation of a TOF laser camera
Li Xingdong, Li Mantian, Guo Wei, Chen Chao, and Sun Lining
Relative pose estimation is a hot research topic in the community of robotic vision. 6 DOF pose transformation was estimated by two frames data. Several effective algorithms were proposed to guarantee the precision of the estimation which made full used of TOF camera. Iterative Closest Point(ICP) algorithm was used to Relative pose estimation is a hot research topic in the community of robotic vision. 6 DOF pose transformation was estimated by two frames data. Several effective algorithms were proposed to guarantee the precision of the estimation which made full used of TOF camera. Iterative Closest Point(ICP) algorithm was used to estimate the pose transformation, in order to conquer the divergence problem of ICP, scaled Invariant Feature Transform(SIFT) feature pairs were employed to compute the initial value for ICP. The contrast of the image was increased for extracting the effective features by scaling the original gray image according to principle of statistics. Multiple frames were fused to improve the accracy of depth measurement based on the fact that the longer the exposure time was, the higher the accuracy was, and every pixels in the fused frame were captured with the longest valid exposure time. A methed for measuring the difference of two 6 DOF pose transformations was proposed, which was applied to track the iterations of ICP. The experiments have demonstrated the effectiveness of the algorithms proposed in this paper..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 2231 (2015)
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