Journals >Infrared and Laser Engineering
Contents
2016
Volume: 45 Issue s1
37 Article(s)
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[in Chinese]
Observation and analysis of optical turbulence in Northwest plateau
Chen Xiaowei, Li Xuebin, Sun Gang, Liu Qing, Zhu Wenyue, and Weng Ningquan
Spatio-temporal evolution of optical turbulence is important for site-testing and optimizing the performance of adaptive optical systems. Measurements were taken over three years using surface layer atmospheric parameter system and differential image motion monitor. Microthermal sensors measured structure constant of rSpatio-temporal evolution of optical turbulence is important for site-testing and optimizing the performance of adaptive optical systems. Measurements were taken over three years using surface layer atmospheric parameter system and differential image motion monitor. Microthermal sensors measured structure constant of refractive index and differential image motion monitors measured atmospheric coherent length and isoplanatic angle. Analysis of structure constant of refractive index showed the monthly and seasonal evolution of surface optical turbulence. Different parameters were analyzed during inversion time. The vertical profile of atmospheric structure constant of refractive index was gained based on Hufnagel-Valley mode1 for night,day and inversion time and different characters were found for different profiles．Based on longtime experiments, the results are credible and valuable for engineering application.isoplanatic angle.
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 111001 (2016)
Photo-thermal interferometer measurement of absorbent constituents in atmosphere
Li Shuwang, Shao Shiyong, Mei Haiping, and Rao Ruizhong
The absorption of atmospheric aerosol particle affects earth′s radiation balance and laser transmission in atmosphere, especially high energy laser. The precise measurement of aerosol light absorption is paid more and more attention. The basic principles of the photo-thermal interferometry for measuring aerosol absorptThe absorption of atmospheric aerosol particle affects earth′s radiation balance and laser transmission in atmosphere, especially high energy laser. The precise measurement of aerosol light absorption is paid more and more attention. The basic principles of the photo-thermal interferometry for measuring aerosol absorption coefficient, demodulation algorithms and calibration principle were introduced. A fiber structure photo-thermal interferometer instrument was developed, and the feasibility was verified by measuring the absorption of N2, NO2 and black carbon aerosol. Finally, quantitative analysis was executed with the standard NO2 gas at 532 nm whose detection limitation was 3.976 mg·m-3. The qualitative and quantitative analysis demonstrate that the fiber structure photo-thermal interferometer has great potential in practical aerosol absorption measurement..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 111002 (2016)
[in Chinese]
Coherently coupled soliton pairs in biased two-photon photorefractive crystals with both linear and quadratic electro-optic effects
Hao Lili, Hou Chunfeng, Mu Haiwei, Li Xianli, Bai Yongqiang, Wang Qiang, and Zhao Yuan
The coherent coupling of two spatial solitons propagating along the same line in biased two-photon photorefractive crystals with both the linear and quadratic electro-optic effects was investigated. It was proved that coherently coupled dark-dark and bright-bright spatial optical soliton pairs can be supported in the sThe coherent coupling of two spatial solitons propagating along the same line in biased two-photon photorefractive crystals with both the linear and quadratic electro-optic effects was investigated. It was proved that coherently coupled dark-dark and bright-bright spatial optical soliton pairs can be supported in the steady regime under appropriate conditions. These soliton pairs owe their existence and properties to the co-effects of both the linear and quadratic electro-optic effects where photorefractive effect may be enhanced, weakened or even counteracted because of the interaction of these two electro-optic effects. Moreover, the effects of the externally applied electric field, the initially phase difference and the intensity ratio of the two coherent beams on the existence conditions, properties of these spatial soliton pairs and self-deflection of coherently coupled bright-bright soliton pairs were discussed in detail, which lays the theoretic foundation for practical application of coherently coupled spatial soliton pairs.coherent coupling.
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 108001 (2016)
[in Chinese]
Design of an X-ray detecting system based on square polycapillary X-ray lens
Yi Longtao, Sun Tianxi, Wang Kai, Peng Shiqi, Han Yue, Zhang Shuang, and Liu Zhiguo
An X-ray detecting system based on square polycapillary X-ray lens was designed, which had a very small X-ray collection angle. The square polycapillary X-ray lens is an X-ray control device based on total X-ray reflection. The X-ray in large range can be focused on an X-ray CCD detector by the square polycapillary X-rAn X-ray detecting system based on square polycapillary X-ray lens was designed, which had a very small X-ray collection angle. The square polycapillary X-ray lens is an X-ray control device based on total X-ray reflection. The X-ray in large range can be focused on an X-ray CCD detector by the square polycapillary X-ray lens. By measuring the transmission characteristic of the square polycapillary X-ray lens and creating the data modelling, the data detected by the X-ray CCD detector could be corrected and the information of the X-ray in the entry end of the square polycapillary X-ray lens could be restored. The transmission characteristic of the square polycapillary X-ray lens was simulated by the light trajectory tracking method. The results show that this system is suitable for large area X-ray imaging when the energy of the X-ray is lower than 20 keV. It is also suitable for collecting X-ray to improve the detection efficiency when the energy of the X-ray is lower than 14.6 keV. The above characteristics show that this system is not only suitable for some special detecting such as pulsar navigation, but also suitable for normal X-ray detecting..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 117001 (2016)
Measurement methods for parallelism of optical paths for vehicle-based laser platform
Shi Long, Chen Ning, Wang Bing, Shao Shuai, Yang Ciyin, Dong Yuxing, and Guo Ruhai
For the flexible requirement to the photoelectric instrument, the vehicle platform is needed to load the transmitting light path and receiving light path, often including several lasers and many mirrors. There have been some methods to measure the parallelism of optical paths for the fixed platform which is not suitablFor the flexible requirement to the photoelectric instrument, the vehicle platform is needed to load the transmitting light path and receiving light path, often including several lasers and many mirrors. There have been some methods to measure the parallelism of optical paths for the fixed platform which is not suitable for the vehicle platform. Therefore, a certain improvement should be made to the measurement methods for parallelism of optical paths for the vehicle-based photoelectric system. In our system, the optical paths of four laser systems and three imaging system need to be adjusted into the same line or paralleling each other. Therefore, the requirements for the vehicle platform are more complicated for the parallel test. According to the feature of the platform based on the vehicle, a systemic method was presented for the parallel test. The measurement results show that these methods are simple and practical for the measurement of parallelism in vehicle-based photoelectric devices and the measurement errors between each light path are all less than 15 μrad..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 117002 (2016)
[in Chinese]
A squeezed lattice high negative dispersion and high birefringence photonic crystal fiber
Wu Limin, Song Peng, Wang Jing, Zhang Haikun, Zhou Cheng, Chen Tao, and Zhang Feng
A squeezed high birefringence Photonic Crystal Fiber (PCF) with high negative flattened dispersion characteristics was proposed. In order to obtain the high birefringence characteristics, the cladding of PCF was made of squeezed triangular lattice and elliptical air holes. In order to improve the flexibility of controlA squeezed high birefringence Photonic Crystal Fiber (PCF) with high negative flattened dispersion characteristics was proposed. In order to obtain the high birefringence characteristics, the cladding of PCF was made of squeezed triangular lattice and elliptical air holes. In order to improve the flexibility of controlling the dispersion, the core of PCF was added into a small defect air hole. The birefringence and dispersion characteristics were analyzed by super lattice method. The simulation results show that the designed PCF offers ultra flattened negative dispersion (-667±7 ps·nm-1·km-1) in a broad range of wavelengths from 1.3 μm to 1.8 μm, the birefringence can be reached the magnitude of 10-2 and the high birefringence can be reached 2.21×10-2 at 1.55 μm. Based on the high negative dispersion and high birefringence characteristic, PCF will be widely used in optical transmission system and optical fiber sensing..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 120001 (2016)
An advanced integrated avalanche photodiode with Si and Ge material
Wei Jiatong, Chen Liwei, Hu Haifan, and Liu Zhiyuan
An advanced avalanche photodiode(APD) was put forword which was integrated by the Si Separate Absorption, Charge, Multiplication(SACM) and Ge SACM APDs. This advanced APD has enlarged the detected wavelength range to 200-1 400 nm. Furthermore, the key parameters which were used to characterize the APD performance, suchAn advanced avalanche photodiode(APD) was put forword which was integrated by the Si Separate Absorption, Charge, Multiplication(SACM) and Ge SACM APDs. This advanced APD has enlarged the detected wavelength range to 200-1 400 nm. Furthermore, the key parameters which were used to characterize the APD performance, such as the electric field distribution, the dark current and photocurrent, the gain, and the sensitivity of the APD were researched. The simulation results demonstrated that the breakdown voltage of the advanced APD is 145 V, the peak response is 22 A/W at 900 nm wavelength as cathode is 140 V, and the current gain of the advanced APD could get 50 at 400 nm wavelength before breakdown. The fabrication process was also discussed..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 120002 (2016)
[in Chinese]
Spectral scattering inversion method of GEO satellite components
Xu Rong, and Zhao Fei
The core of the satellite characteristics inversion based on mixed satellite spectra is the mathematical model and inversion algorithm. Theoretical model of spectral mixing was built with experiments conducted to justify the model. First, theoretical analysis of components′ spectral scattering model, linear spectral miThe core of the satellite characteristics inversion based on mixed satellite spectra is the mathematical model and inversion algorithm. Theoretical model of spectral mixing was built with experiments conducted to justify the model. First, theoretical analysis of components′ spectral scattering model, linear spectral mixing model and unmixing methods of satellite′s spectral data was conducted. Then, experiments were designed to measure and calibrate the spectral BRDF of a high-fidelity GEO satellite and its components, while the spectral scattering characteristics of component and material were discussed. Finally, nonnegative constrained least square methods were utilized to unmix the satellite′s spectral data, with the largest relative residue less than 10%. Experiment results show that the linear spectral mixing model and nonnegative constrained least square unmixing methods have practical meaning in explaining spectral data of satellites and inversing satellite conditions..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 123001 (2016)
Prediction method of single wheat grain protein content based on hyperspectral image
Wu Jingzhu, Liu Qian, Chen Yan, and Liu Cuiling
The characteristics of wheat protein content has high heritability, so fine-quality breeding can be achieved by selecting the high-protein wheat seed. Combined with chemometric methods′ hyperspectral imaging technique was used to build the average model to achieve fast prediction of single wheat seed protein content. IThe characteristics of wheat protein content has high heritability, so fine-quality breeding can be achieved by selecting the high-protein wheat seed. Combined with chemometric methods′ hyperspectral imaging technique was used to build the average model to achieve fast prediction of single wheat seed protein content. In the experiment, 47 unit wheat seed samples′ hyperspectral images were collected by GaiaChem-NIR system, and the average spectra was obtained by image process methods. Then, synergy interval partial least squares was applied to select the characteristic spectral regions to optimize the prediction model of wheat seed protein content. The optimal models′ determination coefficient is 0.94, the root mean square error of prediction is 0.28%, and the residual predictive deviation(RPD) is 3.30. Finally, the average model was applied to predict the protein content of each pixes of single wheat seed, and calculated the average as the single wheat grain protein content. The experimental results showed that different wheat grain′s protein content value predicted by the optimal model existed difference. Ueanwhile, the prediction values varied around the average protein content of its sample, which reflected that the average model is accurate and feasible to predict single wheat grain’s protein content. Therefore, the studied method provides a new way to select the high-protein wheat seed in the process of breeding, which can promote the development of wheat fine-quality breeding..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 123002 (2016)
[in Chinese]
Simulation and optimization of axial supporting structures for theodolite primary mirror
Xie Jun, He Fengyun, Wang Jing, Gao Ge, Zhao Tianjiao, and Liu Zhenyu
In order to obtain the effect of supporting structures on the surface error of theodolite primary mirror, the topology optimization and parameter analysis of axial supporting structures of primary mirror were performed. First, contact boundary condition was used to establish the detail finite element model of primary mIn order to obtain the effect of supporting structures on the surface error of theodolite primary mirror, the topology optimization and parameter analysis of axial supporting structures of primary mirror were performed. First, contact boundary condition was used to establish the detail finite element model of primary mirror supporting structures. The surface error of original supporting structures was analyzed and the surface error RMS was obtained under both horizontal optical axis condition and vertical optical axis condition. Then, a 4D interferometer was used to measure the surface error RMS under lateral supporting condition. Results show that the deviation of surface error RMS of numerical results and experimental results is 13.2%, which verify the accuracy of simulation method. At last, the topology optimization of the primary axial supporting structures was carried out. The new axial supporting structures were made according to the topological configuration. After that, the parameter analysis was carried out on some important dimensions of axial supporting structures. Results show that the primary mirror surface error RMS of optimized supporting structures is obviously better than the original one. The original surface error RMS of axial supporting is 11.49 nm, while the optimized one is 8.38 nm. The research is an important reference to the design of primary mirror supporting structures..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 118001 (2016)
Simulation of compound-axis tracking systems based on EasyLaser
Yue Yufang, Xie Xiaogang, and An Jianzhu
Compound-axis servo system is effective on the improvement of tracking stability and precision for optical beam pointing system. Its entitative simulation models were categorized into scene model, target imaging model, prediction model and tracking control model, etc. EasyLaser was general component simulation softwareCompound-axis servo system is effective on the improvement of tracking stability and precision for optical beam pointing system. Its entitative simulation models were categorized into scene model, target imaging model, prediction model and tracking control model, etc. EasyLaser was general component simulation software. Based on friendly modeling method for used and program auto growing technology of EasyLaser, component-based compound axis tracking system simulation method was proposed. The Simulink circumstance nest mode based on Matlab engine was discussed and simulation creditability was proved. Furthermore, amalgamation of kinematics, control, optical propagation was partially analyzed, some assistant components were proposed. Through numerical solving method, control driver decoupling procedure was simulated automatically. Component simulation problem for compound-axis system with structure and optical layout multiplicity was solved at all. Simulation example of compound-axis joint with adaptive optics system illustrates that the component simulation method has the capacity of retaining simulative creditability and enhancing the simulative facility and adaptability..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 118002 (2016)
[in Chinese]
Application of UAV remote sensing technology in open-pit slop mapping
Liu Jun, Wang He, Wang Qiuling, and Liu Xiaoyang
3D modeling and visualization of the slope body is an essential prerequisite for objective evaluation of open-pit slop stability. Taking an open-pit slope where a small scale landslide happened as the study object, open-pit slope sequence images were first obtained from unmanned aerial vehicle(UAV) with a consumer-grad3D modeling and visualization of the slope body is an essential prerequisite for objective evaluation of open-pit slop stability. Taking an open-pit slope where a small scale landslide happened as the study object, open-pit slope sequence images were first obtained from unmanned aerial vehicle(UAV) with a consumer-grade camera. And then, dense 3D point clouds were generated based on computer vision technology. Finally, high-resolution 3D digital models of open-pit slope were made. The experiment shows that the presented method can quickly construct an open-pit slope fine terrain, effectively reduce the operation cost and labor intensity. Moreover, due to this technology breaks the limitation of traditional method of single point measurement, reconstructed model can accurately expressed the global and local characteristics of open-pit slope, which can provide powerful support for the correct analysis and evaluation of slope stability, especially suitable for dynamic deformation monitoring of the potential risk open-pit slope..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 114001 (2016)
New aircraft terrain matching algorithm based on particle swarm optimization
He Yanping, Liu Xinxue, Cai Yanping, Li Yaxiong, and Zhu Yu
In order to improve the positioning accuracy of traditional terrain matching algorithm, a new aircraft terrain matching algorithm based on particle swarm optimization was put forward. The search scope of true location was programmed by taking the measured position of referenced navigation system as the center, terrain In order to improve the positioning accuracy of traditional terrain matching algorithm, a new aircraft terrain matching algorithm based on particle swarm optimization was put forward. The search scope of true location was programmed by taking the measured position of referenced navigation system as the center, terrain elevation data was extracted from the referenced topographic map, then the particle swarm optimization algorithm was introduced into the matching area for searching, and the parameter of pixel height of the terrain profile was used as the particle in particle swarm. On this basis of above, correlation function of normalized product was applied as fitness function of particle, then the degree of similarity of the referenced map with profile of real-time image was compared by maximum fitness value, finally through the simulation analysis, comparison of matching accuracy and time based on TERCOM algorithm and PSO algorithm was presented. Simulation results show that the effect of matching based on PSO algorithm is better than traditional TERCOM algorithm, and matching time is slightly longer than TERCOM, but meet the real-time requirement..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 114002 (2016)
[in Chinese]
High sensitive near infrared imaging system based on single element detectors
Huo Juan, Li Mingfei, Yang Ran, Zhao Lianjie, Zhang Anning, and Mo Xiaofan
After tens of years development, photo-electronic imaging during day and night has entered the practical stage, and playes an important role in military, aerospace, astronomy, etc. In order to realize the photo-electronic imaging in low-light-level, a new-type of imaging system was proposed by analyzing the Image-IntenAfter tens of years development, photo-electronic imaging during day and night has entered the practical stage, and playes an important role in military, aerospace, astronomy, etc. In order to realize the photo-electronic imaging in low-light-level, a new-type of imaging system was proposed by analyzing the Image-Intensifier Tubes and near-thermal imaging. In this new-type of imaging system, spatial light modulator and single element detectors could be used to modulate and detect the information of the objective, after that correlation algorithm was used to restore the objective image. In experiment, a setup based on single element detectors was built to take an image of the television tower for a long distance about 17 km range. High sensitive imaging could be realized by this new-type of imaging system. The results demonstrate that this new imaging system is a promising approach to achieve photo-electronic imaging in low-light-level, such as moonless night.correlation algorithm.
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 104001 (2016)
Vignetting correction method for the infrared system based on polynomial approximation
Li Zhaolong, Shen Tongsheng, and Lou Shuli
Vignetting effect during infrared imaging is the phenomenon that image plane center region is bright but edge is dark. The vignetting effect is very serious, so it is necessary to correct the vignetting effect when the system is used. First, the cause of the vignetting effect was analyzed. Then, a fast correction methoVignetting effect during infrared imaging is the phenomenon that image plane center region is bright but edge is dark. The vignetting effect is very serious, so it is necessary to correct the vignetting effect when the system is used. First, the cause of the vignetting effect was analyzed. Then, a fast correction method was proposed. The background information was extracted, and the background gray distribution was obtained by polynomial approximation. To evaluate the correction effect, the concept of variance between rows which has statistical significance was put forward. To verify the correction method, two kinds of scenes were used. Variance between rows was reduced to 13.6% and 3.8% compared with uncorrected images. The effect of the correction method is ideal..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 104002 (2016)
Radiation simulation technology for IR capture and tracking device
Xu Zhenling, Yang Miaomiao, Wang Min, Liu Lianwei, and Guo Zhenghong
The radiation simulation system for IR acquisition and tracking device were introduced based on the DMD dynamic infrared scene projector. The optical principle of the DMD projector was introduced. The requirements and methods of the optical matching between the DMD projector and system under tested were analyzed. The tThe radiation simulation system for IR acquisition and tracking device were introduced based on the DMD dynamic infrared scene projector. The optical principle of the DMD projector was introduced. The requirements and methods of the optical matching between the DMD projector and system under tested were analyzed. The time modulation of the DMD projector was introduced, and the requirements and methods of the synchronization between the DMD projector and system under tested were analyzed. The factors which influence on the energy transmission between DMD projector and system under tested were analyzed, and the methods of calibration and energy matching between DMD projector and system under tested were analyzed. The experiments were carried out for certain IR acquisition and tracking device using the simulation system, and some performance of the device were simply assessed..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 104003 (2016)
Modeling infrared radiance and calculating spectral emissivity based on RBF network
Xi Jianhui, Xu Zhenfang, Fu Li, and Wang Qi
A method of modeling infrared radiance based on RBF neural network was built, then the target spectral emissivity was estimated. When measuring the infrared radiation characteristics of the target surface in the 3-14 μm band by FTIR spectrometer, the infrared radiance will be absorbed by carbon dioxide, water vapor, etA method of modeling infrared radiance based on RBF neural network was built, then the target spectral emissivity was estimated. When measuring the infrared radiation characteristics of the target surface in the 3-14 μm band by FTIR spectrometer, the infrared radiance will be absorbed by carbon dioxide, water vapor, etc, and affected by some stray radiation. In this paper, the effective learning samples were firstly selected combined with the theory of infrared transmission. Then the samples based on the RBF network were fully learned, and a target infrared radiance model was built. And this model was used to estimate the radiance in the band of atmospheric absorption and stray radiation. A more complete target spectral emissivity curve was finally calculated. Compared the calculating results of blackbody with theoretical emissivity, the maximum relative error is 1.5%. The verification of temperature measurement also shows that the RBF neural networks can be built efficiently to estimate target spectral emissivity.方面的研究。.
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 104004 (2016)
Influence of particle radius of composition on radiation characteristics of infrared decoy
Yang Chunling, Zhang Zhendong, and Liu Guocheng
Infrared decoy is a common infrared countermeasures weapon, which has a significant jamming effect on infrared-guided weapons. Among many kinds of infrared decoys, the method of releasing some composition to generate a jamming radiation source is still widely used in practice. In the development and manufacturing proceInfrared decoy is a common infrared countermeasures weapon, which has a significant jamming effect on infrared-guided weapons. Among many kinds of infrared decoys, the method of releasing some composition to generate a jamming radiation source is still widely used in practice. In the development and manufacturing process of this kind of decoy, the particle radius of composition has a great influence on decoy＇s radiation characteristics. To study the influence of the particle radius of composition, in this paper, the structure and working principle of infrared decoy were analyzed, the infrared characteristic model of decoy based on discrete phase model (DPM model) was built, the relationship between particle radius of infrared decoy and radiation characteristics was summarized. Finally, through fitting simulation data base on the least square method, the optimal particle radius of 3.72 mm was found while infrared decoy had maximum radiation intensity. This method lays a research foundation for the particle radius of composition of infrared decoy, and also has great guiding value in the field of decoy＇s research and simulation..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 104005 (2016)
Effect of diffuse reflection path-length of near-infrared on sensitivity of glucose concentration detection
He Jun, Xu Kexin, Liu Rong, and Li Chenxi
Near-infrared photons propagate in the mixed solution of intralipid and glucose and form diffuse reflection. In steady state, the scattered photons at the detection spot include ballistic photons, quasi-ballistic photons, and scattered photons, and part of ballistic photons and scattered photons decrease the detection Near-infrared photons propagate in the mixed solution of intralipid and glucose and form diffuse reflection. In steady state, the scattered photons at the detection spot include ballistic photons, quasi-ballistic photons, and scattered photons, and part of ballistic photons and scattered photons decrease the detection accuracy of glucose concentration. By Monte Carlo time-domain simulations of 10% and 3%intralipid-glucose solution respectively, different path-length components of diffuse reflection at different detection spots were statistically analyzed. It is shown that both the peak time of the detection time expansion curve and diffuse reflection photons in the average flying time can improve the detection accuracy of the point of floating reference, where the diffuse reflection is the most insensitive to the glucose concentration. Moreover, these photons increase, at the maximum intensity of diffuse reflection, the coefficients of linear dependency between the intensity of diffuse reflection and glucose concentration. Thus, extraction of the diffuse reflection corresponding to this path-length improves the detection sensitivity of glucose concentration..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 104006 (2016)
Numerical calculation of 3.8 滋m and 1.55 滋m laser radiation transmission characteristic under foggy condition
Zhang Zeyu, Xie Xiaoping, Duan Tao, Wen Yu, and Wang Wei
Fog is an inevitable weather factor affecting the performance of free space optical communication. Selecting the appropriate laser wavelength can effectively reduce the influence. Three atmospheric visibility of mist, fog, haze were considered in this paper. The transmission characteristic of mid-wave IR wavelength at Fog is an inevitable weather factor affecting the performance of free space optical communication. Selecting the appropriate laser wavelength can effectively reduce the influence. Three atmospheric visibility of mist, fog, haze were considered in this paper. The transmission characteristic of mid-wave IR wavelength at 3.8 μm was compared with the traditional near-infrared wavelength at 1.55 μm that both belong to atmospheric transmission windows. Using Monte Carlo method, the propagation of a large number of photons along the horizontal direction was numerically simulated. Relationship between the relative light intensity and different receiving surface radius, photon transmittance under different transmission distance and different atmospheric visibility were worked out. The result reveals that the mid-wave IR wavelength at 3.8 μm, the light intensity is more concentrated under the same radius of receiving surface, and photon transmission is higher under the same propagation distance and less affected by atmospheric visibility. The wavelength at 3.8 μm is more suitable for horizontal link of free space optical communication in the fog than 1.55 μm..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 104007 (2016)
[in Chinese]
Applied research on the homogenization technology of laser illumination
Zhao Huifu, and Cui Qingfeng
In order to achieve laser uniform illumination, a new laser homogenization system was designed based on the analysis of regular homogenization technology, and the homogenization technology and the uniformity of laser illumination were researched. The new homogenization system used brushless motor to drive a light shapiIn order to achieve laser uniform illumination, a new laser homogenization system was designed based on the analysis of regular homogenization technology, and the homogenization technology and the uniformity of laser illumination were researched. The new homogenization system used brushless motor to drive a light shaping scatterer to rotate at a frequency faster than the electronic shutter of cameras, making multiple light superimposed in integration time to form a uniform illumination effect. The new homogenization system can eliminate laser speckles and interference fringes, and realize the purpose of homogenization. Experimental results show that the new homogenization system makes the illumination uniformity reach up to 95% and the energy efficiency reach up to 90% in the effective area. The new homogenization system improves the uniformity of illumination and utilization rate of laser, thus improves the image quality of the illuminated target..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 106001 (2016)
Effect of high power laser pulse on the electroconductivity of multi-crystalline silicon wafer
Xu Defu, Xiao Xiao, and Li Yude
In order to decrease the quantity of crystal bundary, dislocation, micro-defect and transition group impurity contained in multi-crystalline silicon and further to increase solar cell′s photoelectric conversion efficiency, the silicon wafers were preprocessed for solar cell utilizing the laser pulse which was produced In order to decrease the quantity of crystal bundary, dislocation, micro-defect and transition group impurity contained in multi-crystalline silicon and further to increase solar cell′s photoelectric conversion efficiency, the silicon wafers were preprocessed for solar cell utilizing the laser pulse which was produced by TEA CO2 laser. The laser pulse duration is about 200 ns and the wavelength is about 10 ?滋m. Multi-crystalline silicon wafers were placed in 20 mm Hg hydrogen gas and irradiated by different wavelength laser pulse and different pulse numbers, twenty-five samples were manufactured. After removing the affected layer, the sample′s electrical resistivity was metered using S2T-2A four point probe tester. The result shows that all sample′s electrical resistivity is cut down in different degree. Specifically the sample′s electrical resistivity decline rate is the largest and its maximum is 50%, which is irradiated by P18 and P20 brunch and irradiated by three pulses. The lifetime of minority carrier of all samples was tested with high frequency photoconductive lifetime tester, the outcome of experiment indicates that all sample′s minority carrier lifetime is increased. Especially the samples lifetime is raised largely which are irradiated by P18 and P20 brunch and irradiated by three pulses, their increasing amplitude reaches 30%..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 106003 (2016)
Low-pass spatial filter for laser beam based on cutoff filters
Zheng Guangwei, Zheng Qiurong, and Chu Xingchun
Due to the fine optical characteristics of cutoff filter, the configurations based on two pieces of long-pass cutoff filter or two pieces of short-pass cutoff filter were put forward respectively. Based on the geometrical optics, the performances of these two configurations were analyzed. The results show that the anguDue to the fine optical characteristics of cutoff filter, the configurations based on two pieces of long-pass cutoff filter or two pieces of short-pass cutoff filter were put forward respectively. Based on the geometrical optics, the performances of these two configurations were analyzed. The results show that the angular spectrum bandwidths of these two configurations depend on both the intersection angle between the cutoff filters and the angular bandwidth of transition zone. For the long-wave-pass cutoff filter, the intersection angle must be no less than two times of its cutoff angle. While for the short-wave-pass cutoff filter, the intersection angle must be no more than two times of its cutoff angle. Theoretically, its minimum bandwidth is equal to the angular bandwidth of transition zone, when the intersection angle is two times of the cutoff angle..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 106004 (2016)
System of laser actively evading flying objects based on image acquisition using CCD
Xiong Jun, Xia Yuan, Yang Yong, Cheng Xuewu, and Li Faquan
Lidars emit high intensity of laser beam to the sky, which has a potential threat to the flyers. For the flight safety and the safe operation of lidar, a method was proposed for laser actively evading flying objects and an experimental setup was built up. The system utilized a CCD to achieve image acquisition of the aiLidars emit high intensity of laser beam to the sky, which has a potential threat to the flyers. For the flight safety and the safe operation of lidar, a method was proposed for laser actively evading flying objects and an experimental setup was built up. The system utilized a CCD to achieve image acquisition of the airspace around the lidar emitting beam in real time. The images were transmitted to the PC and processed by the control software. Finally the shutter in the lidar emitting path was controlled to turn on or turn off according to the results of the imaging process. When flyers fly into the field of view of the CCD, the shutter can be turned off automatically to cut off the laser emission path so that to ensure the flight safety and the safe operation of lidar..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 106005 (2016)
[in Chinese]
1.55 μm all-fiber coherent Doppler lidar for wind measurement
Hu Yang, and Zhu Heyuan
Light detection and ranging (LiDAR) offers a method of remote wind speed measurement. A kind of all-fiber coherent Doppler lidar was proposed, whose components were connected via optical fibers. The simplicity of the structure is quite convenient for adjustment. First, the signal processing method used in this system wLight detection and ranging (LiDAR) offers a method of remote wind speed measurement. A kind of all-fiber coherent Doppler lidar was proposed, whose components were connected via optical fibers. The simplicity of the structure is quite convenient for adjustment. First, the signal processing method used in this system was used to measure the simulated Doppler shift. The simulation results indicate that the more noise is added to the signal, the more errors will be obtained from the calculation. Second, the lidar system was utilized to measure the velocity of a hard target. The results conform very closely to the reference, whose absolute errors are less than 0.046 m/s. Finally, the lidar system was used to measure the speed of the water steam. The results deviate from the reference more than that of a hard target, whose maximum absolute error rises up to 0.925 m/s. The simulation and experiment results validate the accuracy and stability of the lidar system..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 130001 (2016)
High spectral resolution lidar for measuring atmospheric transmission
Zhao Ming, Xie Chenbo, Zhong Zhiqing, Wang Bangxin, Wang Zhenzhu, Shang Zhen, Tan Min, Liu Dong, and Wang Yingjian
A high spectral resolution lidar(HSRL) based on injection-seeded laser and iodine absorption filter has been developed. The basic principle, data processing method and configuration of HSRL were introduced. The HSRL measurement of atmospheric transmission in cloud and dust cases were presented,and compared with the resA high spectral resolution lidar(HSRL) based on injection-seeded laser and iodine absorption filter has been developed. The basic principle, data processing method and configuration of HSRL were introduced. The HSRL measurement of atmospheric transmission in cloud and dust cases were presented,and compared with the results retrieved by the traditional Fernald method. Due to the nonidentity in physical and optical properties of different aerosols and cloud, the lidar ratio assumed in Fernald method cannot agrees well with the real atmosphere and produces considerable error in atmospheric transmission. Utilizing different spectral width of molecular scattering and particle scattering, the HSRL could separate two kinds of signals with iodine filter. Therefore, HSRL can measure the atmospheric transmission quantitatively without the additional assumption of lidar ratio..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 130002 (2016)
Estimating noise scale factor and SNR of atmospheric lidar
Deng Pan, Zhang Tianshu, Chen Wei, Liu Jianguo, and Liu Yang
The signal-to-noise ratio(SNR) of Lidar (light detection and ranging) reflects its radiance and is one of the most important parameters for evaluation of lidar return signal quality. However, it is very difficult to estimate the value of SNR quantitatively in practical engineering. At the first, the algorithm was used The signal-to-noise ratio(SNR) of Lidar (light detection and ranging) reflects its radiance and is one of the most important parameters for evaluation of lidar return signal quality. However, it is very difficult to estimate the value of SNR quantitatively in practical engineering. At the first, the algorithm was used to estimate lidar returns noise scale factor(NSF) and SNR. Then, the value of NSF of the Rayleigh lidar were estimated by measuring 0-40 km atmosphere day and night with 532 nm wavelength laser, which is 0.07 in daytime and 0.034 in nighttime. Finally, the SNR of the atmospheric lidar was estimated by the value of NSF in daytime. Result shows that the method which based on the NSF in nighttime of lidar to estimate the value of SNR is feasible. The evaluating of NSF and SNR of the lidar can be used as the basis for its overall design and inversion..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 130003 (2016)
Long-term frequency stabilization system in 532 nm wind lidar
Guo Wenjie, Yan Zhaoai, Hu Xiong, Guo Shangyong, and Cheng Yongqiang
The 532 nm Doppler lidar developed by the National Space Science Center, Chinese Academy of Sciences, is mainly used to measure the atmospheric wind field, temperature, and density. Maintaining a same reference frequency is a key technology to ensure the normal operation of the Doppler lidar. This lidar system uses seeThe 532 nm Doppler lidar developed by the National Space Science Center, Chinese Academy of Sciences, is mainly used to measure the atmospheric wind field, temperature, and density. Maintaining a same reference frequency is a key technology to ensure the normal operation of the Doppler lidar. This lidar system uses seed injection technique to obtain a single mode pulse laser, and maintains the same reference frequency by locking the seed laser into the iodine absorption line. The frequency of the seed laser can be adjusted by two mechanisms: applying a voltage to a piezoelectric(PZT) crystal or changing the temperature of the laser crystal. The response speed of the two kinds of tuning mechanism is different. PZT tuning has a fast response speed but a narrow tuning range, while the thermal tuning has a wide tuning range and a low response speed. A long-term frequency stabilization system was designed by coordinating the two kinds of frequency tuning mechanism. And a Proportion Integration Differentiation(PID) algorithm was used to calculate the feedback voltage. The system did not require a acquisition card with a large range of output voltage. In this system, the laser frequency drift in long term and large range will be tuned by thermal tuning mechanism, while the instantaneous frequency drift will be responded by PZT tuning. The accuracy of the new frequency stabilization system is 350 kHz. The system can work well as long as twenty hours..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 130004 (2016)
Shock absorption design of the receiving system for re deployment of sodium lidar
Cheng Yongqiang, Hu Xiong, Yan Zhaoai, Guo Shangyong, Sun Yiqiao, and Zhang Xu
In the process of the re deployment, in order to prevent the adverse effects and assure the stability and accuracy of the sodium Doppler fluorescence lidar in the near space environment of the Chinese Academy of Sciences(Langfang, 39°N, 116°E), the shock absorption design of the receiving system in sodium lidIn the process of the re deployment, in order to prevent the adverse effects and assure the stability and accuracy of the sodium Doppler fluorescence lidar in the near space environment of the Chinese Academy of Sciences(Langfang, 39°N, 116°E), the shock absorption design of the receiving system in sodium lidar was mainly carried out. Firstly, the three-level shock absorber design was carried out by selecting the air suspension chassis, the main mirror of the telescope, and the platform for the installation of the telescope. Through simulation, it was found that the impact displacement of the telescope platform is less than the design requirements of the primary mirror of the telescope. Secondly, by the sports truck experiment, the maximum vibration acceleration of the main mirror chamber was found to meet the requirements of the design input of the telescope. In the end, the reliability of shock absorption design of the long distance transportation is further verified by the observation experiment of the sodium doppler fluorescence lidar..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 130005 (2016)
Airborne LiDAR point cloud data classification based on relevance vector machine
Liu Zhiqing, Li Pengcheng, Guo Haitao, Zhang Baoming, Chen Xiaowei, Ding Lei, and Zhao Chuan
Aiming at the limitations of support vector machine(SVM) applied in Airborne LiDAR(Light Detection And Ranging) point data classification, such as weak model sparseness, predictions lack of probabilistic sense, and kernel function which must satisfy Mercer′s condition, a novel LiDAR point cloud data classification methAiming at the limitations of support vector machine(SVM) applied in Airborne LiDAR(Light Detection And Ranging) point data classification, such as weak model sparseness, predictions lack of probabilistic sense, and kernel function which must satisfy Mercer′s condition, a novel LiDAR point cloud data classification method was proposed based on relevance vector machine(RVM). Firstly, the sparse Bayesian classification model and the process of parameter inference and prediction were analyzed. Then, the classification problem was transformed into the regression problem by making use of Laplace′s method. Next, the hyperparameter estimation was attained by utilizing maximum likelihood method and a sequential sparse Bayesian learning algorithm was selected to improve training speed. Finally, multiple classifiers were built to realize multi-class classification. The LiDAR point cloud datum from Niagara and Africa were selected for experiment based on SVM, and experimental results show the advantages of classification method based on RVM..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 130006 (2016)
[in Chinese]
On-board space debris recognition and accurate positioning method
Zhai Guang, Zhao Qi, and Zhang Jingrui
A method of detecting and recognizing space debris based on visible light camera and laser range finder was proposed in this paper. The shape of imaging was determined by the relative velocity, and distance of space debris. In order to matching different images, an ellipse that had the same second-order central moment A method of detecting and recognizing space debris based on visible light camera and laser range finder was proposed in this paper. The shape of imaging was determined by the relative velocity, and distance of space debris. In order to matching different images, an ellipse that had the same second-order central moment was adopted to describe the edge of image. Based on the features of ellipse, the rules of matching images will be established. By matching different images, the coordinate and azimuth angles can be calculated. If only the azimuth angles were available, the relative position-velocity filter was used for guiding the laser range finder. When the laser range finder worked properly, the extend-Kalman filter was used for getting accurate movement information of the target..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 129001 (2016)
Optimized one-dimensional fluid mechanics model for laser cleaning up space debris
Zhu Yin, Chen Hao, Xu Rong, and Zhao Fei
The optimizedfluid mechanics model was fabricated to solve the plasma of space debris excited by nanosecond pulse laser. Fluid mechanics model was divided into solution of plasma state equation, energy coupling between laser and space debrisand momentum coupling coefficient. In each module implements, time and space diThe optimizedfluid mechanics model was fabricated to solve the plasma of space debris excited by nanosecond pulse laser. Fluid mechanics model was divided into solution of plasma state equation, energy coupling between laser and space debrisand momentum coupling coefficient. In each module implements, time and space distribution of temperature, velocity, pressure and density of debris plasma were analyzed. Considering the influence of plasma shielding effect to the laser efficiency, innovation was putt forward to achieve the highest efficiency of laser to clean up space debris by the method of absorption mechanism of layer by layer. Influences of pluse width and power density to the momentum coupling coefficient were acheived. Finally, comparing the result to experimental experience data prove the verification of the simulation..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 129002 (2016)
[in Chinese]
Characterization techniques of space objects based on point target information
Zhuang Xuxia, Ruan Ningjuan, and Zhao Sisi
Characterization of space objects creates a better understanding about the operational status and behavior of the RSO and point target detection is the main means to obtain information of space objects. While it is difficult to derivate the object characteristics from the product resulted from many unknown parameters, Characterization of space objects creates a better understanding about the operational status and behavior of the RSO and point target detection is the main means to obtain information of space objects. While it is difficult to derivate the object characteristics from the product resulted from many unknown parameters, and amied to this problem, basic properties of the space objects were analyzed in this paper, then several advanced characterization methods were researched. The results show through proper algorithm design, much effective information could be mined from mesured data of point targets..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 126001 (2016)
Color image fusion method for enhancing situation awareness of ICA
Luo Yuan, Zhang Ke, and Ji Ming
Airborne sensors reconnaissance and ground data fusion processing is the fourth grade of UAV situation awareness that planned by USA Office of the Secretary of Defense. Independent Component Analysis(ICA) that applied to the image processing field is a novel method of transform domain in the analysis of human visual syAirborne sensors reconnaissance and ground data fusion processing is the fourth grade of UAV situation awareness that planned by USA Office of the Secretary of Defense. Independent Component Analysis(ICA) that applied to the image processing field is a novel method of transform domain in the analysis of human visual system characteristics based on sparse coding theory, with multiple directions, excellent characteristic extraction and edge modeling feature. Color transfer is the best way to get natural sense color fusion image. The combination of studies highlighted the band characteristics of the natural sense color fusion method so as to enhance UAV situation awareness. Training image database was established according to the scene and the independent band feature information was extracted to construct ICA domain analysis kernel and synthesis kernel. In the ICA domain, the gray fusion image was generated applying area energy fusion rules, the gray fusion image color information was given using source image linear projection to the color channel. The various channels of source color fusion image and color reference image were multi-resolution decomposed using steerable pyramid, each channel transfer mean and variance were independently completed. Finally a similar color fusion image was obtained. Eye perception and objective evaluation show that outstanding band features and natural color enhance detail information to further improve the airborne platforms scene perception..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 126002 (2016)
Automated seamline generation along skeleton for remote sensing image mosaicking considering complex background
Zhang Hansong, Chen Jianyu, Hou Shutao, and Huo Yiren
In response to geometry seamline detection with average separation of overlapped region and beautiful shape for remote sensing images mosaicking considering complex background, a fast automated geometry seamline generation approach along skeleton was proposed on image analysis. Firstly, different kinds of region for imIn response to geometry seamline detection with average separation of overlapped region and beautiful shape for remote sensing images mosaicking considering complex background, a fast automated geometry seamline generation approach along skeleton was proposed on image analysis. Firstly, different kinds of region for image mosaicking were marked in view of background value. Secondly, each block overlapped region to be processed was considered as one image object, the footprints of these image objects were detected and re-marked following specific rules pixel by pixel until the overlapped regions to be processed don′t exist. Finally, the geometry seamline along skeleton was marked on four neighborhood search. The experimental result shows that even if the overlapped region is complex polygon considering background value, the fine seamline can be quickly automatically selected. The algorithm robustness is better than those algorithms on graphic analysis..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 126003 (2016)
Moving target tracking algorithm based on improved Kernelized correlation filter
Xing Yunlong, Li Aihua, Cui Zhigao, and Fang Hao
As Kernelized correlation filter is difficult to deal with the problems of illumination changes and total occlusion of the target, a target tracking algorithm based on improved Kernelized correlation filter was proposed in this paper. Firstly, a Gaussian Kernel correlated operator based on the phase characteristics wasAs Kernelized correlation filter is difficult to deal with the problems of illumination changes and total occlusion of the target, a target tracking algorithm based on improved Kernelized correlation filter was proposed in this paper. Firstly, a Gaussian Kernel correlated operator based on the phase characteristics was proposed to improve the ability of the algorithm to adapt to the change of the light intensity. Then, a tracking mechanism of predicting-tracking-correction based on Kalman filter and an occlusion-handling mechanism were proposed to improve the accuracy of tracking while the target was totally occluded. In the aspect of model updating, an adaptive updating strategy was adopted. The models with better tracking effect were used to establish the alternative model and replace the models with bad tracking effect to correct the problems of model migration and characteristics losing. The experimental results show that the improved algorithm can effectively improve the ability to adapt to the illumination changes and keep a good tracking effect while the target is totally occluded..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 126004 (2016)
Error analysis and consistency improvement for human skin color videos
Yan Yonggang, Deng Xiaoling, Ma Xiang, and Ouyang Jianfei
Skin color video measurements are very important in remote and non-invasive physiological monitoring, and its consistency always affects the measurement accuracy of physiological parameters like heart rate. An image-stabilization method was presented based on Scale Invariant Feature Transform (SIFT) and Wavelet TransfoSkin color video measurements are very important in remote and non-invasive physiological monitoring, and its consistency always affects the measurement accuracy of physiological parameters like heart rate. An image-stabilization method was presented based on Scale Invariant Feature Transform (SIFT) and Wavelet Transform(WT), and was applied to improve the consistency of skin videos image. The video image error was analyzed and an error mathematical model was built. Based on that, the matched pair-points of skin video images was extracted using SIFT algorithm, and on the global motion parameter estimation was carried for the skin videos image to achieve the motion compensation. Finally, a statistics computation was used to evaluate the consistency effects. The results show that the proposed method is valid and correct for improving the consistency of skin videos image, and it lays a foundation for further physiological parameters calculation and studying the optical characteristics of the acupoints..
- Publication Date: Dec. 01, 2016
- Vol. 45 Issue s1 126005 (2016)
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