Journals >Infrared and Laser Engineering
Contents
2018
Volume: 47 Issue 6
38 Article(s)
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[in Chinese]
Measuring method of fiber focal ratio degradation based on a four-quadrant detector
Zhang Meiling, Zou Hua, Liu Jinsheng, and Wang Linzheng
A method of measuring focal ratio degradation of fibers based on a four-quadrant detector was proposed to improve the measurement accuracy of focal ratio degradation in fibers. The output spot of fibers was re-imaged on to the four-quadrant detector, and the spot position sensitivity of detectors was got through scanniA method of measuring focal ratio degradation of fibers based on a four-quadrant detector was proposed to improve the measurement accuracy of focal ratio degradation in fibers. The output spot of fibers was re-imaged on to the four-quadrant detector, and the spot position sensitivity of detectors was got through scanning the surface of the four-quadrant detector with a steering mirror, the actual size of the output spot and focal ratio degradation were measured indirectly in turn in this method. The relationship between the spot position sensitivity and the spot radius was deduced in detail. Meanwhile, the influences of the channel width of four-quadrant detectors on the focal ratio degradation were seriously studied..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 617001 (2018)
Field calibration method for three-line structured light vision sensor
Zou Yuanyuan, Li Pengfei, and Zuo Kezhu
The three-line structured light vision sensor is widely used in industrial field measurement due to it has many advantages such as speedy and abundant information. In order to calibrate the three-line structured light vision sensor on-field with high accuracy and high efficiency, a new calibration method based on suppoThe three-line structured light vision sensor is widely used in industrial field measurement due to it has many advantages such as speedy and abundant information. In order to calibrate the three-line structured light vision sensor on-field with high accuracy and high efficiency, a new calibration method based on support vector machine was proposed. Firstly, a calibration target was designed. Secondly, calibration images were captured and feature points were identified. And then sub-pixel coordinates of feature points were extracted. Thirdly, a direct mapping model according to image coordinates and three dimension coordinates of feature points was built based on support vector machine. Finally, image coordinates of the calibration points were put into the model and their three dimension coordinates could be obtained. So the three-line structured light vision sensor could be calibrated directly. Experimental results demonstrated that this direct calibration method had high accuracy; its mean absolute error was 0.021 1 mm in Y direction and 0.015 0 mm in Z direction. It concludes that this method is easy, fast and suitable for field calibration..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 617002 (2018)
Optimization design of strengthening components for linear motion system of the novel optical testing target
Zhang Shaojun, Gao Yunguo, and Xue Xiangyao
A novel type of optical testing target indoor can be used to simulate the outfield target with complex trajectory, profited from the linear motion system in the structural components. But, the problem of the large span and low stiffness linear motion system of novel optical testing target reduced the testing accuracy oA novel type of optical testing target indoor can be used to simulate the outfield target with complex trajectory, profited from the linear motion system in the structural components. But, the problem of the large span and low stiffness linear motion system of novel optical testing target reduced the testing accuracy of the novel optical testing target. So, firstly, based on the Euler-Bernoulli beam theory, a solution to strengthen the structure in a limited space was proposed. Then, combined with the dynamic characteristics of the linear module structure, the layout of the strengthened beam and the reinforcing plate around it was arranged and the dimensions of the strengthening components were determined by an integrated optimization technique. Finally, modal analysis and vibration test for linear motion system after the installation of the department were implemented. Results show that the first order natural frequency and the second order natural frequency of integral structure of linear motion system are 36 and 55 Hz respectively, and the experimental data are in good agreement with the simulation design date that are 32 and 54 Hz respectively and increases by 1.86 time comparing with the initial structure that first order natural frequency is 14 Hz. These results verify the rationality and reliability of the design of reinforced assembly, at the same time, the structural performance of the strengthened linear motion system meets the requirements of the novel photoelectric testing target, such as light weight, high rigidity, strong anti-interference ability and so on..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 617003 (2018)
Analysis and amendment on the sensitivity of large target area light screen
Yuan Yun, and Tian Hui
In order to solve the problem of unevenness in sensitivity distribution of 10 m×10 m large target area detection in indoors, the sensitivity distribution of the lens light-screen detection sensor was studied. According to the theory of lens photometry, the main factors influencing the sensitivity of light-screen dIn order to solve the problem of unevenness in sensitivity distribution of 10 m×10 m large target area detection in indoors, the sensitivity distribution of the lens light-screen detection sensor was studied. According to the theory of lens photometry, the main factors influencing the sensitivity of light-screen detection were analyzed. The mathematical model of detection sensitivity was established, and the change trend of the amplitude of the projectile signal in different positions of the light-screen was obtained. Finally, the sensitivity correction scheme was proposed, and the evenly sensitivity distribution of the detection screen was realized by changing the luminous brightness of the light source at different positions. Using the air gun to verify the modified detection light-screen shows that the sensitivity to meet the evenly requirements of large target area sensitivity..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 617004 (2018)
Application of new terminal sliding mode in photoelectric stabilized platform
Ren Yan, and Niu Zhiqiang
In order to improve the tracking precision of the photoelectric servo stabilized platform, a new terminal sliding mode control algorithm was proposed to solve the influence of the disturbance. Firstly, a new terminal sliding mode disturbance observer was constructed to realize fast estimation and real-time compensationIn order to improve the tracking precision of the photoelectric servo stabilized platform, a new terminal sliding mode control algorithm was proposed to solve the influence of the disturbance. Firstly, a new terminal sliding mode disturbance observer was constructed to realize fast estimation and real-time compensation for interference in the system. Secondly, combining the idea of finite time convergence with adaptive control theory, a new terminal sliding mode controller was designed to improve the tracking accuracy of the system, adjust the switching gain online, and reduce the chattering of the sliding mode controller effectively, so that the system state was quickly converged to the designed sliding surface in the limited time, and take fine compensation for non-estimated interference. Finally, the stability of the closed-loop control system was proved by Lyapunov theory. The experimental results indicated that this control strategy can ensure the tracking accuracy of photoelectric tracking system for moving targets. The error of tracking is less than 0.002°at the 0.05 Hz and less than 0.034°at 2 Hz, and the robustness of the system is enhanced..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 617005 (2018)
Cooperative guidance law design with impact angle constraint based on second-order sliding mode controller
Shi Zhen, He Chendi, and Zheng Yan
For the problem of multi-missiles intercepting single maneuvering target, the cooperative guidance law with impact time and angle constraints was presented. Firstly, considering the system dynamics equation and the multi-agent consensus algorithm, a second order sliding mode controller along the line of sight(LOS) was For the problem of multi-missiles intercepting single maneuvering target, the cooperative guidance law with impact time and angle constraints was presented. Firstly, considering the system dynamics equation and the multi-agent consensus algorithm, a second order sliding mode controller along the line of sight(LOS) was proposed based on integral sliding mode control concept to guarantee salvo interception. Then an higher order sliding mode observer (HOSMO) was designed to estimate external disturbances of the perpendicular to the LOS. In addition, the sliding mode controller with HOSMO was proposed to guarantee the LOS angles converge to desired commands and the LOS angle rates converge to zero. Moreover, the stability of the two subsystem channels were proved by Lyapunov theorem. Simulation results illustrate the effectiveness of the proposed cooperative guidance law..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 617006 (2018)
A real-time detection approach to pavement rutting based on line laser in nature condition
Hong Ziming, Chen Kun, Jing Genqiang, and Ai Qingsong
A real-time laser path detection method of pavement rutting line was studied in this paper. In traffic running condition of normal driving mode, the lasers were used to continuously emit line laser to the pavement. A sequence of pavement rutting laser line images were acquired dynamically by a high-resolution camera anA real-time laser path detection method of pavement rutting line was studied in this paper. In traffic running condition of normal driving mode, the lasers were used to continuously emit line laser to the pavement. A sequence of pavement rutting laser line images were acquired dynamically by a high-resolution camera and pavement rutting were detected in moving situation in real time. Aiming at the problem of difficult to extract the rutting laser line under the strong interference of the pavement complex background, the characteristics of the rutting laser image of the pavement were analyzed. The definition of non-negative feature measure and the formula of non-negative intensity were given. A method of extracting rutting laser line based on non-negative feature and peak continuity was proposed. Rather than using conventional methods of image processing, the significant and non-significant ridges of the rutting laser line were tracked rapidly using peak continuity to achieve fast and accurate extraction of the rutting laser line with complex background. A large number of verifying tests for different pavements were carried out under conditions of driving, opening traffic, and without blocking other transportation. The experimental results verify the effectiveness and accuracy of the proposed method and solve the problem of fast and accurate extraction of the rutting laser line under natural running conditions. It provides a key technical support for the automatic on-line detection of the pavement rutting and quality evaluation of road surface..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 617007 (2018)
[in Chinese]
Electronic shutter for frame-transfer EMCCD using anti-blooming channel to bleed off charges
Zhang Mengjiao, Cai Yi, Ye Liang, Chen Yuanjin, Xu Chunye, and Wang Lingxue
To resolve the issues of the image blurring of high-speed moving objects and the imaging saturation of high brightness objects and missing detail, an electronic shutter method for frame-transfer EMCCD using anti-blooming channel to bleed off charges and external time frequency control was proposed. Through bleeding offTo resolve the issues of the image blurring of high-speed moving objects and the imaging saturation of high brightness objects and missing detail, an electronic shutter method for frame-transfer EMCCD using anti-blooming channel to bleed off charges and external time frequency control was proposed. Through bleeding off the charges in light sensitive area into the anti-blooming channel which adjacent to the storage area, an adjustable electronic shutter among 1/25 s and 1/1 000 s was realized. And at the same time, the standard video signal was output continuously. The relationship between the illumination intensity and the maximum bleeding-off current of the anti-blooming drain was formulated. The smear effect induced by the short exposure time (shutter time) was corrected online through writing the correction algorithm into the FGPA chip of the EMCCD readout circuit. A prototype system using frame-transfer EMCCD with anti-blooming channel was built up to conduct imaging experiments. The results verify that this electronic shutter can effectively decrease the image blurring of rotating objects and facilitate high dynamic range imaging in the nighttime..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 620001 (2018)
[in Chinese]
Bit error rate analysis of the spatial X-ray communication system
Li Yao, Su Tong, Shi Feng, Sheng Lizhi, Qiang Pengfei, and Zhao Baosheng
Since the concept of X-ray communication was introduced, there is a great deal of research on the core components, such as X-ray source, receiving antenna and X-ray detectors. However, few people focus on the theoretical basis. Therefore, this paper aims at establishing a primary theoretical model of X-ray communicatioSince the concept of X-ray communication was introduced, there is a great deal of research on the core components, such as X-ray source, receiving antenna and X-ray detectors. However, few people focus on the theoretical basis. Therefore, this paper aims at establishing a primary theoretical model of X-ray communication. At start, the power transmission process that to establish the link power equation was analysed. In addition, bit error ratio model based on Poisson distribution was established by analysing major noise sources. After that, the core parameters of X-ray communication, such as transmitting speed, communication distance, bit error ratio can be decided by a giving transmission power. Finally, in order to verify the bit error ratio model and link power equation, the signal photons of micro channel plate detector output under various X-ray anode voltage and modulations was testified. Experimental results accorded well with the theoretical analysis, OOK and 4-PPM modulation model can achieve 10-4 to 10-5 bit error ratio level. These models would improved the transmission theory and laid foundations for the application of future spatial X-ray communication to some extent..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 622001 (2018)
[in Chinese]
Design of high density modularity TDI CCD imaging system
Sun Zhenya, Liu Dongbin, Fang Wei, and Zhang Da
In order to improve the high density assembly technology of remote sensing camera, a high density TDI CCD imaging system was designed with multichip module technology. First, TDI CCD focal plane with mechanical splicing technology was made to a copied unit. Then, the output energy of CCD output image signals was improvIn order to improve the high density assembly technology of remote sensing camera, a high density TDI CCD imaging system was designed with multichip module technology. First, TDI CCD focal plane with mechanical splicing technology was made to a copied unit. Then, the output energy of CCD output image signals was improved by a transistor emitter follower, they were transmitted to the analog front-end chips. Then they were converted into the 14 bits digital signals. After that they were integrated and processed through field programmable gate array (FPGA). In the end, through TLK2711 high-speed chip they were sent to data acquisition card on the computer. All the driving signals and processing signals of the imaging system were produced by the FPGA. The computer can control the imaging system and exchange the parameter through RS422 communication bus. The experimental results show that the area of driving layout cut down 2/3 than convention design. It realized the camera′s high density assembly adopting the design of the mechanical and electrical integration of heat. And the total data speed can reach 3.6 Gbps in this imaging system, SNR can reach 52.6 dB..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 618001 (2018)
Light mode converter in immersion lithography lighting system
Li Meixuan, and Dong Lianhe
The lighting mode convertor module in NA1.35 immersion lithography lighting system design has been designed and tested. The lighting mode convertor system can be realized by using diffractive optical element(DOE) in the design and analysis, including the traditional lighting mode, diode lighting mode and quadrupole ligThe lighting mode convertor module in NA1.35 immersion lithography lighting system design has been designed and tested. The lighting mode convertor system can be realized by using diffractive optical element(DOE) in the design and analysis, including the traditional lighting mode, diode lighting mode and quadrupole lighting models. And then different lighting models of diffractive optical elements for the design results were presented. The results were simulated and the experimental results were analyzed, which proved the feasibility of the design. The research results show that when the input optical field is divided with the number of array of 20×20 units, the diode lighting and quadrupole lighting models of diffractive optical elements are with numbers of 32 steps, the traditional lighting mode of 128 steps, the uniformity of diffractive optical elements as lighting mode converters and the diffraction efficiency are able to meet the design requirements. From the basis principle, the experimental validation of diffractive optical elements correctness and feasibility of the laser mode converter design can meet the requirements. The results can be applied to the immersion lithography lighting mode convertors in the immersion lithography lighting system structure, which have the great certain theoretical value and engineering significance..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 618002 (2018)
Formation and focusing characteristics of Pearcey beam
Hu Hanqing, Wu Fengtie, Hu Run, Yang Yanfei, and Zhu Qingzhi
Pearcey beam was obtained by designing a simple optical element-parabolic slit aperture. Based on the generalized Huygens-Fresnel diffraction integral in the spatial domain, the Pearcey beam expression of the system was derived. Numerical simulations and experiments verify the generation of Pearcey beams. At the same tPearcey beam was obtained by designing a simple optical element-parabolic slit aperture. Based on the generalized Huygens-Fresnel diffraction integral in the spatial domain, the Pearcey beam expression of the system was derived. Numerical simulations and experiments verify the generation of Pearcey beams. At the same time, the self-focusing characteristics of the Pearcey beam were studied, and the effect of the focal distance of parabolic silt aperture on the focal spot was discussed. The experimental results show that the size of the self-focucal spot was consistent with the numerical simulation. The results provide theoretical and experimental basis for the Pearcey beam for optical trapping..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 618003 (2018)
Design of support structure for deep space detection remote sensing camera
Ma Cong, Li Wei, Zhang Yuanqing, Li Xiaobo, and An Mingxin
The support structure is a key component for connecting satellites and cameras to provide protection and space application requirements for cameras during launch and on-orbit surround stages. The vibration load of the deep space probe is 13 g(that of the earth exploration satellite is 8-9 g). The supporting structure sThe support structure is a key component for connecting satellites and cameras to provide protection and space application requirements for cameras during launch and on-orbit surround stages. The vibration load of the deep space probe is 13 g(that of the earth exploration satellite is 8-9 g). The supporting structure should overcome the damage of the camera structure caused by the violent vibration and the thermal stability of the optical system, which has high design difficulty. In this paper, two different support forms of rigid foot and slider foot were designed by analyzing the structural characteristics of different support forms. The two kinds of support forms were designed from the balance of stiffness and thermal stability. The "A rigid foot+two flat foot" program was eventually adopted. The first-order frequency of the support structure is 58 Hz, which is much higher than that of the satellite base frequency. The simulation results show that the deflection angle of the primary mirror is 3.66″, the maximum angle change of second mirror and third mirror relative to primary mirror is 7.85″. They all meet the design requirements. Vibration and imaging tests show that the camera is working properly..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 618004 (2018)
[in Chinese]
Infrared pedestrian detection method in low visibility environment based on multi feature association
Liu Feng, Wang Sibo, Wang Xiangjun, Zhao GuangWei, and Huo Wenjia
Aiming at the problem of personnel monitoring and protection in low visibility environment, an infrared pedestrian detection method based on multi feature association was proposed, the primary classifier was constructed by using the aspect ratio of interest region and the Haar feature of head, and the improved HOG-SVM Aiming at the problem of personnel monitoring and protection in low visibility environment, an infrared pedestrian detection method based on multi feature association was proposed, the primary classifier was constructed by using the aspect ratio of interest region and the Haar feature of head, and the improved HOG-SVM was used to complete the final pedestrian recognition. An improved HOG feature extraction algorithm and an adaptive scaling factor acquisition algorithm were proposed, and the interframe time was effectively reduced on the basis of guaranteeing the detection accuracy. In view of the occlusion of the target, the occlusion detection and local feature recognition were proposed, which further improved the robustness of the detection system under complicated circumstances. The experimental results show the detection method can achieve the detection rate of 91%, which is better than the existing algorithms, and also meets the real-time monitoring requirements of the system. It is suitable for low visibility and dust working environment..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 604001 (2018)
Monitoring of laser metal-wire additive manufacturing temperature field using infrared thermography
Zhu Jinqian, Ling Zemin, Du Farui, Ding Xueping, and Li Huimin
For achieving precisely "controlling shape and performance" of components by additive manufacturing, scientific understanding is needed for thermal process. Taking laser metal-wire additive manufacturing (AM) under vacuum and using single-pass as an example, the thermal process was monitored based on infraredFor achieving precisely "controlling shape and performance" of components by additive manufacturing, scientific understanding is needed for thermal process. Taking laser metal-wire additive manufacturing (AM) under vacuum and using single-pass as an example, the thermal process was monitored based on infrared (IR) thermography. The effect of wire feeding speed on temperature field, thermal cycle, cooling rate was analyzed. The width of cladding layer and defect were studied based on IR thermography. The results show that the temperature monitoring was achieved. Along the length of cladding layer, the maximum temperature for monitoring point increased and then the cooling rate decreased. With wire feeding speed increasing, it led to the decrease of cooling rate for monitoring point at 1/4, 2/4, 3/4 of cladding layer. In addition, the width of cladding layer could be predicted and the location of defect could be located with the help of IR thermography analysis.先进焊接与连接国家重点实验室面上项目(AWJ-M16-03).
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 604002 (2018)
[in Chinese]
500 kHz A-O Q-switched Nd:YVO4 laser pumped by dual-end wave-locked 878.6 nm laser diode
Fan Haoran, Yu Yongji, Zhu He, Xing Shuang, Wang Yuheng, and Jin Guangyong
A dual-end-pumped acousto-optics Q-switched Nd:YVO4 laser pumped by a wave-locked 878.6 nm laser diode can stable work at a repetition of 500 kHz at 1 064 nm. At the repetition frequency of 100 kHz, an output power of 18.2 W at 1 064 nm for an absorbed pump power of 58 W,corresponding to an optical to optical efficiencA dual-end-pumped acousto-optics Q-switched Nd:YVO4 laser pumped by a wave-locked 878.6 nm laser diode can stable work at a repetition of 500 kHz at 1 064 nm. At the repetition frequency of 100 kHz, an output power of 18.2 W at 1 064 nm for an absorbed pump power of 58 W,corresponding to an optical to optical efficiency of 31.3%,the pulse width was 15.2 ns. At the repetition frequency of 500 kHz, an output power of 26.1 W at 1 064 nm for an absorbed pump power of 58 W, corresponding to an optical to optical efficiency of 45%, the pulse width was 44.2 ns, the stable working range extended from 100 to 500 kHz, and the beam quality was significantly improved compared with the traditional mode, and the transfer efficiency was also improved. The experiment shows that taking advantage of direct pumping by wave-locked 878.6 nm laser diode is helpful to reduce the heat effect of crystals, improve beam quality and optical to optical efficiency, and get more narrow pulse width laser output, and it has excellent temperature in a certain range.吉林省科技厅青年基金(20150520103JH); 吉林省科技厅重点科技攻关(20170204046GX).
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 606001 (2018)
Experimental investigation on direct generation of high order transverse mode laser
Chen Xiafei, Zhang Kailun, Chen Ziyang, Li Xiaoyan, and Pu Jixiong
Generation of higher-order Laguerre-Gaussian(LG) beams (vortex beams) and higher-order Hermite-Gaussian(HG) beams directly from the laser was theoretically and experimentally studied. The intensity distribution characteristics of higher-order LG beams and higher-order HG beams were theoretically studied, and the numeriGeneration of higher-order Laguerre-Gaussian(LG) beams (vortex beams) and higher-order Hermite-Gaussian(HG) beams directly from the laser was theoretically and experimentally studied. The intensity distribution characteristics of higher-order LG beams and higher-order HG beams were theoretically studied, and the numerical simulation results were given. The Pr:YLF crystal was end-pumped by a 445 nm blue semiconductor laser, under certain conditions, the higher-order LG beam and the higher-order HG beam of wavelength 640 nm was directly delivered from the plano-concave laser cavity. The experimental results show that the higher-order LG beams and the higher-order HG beams from the laser cavity are in agreement with the theoretical simulation. It is shown that the device for generating the higher-order modes is simple. The results of this paper seems very important for generation of higher-order laser beams and their applications..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 606002 (2018)
Design and implementation of orthogonal gain type passively Q-switched laser
Li Yang, Li Shutao, Li Yao, and Wang Chao
In order to improve the stability of the passively Q-switched pulses, the gain orientation of the Nd:YVO4 was taken advantage and an electro-optic crystal was used to rotate the line polarized light vector by 90°, then the intracavity gain mutation can be realized, thereby stable output of the passively Q-switchedIn order to improve the stability of the passively Q-switched pulses, the gain orientation of the Nd:YVO4 was taken advantage and an electro-optic crystal was used to rotate the line polarized light vector by 90°, then the intracavity gain mutation can be realized, thereby stable output of the passively Q-switched was realized. Through this method, when the reflectivity of the coupling output mirror was 80% and the initial transmittance of the saturated absorber was 83.06%, the output power reached 4.68 W at a given pump power of 22 W, high repetition rate output with repetition frequency of 49.16 kHz and the pulse width of 26.28 ns was obtained in the experiment of LD continuously pumped Nd:YVO4 passively Q-switched. In the case of the pump current from 10 W to 22 W, a stable passive Q laser output was obtained. The pulse-to-pulse amplitude fluctuation was less than ±2.4%. The inter-pulse timing jitter of the Q-switched pulse train was found to be less than ±5%. The instability of repetition rate was less than 1%. For a slope efficiency of 34%, the corresponding optical-to-optical conversion efficiency reached 21.27%..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 606003 (2018)
Stimulated gain and spontaneous loss pump-probe microscopy
Ho Bowei, Liang Yizhi, Hsu Chelun, Das Subir, and Kao Fujen
In this work, the pump-probe microscope was used to study the stimulated gain and spontaneous loss phenomenon. A pulsed diode laser, λpu=635 nm as the pump (excitation) beam and a mode-locked Ti-sapphire laser, λpr=780 nm, as the probe (stimulation) beam were applied. For stimulated gain, the pump beam was modulated atIn this work, the pump-probe microscope was used to study the stimulated gain and spontaneous loss phenomenon. A pulsed diode laser, λpu=635 nm as the pump (excitation) beam and a mode-locked Ti-sapphire laser, λpr=780 nm, as the probe (stimulation) beam were applied. For stimulated gain, the pump beam was modulated at a frequency, f1, and the probe beam was demodulated accordingly to extract the signal in the transmission direction with a photodiode as the detector (PDA 36A, Thorlabs). For spontaneous loss, the probe beam was modulated at frequency, f2, the spontaneous loss signal was then demodulated from the fluorescence detected in the reflection mode by a PMT. In all cases, a high performance lock-in amplifier (HF2LI, Zurich Instruments) was used. The output signal of the lock-in amplifier was then fed to the A/D channel of the scanning unit for image reconstruction. The scan rate was set at a frequency 500 Hz, to match the time constant (1.99 ms) of the lock-in amplifier. By demodulating fluorescence signal, the fluorescence lifetime and optical section images can be obtained with greatly reduced background, in which shot noise was attributed. Additionally, the signal-to-noise ratio was improve and penetration depth like multiphoton microscopy was enhanced, without expansive femtosecond lasers..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 606004 (2018)
Study of single-fundamental-mode square-lattice photonic crystal vertical cavity surface emitting laser
Yuan Jun, Zhang Zhengping, and Xie Yiyang
The high single fundamental mode output power vertical cavity surface emitting laser (VCSEL) has been attracted many attention due to its important applications in the fields of optical communications, sensing, atomic frequency standard and opto-electronic hybrid integration. With suitable photonic crystal structure anThe high single fundamental mode output power vertical cavity surface emitting laser (VCSEL) has been attracted many attention due to its important applications in the fields of optical communications, sensing, atomic frequency standard and opto-electronic hybrid integration. With suitable photonic crystal structure and distribution, the lateral modes of VCSEL can be effectively controlled by introducing the photonic crystal structure into the top distribution Bragg reflector (DBR). In this paper, square array photonic crystal structure was introduced into the VCSEL to control the transverse mode and single fundamental mode output power. The plane wave expansion and the full-vector three-dimensional finite difference time domain method (FDTD) method were used to analyze the photonic crystal structure and arrangement. The important parameters such as the period, the duty cycle and the etching depth of the square arrangement photonic crystal were obtained by using these methods. The high output power square lattice photonic crystal single fundamental mode VCSEL was reported. The single fundamental mode output power of the square lattice photonic crystal VCSEL is larger than 3 mW and the side mode suppression ratios (SMSRs) is more than 40 dB..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 606005 (2018)
Development of an underwater combined Raman-fluorescence detection system and preliminary test
Zhang Feng, Guo Jinjia, Liu Chunhao, Luo Zhao, and Zheng Rong′er
A variety of chemosynthetic micro-organisms inhabit the deep sea hydrothermal vent environments. Steep chemical and thermal gradient, rapid and turbulent mixing and biological processes produce a multitude of diverse mineral phases. Raman spectrometer system is well suited to mineral speciation measurements and has beeA variety of chemosynthetic micro-organisms inhabit the deep sea hydrothermal vent environments. Steep chemical and thermal gradient, rapid and turbulent mixing and biological processes produce a multitude of diverse mineral phases. Raman spectrometer system is well suited to mineral speciation measurements and has been successfully used for the detection in deep sea hydrothermal environments so far. However, to further understand the interaction of mineral and microbial processes, a Raman system optimized for mineral identification that incorporates a fluorescence for microbial processes is needed. In order to meet the requirement of deep sea hydrothermal research, a new compact spectroscopy Raman-fluorescence combined system prototype was presented. The combined system was composed of a double wavelength laser which can emit both 532 nm and 266 nm wavelength, the 532 nmwavelength was used for Raman spectroscopy excitation, and the 266 nm wavelength was used for fluorescence excitation, and two miniature optical fiber spectrometer. The double wavelength laser beam was split into two paths according to the wavelength and entered into the seawater or liquid solution by different quartz window. The produced Raman and fluorescence signals were collected by a back-scattering optical set-up and coupled into Raman spectrometer and fluorescence spectrometer separately. The whole system was housed in a L790 mm×Φ270 mm capsule with an optical window on the end, and the computer, power were also contained into it. The power supply, system control, and signal delivery were provided through an 8 pins cable. Systematic experiments had been carried out with seawater and pseudo-nitzschia samples in laboratory. The results show that the Raman and fluorescence spectra could be obtained simultaneously with moderate sensitivity. Some experiment results ware acquired at Qingdao coast. It is hoped this prototype could be fully developed in hydrothermal area detection in the near future..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 606006 (2018)
High-peak-power and short-pulse laser with a Yb:YAG/Cr4+:YAG/YAG composite crystal
Li Jingzhao, Chen Zhenqiang, and Zhu Siqi
A compact diode-end-pumped passively Q-switched laser was built up with a Yb:YAG/Cr4+:YAG/YAG composite crystal for generating a high-peak-power and short-pulse laser at 1 029 nm. The affect and mechanism of pump power and initial transmission on output pulsed performances were studied. By experimental comparison, it iA compact diode-end-pumped passively Q-switched laser was built up with a Yb:YAG/Cr4+:YAG/YAG composite crystal for generating a high-peak-power and short-pulse laser at 1 029 nm. The affect and mechanism of pump power and initial transmission on output pulsed performances were studied. By experimental comparison, it is found that the composite crystal with initial transmission of 85% gets the best pulsed performances, which the pulse peak power reaches to 87 kW with pulse width of 3.14 ns at incident pump power of 7.2 W. Moreover, variation of output spectrum with incident pump power is studied, which reveals that this composite crystal has good thermal property. Therefore, both bonding nondoped YAG crystal and using low initial transmission can contribute to high-peak-power and short-pulse laser output..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 606007 (2018)
[in Chinese]
Full Stokes polarization correlated imaging
Zhang Jiamin, Shi Dongfeng, Huang Jian, and Wang Yingjian
In recent years, with the rapid development of associated imaging technology, it has been widely applied in many fields and has attracted great attention. The polarization detection technology can distinguish different material objects and enhance the system ability of detecting and identifying. In this paper, with theIn recent years, with the rapid development of associated imaging technology, it has been widely applied in many fields and has attracted great attention. The polarization detection technology can distinguish different material objects and enhance the system ability of detecting and identifying. In this paper, with the advantages of polarization detection techniques and associated imaging techniques, the Walsh-Hadamard speckle was used to illuminate the scene, the scene reflection light was detected by time-sharing polarization, and the full Stokes polarization correlation imaging of the scene was realized. The corresponding experimental system was set up, and the imaging experiments of multi-material objects were carried out. Using the signals of different polarization states and illumination speckles, the Stokes parameters images of objects were obtained by calculating. The distinguish of different material objects and the objects with the same material and different structures in the same scene were realized. Through the evolutionary compression sampling recovery technology, the images were restored at different sampling ratios. The results show that the evolutionary compression sampling recovery technology can restore clear full polarization information at a lower sampling rate..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 624001 (2018)
Analysis and performance test of the high temporal resolution framing imaging technology
Bai Yanli, Yao Rongbin, Gao Haiying, Dang Xuanju, and He Guomin
In order to obtain more implosion movement information of inertial confinement fusion and measure the temporal-spatial characteristics of plasma during fusion combustion phase, the framing tube was studied whose exposure time was better than 30 ps, using electron beam pulse-dilation and composite lenses imaging technolIn order to obtain more implosion movement information of inertial confinement fusion and measure the temporal-spatial characteristics of plasma during fusion combustion phase, the framing tube was studied whose exposure time was better than 30 ps, using electron beam pulse-dilation and composite lenses imaging technology. The reason of performance difference between two tubes was analyzed through the tubes structure, working principle and measurement. The study result shows that the MCP gated framing tube has better spatial resolution performance and the new framing tube has more excellent temporal resolution performance. The spatial resolution and exposure time of MCP gated framing tube is ~53 μm(the modulation is 4%) and 97 ps, respectively. And, the new framing tube is ~74 μm(the modulation is 3%) and 21 ps, respectively. The mass reliable data is provided to study inertial confinement fusion through the high temporal resolution framing imaging technology..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 624002 (2018)
[in Chinese]
Computer-generated holographic algorithm based on layer structure using angular spectrum propagation theory(Invited)
Cao Liangcai, He Zehao, Zhao Yan, and Jin Guofan
A computer-generated holographic(CGH) algorithm based on layer structure using angular spectrum propagation theory was proposed in order to improve the calculation speed and the reconstruction quality. The 3D scene was stratified, and the sub holograms of each layer were obtained by angular spectrum diffraction method.A computer-generated holographic(CGH) algorithm based on layer structure using angular spectrum propagation theory was proposed in order to improve the calculation speed and the reconstruction quality. The 3D scene was stratified, and the sub holograms of each layer were obtained by angular spectrum diffraction method. The hologram of the whole 3D scene was generated by the superposition of these sub holograms. Because there was no paraxial approximation in angular spectrum diffraction method, the algorithm could be applied to different kinds of 3D models. Besides, the computational complexity of the algorithm depended on the number of layers rather than the complexity of 3D scenes, so the computation speed could be increased by 2-3 orders of magnitude. The algorithm provides an effective solution for dynamic 3D display..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 603001 (2018)
Research on collimation of LED naked eye 3D display technology based on ray tracing
Si Tongling, Piao Yan, and Li Min
In the integrated imaging naked eye 3D display based on LED, the divergence angle of the pixel point of LED large screen was very large. Flat convex and double convex lens are often employed. The reconstructed light of the image diverges and the pixel crosstalk between adjacent lens units was large, resulting in uncleaIn the integrated imaging naked eye 3D display based on LED, the divergence angle of the pixel point of LED large screen was very large. Flat convex and double convex lens are often employed. The reconstructed light of the image diverges and the pixel crosstalk between adjacent lens units was large, resulting in unclear images during the reproduction of the three-dimensional scene with the reduced imaging quality. The imaging process of integrated imaging based on LED was analyzed according to the principle of ray tracing. The relationship of crosstalk between different shapes of the lens array and adjacent lens units of LED integrated imaging was investigated. A single meniscus lens was used to effectively control the divergence of the reconstructed light. The reconstructed light passing through the lens was more convergent and collimated. The emergent rays through the lens becomes more parallel and the crosstalk between adjacent lens units was reduced effectively. By comparing the simulation result of the letter model, the meniscus lens was more suitable for LED integrated imaging. The imaging effect of the meniscus lens is better than that of the other lens..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 603002 (2018)
Single-channel color image encryption using cylindrical diffraction and color space converting
Chang Keming, Chen Ye, Wang Ying, and Wang Jun
In order to solve the problem of vulnerable to attacks caused by symmetry in traditional cryptographic systems, a new single-channel color image encryption using detour cylindrical diffraction and color space conversion algorithm was proposed in this paper. In the process of encryption, firstly, the color image was traIn order to solve the problem of vulnerable to attacks caused by symmetry in traditional cryptographic systems, a new single-channel color image encryption using detour cylindrical diffraction and color space conversion algorithm was proposed in this paper. In the process of encryption, firstly, the color image was transformed into a single channel image in YCbCr4:2:0 format, then the image was encrypted by twice cylindrical diffraction and phase truncation operations. In the process of decryption, the keys were combined with the cipher text, and the color original image was reconstructed after twice inverse cylindrical diffraction. Because the cylindrical diffraction process was an asymmetric process, the proposed algorithm can overcome the symmetry characteristic of the encryption system based on plane diffraction. Applying it to the encryption system based on phase truncation can further improve the security of the encryption system. The simulation results show that the algorithm can effectively encrypt the color image with single channel, which not only can restore the original color image with high quality, but also has high security..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 603003 (2018)
A large-scale multi-projection light-field display based on multi-view sampling calibration
Ni Lixia, Li Haifeng, and Liu Xu
A large-scale multi-projection light-field 3D display system based on multi-view sampling calibration was proposed. In this system 360 projectors were arranged in a circle under an anisotropic cylindrical diffuser with 3 m diagmeter and 1.8 m height and projecting images onto the diffuser. Light field of 3D scenes was A large-scale multi-projection light-field 3D display system based on multi-view sampling calibration was proposed. In this system 360 projectors were arranged in a circle under an anisotropic cylindrical diffuser with 3 m diagmeter and 1.8 m height and projecting images onto the diffuser. Light field of 3D scenes was accurately reconstructed inside the screen and can be observed by multiple viewers from different angles and positions simultaneously around 360°, as well as providing smooth motion parallax. Rendering frame rate of dynamic scenes can achieve 30 frame/s and above, offering fluent visual experience. To realize this system, a wide-field projection lens with cylindrical lenses was designed to enlarge image of the projectors. Then an automatic light-field calibration method based on multi-view sampling was proposed to eliminate distortion, which was induced by non-linear distortion of the projection lens and system assembly error, from the projection images. After calibration, light field projected by 360 projectors can be fuszed together seamlessly..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 603004 (2018)
Integral imaging 3D display based on variable-aperture pinhole array
Fan Jun, Wu Fei, Lv Guojiao, Zhao Baichuan, Deng Huan, and Wang Qionghua
To resolve mutual restriction of viewing angle and optical efficiency, an integral imaging (II) 3D displayer based on a variable-aperture pinhole array was proposed. The imaging model of the II 3D displayer based on the variable-aperture pinhole array was established. The calculation formulas of the viewing angle and oTo resolve mutual restriction of viewing angle and optical efficiency, an integral imaging (II) 3D displayer based on a variable-aperture pinhole array was proposed. The imaging model of the II 3D displayer based on the variable-aperture pinhole array was established. The calculation formulas of the viewing angle and optical efficiency were obtained by using geometrical optics. How to adjust the viewing angle and optical efficiency by changing the aperture width of the pinhole was illustrated in detail. A prototype of the II displayer based on the variable-aperture pinhole array was developed. The variable-aperture pinhole array was electrically controlled by using a liquid crystal display screen. The experimental results prove that the viewing angle and optical efficiency of the 3D image were respectively enhanced by increasing and decreasing the aperture width of pinhole..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 603005 (2018)
Data compression coding technologies for computer-generated holographic three-dimensional display
Gu Huarong
Holographic three-dimensional(3D) display can reconstruct the light field of a real scene, providing all depth cues and becoming one of the best solutions for true 3D display. Computer-generated holographic 3D display only needs to know the mathematical description of the object light wave, can flexibly control the wavHolographic three-dimensional(3D) display can reconstruct the light field of a real scene, providing all depth cues and becoming one of the best solutions for true 3D display. Computer-generated holographic 3D display only needs to know the mathematical description of the object light wave, can flexibly control the wavefront, and display a virtual 3D object. However, the huge amount of data and the amount of calculations hinder the practical application of computer-generated holographic 3D display. This paper presented data compression coding techniques for multiple stages in computer-generated holographic 3D display, including sparse sampling of 3D objects, optimization and parameter optimization of holographic 3D video compression coding, holographic fractal compression algorithm, effectively reducing the amount of data. And the parallel computing capabilities of GPUs were utilized to enable fast calculation of holograms..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 603006 (2018)
[in Chinese]
Research of 3.7 μm and 4.8 μm double band-pass filter on the surface of Al2O3
Yue Wei, Han Long, Zhang Kuo, Han Yongchang, and Zhao Mingyan
The characteristics, preparation and testing methods of 3.7 μm and 4.8 μm double band-pass filter on the surface of alumina substrate were introduced in the background of infrared optical and thin film technology. Alumina(Al2O3) was used in medium wave infrared optical systems usually because of its wide light transmisThe characteristics, preparation and testing methods of 3.7 μm and 4.8 μm double band-pass filter on the surface of alumina substrate were introduced in the background of infrared optical and thin film technology. Alumina(Al2O3) was used in medium wave infrared optical systems usually because of its wide light transmission area and good fastness and ease of use in optical systems. The two-band band-pass filter with excellent reliability and spectral characteristics were successfully developed by means of speed control and ion assisted process. The films were characterized by software optimization and double-coating of pass-filters. The analysis shows that the design structure and the optimization algorithm have a significant impact on the passband flatness, cut-off depth and transmittance of the film. Preparation process, in addition to the appropriate evaporation rate, the use of slow evaporation and weak ion energy assist was also very important key technology. The final spectral transmittance test averaged over 87% and passed environmental tests to meet the usage requirements..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 621001 (2018)
Influence of thermal annealing on mechanical and thermoelastic characteristics of SiO2 films produced by DIBS
Leng Jian, Ji Yiqin, Liu Huasong, Zhuang Kewen, and Liu Dandan
Mechanical and thermoelastic charecteristics of optical films are important to ensure the performance of optical coating systems. SiO2 films were prepared by dual ion beam sputtering (DIBS) on Si and Schott Q1. The mechanical and thermoelastic properties of films as-deposited and annealed were systematically investigatMechanical and thermoelastic charecteristics of optical films are important to ensure the performance of optical coating systems. SiO2 films were prepared by dual ion beam sputtering (DIBS) on Si <110> and Schott Q1. The mechanical and thermoelastic properties of films as-deposited and annealed were systematically investigated. The results show that reduced Young′s modulus (Er) is elevated to 72 GPa while the film was annealed at 750 ℃, and hardness (H) increases to over 10 GPa. The as-deposited films show compressive stress and the stress could be dramatically released while annealed over 450 ℃, incicating that heat treatment could improve the internal stress of SiO2 film. Poisson′s ratio (vf) of annealed SiO2 films is around 0.18, and Young′s modulus (Ef) of as-deposited and annealed films is larger than that of fused silica, and elevated over 50 GPa while annealed at 750 ℃. Thermal expansion coefficient (αf) decreases from 6.78×10-7 ℃-1 to the minimum value 5.22×10-7 ℃-1 while annealed at 550 ℃..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 621002 (2018)
Dispersion effect on optimized design of anti-reflection coatings for passivated silicon solar cells dispersion
Wang Anxiang, Zhang Xiaojun, and Li Jijun
Based on the refractive index dispersion effect, the weighted average reflectivity was used as evaluation function, and the best film thickness parameters of the anti-reflection coatings for the space silicon solar cell was obtained by the intelligent optimization algorithm. The optimization results were compared with Based on the refractive index dispersion effect, the weighted average reflectivity was used as evaluation function, and the best film thickness parameters of the anti-reflection coatings for the space silicon solar cell was obtained by the intelligent optimization algorithm. The optimization results were compared with that of the anti-reflection coatings designed without considering the dispersion. It displayed that after optimizing, the minimal weighted average reflectivity of the MgF2/TiO2 and SiO2/ TiO2 anti-reflection coatings were reduced by 36.6% and 37.6% under considering the dispersion effect than that without considering dispersion effect. And then the MgF2/TiO2 and SiO2/TiO2 anti-reflection coatings were deposited on the silicon solar cells with a thickness of 15 nm SiO2 passivation layer and optimized again. Comparing without considering dispersion effect, the minimal weighted average reflectivity in the case of dispersion was reduced by 43.9% and 33.7% for the MgF2/TiO2 and SiO2/TiO2 coatings with passivation layer, respectively. The optimal design of the anti-reflection coatings were carried out for the space silicon solar cells with different thickness passivation layer. It was found that the minimum weighted average reflectivity of the anti-reflection coatings increased with the increase of the thickness of the passivation layer, meaning that the anti-reflection effect got weaker and weaker. Finally, the anti-reflection coatings were redesigned when the thickness of the passivation layer was also considered as an inversion parameter considering the refractive-index dispersion effect or not. The results show that the anti-reflection film is more optimization by considering the dispersion. For the MgF2/TiO2/SiO2(passivation layer) film system, the optimal film thickness parameters are d1(MgF2)=97.6 nm, d2(TiO2)=40.2 nm, d3(SiO2)=4.9 nm. For the SiO2/TiO2/ SiO2(passivation layer) film system, the optimal film thickness parameters are d1(SiO2)=85.1 nm, d2(TiO2)=43.4 nm, d3(SiO2)=1.8 nm..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 621003 (2018)
[in Chinese]
Research on UAV target recognition algorithm based on transfer learning SAE
Xie Bing, Duan Zhemin, Zheng Bin, and Yin Yunhua
UAV in complex battlefield environment, because the two sides of the UAV shape, color and other characteristics are more similar, how to identity enemy UAV accurately is the key to realize the autonomous navigation and combat mission execution. However, due to changes in the speed, shape, size, attitude of enemy UAV anUAV in complex battlefield environment, because the two sides of the UAV shape, color and other characteristics are more similar, how to identity enemy UAV accurately is the key to realize the autonomous navigation and combat mission execution. However, due to changes in the speed, shape, size, attitude of enemy UAV and the impact of meteorological and environmental factors, they can not be accurately identified and classified. Aiming at this problem, a kind of sparse auto-encoder(SAE) based on the transfer learning was proposed, and the target objects in the multi-frame aerial images were identified. The algorithm firstly used SAE to study the unsupervised learning of a large number of unmarked samples in the data concentration of source domain, and obtained its local characteristics. Then, the global feature response of the aerial image in the target domain was extracted by the convolution neural network (CNN) algorithm. Finally, the different categories of target objects were identified and classified by the Softmax regression model. The experimental results show that new algorithm proposed in this paper for multiple target objects in aerial multi-frame images is better than more traditional non-transfer learning SAE algorithm, and underlying visual feature recognition transfer learning algorithm, which has higher recognition rate..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 626001 (2018)
Digital holography subpixel displacement aperture synthesis
Zhao Yadi, Cao Xiaohua, Chen Bo, and Sun Tianqi
Aperture synthesis is an effective means to improve the image resolution. For synthetic-aperture digital holography, an aperture synthesis method on sub-pixel displacement accuracy was proposed. The optical field was reconstructed by Fresnel diffraction formula based on fast Fourier transformation, and the displacementAperture synthesis is an effective means to improve the image resolution. For synthetic-aperture digital holography, an aperture synthesis method on sub-pixel displacement accuracy was proposed. The optical field was reconstructed by Fresnel diffraction formula based on fast Fourier transformation, and the displacement of hologram was transformed into piston phase and tilt phase by using the shift property of Fourier transformation, so that the digital holographic aperture synthesis with arbitrary displacement was realized. A digital off-axis holographic aperture synthesis experiment was carried out, and the experimental results verify the effectiveness of the proposed method. Furthermore, the method can effectively reduce the computational complexity under the premise of sacrificing a certain resolution, and has good real-time performance, and reduces the hardware configuration requirements of the processor..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 626002 (2018)
An narcissus effect correction method based on spatial and time domain estimation
Wei Wei, Xiang Wei, and Zhao Yaohong
Narcissus effect was an important factor that influence the imaging quality of the cooled infrared detector. Although it can be removed by non-uniform correction techniques, narcissus effect will reappear once the operating conditions have changed. Through analyzing the manifestation of narcissus effect, a correction aNarcissus effect was an important factor that influence the imaging quality of the cooled infrared detector. Although it can be removed by non-uniform correction techniques, narcissus effect will reappear once the operating conditions have changed. Through analyzing the manifestation of narcissus effect, a correction algorithm based on adaptive spatial-temporal filtering was proposed. First, spatial domain estimation of Narcissus effect was captured by wavelet transform. Then, time domain estimation of Narcissus effect was gained by adaptive time domain low-pass filtering. Finally, the correction was applied by subtracting the estimated spatial-temporal noise from the original image. Experimental results on simulated and actual infrared image sequences have verified the effectiveness of the proposed algorithm..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 626003 (2018)
Manifold learning of depth label for single image
Ye Hua, and Tan Guanzheng
The spatial position of the background and foreground determines the relative depth of the scene in the image. Using similarity characteristics of the local region of image and properties of dimensionality reduction of the manifold structure, the depth sortingindexing performance of the DCT high coefficientsfrequency dThe spatial position of the background and foreground determines the relative depth of the scene in the image. Using similarity characteristics of the local region of image and properties of dimensionality reduction of the manifold structure, the depth sortingindexing performance of the DCT high coefficientsfrequency distribution in the salient region was applied, the probability image map model of Markov Random Field(MRF) was defined to establish a relationship between the local feature and depth of different locations in the image. By segmenting the object, detecting relative blurring of the salient regions, and finally the relative depth map of the scene in the image was estimated. Through learning data embedding of manifold of the image, the probability density function of the data manifold distribution was migrated, the probability density function of category labels of object which followed similar manifold distributions was obtained. The blurred extent of salient regions was detected further, the high -frequency coefficient of discrete cosine transform (DCT) of multi -scale gradient amplitudes was fused, then depth mark index was calculated according to the high frequency characteristics of the fuzzy change to determine the hierarchical order of the depth tags, and the category tags were merged to generate a depth map. In this model framework, the blurred and unambiguous areas in a single image were detected to obtain the relative depth of the scene in the image, without knowing the priori settings of the camera or the type of blur. The depth estimation performance of the image was evaluated by using the MRF depth map model in a typical depth map estimation data set. The experimental results show the accuracy of the method in detecting scene distribution and ordering the depth of scene. It verifies the validity of the method..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 626004 (2018)
Efficient visual target tracking algorithm based on deep spectral convolutional neural networks
Guo Qiang, Lu Xiaohong, Xie Yinghong, and Sun Peng
The visual target tracking algorithm based on deep learning spectrum convolutional neural networks was presented. The spectral pooling was adopted instead of max pooling in the deep convolutional neural network, then the softmax loss layer was replaced with Bayesian theorem to compute maximum classifier score, and inteThe visual target tracking algorithm based on deep learning spectrum convolutional neural networks was presented. The spectral pooling was adopted instead of max pooling in the deep convolutional neural network, then the softmax loss layer was replaced with Bayesian theorem to compute maximum classifier score, and integrated it into the deep neural network tracking framework. The location of the target can be obtained by calculating the probability distribution of the input samples. The advantages of feature dimension reduction at random with spectral pooling and computation efficiency was taken to avoid much spatial information lost, which also helped to improve the computation speed. Compared with the original algorithm and other state-of-the-art methods, the proposed tracking method shows excellent performances on test baseline dataset..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 47, Issue 6, 626005 (2018)
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