2014 Vol. 43, No. 10
2014, 43(10): 3175-3182.
Obvious differences of infrared polarization information exist in different objects and different states of the same object. These differences can constitute the target detection information. The physical innate characteristic of target detection based on infrared polarization imaging technology was briefly introduced. The principle of the polarized bidirectional reflectance distribution function was mainly elaborated. The infrared polarization imaging detection models were cited. Application advantages of infrared polarization imaging technology were outlined. The structure classification and the characteristic of the infrared polarization imaging system were concisely summarized. Progress in target detection and recognition field of infrared polarization imaging technology was described. The imaging theory, the basic research experiments and the applications in target detection of the infrared polarization imaging technology were described in details. In the end, the advantages of infrared polarization imaging were pointed out, and some advices to the development of the field in our country were put forward.
2014, 43(10): 3183-3187.
Super-resolution(SR) imaging is an effective and economical way to increase the image resolution in spite of the detector limitation, therefore is widely used in many infrared(IR) focal plane array(FPA) imaging application. The ideal square pixel active area(PAA) model is widely used in research of microscanning (MS) based IR SR imaging. However, according to the micrographs of practical IRFPA productions, the PAAs of these productions are actually not a strict square. Three different PAA shapes were analyzed to discuss their effect in MS based IR SR imaging, and experimental results were coincident to theoretical simulation. The results indicate that: using square PAA causes 41% inaccuracy in some limit cases; more closer the Z shape to rectangle, higher value of Z shape MTF; simulation model based detector active area shape can effectively improve accuracy for IR SP research.
2014, 43(10): 3188-3192.
Aiming at the slow response speed, low sensitivity, poor vibration resistance of existing Fourier transform infrared spectrum telemetry, a new method was put forward with static solid wedge interference as the core. UL 371-042-04 uncooled infrared focal plane array detector was selected as the core component of interference signal detection. Driving circuit was designed based on the analysis of the basic theory of static solid wedge interference and detector performance. FPGA as the main part of sequential control, designed input and verified simulation of the work timing of detector with Verilog hardware description language programming in Xilinx ISE 12.4 development environment. It can make the interference signal go through high-speed AD sampling and FPGA outside enlarge SRAM cache, the processed signals are sent to PC LABVIEW for data processing and imaging via USB finally. Kealized the infrared wavelengths of static solid wedge interference signal spectrum imaging by simulating and experimenting to verify its feasibility, provided preparation for further study of interferometric imaging spectrometer imaging technology.
2014, 43(10): 3193-3198.
This research builds upon the traditional composition of the infrared flare(Magnesium/Teflon, MT), and red phosphorus and copper oxide were chose as functional additives, a composition of thin-film infrared flare with low flame temperature was optimized based on its burning time, flame temperature and radiation intensity. In addition to respective conductivity of the material component were chosen as parameters, combustion rates of different prescriptions were analyzed based on their conductivity, and an indication of the impact of combustion temperature and radiation intensity was fiven. The results of the study show that red phosphorus and copper oxide added can improve combustion stability under lower flame temperature. When the content of red phosphorus was 25%, magnesium powder was 25%, copper oxide was 10%-15%, teflon was 35%-40%, the combustion of the 0.03 cm-thick thin film was most stable, and its combustion time is greater than about 3 s, the most radiation intensity is 1.5 W/sr, the flame temperature is about 800 ℃.
2014, 43(10): 3199-3204.
Using the combination of blackbody and collimator is one of the important means for infrared radiation calibration. However, due to the presence of thermal radiation, stray radiation nosie will be transmitted to the detector, generating calibration error and affecting calibration accuracy. In this paper,the stray radiation theoretical model of collimator was established, and the stray radiations of mirror surface under different working temperatures or surface emissivities were analyzed quantitatively to determine the impact on infrared radiation calibration. At the same time, some corrective measures for stray radiation were given to remove the impact on the infrared radiation calibration caused by stray radiation and improved the infrared radiation calibration accuracy.
2014, 43(10): 3205-3210.
Infrared thermal imaging systems are widely applied with the ability of all time observation. In order to test and evaluate the performance of high-resolution infrared thermal imaging systems, a large number of thermal infrared images in different imaging conditions are needed as input data sources. To obtain credible thermal infrared simulated images of ground, a TIR imaging simulation method for complex terrain was proposed. Combined with factors of terrain, light, shadow and radiation from neighborhood on relief surfaces, the generation and transmission mechanism of thermal radiation on 3D terrain surface was studied systematically. Thermal infrared images of terrain surface on different time in a day were simulated by using optical remote sensing images and DEM data. The results indicate that, the TIR image sequences made by this method accord with the daily changing law of thermal radiation on ground, therefore, an effective way of producing IR reference images by visible images is provided.
2014, 43(10): 3211-3216.
Closed-loop simulation based on digital image injection is an effective testing means of IR imaging guidance weapon countermeasure and complicated environment adaptability, it collects frame angle of seeker and real-time simulates to generate IR image when the detector of IR seeker is replaced by image simulation computer and injection device, the image is injected by injection device. The principle of closed-loop simulation test were analyzed, software, hardware platform and work scheduling of simulation test system were designed, miss distance time delay and miss distance error were calculated, consistency analysis platform of simulation test and actual work was built, yaw and pitching angle velocity error and homing precision were analyzed by miss distance time delay and miss distance error. The result shows that the condition of simulation test and actual work of seeker was consistent, simulation test system was scientific. The research results provide theoretical support for developing closed-loop injection simulation test.
2014, 43(10): 3217-3221.
It has been the focus of the study for effective detection of low altitude penetration target which has low altitude, short flight time. To 2.7 m, 4.3 m wavelength as the center of the detection system, a near space infrared detection image plane irradiance model was established. SBIRS space-based infrared system and the near space detection system were simulated. Simulating typical target trajectory, considering the atmospheric effects, infrared radiation image plane irradiance and modulation contrast of object and background of boost phase and post-boost phase at SBIRS and near space platform were obtained. Simulation results show that near space platform has a higher signal contrast and a longer detection time than SBIRS. For TBM's post-boost phase, the detection effect of 4.3 m is better than that of 2.7 m as detection center wavelength.
2014, 43(10): 3222-3227.
In order to evaluate the importance of the radiation influence between buildings and provide theoretical support for the infrared multispectral simulation method and ATR algorithm research, some research in waveband 3-5 m and 8-12 m was done and a radiation influence calculation model between buildings was built in this paper. When the direct solar radiation existed, it was not necessary to consider the radiation influence between buildings in 3-5 m, because the influence was tiny enough to be ignored, while it should not be ignored in 8-12 m because of the apparent influence. A virtual scene with two cooling towers was build and the radiation in 8 m, 9 m, 10 m, 11 m and 12 m were selected to calculate the radiation influence between the cooling towers. According to the result, the radiation influence in 8 m, 9 m and 10 m is greater than 10%, while that in 11 m and 12 m was smaller. The scene simulation for the radiation influence between the cooling towers is done, which shows the radiation influence at different wavelength with the changes of radiation distance.
2014, 43(10): 3228-3232.
Camouflage is an important factor for winning the modern warfare by preserving fighting capacity. Hyperspectral imaging technology is an efficient method for camouflage detection for its ability of detecting and utilizing targets' spectral information. Traditional camouflage effect evaluation method mainly based on spatial characteristics, which cannot work when hyperspectral imaging technology is used. So a new camouflage effect evaluation method was proposed for hyperspectral detection, which was based on the comprehensive similarity of camouflage and background combined characters of spectrum and its derivative. Target with higher comprehensive similarity meant better camouflage effect. Experiment was conducted to assess the camouflage effects of three camouflage materials by the new method. The camouflage effect of green cloth outperforms others with the comprehensive similarity 0.976 6. And error rate based on hyperspectral classification technology was proposed to verify the objectivity of the new method. The new camouflage effect evaluation method has a certain guiding significance for the design of the new camouflage material.
2014, 43(10): 3233-3237.
With the development of electronics technology, flip-chip technology has been used extensively in microelectronic packaging. However different disadvantages occurred in traditional detection methods. Therefore, in this paper a novel approach was investigated for solder joint inspection which was based on the active thermography. Non-contact thermal excitation was applied on the specimen, and the temperature distribution of the specimen wss obtained by the infrared camera. Eigenvalues including wavelet entropy were obtained by the wavelet transform process and self-organizing map wss used for data training to classify the signals. The experimental results prove that different defects in the solder bumps can be effectively mapped on different locations by the SOM, and they can be classified and recognized from the reference ones by this method. Therefore, the method investigated in this paper is effective in detecting defects in flip-chips.
2014, 43(10): 3238-3243.
The delay and pertinence of observation sequence in the infrared tracking system affect estimation to the target estate. In the course of tracking, delay of observation sequence induces the error between the measurement and truth, and then estimation based on the measurement is inaccurate, at the same time, pertinence of observation sequence affects the estimation result too. To assure the veracity of prediction, firstly, the system model was modified by ellipsoidal set form to overcome the pertinence of observation sequence, and at the same time, the innovation re-organization technique was introduced to eliminate the observation delay. With the innovation re-organization, the system structure was changed and a model without delay was obtained. At last, a delayed ellipsoidal set filter(DESF) was presented. Result of simulation shows that, DESF algorithm could overcome the effect of pertinence of observation sequence, and compared with filter designed without innovation re-organization, the tracking precision is better.
2014, 43(10): 3244-3251.
The basic concept of adjust-free solid state laser was introduced. The latest progress of adjust-free solid state laser used for smart and light laser, multiple wavelength output, and improving the beam quality of high power/energy laser were generally summarized. The development trend of double corner cubes resonator was also introduced. At last, the latest progress of mutual injection phase-locked lasers combination based on corner cube was reported. The mutual injection phase-locked coherent combination of both fiber lasers and solid state lasers have been realized. And these researches indicate that it is an effective way to obtain high reliable, high power /energy and high beam quality laser output.
2014, 43(10): 3252-3256.
The 2 m laser is in the atmosphere window and the eye-safety wavelength regions. Therefore, it is expected to have potential application in wide range of fields. The lasers can be a light source of Coherent Doppler Wind Lidars and Differential Absorption Lidars. In order to develop a laser light source of Coherent Doppler Wind Lidars, a pulse LD end pumped Q-switched Tm:YAG laser was developed by using a plano-concave cavity with a acousto-optical (AO) Q-switch. The center wavelength of the output laser was measured to be 2 014.9 nm. In the repetition frequency of 100 Hz, a maximum single energy of 6.11 mJ after Q-switching operation and the narrowest pulse width of 324.7 ns were achieved at room temperature, whose slop efficiency was 13.56%. The Mx2 was 1.31 and the My2 was 1.35.
2014, 43(10): 3257-3261.
Resonator fiber gyro system requires narrow linewidth and high stable output. In order to satisfy the testing requirements of frequency deviation of resonant signal, two systems of optical frequency locking were designed and the testing platform was set up. During the experiment, the wavemeter was used to monitor the fluctuation of wavelength before and after lock frequency. For plan two, two different kinds of instrument' frequency locked parameters were set, then the accuracy of locking frequency was monitored and analyzed, it was obtained that the accuracy of locking frequency could reduce 1 times under different parameters. The testing result of two plans were same that the wavelength after locked frequency was 0.2 times than before and the curve was smooth and flat, and the fluctuation of output wavelength of laser was narrowed largely after locked the frequency and the real-time of locked feedback was improved. It provides the technical support for narrowing laser spectrum and track-locking laser frequency by PI circuit.
2014, 43(10): 3262-3268.
An all-fiber switchable multi-wavelength erbium fiber laser was proposed in this paper. A sinusoidal phase modulator composed of a piece of single-mode fiber around a piezoelectric transducer was inserted in the ring cavity, combined with an all-fiber Mach-Zehnder interferometer based on cascade in-line two-taper as the comb filter, which suppressed the mode competition owing to the homogeneous broaden line in erbium-doped fiber and eliminated the unstable wavelength lasing. Simultaneous and stable five-wavelength lasing was observed with 0.804 nm intervals at room temperature. The signal to noise ratio is higher than 40 dB, the 3 dB bandwidth is about 0.023 nm, and the five lasing lines in power differences are less than 14 dB. Meanwhile, the laser has highly flexible wavelength switchable property. By adjusting the driving signal and polarization controller, single wavelength lasing output, switchable dual, triple and ever more wavelengths lasing output could be realized. These advantages enable this laser as a potential candidate for high-capacity wavelength division multiplexing systems and mechanical sensors.
2014, 43(10): 3269-3275.
At the moment non-scanned imaging LADAR system whose advantage is rapidly imaging cannot work beyond a relatively short operating distance due to the restriction of laser power and attenuation of the signal. Therefore designing a new-type non-scanned heterodyne LADAR system with APD array detector is a imperative solution to this problem. The design of lighting systems is the concentration since different heterodyne efficiencies correspond to different optical systems and then decide the performance of the LADAR system directly. In this paper, it was discussed that the heterodyne efficiency of the system using a single expanded oscillator laser beam lighting system with a single collector lens stays only at 10-5 level which is far away from practical applications. Then, as a improvement design, array lighting theory was adopted with a micro lens array collector device played before the detector array, the maximum heterodyne efficiency of which reached 0.82 by calculation. The conclusion drawn in this paper proves the feasibility of array lighting heterodyne LADAR system theoretically and form the foundation for further research on heterodyne LADAR system with APD array detector.
2014, 43(10): 3276-3281.
Traditional 3-D laser imaging systems are based on real aperture imaging technology, whose resolution would decrease with range's increasing. An advantage of synthetic aperture imaging technology over real aperture imaging is that the resolution of the imaging system is constant with range's increasing. In this paper, a novel 3-D imaging system was given, which was based on synthetic aperture technology. According to the characteristic of the signal, a suitable data progressing method was proposed based on the flood-light transmitting mode and multi-beam receiving mode. Firstly, in the range dimension, the signal with large time bandwidth product was adopted to obtain high resolution with the help of dechirp technology. Secondly, in the along-track dimension high resolution was obtained by synthetic aperture technology, in which the phase error caused by long scan duration was taken into account and compensated. Thirdly, in the cross-track dimension traditional real aperture array imaging method was adopted. Finally, simulation was provided to demonstrate the effectiveness of the proposed system.
2014, 43(10): 3282-3286.
The backscatter lidar technique is widely applied to atmospheric aerosol detection, but the blind and transition regions restrict its detecting range and precision in near distance. Side-scatter lidar technique without above shortage can detect aerosol continuously in near distance, and has good precision. A side-scatter lidar system was developed, which is composed of transmitter, receiver, geometric calibration, and data acquisition subsystems. Comparison experiment with backscatter lidar indicates that the data acquired from this lidar are reliable and the near detection effective range is from 0.02-4 km. This system can be used for study the spatio-temporal distribution of atmospheric aerosol in near surface further.
2014, 43(10): 3287-3291.
In order to make a laser diode(LD) work stably, a highly efficient temperature control system was designed and implemented. The system was made up of the MSP430 microcontroller, negative temperature coefficient thermistor(NTC) and thermoelectric cooler(TEC), respectively, as control unit, temperature sensor and actuation element. Based on the self-tuning fuzzy PID algorithm, the negative feedback loop was adopted for controlling the temperature of a laser diode and enabling it to work stably. Experimental results show that the system stabilized the temperature within 250.05 ℃ in 68 seconds when it rose from 21.9 ℃ to 25 ℃. After 94 seconds, the temperature can stay within 250.008 ℃. Compared with a conventional PID control system, the temperature control system based on self-tuning fuzzy PID algorithm can adaptively adjust PID parameters in the system without manual operation. Therefore, the system has a better dynamic performance.
2014, 43(10): 3292-3297.
Mobile LiDAR system is a multi-sensor integrated system, including laser scanner(LS), global positioning system(GPS), inertial navigation system(INS), and so on. Space registration is the key to get high precision 3D mapping. The installation angle error of LS is one of the main factors which influence the measurement accuracy. The related coordinate systems and transformations were introduced first. A method using vertical facade of a building wall to calibrate installation angles between LS and INS was proposed. A vehicle-borne LiDAR 3D mapping system was built to test the method.
2014, 43(10): 3298-3302.
In order to study on surface plasmon polaritons (SPPs) which have Airy plasma characteristics, the special nature of Airy plasma was analyzed and simulated. Based on the principle of SPPs lasing, the theoretical of Airy plasma eigenstates was analyzed. The nature of Airy plasma on the grating structures of SPPs lasing was studied. The results indicates that the Airy surface plasmon not only have characteristics with amplification in near field energy zoom and fast spread, but also can control spread using its characteristics; Airy surface plasmon can control energy loss only in rang width, which cannot appear Airy surface plasmon when its width is less than 600 nm; lasing energy of different width have same trend; Airy surface plasmon can achieve fast spread in the condition of low excitation energy, it has not obvious effect when increase lasing energy after 2.3 eV. There is a positive significance for studying strong localization of SPPs, surface optical processing with SP and linear control SP of no diffraction.
2014, 43(10): 3303-3308.
Aiming at the laser remanufacturing of gas corrosion crack in the root of the FV520(B) steel blade for air blower, remanufacturing process parameters were optimized through orthogonal experimental analysis. Through analyzing the breakage in the root of FV520(B) steel blade simulator, the repairing scheme for laser scanning was planned, the metallographic structure and phase composition of the repaired region were observed and analyzed, the hardness was also tested. The results show that, the 1.1 kW laser power, the 250 mm/min scanning speed, the 8.10 g/min power feeding rate, the 150 L/h carrier gas flow are the optimized process parameters for special material and remanufacture system,the multi-scanning paths are synthetized to decrease the thermal cumulative effect between layers, the dimension precision between the repaired and the original one is 0.8 mm, there is strong metallurgical bonding between the cladding layer and the substrate, the hardness of the cladding layer surface is the highest, its average value is 675 HV0.2, the interface can reach 610 HV0.2, the cladding layer has better metallographic structure and hardness property.
2014, 43(10): 3309-3312.
In order to understand the effect of laser wavelengths on initiation threshold, reduce the laser initiation energy of energetic materials, and improve miniaturization design of excitation source of laser initiation, dissociation spectral and initiation threshold of pentaerythritol tetranitrate(PTEN) under wavelength 1 064 nm and 532 nm laser were tested by time-of-flight mass spectrometer and bruccton up and down method, and effect of laser wavelengths on initiation mechanism was analysed. Results show that laser initiation of energetic materials has selectivity for wavelengths, and every kind of energetic material possess some characteristic absorption wavelengths which are beneficial to laser initiation. There are different dissociation mechanisms for different laser wavelengths(1 064 nm and 532 nm). Compared with 532 nm laser, 1 064 nm laser, which close to characteristic absorption of PETN, can accelerate dissociation of PETN, and decrease 50 percent firing energy by 14 percent. Therefore, using characteristic absorption wavelengths of energetic materials as excitation source of laser initiation, can effectively reduce initiation threshold of energetic materials.
2014, 43(10): 3313-3320.
Knowing that optical surface should have strong surface description and fitting ability and that ray-tracing speed of the surface should be fast, the fitting method and ray tracing algorithm of NURBS free-form surface were studied. Fitting mild slope asphere, deep slope asphere and peaks surface respectively to NURBS surface using Multilevel B-splines approximation(MBA), all of the fitting residual errors were less than 10 nm, and it proved the NURBS surface is qualified for various free-form surface. Several high-precision and fast methods for inversion of NURBS surface were studied, and the ray tracing algorithm's speed was 3 times faster than traditional derivative algorithm. Given an appropriate iterative initial value, the time for calculating each point could be minimized to 0.3 ms. Examples of successfully using NURBS surface in optomechanical analysis of free-form surface prism system and in CODEV user-defined surface, show that the NURBS surface is fully adequate in optomechanical design, analysis and fabrication.
2014, 43(10): 3321-3328.
Star sensor's image plane can have three kinds of displacement after a long time working in space, and the displacements are the principal point drift, incline displacement and rotation displacement. These displacements can severely decrease star sensor's measuring accuracy, therefore it's necessary to analyze and calibrate them. The previous researches have only considered the principal point drift of image plane, which is three-degree-of-freedom. In contrast, the image plane displacements under the rest three degrees of freedom, that are the incline displacement and the rotation displacement, have been modeled in this paper. These two kinds of displacement's influences on star sensor's accuracy have been analyzed. And the necessity to calibrate them has been pointed out. At last, the Extended Kalman Filter has been used to on-orbit calibrate the six-degree-of-freedom image plane displacement. And the simulation results reveal that the on-orbit calibration algorithm can effectively calibrate the image plane displacement of star sensor. The measuring accuracy of star sensor has been increased to 0.23 after the calibration. Therefore the new six-degree-of-freedom image plane displacement model has made up the deficiency of the conventional displacement model and enhance the performance of star sensor greatly.
2014, 43(10): 3329-3333.
The dual-band infrared optical system can track the band informantion stretch from mid-wave infrared to long-wave infrared, which can greatly improved the information acquisition. A dual-band infrared optical system based on the compact principle was designed, the optical system can imaging clearly continuous from 4.4-8.8 m/17.8-8.8 m, the F# strictly matched with cold light bar that the cold light bar effect reached 100%. While the system using the passive athermal methods to get rid of temperature compensation problem and finally realized the dual-band of athermalization. The result shows that: the design of the system structure is relatively simple, and can get stable good imaging quality in continuous bands from -40 ℃ to 60 ℃, satisfying the requirements of a standard infrared thermal imager.
2014, 43(10): 3334-3337.
SiO2 films were deposited on fused silica substrates by ion beam sputtering technology and the effects of thermal treatment on optical properties were studied by ellipsometry technology and surface thermal lens technology. The effects of thermal treatment temperature on refractive index of IBS-SiO2 films were very large, as the increase of thermal treatment temperature, refractive index of SiO2 films first decrease and then increased, when the thermal treatment temperature was 550 ℃, the refractive index was the minimum. After thermal treatment, the weak absorption of SiO2 films were all reduced, the value of weak absorption was about 2 ppm. When the thermal treatment temperature was 550 ℃, the least weak absorption of 1.1 ppm was obtained. The results show that refractive index and absorption properties of IBS-SiO2 films can be largest improved by the proper thermal treatment temperature.
2014, 43(10): 3338-3341.
The direct fraction of sun irradiation is used to focus on Fresnel lens in High Concentrated Photovoltaic technology, electric energy is produced through photoelectric inversion. However, because of many factors in practice like the low tracking accuracy of tracker, structure vibration by winds and atmospheric scattering, the direct normal irradiation to the Fresnel lens can not be guaranteed. To solve this problem, a removable secondary mirror whose shape was a reverse cone with no top was added between the Fresnel lens and solar cells to increase the acceptance angle of the solar module. A design example was given, and analyzed by optical simulation with the software of Solidworks and Tracepro. The conclusion indicates the removable secondary mirror can increase the acceptance angle and improve the irradiance uniformity of the focus spot.
2014, 43(10): 3342-3346.
The conventional surgical microscope uses eyepiece lens systems which have very small exit pupil to occur when the observer moves his head during observation, thereby obliging the observer to keep his head at a constant position while he performs the operations described above. Therefore, the conventional surgical microscope has a defect that it gives a strong feeling of fatigue when he continues observation for a long time. Two dimensional microlens array(MLA) can be used in wearable applications as exit pupil expanders to increase the size of the optical system exit pupil. Fourier optics theory was used to derive the analytical formulas, and physical optics beam propagation was used for numerical computations. The MLA's reflective surface was spaced from the other focal curve about a focal length. A dual-MLA is proved that can produces excellent exit-pupil, and it can often generate output beamlets that have a more uniform brightness.
2014, 43(10): 3347-3351.
A brand new type of terahertz/sub-millimeter wave detector based on InGaAs material grown on semi-insulate InP substrate was proposed with an Metal-Semiconductor-Metal(MSM) structure. High Frequency Structural Simulator(HFSS) software was firstly used to characterize the metallic planar antenna by calculating its resistance, standing-wave ratio(SWR), and the radiation pattern. Detectors with symmetrical metallic antenna were fabricated by a serious of technical process mainly including photolithograph, etching, and sputtering. Photoresponse of the detector with respect to the bias current and the modulation frequency was measured by a homemade measure system with a 0.037 5 THz Gunn oscillator terahertz source. The results show large photovoltage signal and fast respond speed (300 s) of the device. The voltage sensitivity of the detector at 0.037 5 THz reaching to 6 V/W was further obtained by the calibration of a Golay cell detector. And the noise equivalent power(NEP) at this frequency was 1.610-9 W/Hz1/2.
2014, 43(10): 3352-3355.
For the miniaturization and portability demands of solar simulator, a portable solar simulator was designed. Illumination in 1.2 m1.2 m rectangular irradiated area not less than 0.02 solar constant was required; furthermore, the un-uniformity of irradiated surface less than 5% was also needed. The system mainly consisted of short-arc xenon lamp, ellipsoidal reflector, fiber optic beams, and a group of collimating lens. Through software simulation and experimental verification, the results met all the requirements. Experimental results show that the method that designing a portable solar simulator with short-arc xenon lamp, ellipsoidal reflector, fiber optic beams, integral stick, and projection collimator lens group is effective and feasible.
2014, 43(10): 3356-3362.
The digital closed-loop quartz flex accelerometer (DCLA) can effectively solve the precision loss which exists in the output current to the digital conversion of the traditional analog quartz flex accelerometer, and the accuracy of the DCLA mainly depends on the differential capacitance detection circuit. The working principle of DCLA was introduced, and the signal detection scheme was studied. According to the signal characteristics, with the method of single carrier modulation and demodulation technology, triangle wave modulation technique was applied to implement the capacitance detection, and the digital correlative demodulation scheme was proposed to extract the amplitude signal. To build the DCLA experimental prototype, under the 0 g/1 g stability test, the bias stability of 0 g/1 g was 17.595 0 g, 19.363 7 g and 20.715 3 g, respectively. Currently, the result shows that the precision of the DCLA is basically equal to the traditional analog accelerometer, which verifies the correctness of the signal detection method.
2014, 43(10): 3363-3367.
Theoretical study about mirror shows, in application range, transmissivity has a simple linear relationship with the axial stress to photonic crystal. Accordingly, a new structure accelerometer with axially deformed tiny beams was designed. Tiny beams are sensitive, so the sensitivity and frequency of free vibration of the structure will be increased significantly when tiny beams were in axial position. Using mirror triply periodic photonic crystal replace the original pressure sensitive resistor as the sensing element. Detecting the transmissivity of the photonic crystal, the magnitude of the acceleration can be calculated. It is shown that this structure can measure less than 0.4 mgn when the transmissivity intensity changes one out of 1 and its measuring range is up to 3.2 gn.
2014, 43(10): 3368-3372.
Due to a high transmission in the infrared range as well as the high linear refractive index and nonlinearity, chalcogenide glass was a good candidate for mid-infrared supercontinuum generation. Since the wavelengths of pump sources for pumping nonlinear mediums are usually less than 2 m, it is valuable to study their material dispersion. Used four different forms of equation to fit the refractive index versus wavelength curves, three different kinds of chalcogenide glass was simulated:As2S3, As2Se3 and Ge33As12Se55, also we got their material dispersion curves by the former simulation results. Their zero-dispersion wavelengths are 4.8 m, 7.2 m, 6.1 m, respectively. While proved that it is not suitable to use refractive index data at short wavelength to fit and simulate the trend at long wavelength for chalcogenide glass.
2014, 43(10): 3373-3377.
For the airborne laser communication, optical axis stabilization is the key to keep laser communication link. Conventional coarse tracking controlling method can not effectively overcome the effect of system model parameter change and their influence of uncertainty. According to control requirement, the variable structure controller(VSC) and self-adjusting fuzzy control method was fused, which can force system state to reach sliding surface. Theoretical research and simulation results show it can fully adapt to the disturbance and parameter changes of airborne communication platform. So it has great robustness, and is expected to apply in engineering.
2014, 43(10): 3378-3382.
The fiber-optic distributed disturbance sensor(FDDS) based on merged Sagnac interferometers is proposed and investigated. The disturbance causes a phase modulation and can be detected by the Sagnac interferometer. The proposed sensor includes three Sagnac interferometers merged sharing one broad-band source(BBS). The interference signal is acquired by two photo detectors(PDs) respectively. Since the coherent length of the source is too short for the lightwave propagating along different optical paths to interfere, there are only three paths of the light can interfere. One of the PDs detects the summation of the signals from two Sagnac interferometers which have the same loop length. The other PD measures the interference lightwave from the interferometer comprise of the Faraday rotator mirror (FRM) and the sensing fibers. The disturbance can be located by conducting mathematical operations to the detected signals. The experimental results show that the proposed sensor can locate the disturbance. The maximum location error is 370 m and the average location error is 270 m during 10 times experiments.
2014, 43(10): 3383-3387.
The technique was presented to simultaneously measure the vibration and strain, vibration and temperature with the Single-mode-Multimode-Single-mode(SMS) fiber structure by employing a kind of digital signal processing technique of Single Channel Blind Source Separation(SCBSS). In the simultaneous measurements of the vibration and stress, the measurement error of vibration frequency was only about 0.17 Hz and the load time of the stress was exactly same as the operation. In the simultaneous measurement of the vibration and temperature, the error of the vibration frequency was less than 0.60 Hz, and the temperature error were less than 7.13% and 8.03% for linear cooling and natural warming, respectively. The SMS optical fiber sensing can measure multi-parameters easily with low cost and high accuracy by employing the SCBSS, which can be used in other optical fiber sensing systems to obtain multi-parameters.
2014, 43(10): 3388-3393.
The detection of polarization axis is a key technology in application of polarization-maintaining fiber(PMF). In the azimuth system for PMF based on image processing, the false edge of the stress circle in edge detection made the center location incorrect. In order to solve the problem, a method based on least square fitting was proposed. This method wiped out the incorrect edge in the process of iteration. When the number of point for iteration was smaller than a threshold, it came back to the original set of point for iteration. Experimental result show that the algorithm can avoid the disturbance made by noise and the incorrect edge. When coming to the real cross-section image, it shows strong robustness.
2014, 43(10): 3394-3398.
Phase modulation spectroscopy is an important method of signal detection in resonator optic gyro. By the use of expansion of Bessel function and optical field overlapping method, the transmission properties of optical fiber ring resonator was analyzed. A testing system of resonant properties was set up. Based on the LiNbO3 phase modulation, the experiments to research resonant characteristics and demodulation curve features was carried out under different frequencies and voltages of modulation, and the experimental result was analyzed, then the relation of frequency and voltage of modulation and resonant and demodulation signal of fiber ring resonator was obtained. The splitting phenomenon of resonance dips during the experiment was measured and analyzed. By fitting the data, the relation of critical frequency and voltage of modulation of splitting phenomenon of resonance dips occurs was obtained.
2014, 43(10): 3399-3403.
In order to solve the problem of simultaneous filtering in the multi-channels of wavelength division multiplexing(WDM) system, the design and research of modulation scheme caused by the defects of a hetero-structure photonic crystal multi-channel filter were proposed. From the numerical simulation results, it was shown that the multi-mode filtering property of ring cavity could be overcome and the single wavelength selection and filtering for one channel could be obtained by introducing the point defect in the photonic crystal ring cavity filtering channel. The output resonant wavelength of this filter could be adjusted by changing the refractive index of the point defect of each channel, and the tunable filtering function of each channel was independent. The output resonant wavelength would shift towards the longer wavelength direction when the refractive index of point defect increased. The hetero-structure photonic crystal designing method could provide some theoretical references to realize filtering function for the multi-channel filtering in WDM system.
2014, 43(10): 3404-3409.
A new method for displacement measurement with a single grating was proposed in the present study. In this method, the magnified grating image was received by image sensor and sent into the computer. Then, the digital Moir fringes were generated by overlaying the grating image with its mirror image, and the Moir fringe pitch was directly subdivided by image sensor pixels, which had a good space consistency. Compared with the traditional displacement measurement method that generated Moir fringes with the superposition of two gratings, this method totally eliminated the interval between two gratings, was easier to assemble and adjust, and had a lower cost for subdivision. The subdivision system with the resolution of 0.04 m, which consisted of the grating with 20 m pitch and the CMOS image sensor with the pixels of 2 0481 536, was tested on the Abbe comparator platform. The results show that the maximum displacement error is less than 0.18 m.
2014, 43(10): 3410-3415.
For the purpose to test large aspheric surface by Coordinate Measuring Machine(CMM), the new method combined three coordinate measuring and subaperture stitching testing was proposed. The basic principle and flow chart of the method were analyzed, the synthetical optimization stitching mode and effective stitching algorithm were established based on primary aberration and least-squares fitting. A large off-axial SiC aspheric surface with the aperture of 1 200 mm434 mm was tested by this method with 2 subapertures. For the validation, the whole asphere was also measured by profilometry. The PV and RMS between the two methods is 0.073 m and 0.042 m, respectively; the PV and RMS of residual error is 0.325 m and 0.055 m, respectively.
2014, 43(10): 3416-3422.
A monostatic radar at 140 GHz frequency band has been developed for scale-model targets imaging and radar cross section(RCS) measurements. The coherent transceiver using all solid state technique adopts a multiplier chain driving by Ka band source as the transmitter to get an output power of about 0.5 mW in the 5 GHz bandwidth and a Schottky diode subharmonic mixer as the receiver to realize coherent detection. This compact range radar has demonstrated good signal-to-noise obtaining100 dB dynamic range with 3 cm resolution. In addition to inverse synthetic aperture imaging of targets, the system can also measure full angle RCS of selected targets with rotation. Measurements were made on 1/720th scale models of aircraft carrier, simulating P-band frequencies according to scaling laws. The results give some references for the full scale RCS used in P-band radar.
2014, 43(10): 3423-3427.
A new method for the in-flight calibration of camera's intersection angle was put forward. It is different from the photogrammetric resection which is widely used at present. Take the three-line-array CCD surveying and mapping camera as example, through the analysis of its working principle, the geometric model to calculate the camera's intersection angle was established, and the correlative experiment using the image data of TH satellite was carried out. Result shows that this method is feasible, and the outcome is very close to the conclusion got by the photogrammetric method. Meanwhile, the affection of the orbit determination precision and the ground control points' precision on the camera's intersection angle was calculated and analyzed. Compared with the photogrammetric method, it is easier to understand, and can further be used to calibrate the off-axis angle of the multispectral camera and high definition camera in-flight. It is of great significance.
2014, 43(10): 3428-3433.
In order to verify the estimated wavefront ability of the phase retrieval wavefront sensor (PRWS) system, a measured spherical mirror of experiment platform with the method of PRWS was set up, whose structure was simple and there was little affection of the platform and even can be ignored, even use the camera of the imaging system to estimate the whole optical system without changing anything. In order to validate the veracity of PRWS, PRWS measurement results were compared with ZYGO interferometer measurement results, experimental results demonstrate that good agreemented is obtained among the errors distribution, PV value and RMS value of ZYGO interferometer, so using PRWS technology can effectively estimate the aberration of spherical mirror.
2014, 43(10): 3434-3438.
The piezoelectric ceramic plays an important role in the precision control system, but it lacks effective and precise measurement methods for its actual high frequency response in fast control system. The present methods of measuring characteristics of piezoelectric ceramics were summarized in this paper and their difficulties and shortages were also analyzed, the laser feedback interference principle based Nd: YAG microchip laser feedback interference measurement system was used to study the dynamic characteristics of piezoelectric ceramics. The displacement of two kinds of piezoelectric ceramics was measured with the drive frequency range from 100 Hz to 7 kHz, and the corresponding displacement scale was 7-34 nm. The accuracy could reach nanoscale, accurate measurement under higher drive frequency was also achieved. The method has very high measurement accuracy, and lower requirements on the measured object.
2014, 43(10): 3439-3443.
A method to estimate spacecraft attitude using Risk Sensitive Filter was presented based on Cubature Rules(CF-RSF). The objective was to solve the uncertain problem of system model and noise in complex condition. Introducing risk sensitive function, this scheme overcame the poor robustness and even divergence of filter caused by system uncertainty, and solved nonlinear integral problem using cubature rules. The filter accuracy and robustness on system uncertainty were both improved, and the computational complexity was decreased. The simulation shows that the developed algorithm is effective.
2014, 43(10): 3444-3450.
The optic-electronic measure pod works under the condition that high speed, high altitude, high weed carry and many librations. And the bulk of the pod is not too big which is enslaved to the air characteristic. So the inner structure of the pod should entirety fit that rigor condition. And the structure should be gathering together. First of all, the pod head design was analyzed, which was the most important requirement-cramped space. The pod head maximum size was 390 mm600 mm. But the space contained three pairs of bearings, four frame, two sets of visible light TV system, a set of optical path of rapid control system and related control circuit, the gyro etc. Therefore, to carry on the corresponding structure optimization design and analysis for the system is reasonable in such narrow space configuration. According to the full demonstration analysis, a series of design requirements was put forward. Based on the design request, the parameters of important parts of the pod head were calculated with model chose and structure design. The mode and statics of radix seat and the across rolling frame were analyzed based on the MSCPATRAN software which can validate the structure design rationality.
2014, 43(10): 3451-3456.
A measurement system for testing the photoelectric parameters of CCD was developed. It can realize automatic testing for the photoelectric parameters of various types of linear or area CCD, including invalid pixels, relative spectral responsivity, saturation irradiance, responsivity, equivalent noise irradiance, dynamic range, linearity, threshold illuminance, nonuniformity. The measurement system for relative spectral responsivity of CCD was based on the method of direct comparison of single optic path. The other parameters measurement system was built on a special designed integrating sphere light source. Four halogen lights was plant in four secondary integrating spheres, then cascaded with main integrating sphere using high-precision electric diaphragm. After calibrated, the light meter planted on the wall of main integrating sphere can test the luminance of export in real-time. The color temperature of the light source unchanged, the luminance of export was uniform, and can adjust in a large dynamic range continuously. The demand of testing the photoelectric parameters of CCD was satisfied. The photoelectric parameters of CCD47-10B was tested, and then the uncertainty of those systems was analyzed. Results indicate that the spectrum range of measurement system of relative spectral responsivity is 400-1 000 nm, the uncertainty is 4.37%. At the distance of 23 mm from exit port of source in measurement system for photoelectric transform parameters of CCD, the dynamic range of luminance was 0-235 lx, and the irradiance uniformity within 80 mm has reached 99%, the uncertainty is 4.9%. The measurement system can be used in testing the photoelectric parameters of aerospace-grade CCD and filtering it.
2014, 43(10): 3457-3461.
In order to improve the cruising guidance ability of the remote anti-ship missile and to increase the effctive range, based on the objective analysis for the future sea battlefield and the features of the celestial navigation about small field of view, a celestial angle measurement based guidance way was put forward which will serve as the main method for the guidance of remote missile on it's cruise phase, gave out the system analysis for feasibility and listed the superiorities. With the new concept of guidance angle, the guidance system can be divided into three stages, namely initial parameters's binding and calculation, guidance angle's correction and terminal guidance confirmation, their respective calculation formula and related derivation were given, a specific example was used to carry out computer simulation. The simulation results show that guidance system can serve as an effective cruise guidance method, it witnesses a successive guidance angle and a permitted error, which bears important significance for the overal design of modern missile.
2014, 43(10): 3462-3466.
Gyro is popular equipment in the inertial stabilization control system. There is one velocity stabilization control loops with gyro in classic control system, one of the main limitations to inertial stabilization system is control bandwith for gyro-based inertial control system. High control bandwith is too difficult to gain because of nonlinearities, such as mechanical resonances. A new control structure of multi-stablization control loop was introduced where an acceleration feedback loop is added into the velocity control loop. The angular accelearation signal was from two accelerometers, and not was calculated with velocity and position signal. Using Lyapunov theorem, the stability of the multi-stabilization control loops were verified, and the friction of inertial stabilization system could be reduced with acceleration feedback. The torque attenuation with multi-stabilization control loops was equal to accelaration feedback loop's attenuation multiplied by gyro feedback loop's attenuation. The experiments show the multi-stablilization control loops improve the performance of inertial control system.
2014, 43(10): 3467-3473.
Aerial camera is an important device on obtaining information by the method of air-to-ground investigation and measurement. The way of forward flight together with pendulum scanning in the direction of wingspan is commonly used for broadening the field of view of aerial camera. The problem of image motion compensation was focused on, which was produced by broadening the field of view. The image motion compensation formulas of the flight and wingspan direction were further derived, and the high practicability compensation scheme was proposed. Based on the MATLAB/Simulink environment,the mathematical model of image motion compensation was simulated and verified. Simulation results show that the compensation scheme is achievable. In the hardware experiment, the circuit which was mainly made of the FPGA chip was used to achieve the function of image motion compensation. The experimental and simulation result curves are in good agreement. The effect images further certificate that the image motion compensation is an indispensable link in improving the imaging quality and resolution.
2014, 43(10): 3474-3479.
An adaptive bandwidth object tracking method based on particle filter was proposed. Classic Particle Filter based tracking algorithm uses fixed kernel-bandwidth, as the scale changes obviously, the target may not be tracked effectively. So the principal component analysis method was introduced into the particle filtering framework to analysis the covariance matrix of the pixels within the target region. Then the most ideal tracking window including target direction and scale can be calculated. The experimental results show that the method can be adaptive to the variation of local structure of the target, moreover, spatial location and scale are good.
2014, 43(10): 3480-3485.
Take the shape, orientation, location estimation and recognition of the target object, which is based on the laser imaging radar 3D point cloud, as the application background. According to the characteristics of the warhead shape, model it as a cone approximately, and characterize it by 6 parameters. The estimation method of conical target parameters by the L-M (Levenberg- Marquardt) algorithm was put forward, which were based on LADAR 3D point clouds, and pointed out that this method could also be used for the recognition of conical target. The result of the simulation experiment shows the relationship between the estimation errors of parameters with the distance resolution and point cloud scale of the laser radar separately. The simulation and experimental results show that, this method could accurately estimate the parameters of conical warhead target in a certain observation distance resolution, and according to the optimization results of objective function and the obtained parameters the target could be identified.
2014, 43(10): 3486-3491.
An infrared moving object detection method which combines Reichardt-type two dimensions Elementary Motion Detectors inspired by biological vision and region growing method was proposed to solve the two dimensions EMDs' sensitive problem in dynamic scenes. EMDs detected the most intensive motion vector signal in temporal domain which was then used as the seeds of the region growing. Region growing method was applied to make a segmentation of the target by its infrared radiation characteristic much different from background in spatial domain. The simulation illustrates that, combing the EMDs in temporal domain with the region growing method in spatial domain achieves much better detection performance in infrared frames than the original Reichardt's model. Compared with other methods, the proposed method could achieve a higher SCR.
2014, 43(10): 3492-3496.
Laser spot detection is the key technique used in optical measurement, and widely used in optical measurement system, optical automatic alignment system and laser communication target tracing. In order to improve the optical measurement and anti-interference of spot center and radius, a kind of laser spot center detecting algorithm was put forward based on the optimal arc, according to the symmetry of a circle, the algorithm overcame the interference edges, and then selected the arc with good sysmmetry as the optimal arc to provid the fitting data, calculated center and radius of a circle by using the least squraes method. And it was compared with other commonly used algorithms. Experiments show that the proposed algorithm has high orientation precision for the center and radius, fast speed, and can improve the anti-interference of testing center. The algorithm is suitable for real-time detection.
2014, 43(10): 3497-3503.
In order to improve the precision and accuracy of iris location, and furthermore enhance the recognition rate of the iris recognition system, a iris location algorithm based on Vector Field Convolution (VFC) was proposed to locate the iris inner boundary accurately. Firstly, minimum grey value method was used to determine initialization contour of VFC model automatically, so that the iris inner boundary could be located precisely under the internal and external force of active contour, then the improved Daugman algorithm was adopted to locate the iris outer boundary. Performed abundant experiments make use of several iris image databases, and also compared with common several kinds of iris localization methods. The experimental results show that the location accuracy of this method is higher, the iris inner edge location is much closer to the real boundary, and the result of location have been improved significantly.
