• Volume 26,Issue 3,2007 Table of Contents
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    • BROAD-BAND TRIPLER OF W-BAND

      2007, 26(3):161-163186.

      Abstract (1513) HTML (87) PDF 176.99 K (2038) Comment (0) Favorites

      Abstract:介绍了一个W频段宽带倍频器.采用反向并联二极管对结构实现宽带倍频.该倍频器输入为WR-28波导到微带过渡结构,输出为WR-10减高波导.在输入功率为5dBm时,在整个W频段输出功率为0.81±1.80dBm,二次谐波抑制度大于25dBc.该倍频器可把Ka频段的信号源扩展到W频段.

    • NUMERICAL MODELING OF MIDDLE WAVELENGTH TWO-COLOR PHOTOVOLTAIC HgCdTe DETECTORS

      2007, 26(3):164-169.

      Abstract (1250) HTML (92) PDF 334.31 K (3712) Comment (0) Favorites

      Abstract:基于二维数值模型,对光伏型中波(MW1/ MW2)HgCdTe双色红外探测器作了模拟计算,器件采用n-p-p-p-n结构、同时工作模式.计算了双色器件光谱响应及量子效率,重点分析了两个波段间的信号串音问题,以及高组分势垒层的作用.模拟结果显示,MW1(中波1,波长较短)对MW2(中波2,波长较长)的串音是辐射透过MW1区在MW2区中吸收引起的,串音与光吸收比近似成正比,而载流子扩散效应可以忽略不计.高组分阻挡层对载流子扩散引起的串音有显著的抑制作用,如果没有势垒层,载流子扩散引起的串音十分明显,甚至成为串音的主导因素.对于60×60μm2探测单元MW1和MW2的结电容大约为1.75pF/pixel.

    • PREPARATION AND DIELECTRIC PROPERTIES OF LiTaO3 THIN FILM ON THE ITO SUBSTRATE

      2007, 26(3):170-173.

      Abstract (1058) HTML (105) PDF 223.73 K (3963) Comment (0) Favorites

      Abstract:LiTaO3 thin films were prepared on the ITO substrate by sol-gel methods. The performance parameters such as orientation, surface morphology, grain size and the thickness of LiTaO3 thin film were studied by XRD, SEM and AFM. The influence of different solvents on the stability of LiTaO3 sols and the influence of different annealing condition on the prepa- ration of LiTaO3 thin film were analyzed either. The relative dielectric coefficient and dielectric loss of the prepared LiTaO3 thin film were measured by using Al/LiTaO3/ITO structure electrode. The experimental results show that the quality of LiTaO3 thin film with every layer crystallized annealing is better than that with pyrolyzed and crystallized annealing alternately. The relative dielectric coefficient is about 53 and dielectric loss is about O. 4 when the measured frequency is 1 kHz. The reason of increaing the dielectric loss of LiTaO3 thin film has been discussed.

    • ANALYSIS ON THE TRANSIENT TEMPERATURE-FIELDS FOR INFRARED RADIATION OF AIRCRAFT SKIN

      2007, 26(3):174-177.

      Abstract (1512) HTML (88) PDF 219.23 K (4808) Comment (0) Favorites

      Abstract:The aircraft skin temperature is a basic factor determining the infrared image of aircraft, so the knowledge on the transient temperature is important. By analyzing the heat transfer mechanism governing the skin temperature, the physical and mathematical models for the transient coupled heat transfer were put forward, in which the effects of internal heat transfer in an aircraft cabin and the aerodynamic convection and radiative heat transfer outside the skin were included. A wall heat flux function was introduced to separate the numerical prediction of internal heat transfer in aircraft from that of thermal effects outside the skin. The thermal network method combined with the Monte Carlo method was used to analyze the internal heat transfer and the FLUENT code was employed to simulate the aerodynamic convection outside skin. By numerical simulation, the transient temperature fields of an aircraft skin under various flight statuses were obtained and discussed.

    • NEW METHOD TO IMPROVE THE ACCURACY OF ATTITUDE DETERMINATION BASED ON AN ONBOARD INFRARED EARTH SENSOR

      2007, 26(3):178-181.

      Abstract (801) HTML (105) PDF 202.64 K (2713) Comment (0) Favorites

      Abstract:红外地平仪提供了卫星星体相对于地球的姿态测量信息.受它在星体上安装精度限制、测量系统噪声和在轨期间星体质量分布变化的影响,直接使用红外测量值进行姿态计算会引入上述误差.如果只采用红外测量的差分值进行姿态计算,再通过滤波,就可以消除上述误差后得到高精度卫星姿态,这种方法充分利用了地球同步在轨卫星位置定点和姿态指向特性,对在轨运行卫星进行长时间姿态确定和实际控制结果表明该方法得到的姿态精度高于0.01°,显著提高了红外定姿精度.

    • INFRARED THERMOGRAPHY TARGET DETECTION BETWEEN CONCRETE STRUCTURE AND PLANT LEAF

      2007, 26(3):182-186.

      Abstract (1052) HTML (83) PDF 264.07 K (2920) Comment (0) Favorites

      Abstract:The principal problem in which infrared thermographic measurements are concerned with is the emissivity of material.Infrared thermographic system was usually used to detect enemy on battlefields.However,landscape engineering is a common camouflage works on battlefields.Thus,according to energy equilibrium law,the leaf emissivity simulate model was set up to estimate the leaf emissivity.Further,the infrared thermographic system was used to analyze the thermography of concrete structure and plant leaf when the environmental temperature difference is within 0.5.The experimental results show that there are approximate linear regression lines between the emissivity parameter of infrared thermographic system vs.the mean temperature of these two targets.But there are obvious different linear regression lines between the emissivity parameter of infrared thermographic system vs.standard error of mean temperature of these two targets.The different characteristic of infrared thermography between concrete structure and plant leaf will promote the detecting ability of infrared thermographic system when the environmental temperature of target area is under the slight temperature difference.

    • PULSAR SIGNAL RECOGNITION BASED ON ONE-DIMENSION SELECTED LINE SPECTRA

      2007, 26(3):187-190195.

      Abstract (1890) HTML (104) PDF 273.64 K (3030) Comment (0) Favorites

      Abstract:For recognizing the signals of pulsars and improving the effect of recognition,non-linear and non-gaussian characteristics of the average pulse profiles of pulsar signals were analyzed by using bispectra technology.Then one-dimension selected line spectra algorithm for extracting pulsar signals' characteristics was proposed.The algorithm makes use of feature core and domain to represent the generality of bispectrum and its distribution domain.And the variance of signal feature vector and the distance between two kinds of signal feature vectors were defined,based on which one-dimension line spectral vector with best interclass separability was redefined.The results of recognition experiments show that the algorithm of one-dimension selected line spectra is suitable for extracting pulsar signals' characteristics.Compared with the selected bispectra,the selected line spectrum has the maximum interclass separability.

    • DSP OF STATIC INFRARED-EARTH-SENSOR BASED ON MATCHING FILTER

      2007, 26(3):191-195.

      Abstract (966) HTML (96) PDF 287.18 K (2215) Comment (0) Favorites

      Abstract:On the basis of analyzing the signal character of the static infrared-earth-sensor, a new digital signal processing based on matching filter was developed to find horizon information from the signal serial with low SNR. The simulation resuits verify the accuracy and feasibility of this method.

    • SUPER-RESOLUTION PROCESSING OF SAR IMAGES BY BASIS PURSUIT METHOD BASED ON FOURIER ATOM

      2007, 26(3):196-200.

      Abstract (1009) HTML (89) PDF 253.22 K (3100) Comment (0) Favorites

      Abstract:The application of the basis pursuit method to SAR super-resolution processing was extended. Firstly, based on the SAR attributed scattering model, a Fourier dictionary with fast implicit algorithm was designed in phase history domain. Secondly, in light of the separable feature of Fourier atom, The dictionaries in column-wise and row-wise of the image were construct, the dimension of the dictionary and the computation burden were greatly reduced. A new and fast iterative algo- rithm was proposed to solve the optimization problem of the basis pursuit. Finally, higher resolution image was obtained by IFFT to the coefficient. Simulation experiments and computational results of measured MSTAR data demonstrate that basis pursuit can be implemented speedy and stably, and it can provide super-resolution at the same time.

    • UNIFORM SAMPLING METHOD OF OPTICAL FIBER FOURIER TRANSFORM SPECTROMETER

      2007, 26(3):201-204.

      Abstract (907) HTML (92) PDF 223.58 K (4110) Comment (0) Favorites

      Abstract:Equal interval sampling of interferogram is realized by a novel uniform sampling method in optical fiber Fourier spectrometer(FFTS).The reference beam and test beam are simultaneously over-sampled.The Interferogram of test beam versus optical path difference is obtained by the relation of sample time versus fringes number and that of interference fringes of test beam versus sample time.Simulation calculation and experimental studies show that the method is effective for eliminating unequal interval sample and many affixation spectra lines.The method can be used in the sample systems not only in FFTS,but also in conventional Fourier spectrometer.Specially,it can also play a significant role in short wavelength Fourier spectroscopy than other methods.

    • RADAR TARGET RECOGNITION BASED ON GENERALIZED DISCRIMINANT ANALYSIS OF QR DECOMPOSITION

      2007, 26(3):205-208.

      Abstract (819) HTML (88) PDF 213.52 K (2950) Comment (0) Favorites

      Abstract:A new generalized discriminant analysis(GDA) method based on QR decomposition was proposed,which would be used in radar target recognition with one-dimensional range profile.Different from the traditional approach of solving GDA by singular value decomposition(SVD),the new algorithm utilizes kernel modified Gram-Schmidt(KMGS) orthogonalization algorithm to extract the optimal transformation matrix directly,which can not only effectively hold the most discriminant information in the null space of within-class scatter matrix,but also make the solution more stable in numeric.Experiments on three measured airplains data show that the proposed method achieves better recognition performance than traditional GDA,while it has lower costs in computation partly,thereby,the real-time performance is improved.

    • ALGORITHM OF IR SMALL TARGETS DETECTION BASED ON SPATIAL FILTER AND ITS APPLICATION

      2007, 26(3):209-212.

      Abstract (2385) HTML (1118) PDF 227.49 K (4906) Comment (0) Favorites

      Abstract:For small targets detection in single frame infrared image, a background clutter suppression algorithm based on an adaptive smooth filter and spatial filter was used to analyse the IR scene model. The method has good performance to detect the small targets in the undulant background and has the merit with no target information loss. At the same time, the algorithm is realized by the digital processor ADSP-TS201S with high performance and successfully applied in an all directional IRST system. The experiment shows that this method has high detection performance for the small target in single frame at low SNR.

    • STUDY ON HIGH RESOLUTION TIME INTERVAL MEASUREMENT MODULE IN PULSED LASER RANGING SYSTEM

      2007, 26(3):213-216221.

      Abstract (2063) HTML (213) PDF 268.18 K (6655) Comment (0) Favorites

      Abstract:The precision of the pulsed laser ranging system was decided by the precision of the time interval measurement. Therefore, a high resolution time interval measurement module was developed. The module is based on the special time-to-digital conversion chip which adopts the delay line interpolation method. The maximum measuring time of the module is 200ms, and the maximum time resolution is 125ps, of which the corresponding distance resolution is 18.75mm. The module is especially suit for the large distance measurement. The hardware and the software of the module as well as the testing results are also presented.

    • INFRARED IMAGE FUSION ALGORITHM BASED ON CONTOURLET TRANSFORM AND IMPROVED PULSE COUPLED NEURAL NETWORK

      2007, 26(3):217-221.

      Abstract (1402) HTML (107) PDF 278.14 K (3319) Comment (0) Favorites

      Abstract:A fusion algorithm based on contourlet transform and improved pulse coupled neural network was proposed. By using the contourlet transform, the input images were firstly decomposed into a number of sub-images with various scale and directional features. Then, based on the IPCNN, a fusion rule in the contourlet domain was given. The fused coefficients could be generated by the IPCNN based fusion rule and the fused image was obtained by performing the inverse contourlet transform to the fused coefficients. The proposed algorithm was successfully applied for the visible image and infrared image fusion. The simulation results confirm the validity of the proposed method.

    • RESEARCH ON MM-WAVE FREQUENCY SYNTHESIZER WITH LOW PHASE NOISE AND FULL-PHASE-COHERENCE

      2007, 26(3):222-224231.

      Abstract (1201) HTML (109) PDF 254.81 K (3571) Comment (0) Favorites

      Abstract:研制出一种小步进全相参毫米波频率合成源.本振部分,对直接数字式合成频率、参考分频比和环路分频比进行三重调节,抑制了直接数字频率合成的杂散,提高了频率分辨率;发射部分,采用二次混频电路,避免了调谐电压预置,简化了电路,并保证了发射信号和本振信号相参.该系统输出在Ka频段,带宽400MHz,步进<1MHz.测试相噪<-90dBc/Hz@10kHz、-97dBc/Hz@100kHz,杂散为-60dBc,跳频时间<15us.

    • VIEWS ON CHINESE REMOTE SENSING DEVELOPMENT

      2007, 26(3):225-231.

      Abstract (987) HTML (81) PDF 442.47 K (4099) Comment (0) Favorites

      Abstract:Notable achievements have been obtained for Chinese remote sensing information acquiring,processing and application.In this study,three aspects about remote sensing were analyzed.The first is the meaning of quantitative remote sensing and the relation between quantitative remote sensing and qualitative remote sensing.The second is the detailed technical factors that affect the qualitative ability and quantitative ability of remote sensing information acquiring,processing and application.The third is the systematic problems which need to be much regarded in Chinese remote sensing projects.It is concluded that 1) to advance Chinese remote sensing project quickly and well,remote sensing quantification must be viewed properly,much attention need to be paid to both quantitative remote sensing and qualitative remote sensing;2) the specific technical units of remote sensing need to be improved one by one to heighten their qualitative and quantitative capability;and 3) the remote sensing projects need to be grasped from systematic level.

    • RESEARCH ON OPERATING TEMPERATURE CHARACTERISTIC OF UNCOOLED MICROBOLOMETER DETECTOR

      2007, 26(3):232-236.

      Abstract (1031) HTML (105) PDF 290.14 K (3732) Comment (0) Favorites

      Abstract:根据非制冷红外热成像技术的基本原理,通过对α-Si微测辐射热计探测器响应性能及功耗特性的分析,得到了探测器噪声等效温差NETD、探测率及功耗与工作温度之间的关系.提出了在环境温度变化范围较大的情况下改善探测器低温环境工作性能的方法--采用多个工作温度点.并对探测器采用0℃和30℃双工作温度点工作进行了实验,实验结果表明,该方法切实有效,可以显著扩展非制冷微侧辐射热计探测器的环境温度适用范围.

    • NOVEL ANISOTROPIC DIFFUSION FILTER

      2007, 26(3):237-240.

      Abstract (1086) HTML (91) PDF 263.92 K (4114) Comment (0) Favorites

      Abstract:The statistic meaning of the diffusivity function of Perona-Malik diffusion filter was analyzed.A statistic interpretation model was proposed that the diffusivity function defines a probability density function(PDF) for the edge estimator as a random variable.This model overcomes the difficulty of no unified theory of designing and selecting the diffusivity functions.A novel anisotropic diffusion filter based on this model was designed.Experiments demonstrate that the novel filter promises the same efficiency in images denoising as PM method,and with less recursion times.So our interpretation model of the diffusivity function provides an effectively method to custom anisotropic diffusion filter for special application.

Editor in chief:Jun-Hao CHU

International standard number:ISSN 1001-9014

Unified domestic issue:CN 31-1577

Domestic postal code:4-335

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