Abstract:<110> oriented ZnTe crystals were grown by Te-solvent method and tested by X-ray diffraction(XRD) and Raman scattering measurements.THz generation and detection characteristics of the Te-solvent-grown ZnTe electro-optic crystals were studied in detail in Terahertz-time domain spectroscopy.Our results show that the <110>-oriented ZnTe crystals can emit high signal noise ratio THz signal pumped by Ti: sapphire laser,and the THz pulse's width is over 3 THz at the room temperature.

Abstract:Some recent results of spectral characteristic study of integrated HgCdTe(mercury cadmium telluride) infrared two-color detector arrays were presented firstly.Many further investigations of spectral and structural characteristics were focused on SW(short wavelength) response of the preliminary two-color detection arrays which exhibited a narrow spectrum.The reason and solution of SW spectrum with small FWHM(full width of half maximum) were then found,and the proper spectrum of two-color detector with an imp...

Abstract:Theoretical research and optimization design of 8mm second harmonic gyroklytron amplifier were reported.A three-cavity,second harmonic gyroklystron amplifier prototype was fabricated according to the results of numerical simulation.Initial experiments show a peak output power of 180 kW at 35 GHz with an efficiency of 13% and a gain of 21dB.A peak output power of 150 kW with a 3-dB bandwidth of 110 MHz(0.3%) at 58kV beam voltage and 25A beam current was obtained.

Abstract:On the basis of studying the principle of passive millimeter wave(PMMW) imaging,a compact 3mm super-heterodyne Dicke-radiometer was developed and the imaging experiment was done.An improved maximum-likelihood(IML) super-resolution algorithm was proposed in order to solve the inherent problem of poor resolution imaging,which was caused by limited aperture dimensions and the consequent diffraction limit.Experiment results indicate that the algorithm is able to complete spectral extrapolation,and enhance super...

Abstract:Aiming at the problem of detection performance of infrared(IR) images,from the typical flow of multi-sensor data fusion algorithm,the relationship among the detection performances of single IR image,IR image sequence,and multi-sensor data fusion algorithm was deduced.The influence of single factor was also analyzed quantitatively.Analytical results show that the detection performance of multi-sensor data fusion algorithm is much better than that of single IR image and IR image sequence.

Abstract:One-dimensional metamaterials were realized by using composite right/left-handed transmission lines(CRLH TLs),the transmission properties of the photonic crystals composed of metamaterials based on microstrips lines were measured and analyzed.The experimental results indicate that the photonic crystals possess Bragg gaps and effective-single-negative(ESNG) gap,and the ESNG gap does not shift when the lattice constant varies by the same factor,and the edges of the gap are determined by zero average permittiv...

Abstract:Since the existence of buried targets influences the surface' IR images changing with time,buried targets were detected by multitemporal infrared images.In order to denoise the exposal nioses of partial IR images,a method of kernel minor component analysis(KMCA) was put forward to denoise multitemporal images and overcome the difficulty in choosing images automatically,thus,the good images could be attained automatically.Then a fuzzy kernel cluster algorithm with spatio and temporal restrictions(STKFCM) was...

Abstract:The noble metal Ag film sample was prepared by the RF(radio frequency) sputtering method.The complex dielectric function and the complex refractive index of the thick Ag film sample were measured by the spectroscopic ellipsometric method in the 1.5~4.5 eV photon energy region.The light refractions at the Ag/air interface for a plane film structure were analytically calculated at three different wavelengths.From the calculation,it was found that the refraction angle at the air side is not equal to the initia...

Abstract:Infrared images have higher noise and lower resolution than visible images.This makes it more difficult to achieve a better disparity image in infrared images by using the method based on region matching.After analyzing the phase congruency transformed image,a new region matching method was presented.First,the images were transformed by phase congruency.Next,the images were matched based on region correlation.The experimental result indicates that the noise of images is restrained and the feature is more di...

Abstract:The radiative transfer solution method of a two-dimensional graded index semitransparent medium was developed.The apparent directional emissivity of the medium with nonlinear refractive index distribution was also analyzed.The results show that the numerical technique of this method has a high numerical precision by which the maximum relative error of apparent directional emissivity is less than 1.6%.Results also show that apparent emission of the medium has an obvious directional pattern.This phenomenon is...

Abstract:Earth radiation measurement(ERM) nonscanner,which includes a total-wave channel and a short-wave channel,is a new type of remote sensing instrument in our country.There is an activity cavity detector in each of these channels.ERM nonscanner is used to stare the earth and measures the earth radiation budget from the low orbit satellite and its field of view covers with the edge of the earth.Being a quantification remote sensor,ERM needs a high precision radiant calibration standard.The method of radiant cali...

Abstract:The remote sensing image should be atmospherically corrected for quantitative application,while removing the adjacency effect is an important step in atmospheric correction.Removing adjacency effect depends on the knowledge of its main impact factors and mechanism.In this study,the main impact factors and mechanism of adjacency effect were investigated,and the adjacency effect of different contrast targets in different conditions was simulated by using MODTRAN model.The results show that the visibility has ...

Abstract:The constant false alarm rate(CFAR) controlling technique of avalanche photo diode(APD) applied in Lidar was studied,and a CFAR controlling circuit based on FPGA was described.Our results show that it is capable of self-adjusting according to the background radiation by means of noise detection,and it can also maintain constant FAR and make the APD in the optimum state of bias voltage.Experimental results indicate that this circuit can well realize CFAR controlling.

Abstract:为了实现全天空红外测云系统辐射传感器业务运行过程中的定标,提出了一种以晴空辐射为标准辐射场的替代定标方法.根据SBDART辐射传输模式计算出的晴空大气向下红外辐射以及辐射传感器对天空观测的输出量化值,利用线性回归方法确定出传感器全场各像元的响应率和偏移量.定标结果分析表明,响应率不确定度为2.03 DN unit/(W·m-2·sr-1),偏移量具有明显的正态分布特征,为空间随机噪声.标准黑体检验表明温度反演平均误差不超过±1.5℃,能够满足系统定量化应用的要求.

Abstract:The Chang'E lunar observation laser altimeter was designed to provide precise altimeter data to accurately map the lunar surface by measuring the time interval between the emission and receiving signal.The relationships of the background radiant power,the multiplication factor,and the optimum signal-to-noise ratio of the receiving system were analyzed.The signal-to-noise ratio experiment for different background radiant power was conducted by using the integrating sphere.The influences of background radiant...

Abstract:Based on the mode-hopping of single mode diode laser,two different currents drive the laser alternately,the laser emits alternately two beam lights whose wavelength is differently,but closely.The first beam light's wavelength is at the absorption peak of methane.The second beam light's wavelength is a little shorter than the first one,which is not absorbed by methane,and it will serve as a reference light beam.The double beam will be converted into an electronic square wave after passing through the gas cel...

Abstract:Contourlet transform was introduced in the SAR image statistical property research work.Based on Contourlet domain Hidden Markov Trees Model,starting from image restore methods,a novel SAR image despeckling method was given.This method combined the SAR image despeckling technology with minimum mean square error(MMSE) and Bayes estimate.A new speckle variation estimate method was given based on Laplacian pyramid(LP).The results comparison with wavelet domain method were given.Experimental results show that t...

Abstract:A novel image quality metrics was proposed.Firstly,images were decomposed into subbands with different scales and directions by hybrid wavelets and directional filter banks(HWD).Secondly,in order to offer a uniform visual sensitivity to different scales and directions subbands for human perception,each subband was masked with contrast sensitivity function(CSF).A rational sensitivity threshold was defined,and then the proportion of sensitivity coefficients in each subband was computed.Variation of visual per...

Abstract:Aiming at the scaling of the noise after multiwavelet decomposition and the characteristic of image,a multiwavelet adaptive denoising method was proposed based on genetic algorithm.This method can adaptivly look for the least RMSE of the denoised image according to genetic algorithm.The experimental results show that this algorithm is superior to the traditional methods.It can not only remove the noise of image,but remain the better edge of image,and this method has more perfect denoising effects.