Editor in chief：Jun-Hao CHU
International standard number：ISSN 1001-9014
Unified domestic issue：CN 31-1577
Domestic postal code：4-335
- Most Read
- Most Cited
- Most Downloaded
Abstract:Due to being influenced by detectors' material,related manufacturing technology etc,every detection element's responsivity of infrared focal plane arrays(IRFPA) is different,which results in non-uniformity of IRFPA.So non-uniformity correction(NUC) is an important technique for IRFPA.The traditional NUC algorithms based on neural network were analyzed in this study.And a new improved NUC algorithm based on neural network was presented. A comparison was made to these algorithms.Experiments results show that the algorithm proposed in this study prevails over other algorithms based on neural network in correction effective and convergence speed.
Abstract:High quality SrBi_(2)Ta_(0.6)Nb_(1.4)O_(9)(SBTN) ferroelectric thin films were fabricated on platinized silicon by PLD.Electrical fatigue and optical fatigue of SBTN ferroelectric thin films were studied,respectively.The fatigue mechanisms in the thin films were analyzed.The results indicate the excellent fatigue resistance of electrical properties under electrical fatigue for SBTN ferroelectric thin films.However,by using the illumination of a 200W Hg arc lamp at 0.9V,it was found that the average remanent polarization was dropped by nearly 51% due to the bias/illumination treatment.The optically induced polarization fatigue in SBTN films is due to trapping of photo-generated charge carriers at domain boundaries.
Abstract:The spectral characteristics of architectural materials covered by different paints were analyzed. Experiment and study show that the changes of spectral characteristics are highly relevant to the paint color and its thickness for different wood and metal plates. Spectral characteristics in short-wave infrared range is least affected by the external paint and can be used to distinguish different materials under the paint. The experimental process and the data qualities are also evaluated. This study is significant for the application of hyperspectral remote sensing in detecting the man-made objects and military camouflage materials.
Abstract:A new method for discrimination of varieties of juicy peach by means of visible-near infrared spectroscopy(NIRS) was developed.First,the spectral curves of three varieties juicy peaches were measured by spectrometer;the pretreated spectra data of juicy peach were analyzed through principal component analysis(PCA).Then the diagnostic information from PCA was used as inputs of multiple discriminant analysis(MDA) for pattern recognition.The 2-dimontional plot was drawn with first and second principal components,which indicated that it was a good clustering analysis for classification varieties of juicy peach.The result of the analysis suggested that the reliabilities of first 8 principal components were more than 94.38%.60 samples from three varieties selected randomly.Then they were used to build discriminating model.15 unknown samples were validated by this model.The recognition rate is 100%.This model is reliable and practicable.So this study can offer a new approach to the fast discrimination of varieties of juicy peach.
Abstract:The basic technology real-time signal processing arithmetic and hardware architecture of infrared image detecting system were presented.Aiming at a large view field infrared detecting system,the real-time processing arithmetic principle and flow,which are applied to omnidirectional infrared target search,were proposed.The scheme of applying high-performance DSP,FPGA and CPCI bus technology was used to compose a signal processing system which has powerful processing capability,high-speed and reliable interface.The experimental result shows that the large field infrared image detecting real-time signal processing system works reliably and stably,and it has achieved the demand of high performance.
Abstract:Solar radiation received by a spaceborne near infrared laser altimeter prototype on orbit with various attitudes was analyzed based on the radiation theory. The working wavelength was 1064nm. With the system responsivity, the solar radiation reflected hy the star surface and received by the laser altimeter when it is working at the normal mode was discussed. And the background noise caused by this radiation was about ten times smaller than the system responsivity and its effect on the system can be neglected. According to the damage threshold of the APD, the solar radiation that directly irradiates the system was analyzed. And the duration of the APD to this radiation in space without any protection on it is 4s.
Abstract:The atmospheric correction algorithm for the TIR band of AMTIS(airborne multi-angle TIR/VNIR imaging System)was presented.This algorithm is suitable for the case in which no atmospheric profile is available.Three parameters are considered in this algorithm: the atmospheric equivalent temperature is determined from the image itself by using a "minimal standard deviation" method or the local air temperature near the surface;the transmittance is calculated from the water vapor content of the column,which can be determined from the surface absolute humidity or from sunphotometer;the emissivity of the pixel is determined from NDVI.The atmospheric correction result is validated by using synchronous experiment data,and the precision of brightness temperature is less than 1.2 K,which is acceptable when the atmosphere profiles is not available.
Abstract:A new kernel density estimation scheme which incorporates gray values, spatial relation and local standard deviations information effectively was proposed. With this scheme, an infrared target extraction method based on kernel density estimation was designed. Firstly, the entire image Was divided into blocks and the confined region that contained the entire target was obtained based on the statistical feature of each blocks. Secondly, the kernel density estimations of the confined region and the corresponding background sample region were estimated. Here, the background sample region is a surrounding image region of the target, but it doesnt contain the target. It is enlarged from the confined target region. Finally, the target was extracted with the contrast of two kernel density estimations under a given threshold. The experimental results show that the proposed method is simple and efficient.
Abstract:The onboard calibration system is the most basic factor of quantitative remote sensing. Based on the description of the onboard calibration theory and experiments, the effect factors on the calibration system were analyzed, including blackbody emission ,temperature measurement precision and temperature sensor response time. Then the solution to these effects and the design principle of the onboard calibration system were given.
Abstract:By the nonlinear theory model of gyrotron traveling wave amplifier in which the influence of velocity spread is contained, the effect of velocity spread on the interaction between electron beam and wave for a W-band gyrotron traveling wave amplifier was studied. The results indicate that the influence of velocity spread in amplifier can be weakened by regulating the interaction length, decreasing the velocity ratio, adjusting the operating magnetic field. It provides the theoretic basis for the optimized design of gyrotron traveling wave amplifier.
Abstract:Equilibrium equation of on-center off-surround shunting network(CSSN) based on difference of Gaussians(DOG) that simulated concentric circle pattern opponent receptive field in retina was analyzed and utilized to enhance and fuse night vision images,which could improve contrast,pop out edge,compress dynamic range,reserve common information and enrich complementary information.Multi-band fusion architectures for color night vision images built on CSSN equilibrium equation were proposed,which included multi-spectrum low-level light visible(LLLV),LLLV(long-wave infrared(LWIR),LWIR/media-wave infrared(MWIR),and LLLV/LWIR/MWIR images.Color mapping rules in these architectures used cool and warm color to present cold and warm targets in infrared,and map LLLV image with plenty of details into green channel as green background.Emulating results show that all architectures obtain natural color appearance.
Abstract:After analyzing the precision and accuracy that can be achieved in the estimation of water quality parameters,as well as the characteristics of Hyperion data,the sensitive bands of different wavelengths and the high correlation coefficients with chlorophyll and suspended sediments concentrations of different algorithms(Ratio,Difference and NDVI)were determined and discussed in details.A hyperspectral model on water quality was developed and validated,and the eutrophic state of Taihu lake and its causes were preliminarily discussed.The precision in estimating water quality parameters by(using) modeling hyperspectral datasets of Little Environmental Satellite(Hj-1) was discussed and compared with that of EO-1/Hyperion.The result reveals the potential of the remote sensing applications of scheduled Hj-1 satellite with hyperspectral sensor on water quality monitoring.
Abstract:Tongue diagnosis is an important diagnostic method in traditional Chinese medicine(TCM).However,one important problem in tongue diagnosis is that its practice is subjective,qualitative and difficult in automated diagnosis.Recently it is a trend to utilize the image processing and pattern recognition technology in aid of the quantitative analysis of tongue image.As the tongue image is often acquired by a commercial digital camera,the pathological information that the image can provide is very limited.In this study,a hyperspectral imaging system,instead of a digital camera was used to acquire the image of the patient's tongue.Experimental results demonstrate that the hyperspectral tongue image acquired by the hyperspectral imaging system has more pathological information of the tongue.It is a new approach for tongue inspection of TCM.
Abstract:Microstrip antennas have many applications in various communicational systems. To meet the requirement of miniaturization of the carry - home equipments, a folded compact microstrip antenna was presented. Based on the curve circuit theory, a new design of a microstrip antenn vas, described. The new design folds the regular microstrip antenna, so that the dimension of the antenna reduced more than 60% compared with the conventional microstrip antenna. The configuration of the antenna is simple and easy to fabricate. Details of the proposed antenna design and simulation results were presented and discussed. The simulation results show the validity of the design.
Abstract:Anomaly detection is an important application of hyperspectral images. Aiming at the problems in current researches, a new anomaly detection algorithm based on spectral analyses was proposed for hyperspectral images. The algorithm used spectral analyses technique to effectively separate target information from complicate backgrounds and greatly suppressed background interferences for detection. And those error data obtained after spectral unmixing with background endmembers only include abundant target information and better follow Gaussian distribution. Principal component analysis was used to transform the error data, and local average singularity was defined to select the most effective principal component for anomaly detection according to high-order statistics. Final detection was realized with conventional RX detector. To validate the effectiveness of the proposed algorithm, numerical experiments were conducted on real AVIRIS data. Experimental results show that the proposed algorithm greatly outperforms the conventional RX algorithm.
Abstract:Aiming at the nonlinear correlation characteristic of visible/near infrared spectra and the corresponding acidity of bayberry juice,one mixed algorithm was presented to predict the acidity of bayberry juice with partial least squares(PLS) and artificial neural network(ANN).The values of correlation coefficient(r),the root mean squared error of prediction(RMSEP),and bias were used to estimate the mixed model.PLS was used to find some sensitive spectra related to acidity in juice,and the values of spectral absorptance corresponding to them were regarded as the input neurons of ANN.Remnant values by subtracting standard values and validation values were regarded as the output neurons of ANN.The calibration equation developed from them was used to predict the constituent values for the independent spectra of 30 samples.The results indicate that the observed results by using PLS-ANN(r=0.939,RMSEP=0.218,Bias=-0.121) are better than those obtained by PLS(r=0.921,RMSEP=0.228,Bias=-0.132).
Editor in chief：Jun-Hao CHU
International standard number：ISSN 1001-9014
Unified domestic issue：CN 31-1577
Domestic postal code：4-335