Journals >Journal of Infrared and Millimeter Waves
Contents
2004
Volume: 23 Issue 6
18 Article(s)
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Research Article
FINITE DIFFERENCE TIMEDOMAIN MODELING OF GRATING-COUPLED QUANTUM WELL INFRARED PHOTODETECTOR
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Diffraction grating isindispensable for quantum well infrared photodetectors(QWIP) in order to improve opticalcoupling because of the limitation of quantum selection rules. A numerical approach basedon finite difference time domain(FDTD) method was presented for investigating thediffraction effect of a metal grating faDiffraction grating isindispensable for quantum well infrared photodetectors(QWIP) in order to improve opticalcoupling because of the limitation of quantum selection rules. A numerical approach basedon finite difference time domain(FDTD) method was presented for investigating thediffraction effect of a metal grating fabricated in QWIP. Simulation results demonstratethat such a complicated structure can be optimized by electromagnetic analysis based onthe FDTD method. Detailed field distribution inside QWIP can be obtained for estimatingthe optical coupling efficiency of the grating..
Journal of Infrared and Millimeter Waves
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 6, 401 (2004)
InAsSb SINGLE CRYSTALS WITH CUTOFF WAVELENGTH LONGER THAN 10μm GROWN BY MELT EPITAXY
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The InAsSb single crystals with a cutoff wavelength of 11μm were succesfully grown on InAs substrates by melt epitaxy. Melt epitaxy differs from the normal crystal growth method such as liquid phase epitaxy(LPE), molecular beam epitaxy(MBE) and metalorganic vapor deposition(MOCVD). Infrared Fourier spectrum measurementThe InAsSb single crystals with a cutoff wavelength of 11μm were succesfully grown on InAs substrates by melt epitaxy. Melt epitaxy differs from the normal crystal growth method such as liquid phase epitaxy(LPE), molecular beam epitaxy(MBE) and metalorganic vapor deposition(MOCVD). Infrared Fourier spectrum measurement confirms that the cutoff wavelenth of InAsSb materials is longer than 10μm. X ray diffraction spectrum reveals that InAsSb epilayers have fairly perfect crystal orientation structure, and have the same crystal orientation as that for the InAs substrates, i.e.,<100>ientation. Hall measurements show that the electron mobility is 4.75×10 4cm 2/Vs and the carrier density is 3.61×10 16 cm -3 at 295K, and the electron mobility is 2.86×10 4cm 2/Vs and the carrier density is 1.50×10 16 cm -3 at 77K. The results show that the material has a potential application for fabricating the photodetectors..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 405 (2004)
APPLICATION STUDY ON DETECTING MULTILAYER CLOUD'S PROPERTIES BY SATELLITE DATA
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Multilayer cloud system, such as density cirrus, thin cirrus cloud overlaying a low level water cloud and density water cloud was detected by using bispectral methods that scatter plot of the near infrared 1.6μm channel reflectance and the 11μm brightness temperatures and brightness temperature difference between 3.75μMultilayer cloud system, such as density cirrus, thin cirrus cloud overlaying a low level water cloud and density water cloud was detected by using bispectral methods that scatter plot of the near infrared 1.6μm channel reflectance and the 11μm brightness temperatures and brightness temperature difference between 3.75μm and 11μm channel data from FY 1D and NOAA. Results show that the methods have a promising facility for identifying areas containing typical multilayer cloud system by multi channel data..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 408 (2004)
NEW DISTURBING TECHNIQUE BASED ON FOAM SCREEN TO IR/MMW GUIDANCE
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The techniques of disturbing on IR and MMW guidance have some shortcomings, such as too short of disturbing time, not wide enough of disturbing range, their severe pollution etc. In order to overcome these shortcomings, a new technique of disturbing was put forward. It is based on a special smoke screen with foams. ItsThe techniques of disturbing on IR and MMW guidance have some shortcomings, such as too short of disturbing time, not wide enough of disturbing range, their severe pollution etc. In order to overcome these shortcomings, a new technique of disturbing was put forward. It is based on a special smoke screen with foams. Its disturbing mechanism, the special prescription and the special process of reaction were studied. And a special equipment was manufactured. The results of tests show that the special foam screen can disturb IR and MMW and the visible light, and its disturbing time can be more than 10 minutes at least. The hangover of this foam screen has no pollution to environment..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 413 (2004)
NOVEL APPROACH TO MULTI-CLASS CLASSIFICATION
[in Chinese], and [in Chinese]
A new multi classifier was proposed based on support vector machines for a N class classification problem, which comprised N 1 support vector machines in the form of a binary tree. The generalization performance of multi classifiers was discussed, and a new learning algorithm, the BTSVM algorithm, was presented based oA new multi classifier was proposed based on support vector machines for a N class classification problem, which comprised N 1 support vector machines in the form of a binary tree. The generalization performance of multi classifiers was discussed, and a new learning algorithm, the BTSVM algorithm, was presented based on high dimension feature spaces. The BTSVM algorithm evaluates example distances by kernel functions, employs the maximization of minimum distances as clustering criteria to obtain two optimal subsets, and generates the optimal classification functions with support vector machine leaning algorithms at each decision node. Theoretical analysis and experimental results show that the BTSVM algorithm is superior to other competitive multi classifiers..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 418 (2004)
STUDY OF HgCdTe p+-on-n LONG-WAVELENGTH HETERO-JUNCTION DETECTOR
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The results of the HgCdTe p + on n long wavelength hetero junction infrared focal plane arrays were presented. HgCdTe p + on n hetero junction material was grown by molecular beam epitaxy(MBE) and in situ doping, and HgCdTe p + on n hetero junction infrared focal plane arrays were fabricated by the process of wet etchiThe results of the HgCdTe p + on n long wavelength hetero junction infrared focal plane arrays were presented. HgCdTe p + on n hetero junction material was grown by molecular beam epitaxy(MBE) and in situ doping, and HgCdTe p + on n hetero junction infrared focal plane arrays were fabricated by the process of wet etching, side wall passivation, side wall matelization, indium bump fabrication and hybridization etc. According to the I V experiments and the dark current mechanism, the effect of all kinds of dark current was calculated and analyzed. The spectral response and detectivity of the device were also measured..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 423 (2004)
ANALYSIS ON THE ULTRA-SPECTRAL CHARACTERISTICS OF WATER ENVIRONMENTAL PARAMETERS ABOUT LAKE
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
For studying the possibility of detecting water quality by remote sensing, simultaneous field experiments at Taihu Lake (one of the three famous eutrophic lake in China) were made in winter and summer to measure the reflected light spectra on water and to get water samples for chemical analysis. Statistical analysis wiFor studying the possibility of detecting water quality by remote sensing, simultaneous field experiments at Taihu Lake (one of the three famous eutrophic lake in China) were made in winter and summer to measure the reflected light spectra on water and to get water samples for chemical analysis. Statistical analysis with experiment data shows that (1) there is good correlation between COD Mn and chlorophyll a concentration;(2)in summer, north Taihu Lake, the reflectivity spectra of light on water is affected mainly by chlorophyll a concentration, which can be expressed by a liner correlation model and it is most obvious at wavelengths larger than 700nm;(3)in winter, the reflectivity spectra of light on water is affected mainly by suspended substance concentration in a wide wavelengh range, which can be expressed by a log liner correlation model or by a liner correlation model more suitably if only the suspended substance concentration less than 100mg/L is considered, and it is more obvious at wavelengths between 500-800nm.The statistical models about lake are made between the surface spectral reflectivity at different wavelengths and the water quality parameters..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 427 (2004)
NOVEL BUTTERFLY SHAPE DEFECTED GROUND STRUCTURE FOR MICROSTRIPLINE
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel butterfly shape defected ground structure for microstrip line was proposed. Its band gap characteristics and slow wave characteristics were discussed. Including the transmission loss, equivalent circuit modeling for the proposed microstrip line was built and its parameters were extracted. The effects of DGS dimA novel butterfly shape defected ground structure for microstrip line was proposed. Its band gap characteristics and slow wave characteristics were discussed. Including the transmission loss, equivalent circuit modeling for the proposed microstrip line was built and its parameters were extracted. The effects of DGS dimensions on stop band characteristics were presented. Furthermore, a compact DGS low pass filter was designed and measured. The validity of the DGS filter is verified by the agreement between simulated and measured results..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 431 (2004)
SAMPLED IR IMAGING SYSTEM SIMULATION & MRTD PREDICTION
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A method for predicting MRTD (Minimum Resolvable Temperature Difference) based on the sampled IR imaging system digital simulation was proposed. Standard four periodical rectangular patterns with typical spatial frequency and radiometric temperature were generated according to signal transfer equation. Then, system geoA method for predicting MRTD (Minimum Resolvable Temperature Difference) based on the sampled IR imaging system digital simulation was proposed. Standard four periodical rectangular patterns with typical spatial frequency and radiometric temperature were generated according to signal transfer equation. Then, system geometric distortion, blur effects, noise characters and nonlinear effects were simulated with modulation transfer function method and pixel processing method, respectively. Finally, MRTD prediction was accomplished according to the statistical discrimination of observers to simulated rectangular pattern. Simulation results show that there is a good agreement between MRTD prediction and MRTD experimental measure..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 436 (2004)
OBJECT DETECTION BASED ON FEATURE EXTRACTION FROM HYPERSPECTRAL IMAGERY AND CONVEX CONE PROJECTION TRANSFORM
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
After introducing the conception of convex geometry and spectral linear model, the relationship between convex cone and hyperspcetral imagery was discussed. A method based on feature extraction and convex cone projection transform for hyperspectral imagery object detection was proposed. The method was tested with hyperAfter introducing the conception of convex geometry and spectral linear model, the relationship between convex cone and hyperspcetral imagery was discussed. A method based on feature extraction and convex cone projection transform for hyperspectral imagery object detection was proposed. The method was tested with hyperspectral data obtained from OMIS Ⅱ. Based on the experiments. the capability of detecting object’s physical property by hyperspectral imagery was also discussed..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 441 (2004)
IMAGE SEGMENTING USING SEGMENTAL DEFORMABLE MODEL BASED ON AFFINE INVARIANTS
[in Chinese], [in Chinese], and [in Chinese]
A segmental deformable model for image segmentation was presented and affine invariants were introduced into the model’s energy function. The contour of the model is deformed hierachically, which keeps the relationship of control points along the contour. Reformative definitions of internal and external energy can reduA segmental deformable model for image segmentation was presented and affine invariants were introduced into the model’s energy function. The contour of the model is deformed hierachically, which keeps the relationship of control points along the contour. Reformative definitions of internal and external energy can reduce computational complexity. In comparison with the classical deformable model, the experimental results demonstrate that the proposed model, which is more effective and more robust to local minima and noise, can achieve better performance for medical image segmentation..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 446 (2004)
METHOD TO DESTRIPE IMAGING SPECTRORADIOMETER DATA OF SZ-3
[in Chinese], [in Chinese], and [in Chinese]
Striping is new problem for imaging spectroradiometer data, which is obtained by multi sensor scanning on spacecraft. The reason causing stripes and the development of striping removal methods were described, and the principle of matching empirical distribution functions was introduced in detail. By using this method, Striping is new problem for imaging spectroradiometer data, which is obtained by multi sensor scanning on spacecraft. The reason causing stripes and the development of striping removal methods were described, and the principle of matching empirical distribution functions was introduced in detail. By using this method, some experiments were done to destripe imaging spectroradiometer data of SZ 3. The result shows that the method of matching empirical distribution functions is available for destirping imaging spectroradiometer data of SZ 3, and the quality of image is improved obviously. This will help to process the future similar instruments data..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 451 (2004)
HIGH-RESOLUTION RADAR TARGET RECOGNITION BASED ON CORRELATION OF INSTANTANEOUS POLARIZATION WVD
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The problem of target recognition with millimeter wave high resolution polarimetric radar was studied. The definition of instantaneous polarization Wigner Ville distribution(InPolWVD) was given, and its Moyal′s formula was derived, which implies the equivalence between the correlation of InPolWVDs in time frequency domThe problem of target recognition with millimeter wave high resolution polarimetric radar was studied. The definition of instantaneous polarization Wigner Ville distribution(InPolWVD) was given, and its Moyal′s formula was derived, which implies the equivalence between the correlation of InPolWVDs in time frequency domain and the correlation of polarimetric signals in time domain. Then, a novel target recognition method was proposed based on the correlation of InPolWVDs. Experiments of demonstrating recognition with five kinds of aircraft targets were presented. The results show that it is an effective target recognition method of high resolution polarimetric radar..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 455 (2004)
METHOD FOR IMAGE SEGMETNATION BASED ON ROUGH SETS
[in Chinese], and [in Chinese]
A method for image segmentation based on rough sets theory was presented. Objects in the clustering process often have similarity relation instead of equivalence relation. Rough sets theory was applied in similarity relation to solve clustering issue. In general, clustering results are easily corrupted by noises. In orA method for image segmentation based on rough sets theory was presented. Objects in the clustering process often have similarity relation instead of equivalence relation. Rough sets theory was applied in similarity relation to solve clustering issue. In general, clustering results are easily corrupted by noises. In order to decrease noise disturbance, maximum membership principle of the boundary points and roughness are defined. Clustering evaluation function was presented on this base. The method provides us a new viewpoint on processing image..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 459 (2004)
SILICA AEROGEL THIN FILMS PREPARED AT AMBIENT PRESSURE
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Silica aerogel thin films were prepared at ambient pressure by sol gel technique. Fourier transform infrared spectroscope(FTIR), scan electron microscope(SEM) and ellipsometer were used to characterize the structure and properties of the films. The refractive index of the resultant aerogel films is as low as 1.067, whiSilica aerogel thin films were prepared at ambient pressure by sol gel technique. Fourier transform infrared spectroscope(FTIR), scan electron microscope(SEM) and ellipsometer were used to characterize the structure and properties of the films. The refractive index of the resultant aerogel films is as low as 1.067, which corresponds to the porosity of 87.7 %, the density of 0.269×10 3 kg·m -3 , the thermal conductivity of 0.020W·m -1 ·K -1 (at 300K), and the dielectric constant of 1.52, These excellent properties mainly attribute to two step acid/base catalysis and the solvent exchange as well as the silylation on the surfaces of colloidal particles..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 465 (2004)
STUDY ON THE PASSIVATION OF Hg1-xCdxTe PHOTOVOLTAIC DETECTORS
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The epitaxial layers of HgCdTe passivated by CdTe and ZnS were investigated with high resolution reciprocal space mapping of X ray diffraction. It was found that the wafers of HgCdTe were bended and mosaic structures were also observed because of the sputtered passivation layers, and the bended wafers and mosaic structThe epitaxial layers of HgCdTe passivated by CdTe and ZnS were investigated with high resolution reciprocal space mapping of X ray diffraction. It was found that the wafers of HgCdTe were bended and mosaic structures were also observed because of the sputtered passivation layers, and the bended wafers and mosaic structures could be recoverred by suitable heating treatment. The experimental results also show that ZnS lacks stability in the high temperature as passivation layer, but CdTe shows excellent performance of high temperature resistance..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 469 (2004)
NEW TECHNOLOGY TO ACQUIRE HIGH RESOLUTION IMAGE UNDER LARGE DEFOUCS
[in Chinese], [in Chinese], and [in Chinese]
In domain of reconnaissance, remote sensing etc., people want to get high resolution image. There has a conflict between the resolution and optical system defocus. In order to acquire high resolution image, some ways are taken to minish the defocus, but these ways affect the cost and weight of the system. In this paperIn domain of reconnaissance, remote sensing etc., people want to get high resolution image. There has a conflict between the resolution and optical system defocus. In order to acquire high resolution image, some ways are taken to minish the defocus, but these ways affect the cost and weight of the system. In this paper, a novel technology was described for extending the depth of focus of incoherent optical systems that does not decrease the resolution of the image. This technology uses generalized aspheric optics to encode images to be invariant to defocus, and digital signal processing to decode the images. It is significant for optical remote sensor to acquire high resolution image under complicated space environment..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 473 (2004)
INTRA-PULSE FEATURE ANALYSIS OF RADAR EMITTER SIGNALS
[in Chinese], [in Chinese], and [in Chinese]
Intra pulse feature extraction is a key issue in advanced radar emitter signal recognition. A novel approach was proposed to extract intra pulse features from radar emitter signals to recognize different radar emitters. Fractal dimensions of radar emitter pulse signals were regarded as the classification features to reIntra pulse feature extraction is a key issue in advanced radar emitter signal recognition. A novel approach was proposed to extract intra pulse features from radar emitter signals to recognize different radar emitters. Fractal dimensions of radar emitter pulse signals were regarded as the classification features to recognize different intra pulse modulations. With the change and distribution information of magnitudes, frequencies and phases of radar emitter signals, the features reflect the laws of intra pulse modulation of radar emitter signals. It is proved in theory that the fractal features are not sensitive to noise, which is also shown in simulation experimental results. Experimental results of fractal feature extraction and automatic recognition of 10 typical radar emitter signals show that the fractal features have large between classes distance and small within class distance, and they achieve high accurate recognition rate, which verifies the approach is valid..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2004
- Vol. 23, Issue 6, 477 (2004)
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