最新刊期
卷 ， 期 3 ， 2004
- 摘要：It’s a primary question for many Bi directional models of Canopy presently that it’s difficult for them to be used in practice due to their complexity. In this paper, multi scatterings and transmission taking place in canopy of vegetation, and reflectance of soil are analyzed respectively, and then the functions between every component of scattering and LAI are put forward. Improving Verstraete’s（1986） Physical Model of Bi directional Reflectance of Vegetation Canopy by adding multi scattering and soil reflectance in the model, a Bi directional reflectance model of canopy soil as proposed and it was proved that the model’s precision can be satisfied only when the first three scattering being taken into account. The shortcoming of the original model has been overcome in this model, and Bi directional reflectance can be calculated directly according to LAI and some other factors, avoiding overlap calculation which results tremendous amount of computation, so the model is easier applied in practice. The precision of the model was verified by experiments.
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发布时间：2021-06-10 - 摘要：Based on numerical difference between the first order and high order Mueller matrix solutions, an iterative method for inversion of surface moisture and fraction per unit area of random small spheroids from polarimetric backscattering measurement is developed. Using numerical simulation and measured AirSAR data of polarimetric Mueller matrix, the inversion of different surface moisture and fraction per unit area are studied.关键词：VRT equation;Mueller matrix;non-spherical particle;iterative inversion
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发布时间：2021-06-10 - 摘要：The commonly used soil moisture retrieval at vegetated area from microwave radiometry data assume a simple model of vegetation, which is characterized by vegetation volume fraction, effective dielectric constant, plant moisture content, etc. This algorithm is successfully applied under lower frequencies and lower vegetation, but the data used in single scattering albedo is simply assigned a fixed value which is independent of frequencies and polarization, sometimes are even set to zero. In this study, a radiative transfer model is used to model the emissivity and transmissivity of forest canopy, which is more realistically characterized as a volumetric medium consisting of discrete scatters （leaves, stems, tree branches, and trunks.） The scattering coefficient is obtained by integrating the Stokes matrix in the whole sphere region, the extinction coefficient is calculated by forward scattering theory. This mode is expected to cover a wider frequency range as well as vegetation species from lower crop to forest canopy. To facilitate the soil moisture inversion from radiometric data, the unknown variables need to be reduced. The possibility of fitting the modeled emissivity and transmissivity of vegetation canopy into simple equations, and the relationships of these parameters between different microwave radiometric frequencies were studied and the results are presented in this paper.
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发布时间：2021-06-10 - 摘要：Remote sensing inversion algorithms exist the problems of land surface parameters retrieval by means of remote sensing physical models, which is also a key problem in remote sensing image interpretation. We developed a priori knowledge based remote sensing inversion strategy. All the available information on parameters gained from the former inversion stages are taken as the prior knowledge in the next stage’s inversion. To do the inversion objectively, we need to describe the information content that the parameters get in each inversion stage, and the reliability of the accumulated knowledge as well. The concepts and theory of unascertained number and blind number are developed from the requirements of describing the uncertain information in application. They have been used in some techniques and producing fields to solve the practical problems, such as that used in the engineering theory. Our new approach is to describe the reliability of the inverted parameter and accumulated knowledge by the definition of the unascertained number. For the inverted parameter, during the inversion stage, the changing of its reliability then can be calculated by using math method of the unascertained mathematics, which is used to judge the inversion result and to modify the prior knowledge about the parameter. This is expected to be a quantitative expression of the accumulation of a priori knowledge. We take the land surface temperatures inversion as an example to show how the new method works.关键词：uncertain information;reliability;remote sensing inversion;a priori knowledge
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发布时间：2021-06-10 - 摘要：Orbit ephemeris and camera data are needed for strict geometric rectification of linear array push-broomimagery, which are often unavailable in practical applications. As a result, the direct linear transform （DLT）, averagepolynomial, improved polynomial and rational function model （RFM） methods are widely used for the approximate geo-metric rectification of this kind of imagery. In this paper, after a brief introduction of several approximate rectification al-gorithms, the emphasis is put on experimental analysis and precision comparison of different kinds of approximate rectifi-cation algorithms using real SPOT and IKONOS images. Experimental results show that the precision of RFM method isthe best and can reach sub-pixel accuracy, the precision of DLT method is about two pixels on the condition of good dis-tribution of control points, the precision of average polynomial method is about one pixel for fiat terrain and much worse foruneven terrain, i. e., varying greatly with different kinds of terrains, and the precision of improved polynomial methodsvaries with the order of polynomials and is nearly irrelative to the types of terrains. If the proper improved polynomialmethod is selected for image rectification, the higher precision can be obtained. Additionally, the balance among preci-sion, complexity, requirements for known data should also be considered for choosing methods from these four approxi-mate image rectification algorithms. Experimental results also show that the improved polynomial method is a better choicefor approximate rectification of linear array push-broom imagery, from the viewpoints of precision, complexity, the num-ber and spatial distribution of control-points and so on.关键词：linear array push-broom imagery;geometric rectification;precision comparison;collinearity equation;direct linear transform （DLT）;average polynomial;improved polynomial;rational function model （RFM）
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发布时间：2021-06-10 - 摘要：As the first Chinese moderate resolution spectrometer in SZ 3 spacecraft, CMODIS contain abundant spectral information with 34 channels in the range from visible to infrared. But sensor to sensor variation within instruments often leads to striping in many channels of CMODIS. The striping noise can distractingly and obstructively affect the interpretation and application of CMODIS data. This paper discusses the methods previously used in striping removal of TM,MSS ,MOS B and presents a new FIR method based on FFT transformation. The Application results of the method to geometrically corrected CMODIS data and non geometrically corrected CMODIS data and quantitative analysis of the results show that the new method can achieve a better result than the previously used methods mentioned in this paper in removing striping noise of CMODIS data and preserve the spectral characteristic of original image .The new method is also applicable in striping removal of other multisensor remote Sensing data.
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发布时间：2021-06-10 - 摘要：The integrating effect of the Point Spread Function （PSF） of a satellite remote sensing system significantly blurred the acquired image and reduced the spatial resolution of the data. This paper firstly analyzed the main factors which result in the image blur. We then discussed the derivative of Linear Spread Function （LSF） by the use of linear step structures that are recorded in the image. The PSF of an image can be approximated by interpolating two linearly separable orthogonal LSFs. Deconvolution filters are derived specifically for each image from its PSF using a Weiner filter in the frequency domain and applying an invert Fourier transform to convert into space domain. The use of Wiener filter could guarantee the achievement of the cleared image while reducing the noise influence. Finally, the deconvolution filters were applied in the 3rd channel of a full scene CBERS 1 image so that it can restore the original signal.A significant improvement of the image quality was achieved.关键词：point spread function（PSF）;image restoration;CBERS-1
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发布时间：2021-06-10 - 摘要：In this paper, a new method, namely the multi feature based method, was presented to classify remotely sensed imagery. A class scheme was firstly defined, in which, every class was decomposed into subclasses if necessary. Then, some suitable features were selected, and every subclass was characterized with a unique combination of these features. Meanwhile, the whole imagery was segmented into image objects, and subsequently the features used were measured, like spectral, geometrical and topological features. Using these features, image objects could be recognized and classified easily. By using the multi features based classification approach, classification accuracy was improved, and the classification results were easier interpreted when compared with the conventional classification method.关键词：classification;image segmentation;class scheme;feature representation
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发布时间：2021-06-10 - 摘要：This paper presents a new method for classifying satellite SAR images based on case based reasoning （CBR） techniques. Because classification is a common task in remote sensing applications, numerous methods have been deve loped for obtaining better classification results. Knowledge based systems （KBS） are considered as a good alternative to traditional classification methods with better performance. There is a need to develop such systems to facilitate the interpretation of remote sensing data in a more efficient way. KBS are useful when concrete knowledge about the application domain is available. It is expected that KBS can automatically classify remote sensing images without operator’s intervention. However, these systems have a bottleneck problem in the solicitation of rules. A solution is to apply CBR method to the classification process. Traditional classification often assumes that spectral properties of a class remain stable in the whole study area. However, the spectral signature of a class is usually subject to fluctuations because of the complexity in nature. The CBR method can easily capture such fluctuations by allocating cases over different terrain features according to stratified random sampling. Moreover, the same case library developed in the previous classification can be reused for time independent classification with satisfactory results. Experiments show that the proposed method can generate the classification results with better performance in term of higher accuracy and fast computation time. The method has been successfully applied to the classification of radar SAR images in the Pearl River Delta, south China.关键词：cases;case-based reasoning;remote sensing classification;SAR;land use
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发布时间：2021-06-10 - 摘要：Desertification is one of the most serious environment and social economic problem nowadays in the world. Desertification causes extensive concern of international academia for its development speed and serious calamity. It’s very significant to study quantitatively the relationships between desertification driving factors and desertification, and to build up dynamic simulation model to predict the expansion of desertification. This paper states how to build up desertification dynamic simulation model based on the cellular automata theory using 3S technology. The design of model based on grid data and embraced two parts: the layer of desertification distributing, and the layer of combination control factor. There fore, the layer of combination control acting as external environment of model impacts and controls the behaviour of desertification expansion. After analyzing syntheses mechanism of desertification expansion, we established six impact factors of desertification, and established this layer’s weight coefficients of drive factors by using optimized Analytic Hierarchy Process （AHP）. After making certain neighbor configuration and transformation rule,we utilized this model to predict desertification expansion in Beijing and its neighbouring areas. The result of the simulation proves that the model is effective to simulate desertification expansion in terms of macroscopic and microcosmic. According to the research we can say that the desertification has influence on Beijing and its neighbouring areas for a long time, but the desertification expansion mainly occurs in the northern areas of Beijing.关键词：desertification;celluar automata;drive factor;dynamic simulation
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发布时间：2021-06-10 - 摘要：By using a radiative transfer model for simulation of microwave brightness temperatures over land surface, the effects of canopy and roughness on passive microwave soil moisture retrieval results have been analyzed. In order to reduce the influence of atmosphere, surface temperature, roughness and canopy, microwave polarization ratio of TRMM/TMI was employed and we got a good result when put the polarization ratio of TRMM/TMI into the use of surface flood area detection and classification. When practied our method over Dongting and Boyang lake area of China in the summer of 1998, the classification results of Radarsat SAR and L SAR surface flood area were used, and we got a Vol./Cal. over 75 0%. Low frequency channels of TRMM/TMI at 10GHz and 19GHz, were effectual in surface flood area detection and classification.关键词：microwave radiance transfer;microwave polarization ratio;flood area classification
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发布时间：2021-06-10 - 摘要：Based on history record,white naped canes follow the low of the earth system: Climate circulation, surface temperature, NDVI,wetlands distributions and establish the migrating roads.During the migrating the stronger survive, and old weak bird discard. Any changes of wetland in migratory road or stopover will bring living problems for the birds. The migratory road corresponds with going the economy and population developing area and old industry areas, so that The result of the study can provide scientific information for sustainable development of the region. In resent years,the Institute of Remote Sensing Applications, CAS, Hokkaido Institute of Environment and the University of Tokyo organized a research project to study migratory roads and monitoring surface condition change using satellite tracking data, satellite imagery data, and surface temperature data. Some results are introduced in this article.关键词：migratory birds;roads;satellite tracking data;satellite imagery;temperature data;canes white-napped cranes
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发布时间：2021-06-10 - 摘要：When stripe rust disease occurs, chlorophyll cells are destroyed and the plant water content is drastically transpired. The optical properties of plant leaves also vary with crop’s biochemical status, which makes it possible to monitor crop’s stripe rust by remotely sensed date. The multi temporal hyperspectral airborne image data were acquired from winter booting stage to milking stage, and the Stripe Rust disease of winter wheat was analyzed using the hyperspectral airborne data. Compared with normal wheat, the image spectral reflectance of disease wheat is higher in 560—670nm bands, lower in near infrared bands; the absorption depth of chlorophyll well in red band and the height of chlorophyll peak in green band are relatively reduced. Therefore, a novel spectral index for stripe rust disease was successfully designed for estimation of the stripe rust disease index, and the degree and area of stripe rust disease were successfully remotely sensed from the multi temporal hyperspectral data based on the disease spectral index.关键词：hyperspectral;pushbroom imaging spectrometer （PHI）;disease index;disease spectral index
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发布时间：2021-06-10 - 摘要：Aided by GPS, geometric correction of aero photos of 70s, TM images of 80s and 90s were accurately done for desertification analysis. And they were also consolidated to the same projection. Based on setting up of accordant interpretation keys and managing and analyzing of desertification land information by GIS, dynamic change of desertification land was investigated in Minqin County of Gansu Province, a typical desertification region. The results show: the area of desertification land in Minqin County tends to enlarging in recent 30a. However, the spreading rate was slow down since 1985. The areas of active dune and semi active dune are increasing continually while the areas of fixed dune and semi fixed dune were controlled effectively. Finally, the reasons of desertification changing of this region were discussed in two aspects including both natural environment and social factors by fieldwork and data analyzing.
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发布时间：2021-06-10
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