最新刊期
卷 ， 期 5 ， 2002
- 摘要：The satellite measurements in the visible and near Infrared band are the contribution of surface reflectance and atmospheric back scattering, and it is very difficult to distinguish one form the other for both contribution have the same order over land. The images from high spatial resolution orbit sensor such as TM5 flying on LANDSAT are very clear to discriminate cloud and the shadow since they are projected on the surface from cloud free pixels in the visible hand. Over a nontransparent cloud shadow, the radiance obtained from satellite measurement is the contribution of atmospheric path radiance and surface diffuse reflection; while, over a bright area surrounding the cloud shadow, besides the contribution of atmospheric radiance and surface diffuse reflection, the surface direct reflection also contributes to the radiance measured from satellite. Based on this theory, the difference between the two radiances and its relationship with the surface reflectance and aerosol optical thickness are analyzed, and a new method to retrieve surface reflectance and serosol optical thickness simultaneously over land is developed. At the end of this paper, sensitivity analysis of measurement, single scattering albedo and aerosol scattering phase function to the retrieval of surface reflectance and aerosol optical thickness are given.关键词：aerosol;albedo;radiative transfer;cloud;shadow
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发布时间：2021-06-10 - 摘要：This Paper describe that in flight radiometric calibration for thermal channels of FY 1C meteorological satellite sensors using Qinghai lake, water surface radiometric calibration site. The radiance of water surface measured by CE312, and then performed atmosphere correction including gas absorption and path radiance which computed by radiative transfer code MODTRAN37,predict the radiance in the satellite sensor entrance pupil. At the same time the spectral response of Satellite sensor and that of ground based sensor are coupled. At last the apparent radiance of sensor spectral channels are compared to the digital count of satellite’s output to give the calibration coefficient. The result show the difference between in flight and on board calibration is about 5%, equivalent to a brightness temperature of 3 K.关键词：vicarious calibration;spectral response match;radiative transfer calculation;apparent radiance
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发布时间：2021-06-10 - 摘要：For climatological and hydrological investigations, the areas covered by snow and their spatial variability are important parameters, particularly in alpine regions. Snow and ice also play important interactive roles in the regional climates through its effect of increasing surface albedo. The interferometric SAR technique not only can produce a high resolution digital elevation models, but also can detect the changes in the surface over the orbit repeat cycle from the correlation properties of the radar echoes. With or without the snow cover, the measurement of interferometer correlation will be shown great difference over, which time describes processes occurring on the time scales of the orbit repeat time and size scales on the order of a radar wavelength. Except backscattering intensities in each scene and their changes between two passes, the coherence measurement between repeat pass will provide another useful measurement for mapping snow covers over large areas. We compare four ERS 1 repeat pass SAR image in the Tibet plateau test area, the first one in March（with snow）, the second one in May（without snow）, the rest two is a tendem in September （without snow）. The result shows that if the ground is completely undisturbed between viewings the signals will be highly correlated. Otherwise, the decorrelation will occur. Lake and snow cover have very low coherence between two data tades with and without snow cover, and the coherence measurements from the bare surface and the short vegetation are significantly higher. On other way, the entire target may show very low coherence if there are great decorrelations due to other parameters, such as spatial baseline, rotation and temporal. We will demonstrate the method and result for snow mapping by using both backscattering and cohe rence measurements with repeat passes ERS 1 image data at the Kunlunshan Mountain, the Tibetan plateau（36°03’N, 91°00’E）. For validation of this method , we compared classification result with that derived from TM image. An accuracy of better than 82% can be achieved if we consider the classification result from TM image as the ground truth. The results show that the coherence measurements provide an effective way to map snow covered area.关键词：SAR interferometry;coherence degree;scattering characteristic;snow mapping
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发布时间：2021-06-10 - 摘要：Image matching is very important in image processing, especially in remote sensing image processing. A nice matchimg method must possess the advantages of high matching precision, fast matching speed and the property of rotation invariant. In this paper, we proposed a novel method for fast image matching based on wavelet analysis with rotation invariant property. The edge of processing image is extracted from the detailed image of wavelet decomposition, which is used to calculate the distance moments of the image; the blurred images are designed for extracting the scale based Concurrent Matrix （SCM） features. A decision tree based on these two types of feature is then formed to implement the matching procedure. Experiments also show that this method is faster, more accurate and better noise robust compared to the traditional model based methods.关键词：image matching;rotation invariant;edge;scale based Concurrent Matrix;decision tree;Texture
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发布时间：2021-06-10 - 摘要：Remote sensing images have special properties compared with other images Considering the special requirements of the compression algorithm for remote sensing images, we proposed an adaptive quadtree partitioning algorithm to partition the image into blocks of different size The gray value of an image block is approximately represented by the mean of that block and the optimal approximation of the original image is then obtained with the amount of data as less as possible The approximation error image is adaptively divided and quantized based on the variance of each block Finally, each component is coded with Huffman code The experimental results show that our compression algorithm has excellent practical performance and is more suitable for the compression of remote sensing images than the JPEG algorithm
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发布时间：2021-06-10 - 摘要：In this study,we present an iterative algorithm for the determination of aerosol optical thickness and the surface reflectance along coastal zone from SeaWiFS measurement.The outgoing radiances and the path radiance were inferred from 6s atmospheric radiative transfer code.Numerical experiments with SeaWiFS measurement were carried out to investigate the sensitivity of the algorithm.The iterative algorithm is applied to determine the surface reflectance in the East Ocean zone of China from SeaWiFS data.关键词：reflectance;aerosol optical thickness;remote sensing
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发布时间：2021-06-10 - 摘要：For the sake of the complicated factor of objects in remote sensing images,"homo spectrum"and"hetero spectrum"co exist usually in remote sensed imagery.However,most traditional supervised merhods take the same classification criteria by spectral statistic properties for various objects in the same image file.This kind of processing influence the accuracy of classification,especially for those images which have the special characteristics such as,complicated scenes,or many differences between temporal and quality of images. For this reason,the authors put forward and have realized an approach for segmentation based classification to solve this problem.The primary procedures are completed by defining the interpretation area and classification manager,and improving the supervised classification algorithm using visual C++ 6.0 language program. Finally,the authors used TM image mosaiced by two scenes,which acquired in two different time for the neighborhood areas,and then implemented the segmentation based classification to do the experiments.The results for this experiment show: （1） The precision using segmentation based classification is obviously improved in comparing with the same schema for the whole image. （2） The interpretation area can be randomly chosen and easily obtained for the sub areas before classification according to the features of images. （3） This method can help users to choose the different schemas for classification according to the properties of the each sub areas freely. （4） This method provides the storage strategy for the classification results,for all sub areas can be stored in one file,or in different files respectively,while it is not necessary to create a new layer to store the file for the results. In short,segmentation based classification for remotely sensed imagery is feasible to classify the imageries which have"homo spectrum"and"hetero spectrum"properties,and to improve the accuracy of by the classification for every sub area divided according to imagery properties.关键词：remote sensing image;segmentation;automatic classification;interpretation area;classification manager
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发布时间：2021-06-10 - 摘要：With six phase of remote sensing images covering Shenzhen river estuary, this paper obtained the mangrove changes in the area over some 10 years. Coupled analysis of the image interpretation results and tidal data revealed that the mangrove increased in area from 1989 to 1996, and changed little from 1996 to 2000 in area but changed in spatial distribution. Binary coding was applied to the images for the distribution of mangrove at each phase, and the coded image revealed that the changes are mainly located at the Mipu mangrove conservation region that lies to south side of Shenzhen river mouth and is under Hongkong administration. Since the image in 1994 had best quality, the other 5 phase of images were recalibrated to that of 1994 with linear regressive method, and the normalize vegetation index was calculated for each phase. Though the results of NDVI can not compared because of different image acquisition time, all the six NDVI images showed that the NDVI values became large from the edge to center of the mangrove covered area.关键词：multi temporal TM imagery;Shenzhen river estuary;mangrove;dynamic change
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发布时间：2021-06-10 - 摘要：Traditional data model takes the geometric object as the modeling target and results directly in decomposing geographic phenomena into a series of objects. Furthermore, the temporal data and spatial data are stored separately. All of those restrict the development of GIS and resources monitoring. Feature based spatio temporal data model can support the next generation of GIS effectively. In this paper, based on the landuse monitoing research project of the five year plan of our country, we propose a new spatio temporal data model based on the states of the changing feature （SCFSTDM） in order to serve for integrating geographic phenomena and geographic information as well as applying object oriented analysis method to support spatio temporal analysis , simulation and data sharing. \;Finally, we develop a prototype of the temporal landuse information system in which there is a spatio temporal database based on the feature. With this system ,we can query states of the feature instance directly, for example, to query the states and to play the developing process of a feature instance, to make the spatio temporal reasoning.关键词：spatio temporal data model;feature;state of the changing feature based spatio temporal data model （SCFSTDM）;temporal landuse information system
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发布时间：2021-06-10 - 摘要：By using digital method of remote sensing and geographical information system techniques, TM images of 1996 and 2000 have been interpreted to establish the database of sandy land of two periods in Shaaxi, Gansu, Ningxia and Qinghai Provinces. Through the study practice and analyzing of sandy land databases,the following points can be concluded:In the study area there is as much as 7,910,807hm 2 sandy land in 2000 and more 6,424hm 2 than in 1996. The percentage of sandy land area over the whole area change from 5 733% in 1996 to 5 737% in 2000, and increases 0 004% in 4 years. In different regions, the change of sandy land is various, such as, it increased 0 004% in Shaanxi Province, decreased 0 017% in Gansu Province, decreased 0 479% in Ningxia Region and increased 0 051% in Qinghai Province. And then based on the change types of sandy land, the factors affecting sandy land changes were analyzed according to the situation of different regions.关键词：RS technique;GIS technique;sandy land in Shaanxi, Gansu, Qinghai province and Ningxia region;macro scale study by remote sensing
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发布时间：2021-06-10 - 摘要：After analyses to spatial planning decision making requirements of agricultural non point source （AGNPS） pollution in the region of Hanjiang River watershed, we designed the structure, function and database of agricultural non point source pollution information system using the methods of integrating GIS integrated and remote sensing. At the end, the information system was developed. The system comprises of three subsystems: the spatial analysis and remotely sensed data processing system, the model management system and the statistics database management system. This system has multifunction with detailed spatial and attribute database including fundamental geographic elements, eco environment, landform, remotely sensed image and statistics data. Agricultural non point source pollution was then detected dynamically. Our integrated system provides a robust and user friendly environment for the standard three step management procedure of non point source pollution:（1）critical area identification. （2） Best Management Practices （BMPs） selection, and （3） comprehensive regional pollution control plan. It will be helpful for local government to make a feasible decision on this issu.关键词：agricultural non point source pollution;dynamic detection;Information system;Hanjiang River watershed
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发布时间：2021-06-10 - 摘要：Grasshopper is a kind of primary pests damaged to a wide rangeland region in the west of China. According to its ecological features, classifying habitat types of grasshopper using remotely sensed is an important research project. The result is very important for rangeland management. For Qinghai Lake region, we applied the Landsat TM images, auxiliary geographical data including DEM, the specific map of rangeland types ect, and GPS Located field data. From the monolithic view point of image processing, geographical data and specialist knowledge, the grasshopper habitat was classitied by applying the methods based on knowledge. The classification accuracy is 84.23%. And three kinds of rengelard: Stipa krylovii, Achnatherum splendens, Stipa purpurea belong to frequently occurred site of grasshopper which take up 29.09% of whole research area. This result provides a basis for scientific management of rangeland pests.
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发布时间：2021-06-10 - 摘要：Attribute uncertainty can directly affect the quality of GIS-based decision making. In this paper, the theories and methods to study the attribute uncertainty and their developments are discussed. And a number of theories and methods have been developed to deal with attribute uncertainties. These may include, for example, GIS-based models; probability theory and statistics-based statistical theories; fuzzy sets, rough sets and cloud theory based soft computing. These theories and methods for describing attribute uncertainties in GIS data are reviewed and analyzed. Furthermore, the future developments of the research in these areas are also briefly summarized.关键词：Attribute uncertainty;GIS;research development
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发布时间：2021-06-10
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