最新刊期
卷 ， 期 2 ， 2007
- 摘要：The key of automated reasoning and extraction of terrain features with contour maps is the mining and description of topologic relations among contour lines.This paper suggests the networks of topologic relations（NTR） to describe the topologic relations among geographical objects,and three kinds of NTRs named the binary subdivision tree（BST）,the incremental contour tree（ICT） and the networks of topologic relations of contour lines（NTRC） are presented to express the topologic relations among complicated contour groups having unclosed contour lines.These models have ultimately dealt with the lateral uncontinuity of contour lines and make the automated reasoning with contour maps more easily and exactly.关键词：knowledge representation;topologic relation;contour groups;geomorphology;network model
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发布时间：2021-06-10 - 摘要：People usually use qualitative terms to express spatial relations,while current geographic information systems（GIS） all use quantitative approaches to store spatial information.The abilities of current GIS to represent and query spatial information about geographic space are limited.If GIS are to be made easier to use,it must be made more intuitive,so that it will help people focus on the work they want to do without thinking about a computer program or application.In order to incorporate the concepts and methods people used to infer information about geographic space into GIS,research on the formal model of common sense geography becomes increasingly important.This paper worked on how to formalize the qualitative natural-language descriptions of spatial relations between linear geographic objects.Based on the result of a human subject test about natural-language description of spatial relations,this paper defines some quantitative topological and metric indices which are related with the natural-language spatial relation terms,and uses these indices to formalize the natural-language representation with a decision tree algorithm,thus bridging the gap between natural-language terms and the computational model of spatial relations.This method provided a way of completely understanding the relationship between the ambiguous natural-language representations and the geometric spatial relations of geographic objects.The rules extracted from the trees can be used in natural-language spatial query systems.关键词：linear geographic objects;topological relations;metric indices;natural language;formalization;decision tree
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发布时间：2021-06-10 - 摘要：This paper summarized the works in 2004,and on the base of radiation transfer theory,improved and added the adjacent effect models with ground synchronization measurement and parameters,abtained the ground measurement synchronized with the acquisition of airborne and spaceborne remote sensing data.Moreover,we practised the experiments of adjcent effect correction respectively for ADS40 and Landsat-5 TM data,especially compared the digital images with atmosphere correction and adjacent effect correction.The result is that the contrast of pixels DN of images considering adjacent effect was much larger than those without adjacent effect correction,and the details were enhenced so that the qualities of remote sensing images were improved in a certain extent.关键词：digital image of ADS40 and Landsat-5 TM;adjacent effect;land-ground measurement data
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发布时间：2021-06-10 - 摘要：Applications for hyperspectral image data are still in their infancy as handling the significant size of the data presents a challenge for the user community.Data compression becomes a key problem.Based on clustering,predicting with single neighbor and self position in multi-bands,and entropy coding,a lossless compression method of hyperspectral images is presented.According to spectral structure,the spectra of a hyperspectral image are clustered by pixels.In every cluster,single spatial neighbor and the same spatial position of the current pixels are used for prediction.Using neighbors in various directions,four predictors are achieved.For each spatial position,one of the predictors is selected to perform the three dimension prediction.The residuals are entropy-coded using the Rice coding.The achieved compression ratios are compared with those of existing methods.The results show that the algorithm is an efficient method.关键词：hyperspectral image;cluster;prediction;Lossless compression
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发布时间：2021-06-10 - 摘要：Corresponding to the problem of being unable to remove terrain scattered jamming from the domains of time,space and frequency,this paper proposes an anti-jamming method based on jittering slope polarity of Linear Frequency Modulated（LFM） signal and limiting processing.This method first jitters chirp rate polarity of LFM signal transmitted by the radar in slow-time domain,then does match-filters for the jamming signals hidden in the radar echoes,since jamming is more powerful than radar echo,the next process of limiting will lower the amplitude of jamming greatly,after limiting process,limited echoes are inversely match-filtered,so jamming and real radar echo are all back to the original time domain,then the next normal imaging process can be implemented which will also provide the real radar echo more gain than jamming,so SJR（Signal-to-Jamming Ratio） is further enhanced.Simulation results testify the anti-jamming performance of the method.关键词：anti-jamming;synthetic aperture radar;jittering chirp rate polarity;limiting process
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发布时间：2021-06-10 - 摘要：Base on the characteristics of bridge in high resolution SAR imagery,we present a new bridge recognition method,it is mainly composed of image segmenting,interesting area locating and bridge recognition.By the histogram equalization,we make it more convenient to determine the segmentation threshold;by the image data sampling,we enhance the efficiency;by the bridge characteristics extraction,we make the result more creditable.In primary processing,we get the interesting areas where bridge（s） are obtained by fast arithmetic.In the subsequent processing,guided with the bridge’s character,we identify the bridge in the interesting areas.In the processing of automatic target recognition in high resolution SAR imagery,accuracy is needed on the one hand,and required is we needed on the other hand.So in this paper,the automatic bridge recognition algorithm focuses on not only the veracity,but also the rapidity.Veracity is ensured by the summarized characters of bridge in high resolution SAR imagery;rapidity is ensured by the methods of data sampling and false interesting areas wiping off.At last,in the recognition part,efficacious criterions are used to distinguish real target.Result shows the ability of this approach in high resolution SAR imagery.关键词：SAR imagery;image segmentation;target detection;bridge recognition
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发布时间：2021-06-10 - 摘要：Since the heat noise of Synthetic Aperture Radar（SAR） imaging system and sea clutter severely affect the performance of automatic targets detection in SAR images,removing noise and homogenizing sea clutter in SAR images to improve performance of targets detection is a challenge for researchers.Considering the noise power exists small scale and the boundaries of target signal exist cross-scale in SAR images,we propose a novel scheme which enhances signal and removes noise based on multiscale products method to detect ship targets.The algorithm applies wavelet transform to SAR image and enhances ship signal and homogenizes background clutter of SAR images in wavelet domain using multiscale products.And then detects ship targets in enhanced SAR images.ERS SAR images are used to test our detection algorithm.The simulating results show that the new detector improves detection performance when it is to compare the two-parameter constant false alarm detector and the detection algorithm based on K-distribution.To estimate the efficacy of our enhancement algorithm,we compute computation complexity of the algorithm and a popular enhancement algorithm which is based on wavelet soft threshold.It shows that our algorithm is easier to implement using hardware.The two enhancement algorithms are applied to SAR image ship targets detection.The detected results show that the detection performance of our algorithm is better than the later.
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发布时间：2021-06-10 - 摘要：Classification of multispectral data with high spatial resolution is investigated.High spatial resolution remotely sensed（HSRRS） images with multispectral bands such as QuickBird and IKONOS provide a large amount of information,thus opening up avenues for new remote sensing applications.However,their availability poses challenges to image classification.Due to the complex spatial arrangement and spectral heterogeneity even within the same class,conventional spectral classification methods are grossly inadequate for HSRRS imagery.In order to overcome this inadequacy,spectral features must evidently be complemented by one or the other means.Shape is an important feature of high spatial resolution remotely sensed（HSRRS） imagery,and it is the manifestation of textures on such imagery.In this paper,a spatial feature index,pixel shape index（PSI）,is proposed in order to describe the shape feature in a local area surrounding a pixel.PSI is a pixel based feature,which measures the gray similarity distance in every direction.As merely the shape feature is inadequate for classification of HSRRS imagery,the spectral bands are added to the input vectors of our classifier.And then a fast fusion algorithm which integrates both shape and spectral features using the support vector machine（SVM） has been developed to interpret the complex input vectors.To test the effectiveness of PSI,some spatial features extracted by wavelet transform（WT）,gray level co-occurrence matrix（GLCM） are utilized for comparison.Experimental results demonstrate that PSI is capable of describing the shape features effectively and leads to more accurate classifications than other methods,meanwhile the classification algorithm fusing spectral and shape features by SVM is feasible.It is also found that spectral and shape features can complement each other and their integration can result in enhanced accuracy.关键词：PSI;spectrum;SVM;fusion;high spatial resolution
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发布时间：2021-06-10 - 摘要：Local Means and Local Standard Deviations method（LMLSD） is one of the most widely used methods for estimating the noise in remote sensing images.It employs local means and local standard deviations of small imaging blocks and can be used to evaluate images with additive noises.But this method is badly affected by land cover types,when the land cover types of the images vary greatly,estimation of noise can be invalid due to the effects of the heterogeneous blocks containing edges and texture features.In order to reduce the sensibility of LMLSD to land cover complexity,two improved methods were designed,one is to reduce the affection of the heterogeneous blocks,and the other is to pick up the Gaussian distribution that shows the characteristics of the heterogeneous blocks.We validated the two methods with two AVIRIS radiance images acquired in the same aerial experiment.In the validation the improved methods show distinctly enhanced robustness compared to the common LMLSD and the estimation of the noise is proved to be more accurate.关键词：noise;standard deviation;edge detection;gaussian distribution
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发布时间：2021-06-10 - 摘要：Airborne LIDAR can collect the point cloud data and construct the surface model of the objects on the earth.But for the production of digital elevation model（DEM） from the point cloud,the classification（filtering）,feature extraction and quality control still pose great challenges.For extraction of DEM in urban area,the segmentation of the point cloud should be carried out.In this article,a method for deriving the DTM based on slope analysis is presented.Firstly,a TIN model is constructed from the original point cloud.The slopes are calculated in the TIN model.Then the segmentation is carried out based on the slopes in the TIN.The triangular region with large slope value is deleted.After the segmentation,the region-growing processing is used to merge the small regions according to the connectivity.The part which can cover the biggest area is considered to be the road.Finally,the terrain model is generated by kriging interpolation with these points.关键词：LIDAR;segmentation;digital terrain model;connect component analysis
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发布时间：2021-06-10 - 摘要：SAR（Synthetic Aperture Radar） image simulation has been widely applied in designing and testifying SAR system,SAR image ortho-correction,Radar image interpretation and target recognition and so on.With the development of space-borne SAR,a large amount of needs for space-borne SAR image simulation will arise.This paper firstly discusses the rationale of SAR image simulation from geometric and radiometric characteristics of SAR image,such as Range Doppler（RD） model,backscattering model,and speckle model.Based on the conventional RD model,different backscattering models are applied to simulation for different topographic characteristics,such as alpine terrain or flat terrain.Especially,the need for land cover data is emphasized in the case of flat terrain and Ulaby-Dobson’s backscattering model is used.Besides,speckle simulation is discussed based on SAR image statistical characteristics in order to obtain more realistic SAR image.Then the flow of algorithm is given and several key steps are analyzed.This paper realizes the algorithm of space-borne SAR scene image simulation based on image characteristics.By using the algorithm,tests are performed on alpine terrain in Xinjiang and flat terrain in Tianjin.The results prove the efficiency and validity of the algorithm.关键词：image characteristics;space-borne SAR;image simulation
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发布时间：2021-06-10 - 摘要：This paper used Nanjing city as the research object for vegetation classification based on IKONOS image.We adopted classification algorithm of decision tree,built knowledge pool on the basis of vegetation spectral information and presented a vegetation classification method based on the spectral information.Then the method was improved by combining textural information and using Homogeneity index.The overall precision of the vegetation classification method based on spectral information was 83.16%,but that of the improved method was upgraded to 91.89%,and kappa coefficient 0.8886.A Quickbird image was used to validate the method,the overall precision was 91.94% and kappa coefficient 0.8783.The result showed the vegetation classification method can classify and discriminate vegetation effectively,and the precision is high.As to vegetation classification with different data source,the method has universality.The vegetation classification method provides theoretical foundation and effective method for extracting vegetation automatically.关键词：high-resolution remote sensing;vegetation classification;knowledge pool;decision tree;Texture
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发布时间：2021-06-10 - 摘要：Computer simulation model is based on the 3D realistic structure of vegetation,and can simulate the canopy radiation regime.In this paper,taking winter wheat as an example,its canopy BRF and spectrum with different LAI are simulated.And in order to qualify the computer simulated results,firstly,the computer simulated BRF is compared with the measured data.In addition,the computer simulated spectrum is compared with the simulated and measured spectrum Prosail model using.From this study,some conclusions are drawn:（1） LAI is an important structure parameter for vegetations,and can depict their growth course;（2） canopy BRF and spectrum based on computer simulation model are reliable and their precision can meet study demands.So computer simulated results can be considered as the measured data for research under certain conditions.关键词：BRF;radiosity;LAI;prosail model;computer simulation
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发布时间：2021-06-10 - 摘要：Texture information can avoid the matter of ’same spectral from different materials’ and ’same material with different spectral’ which must be faced with when making classification with only spectral information of high resolution image,but few people use only texture information to distinguish different vegetation of high resolution image.This paper takes the Zhongshan scenic region of the eastern side of Nanjing City as the study area,and uses the satellite data of IKONOS to explore the methodology of discriminating the different types of vegetation.When texture information is employed,four texture statistics such as: CON（contrast）,COR（correlation）,HOM（homogeneity）,and MCON（make-up contrast） are used.In order to test the result,Vegetation index information is used as well as spectral information,three VI such as: NDVI,MSAVI and SAVI（whose values of L equal to 0.5 and 5 respectively）are used to decide the best one who stands for some vegetation type,and SAVI5（value of L is 5）does well.A threshold is selected in texture and VI information to discriminate every type.From spectral information two methods are used: minimum distance supervised classification and ISODATA unsupervised classification.When processing the image,some steps must go: firstly,recovering the IKONOS image data;secondly,discriminating the vegetation types as: grassland,garden,conifers,mixed forest and bamboo,wide-leaf forest using the different methods,including the discrimination based on the pixel spectral data,the discrimination based on vegetation index,and the discrimination based on minor texture on the images.Through comparing all results the following conclusions have been drawn: texture information has the best classification accuracy,and the VI has better result,and the spectral information only has the worst,from which the result of unsupervised classification is the lowest.We can conclude that texture information can discriminate vegetation types and other material perfectly because it response to the spectral composition and properties of some material.关键词：IKONOS image;vegetation classification;texture information
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发布时间：2021-06-10 - 摘要：In remote sensing images the frequency of thin cloud and mist is lower than that of sceneries.The frequency distribution characteristics of the remote sensing image influenced by the thin cloud and mist are analyzed based on the multi-resolution of the wavelet function.We conclude that the information of the sceneries are in the detail coefficients of lower levels,while the information of the cloud and mist are in those approximate and detail coefficients of higher ones.By increasing the detail coefficients of lower levels,and decreasing those of higher ones and approximate coefficients,the goal for removing the thin cloud and mist is achieved.The experimental results of the proposed algorithm,being evaluated and compared with the homomorphism filtering method,are proved to be satisfying.关键词：remote sensing imaging;mallat algorithm;thin cloud and mist;wavelet coefficient
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发布时间：2021-06-10 - 摘要：In this paper,the imaging principle,sensor model and the data pre-processing procedure of the ADS40 three-line sensor are briefly addressed firstly.Then a comprehensive study is concentrated on the mathematic sensor model of the ADS40 images,in which an efficient iterative searching algorithm was developed to determinate the corresponding scan line given an object point.After that the paper describes an efficient ortho images generation procedure that can be applied directly to the ADS40 Level 0 products.Test results show that the proposed ortho-rectification procedure works well and effectively and also,the accuracy fulfills the requirements of the ortho image generation with corresponding map scale.关键词：three line scanner;geometric rectification;ortho rectification;exterior orientation elements;scan lines
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发布时间：2021-06-10 - 摘要：There are two main problems for simulating distribution of population using RS data: ①how to obtain information of residential type,area and position;②what relation between residential type,area and position and amount of population.Basing on geographical sense and mathematical sense,this paper extends the model of allometric growth of urban population-area study,works out model of rural and urban population-area.Then,taking Songyuan city as a case,using 1∶50000 relief map as assistant data,building up classification system of residential points,using the method of "detaching urban-rural population" based on above the models,this paper uses ETM images to extract information of residential area and simulates population distribution in the urban and rural region.The method used in this paper can be referenced by the theoretic and applied researches for middle-scale population distribution.关键词：urban-rural population;spatial simulating;RS
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发布时间：2021-06-10 - 摘要：The urban area expansion is an important indicator for measuring urbanization level.Based on three Landsat MSS images,ten TM images,one DMC data and one "Beijing-1" small satellite data obtained in 2005,the urban built-up characteristic of Beijing and its impact on the peripheral land during 1973—2005 were analyzed.The urban area was 183.84km2 in 1973 and increased to 1209.97km2 in 2005,the built-up area was increased by 1026.13km2 during the past 32 years and expanded 32.07km2 per year.The built-up area was expanded around the old area and didn’t present manifest change in a certain direction.The expansion rate was distinct from each other and Beijing city was experienced two fast expansion stages comparatively.The increased built-up area originated from different land use type,of which about 54.34% converted from rural area and dependent factory,diggings land and other construction area.The other mainly came from arable land that account for 43.57% of the whole added built-up area.Many factors contributed to the urban land use changes.But four major driving forces,population growth,economic increase,transportation infrastructure improvement and institution and policy change,were the most important factors.Population growth can simulate the built-up area manifestly,the economic increase was the main impetus of the land use,the transportation infrastructure improvement was the impetus for the urban expansion,while policy change determined the macroscopical development and expansion pattern in some degree.关键词：Beijing;built-up area;landsat images;"Beijing-1";remote sensed monitoring
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发布时间：2021-06-10 - 摘要：The experiment was conducted to investigate the relationships amongst the leaf red edge characteristics and physiological and biochemical matters in tobacco leaf,especially pigment contents,in different mature stages.The tobaccos were grown under three levels of nitrogen supply during the period of May 2005 to September 2005.The regression analysis showed there was a significant correlation between the red edge position and chlorophyll a+b contents in tobacco.The results indicated that the red edge position within the range of 693—695nm was able to be used as a good reflection of ripe leaves,and the red edge position of 688nm was confirmed as the character of best overripe.Leaf maturity could be identified through chlorophyll a+b contents estimated by the corresponding red edge positions.Accordingly,this study suggests that the spectral data serve as promising measures to predict the maturity level of tobacco leaf,and also provides a strong support for decision making of tobacco production.关键词：red edge characteristics;leaf of flue-cured tobacco;maturity
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发布时间：2021-06-10 - 摘要：In this paper,an adaptive morphological filter was developed to detect nonground LIDAR points in urban area,based on the continuous region detection and a hierarchical recognition mechanism.First,all continuous regions are labeled,and major ground points are detected by the characteristics of spread and continuity.Second,detached ground points are recognized by the quality of continuity and normalized height.Third,the height within objects occupied regions is calculated by linear interpolation and smoothness.Three datasets from three urban areas,are selected in the test,with different point densities and landscape complexities.Qualitative and quantitative analyses have indicated that this filter could remove most nonground points effectively in moderate complex urban environments,with the advantages of automatic window size determination and outliers detection.关键词：LIDAR/laser scanning;filtering;adaptive morphological filtering;DEM
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发布时间：2021-06-10 - 摘要：Information of paddy rice fields and their spatial distribution is the data source for land use and land cover changes,crop yield estimates,methane emission estimates,food security,and water resources management.A number of studies have explored the potential of remote sensing images to identify paddy rice fields.Those studies that identified paddy rice fields used image classification procedures for TM images and temporal development of the NDVI for AVHRR images.8-day composite MODIS（Moderate Resolution Imaging Spectroradiometer） Surface Reflection products（MOD09A1） provide the potential for the improved characterization of vegetation at large spatial scale.According to the different paddy rice growth stages,multitemporal MODIS images were selected by the flooding and transplanting period,growing period,maturation period,and the fallow period after harvest.Three vegetation indices,Normalized Difference Vegetation Index（NDVI）,Enhanced Vegetation Index（EVI）,and Land Surface Water Index（LSWI） using the shortwave infrared band sensitive to soil moisture and leaf moisture content,were calculated to extract information of paddy rice fields.We compared the paddy rice fields dataset to the dataset extracted from ETM+ images and produced at 40-km gridded data,the results show that the paddy rice extracting algorithm of time-series MODIS data could be applied to monitor paddy rice fields at large spatial scales.关键词：paddy rice fields;surface reflectance;Land Surface Water Index;multitemporal MODIS images
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发布时间：2021-06-10
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