最新刊期
卷 ， 期 3 ， 2005
- 摘要：After cold War,the basic characteristics of military use of space competing between USAand CCP is gradual-ly replaced by the charateristics of synthesize national capacities competition in terms of high-tech and economy.Space be-comes the most innovation elements and high-tech driven field.The major economy countries of the world realize the im-portance of making the strategic space policy plan to rise synthesize national capacities and making efforts to design it in the vision of future.In recent years,the first time after cold war,USA,Japan,and EUhave comprehensively rectified their space policies.With system transfer Russia space policy also carried out adjustment.Facing the newly emerged situation,in terms of space opportunities and challenges,how to identify,analysis and make right decision is and issue of longterm strategic matters.关键词：space policy rectification;opportunities and challenges;major economy countries
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发布时间：2021-06-10 - 摘要：It is not always suitable to use Planck’s law or Stefan-Boltzmann’s law to describe the relation between brightness temperature and radiance for a wide band sensor.But given a Planck’s lawweighted and band averaged emis-sivity and an empirical fit equation between brightness temperature and radiance,it is still very feasible to retrieve compo-nent temperatures from mulit-angle data.In this paper,different equations to fit brightenss temperature and radiance for AMTIS（Airborne Multi-angle TIR/NIR Imaging System）are analyzed:the first approach is to use the stefan-Boltzmann’s law,and a compact equation including a T 4 term is found to be very effective;the second approach is to fit an appropriate wavelength using planck’s law The componnet temperature retrievel errors due to the band average of emissivity is also analyzed.关键词：wide band;TIR;component temperature;Error;band response function;Emissivity
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发布时间：2021-06-10 - 摘要：The accuracy of rayleigh scattering calculation affects the quality of atmospheric correction of the ocean color remote sensing significantly.This paper studies how satellite attitude affect the accuracy of the rayleigh scattering calcula-tion.Satellite attitude directly affects the calculation of the relative geometries of sun and sensor,which determine the rayleigh scattering radiance.The results show that roll angle affects rayleigh scattering calculation markedly,and the cal-culation error can reach10%as the roll angle is2.5°.However,the effects of the pitch angle and yaw angle are small,and the calculation error is only1%as the pitch angle or yaw angle is2.5°.The result also shows that in order to achieve the1%accuracy goal of the rayleigh scattering calculation,the satellite roll angle should be less than0.3°if the satellite attitude isn’t corrected in the ocean color remote sensing data preprocessing stage.关键词：rayleigh scattering;ocean color remote sensing;satellite attitude
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发布时间：2021-06-10 - 摘要：A newmulti-scale scheme for image fusion is presented using texture and edge information in this paper.The origi-nal images are decomposed into texture and edge maps by pyramid structures.The coefficients corresponding to the filtered tex-ture and edge maps are solved by the singular value decomposition and the linear relationship between Gauss filter and Laws tex-ture extract filter.The decomposed images are represented using the texture and edge features in each scale,and fused using the match and salience measures based fusion strategy.To evaluate the fusion results,objective image fusion performance metrics are used.The experiment results demonstrate by several real image date that the proposed scheme can achieve better fusion perfor-mance than the traditional pyamid decomposition methods.关键词：image fusion;image pyramid decomposition;texture extract
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发布时间：2021-06-10 - 摘要：Image resolution enhancement is useful in many applications.However,traditional image resolution en-hancement algorithms often produce images with various artifacts,especially around edges on the image.In this paper,contraposing the disadvantages of traditional algorithms,we present an adaptive algorithm to enhance image resolution.In this algorithm,the texture attribute of images is considered.Appropriate filters are selected in different texture circum-stances.Especially for the edge positions,the resolution enhancement is completed in two iterations in order to improve the precision and try to interpolating along edges,not across them.Therefore,this algorithm is based on edge detection technique.Through a MSE evaluation comparison,this algorithm is better than traditional interpolation methods（quadratic and cubic interpolation functions）.This algorithm does not suffer from ringing and blurring artifacts.It is demonstrated that our algorithm is reasonable and effective.关键词：resolution;enhancement;interpolation;Texture
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发布时间：2021-06-10 - 摘要：In this paper,we present an improved constant false alarm rate（CFAR）algorithm for ship detection in syn-thetic aperture radar（SAR）imagery.The algorithm includes the probabilistic neural networks（PNN）,CFAR tech-nique,golden section method and area growth method.The PNN is used to estimate the probabilistic density function of radar backscatter from sea surface.The CFAR technique is applied to determine a threshold that differs ships form sea surface.The golden section method is used to estimate the shape parameter of the Gauss function while the area growth method is employed to remove the false alarm.The algorithm is applied to detect ships in Radarsat imagery.The compar-ison of the performance between the improved algorithm and the original algorithm is made.The results show that the im-proved CFAR algorithm performed better than the original one.关键词：ship detection;PNN;CFAR;SAR
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发布时间：2021-06-10 - 摘要：To investigate the relation of sun-induced fluorescence peak near700nm with chlorophyll a concentration,data set of the reflectance spectra of red tide species such as Gymnodinium sp.,Heterosigma akashiwo,Ceratium furca and other algae for instance Nitzschia closterium,Dicrateria zhanjiangensis Hu.,Blue algae sp.,Chlorococcum sp.,Platymonas helgolandica var tsingtaoensis,chlorella sp.getting from in situ and culture was used.R maxred normalized to R 560 was correlated highly with chlorophyll a concentration with R>0.82.Along with algae’s difference,the coefficient a of the relationship of R maxred /R 560 with chlorophyll a presented big change.The regressions equation in the form of R maxred /R 560 =a（chl a） b revealed that coefficient a varied from0.037to1.135and b varied from0.094to0.727.Si-multaneously this work established the relationship of the peak position of algal fluorescence with chlorophyll a concentra-tion.All of the Regression coefficients were bigger than0.75except Chlorococcum sp.with0.57.The position of phyto-plankton’s fluorescence peak was shifted to the red light of spectrum.Varied with the species of algae,the shift of peak position was not the same.The Heterosigma akashiwo was the biggest,and the shift of peak position of other algae per10mgm -3 was between0.1and0.3nm.No shift was detected of Dicrateria zhanjiangensis Hu.and Chlorococcum sp.in the scope of experimenting chlorophyll a concentration.关键词：red tide;algae;sun-induced chlorophyll fluorescence（SICF）;chlorophyll a
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发布时间：2021-06-10 - 摘要：Extracting road network from high resolution remotely sensed imagery is much difficult than from the other resolution because high resolution imagery exhibits more complex spectral character.To distinguish them from other spa-tial objects,novel classification tools should be applied in which support vector machine（SVM）is outstanding in its fast training speed and strong capability in non-linear classification tasks.A road network extracting method combining Gaus-sian Markov random field texture model（GMRF）and SVM is proposed.This method can be divided into two main steps:firstly,GMRF is used to obtain the6texture features values of sample pixels,and SVM is trained and then used to clas-sify the whole image with these features into road patches vs.non road patches.After that,the patches are initially con-nected with some morphological operations,and their axes are extracted with thinning operation and then vectorized.Se-condly,a heuristic connecting strategy is used to connect and group the axes of the road patches into final road network.Experiments of road network extracting from IKONOS imagery validate our method.关键词：high resolution remote sensing;Gaussian Markov random field texture model;support vector machine;road network;information extracting
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发布时间：2021-06-10 - 摘要：Begining with analysis and comparison of different models of space,and in combination with the relative results researched by spatial cognitive behaviors,neuroscience,and cognitive psychology,the spatial cognitive mode is studied in this paper.The research shows that the forms of presentation of”space”generally include three kinds,i.e.,perceptional space,cognitive space,and symbolic space.Each of representing forms has individual spatial cognitive mode.According to the difference of spatial cognitive modes,the spatial cognitive model includes three levels,i.e.,spatial feature perception,spatial object cognition,and spatial pattern cognition,and spatial feature and spatial object are two basic units of spatial cognitive model.Using the Great North China as an application region,by the analysis of the strong earthquakes patterns in this region,the spatial cognitive model and its application are illustrated further.关键词：space;spatial cognitive mode;spatial feature;spatial object;spatial pattern
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发布时间：2021-06-10 - 摘要：Linear pixel unmixing is a straightforward and efficient approach to the spectral decomposition of multichannel&hyperspectral remotely sensed scenes.A main drawback to its utilization in operational cases is that the endmember of spectral comˉponents can not be retrieved correctly and automatically.Developing unsupervised methods to automatically abstract endmember is a difficult but significant job.The authors presented an iterative error analysis algorithm to retrieve endmembers and unmixing hyperspectral imagery automatically after obtaining some constraint conditions of selecting endmembers by analyzing error propagation in linear spectral unmixing model,and combined with the property of endmemberwhich is cohesive in spatial.The experimental results show the algorithm is robust by testing various thresholds and initial iterative value.Other experiments for test efficiency and accuracy of the algorithm by employing AVIRIS and PHI hyperspectral data were also done.关键词：automated endmember extraction;mixing pixels;iterative unmixing
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发布时间：2021-06-10 - 摘要：Automatic land use and land cover change（LUCC）detection via remote sensing image has a wide application in the area of LUCC research,nature resource and environment monitoring and protection.Under the condition that one time（T 1 ）data is existed land use and land cover map,and another time（T 2 ）data is remotely sensed imagery,howto detect change automatically is still an unresolved issue. This paper developed a land use and land cover class knowledge-oriented method for automatic change detection under this situation.Firstly,the land use and land cover map in T 1 and remote sensing images in T 2 were registered and superimposed precisely.Secondly,the remote sensing knowledge database of all land use and land cover classes was constructed based on the unchanged parcels in T 1 map.Thirdly,guided by T 1 land use and land cover map,feature statistics for each parcel or pixel in remote sensing images were extracted.Finally,land use and land cover changes were found and the change class was recognized through the automatic matching between the knowledge database of remote sensing information of land use and land cover classes with the extracted statistical information in that parcel or pixel.Experimental results and some practicat applications showthe efˉficiency of this method.关键词：LUCC;remote sensing;change detection;knowledge-oriented
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发布时间：2021-06-10 - 摘要：According to recent studies that there are important differences in maximum light utiliazion efficiency（ε max ）among vegetation types,an estimation model of net primary productivity（NPP）,based on geographic information system（GIS）and remote sensing（RS）technology,is presented.This model has two significant characteristics;（1）NPP can be estimated just using ground meteorological data and remote sensing data.It is relatively easier to acquire data and its application can be enhanced.（2）After the validation with observed data and the comparison with other NPP models,the results showed that the predicted NPP was consistent with observed values,and it can more actually reflect the forest NPP than Chikugo model.In order to validate the NPP model,a case study in Inner Mongolia,China,was carried out.The results showed that the total annual NPP in Inner Mongolia in2002was390.8Mt C.The spatial changes of NPPwere remarkable,and it decreased from northeast toward southwest.Moreover,seasonal variations of NPP were also large.It was about72.7%of the total annual NPP in the three month of June,July and August,and the NPP values was very low（3.59Mt C per month）in January and February.关键词：Geographic information system;remote sensing;MODIS;NPP;Inner Mongolia
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发布时间：2021-06-10 - 摘要：Land vegetation plays a major role in the global climate change through carbon cycle,and climate change in turn afˉfects vegetation growth and its photosynthetic activity.In arid and semiarid area,sparse vegetation cover characterizes environˉments.Thus quantitative temporal series analysis of vegetation distribution and its variations enables observing annual trends,helps to find out the reason for environment variability.There are serious environmental problems,such as deforestation,soil erosion,salinization,and desert encroachment in the northwestern China,its natural conditions is very delicate.In this paper,we built the time series of vegetation change by the NDVI（normalized difference vegetation index）covered northwest regions in recent20years,and analyzd the time serial NDVI variability using three methods,which are simple differencing,slope map of NDVI（and biomass）,and principal component analysis（PCA）.The change image demonstrated that the area of vegetation covers decrease in recent20years in northwestern China,especially in the Loess Plateauwhere precipitation decrease and temperature increase.Only little part,such as the Tianshan Moruntain area,vegetation is increased.The character of vegetation change in northwest showed that the ecological environment in this area is becoming more fragile,such as shrinking of lakes,oasis and wetland,area extending of soil erosion,salinization land,and desert because human activities and global warming.The correlation analysis between NDVI with the temperature and precipitation in northwestern China was carried out.There was significant positive correlation between NDVI and precipitation,and temperature was not strong correlation relatively with NDVI in the northwest China.The results showed AVHRR is reliable for regional vegetation change research after comparingwith the change of precipitation and tempoerature.关键词：NDVI;vegetation cover changes;precipitation;temperature
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发布时间：2021-06-10 - 摘要：In recent yeas,the transportation of Beijing has made a great progress in building up of the ring roads,which have promoted the development of big commercial sites and estate surroundings,at the same time,brought up the change of land use.The objectives of this research are to detect the changes of land use from1988to2008and reflect the improvement of the ecologiˉcal environment,which is also the object to support the2008Olympic games.Considering the above two aims,and after stanˉdardized radiometric normalization correction and geometrical correction of the Landsat TM image of1988,1994,2001and2003in May or June,these images are classified by SOFM（Self Organized Feature Map of Neural network）method.Then the frequency index model,spatial autocorrelation analysis model and urban expansion potential model are adopted in this paper to analyze the land use change information extracted from the classified information.The analytical result of these methods show that from1988to2003the city expansion tendency is obvious.The transformation from farmlands to builtˉup areas is the main resource of urbanization,from2001to2003the green land increased between the fourth ring road and the fifth ring road,and from1994to2003the urban expansion potential index of Beijing city is increased by degrees from the inner fourth ring road to the sixth ring road.Based on all these analytical results we can draw a conclusion that the change character of land use with ring roads driven and the urban expansion process of Beijing city centering the old city and surrounding the ring roads in the past decade.关键词：ring road construction;SOFM classification;remote sensing change detection;land use change
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发布时间：2021-06-10 - 摘要：The ratio and illumination of wheat plant’s leaf and stalk in spectrometer’s field of view change due to wheat lodging,so it is possible to detect the lodging grade by remote sensing technique.Firstly,the spectral difference between leaf and stalk is analyzed,and how canopy spectral reflectance increases with lodge angle is explained.Secondly,because the relative increase of spectral reflectance in visible bands is larger than in near infrared bands,the significant negative correlation model between lodging angle and NDVI was built by statistical analysis.Finally,two LandSat ETM satellite images of April7（before lodging）andMay9,2003（after lodging）were selected,and the ratio of NDVI derived fromthe two images was statistically correlated to the lodging grade,and the lodging grade was successfully regressed.关键词：Spectra;normalized difference vegetation index（NDVI）;lodging;multiˉtemporal
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发布时间：2021-06-10 - 摘要：55surface and subˉsurface samples of expansive soils were collected in the HandanYongnian area,Nanyang district,Pingdingshan area along the middle line of the NorthSouth Diversion Water Project and in Xiangfan area and Zhongxiang districts in Jingmeng city.Clay mineral composition and smectite contents were measured using XRD and dye absorption methods.The effective smectite contents were calculated.Meanwhile the visibleshort wave infrared spectra of the swelling soils was collected,the spectral absorption indices,such as:wavelength position,depth,width,asymmetry,area,were calculated automatically.Then the correlation relationships between the spectral indices and the smectite contents and the colloid contents and clay contents of the swelling soils were statistically analyzed.The results showthat the very high,high,medium,weak potential soils can be identified according to the relative strengths of the2200nm,1900nm,1400nm absorptions in the spectral features of the swelling soils;the smectite contents and the colloid contents and the clay contents of the swelling soils can be estimated with the1400nm and1900nm absorption;the absorption widths of the1900nm and1400nm absorptions can be used to estimate the smectite contents;the absorption area and asymmetry cannot be used to estimate the contents of smectite and colloid and clay;the laboratory spectral measurement and analysis techniques to the dried and homogenous swelling soils can be productively used for quickly,economically,and conveniently identifying swelling soils,and estimating the contents of smectite,colloid,and clay in the engineering sites.关键词：swelling soils;smectite content;Spectra;parameterization;engineering application
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发布时间：2021-06-10
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