For the low and medium spatial resolution remote sensing images,the issues of mixed pixels are particularly prominent,which does not only influence the accuracy of image classification,but also greatly hinder the development of quantitative remote sensing of land surface.Therefore,mixed pixels unmixing of remote sensing images and quantitative extraction of land coverage information have attracted more interest in recent years.In this paper,focused on quantitative extraction of land cover information,a method of integration of the Normalized Spectral Mixture Analysis (NSMA) and Multiple Endmember Spectral Mixture Analysis (MESMA) have been proposed to extract the quantitative information of vegetation,soil and impervious surface using the medium-resolution remote sensing image (Landsat TM),based on Vegetation-Impervious Surface-Soil (V—I—S) Model.Comparative analysis indicated the accuracy of the unmixing by using the Normalized Multiple Endmember Spectral Mixture Analysis (NMESMA) method is higher than that of the conventional fixed endmember of spectral mixture analysis.NMESMA can solve the mixed pixel problem of the high spectral heterogeneity in urban landscape effectively.Therefore,the proposed methodology can be used to extract urban land surface information effectively,and to analyze the urban ecological environment change.
Orthophoto imagery has been widely used in the remote sensing study.However,due to the use of incomplete terrain model,phenomena such as surface features dislocation and block inevitably occurred in the traditional orthophoto has seriously affected the quality of the project and mapping accuracy.This study discussed the principle of using DBM (Digital Building Models) and DEM (Digital Elevation Model) for the true orthorectified imagery and the key technologies of workmanship in producing the true orthorectified remote sensing image.In theory,the True Orthoimage map,produced by DSM and DBM,detected and compensated by block area,could completely solve all of problems of traditional Orthoimage map.It is the best choose of detecting changes,collecting surface features and producing three-dimensional landscape.The advantage is obvious.But,relative to Simple treatments of traditional Orthoimage map,notable feature of Ortho-corrected map is enormous amount of data operations.On the other hand,difficulties and costs to get DBM/DSM is still expensive,so the using of the True Orthoimage map is limited in city.
The SIFT algorithm was used in Unmanned Aerial Vehicle images matching,the distance threshold filter was used to remove too close feature points.In order to reduce the error accumulation which can effect on the results of image mosaic,and shorten the path splicing,an optimal base image selection method was introduced,meanwhile,the Dijkstra algorithm was introduced into the search of stitching path,and the project conversion errors between the two images were used to build the search array.The experimental results indicated that this optimal path method can avoid the influences of the image which has large projection error mosaic with the follow\|up images effectively,and reduce the number of image projection transformation,which can improve the mosaic effect.
For the in-orbit calibration of HY-2 Satellite Radar Altimeter (ALT),three active transponders were developed by Mirslab,CSSAR,CAS,and the schemes and algorithms are designed for fulfilling the calibration requirements.Based on the system design and calibration rationales of HY-2 ALT and the transponders,the echo waveforms and trajectory's presented in the altimeter range window were simulated,and the calibration performance were also evaluated.Besides,the waveform features with multiple transponders are simulated to optimize their deployments.
In complicated topographic mountain area,solar radiation on the surface is always changed for the topographic relief effect.Because the extraction accuracy of RS thematic information was interfered,topographic correction has become one of the indispensable key technologies in improving the precision of quantitative sensing data process.In the existing contemporary terrain correction models,the Minnaert model's basic data is easier to obtain.Besides,the Minnaert model has been improved by Dr.Lu Deng sheng for solving the problem of low calibration precision caused by single Minnaert coefficient k,which makes it become an effective method in mountain remote sensing processing of topographic orthorectificafion.In this paper,the topography is efficiently corrected by Cosine model,Minnaert model and the improved Minnaert model,based on ETM images and the corresponding DEM data of Qingtian county of Zhejiang province.The results showed that the improved Minnaert model can eliminate the effect of topography,and the textural and spectral character of the surface can be also kept.Based on image statistical analysis,the improved Minnaert model effect is much more obvious than Cosine model and Minnaert model.
With the popularity of cell phones having functions of GPS positioning,navigation and camera,there exist increasing demands for real-time identification of urban buildings with mobile terminals.In this paper,image processing algorithms for urban buildings recognition,including SIFT and Local Search,were discussed and compared in details to show that contour lines and their combinations are stable geometric features of buildings,so the algorithms based on contour lines immune to affine transformation,low picture qualities and lens distortion.Besides,the match index based on contour lines can reflect the camera position change.As a result,Local Search was improved;firstly getting the building contour lines by abstracted from pictures photographed by mobile terminals and generated from the 3D-database,secondly utilizing it to find some of the best matches between those contour lines.The improved algorithm can meet the demand of fast building recognition in mobile terminals .
Thermal inertia method has been widely used in soil moisture inversion.By using MODIS data,the real thermal inertia model was used to retrieve soil thermal inertia in Heihe River Basin,provided reliable method and aclurate data for soil moisture research in basin.This paper also used field data to validate the model parameters and results;analysed the seasonal change of temperature differences,Albedo and Thermal Inertia,and compared the correlation between the result of Real Thermal Inertia mode (RTI) and Apparent Thermal Inertia model (ATI) with Soil Moisture(SM).The results showed that the temperature differences,Albedo and thermal inertia nave obrious seasonal variation characteristics;This study confirmed that the RTI model is prior to ATI model in simulating soil moisture.
A new kind of tropospheric aerosol extinction coefficient profile retrieval method with hyper-spectral (0.05 nm) reflected information in oxygen A band is presented.The advantage of this novel method is the Aerosol Optical Depth (AOD) restriction is considered.As two correction factor M and D are introduced,Lagrange multiplier could be chosen automatically and the precision of retrieval increased.To test this method,we do the simulation retrieval with the help of CALIPSO Level 2 aerosol products and new hyper-spectral resolution RT model.Two types of aerosol scene are selected:dust event and clean condition.For dust event,the relative retrieval error is 51%,while in clean condition,the error could be controlled under 20%.If revise profile is added,the retrieval precision will be much better.
GNSS-R(GNSS-Reflectometry) remote sensing is a kind of bistatic radar model.Mimics(Michigan Microwave Canopy Scattering)model is based on first-order radiative transfer equation.It is developed to Bi-Mimics(Bistatic-Mimics)model according to bistatic radar configuration.Bi-Mimics model is adapted to crop bistatic scattering model.In this model,the trunk layer is eliminated and the interactions between the trunk layer and ground layer are canceled.Using this model,numerical simulations about scattering properties at GNSS-R working L-band have been carried out.According to GNSS-R configurations,relationship between specular scattering coefficients and crop biomass is also simulated.And the bistatic radar equation is used to simulate the relationship between crop stem biomass and GNSS-R receiver signals.The simulations indicated that GNSS-R is a kind of technique to monitor crop biomass theoretically,but it needs to be further studied.
Based on the being method of cloud vertical structure determination,combined with high-vertical-resolution radiosonde data,we modify the method of relative humidity threshold.And we determine the cloud vertical structure using the RS92 radiosonde data in De Bilt region in 2007,and analyze the occurrence frequency and the vertical distribution characteristic of cloud.The result shows that it is feasible to analyze the high-resolution radiosonde data of cloud vertical structure using the improved relative humidity threshold method.There are mainly single-layered and two-layered cloud in this region,and the occurrence frequency of signal-layered cloud shows the characteristic of “higher in summer and lower in winter”,the double-layered cloud is the opposite.The occurrence frequency of the mean cloud base height,cloud top height,cloud thickness and the highest cloud top height for all cloud increases with the height.
Synthetic Aperture Radar (SAR) imaging requires huge computation load,thus it needs high-end computation platform to construct the system when comes to real time imaging process.Typical SAR real time imaging systems adopt DSP,FPGA and cluster.This paper presents a new approach that realizes SAR real time imaging processing based on Computer Unified Device Architecture (CUDA),which is a new parallel programming model introduced recently on Graphic Processing Unit (GPU).The study had analyzed the difference between data parallel mode of CUDA and task parallel mode of typical platform,including studied RD algorithm structure and optimized each step according to CUDA parallel programming model,then the corresponding RD algorithm structure is implemented.This poper also conducted the experiment results showed the speed on this platform is about 20~30 times of a common high-end PC(Intel Core-i7 950),and 10 times of the speed required for real time imaging for RadarSat-1.It proves a promising way to realize SAR real time imaging system.
Being considered about the effect of wave states on the wind speed retrieval,in this paper an improved analytical algorithm was proposed based on a four-layer dielectric model and the incident-reflected wave theory.Compared with the analytical algorithms proposed by Zhao et al,this improved algorithm was in a better accord with some empirical algorithms such as Brown algorithm,Young model function and et al.The new analytical algorithm to some extent not only made up for some shortcomings that did not consider sea states in specific practice for analytical model functions,but also overcome some limitations of empirical model functions.This new algorithm would be suitable not only for low wind speed inversion,but also for high wind speed retrieval.Better accuracy and effectiveness of wind speed retrieval can also be obtained.
The Yancheng coastal wetlands are rich in biodiversity and of significant importance in wetland conservation of the world.How to acquire coastal wetland types information more accurately using remote sensing images is significant to wetland researches.The core zone of Yancheng coastal wetlands are taken as a study area and the classification of wetland types is based on ALOS image.We developed the following methods to improve the classification accurately of wetland types.At first,we use the unsupervised classification method to conduct the primary classification system for the coastal wetlands.Then,the reason for limiting the accuracy of wetland types were found,especially in the ecotones of wetland types.The ecotones among reed marsh,spartina alterniflora marsh and suaeda heteroptera kitag marsh have been revised by using the spectral feature of wetlands,texture,principal component analysis and relative knowledge rules.In addition,the rest parts were revised by GIS rules.Finally,the precision of classification was tested by the GPS data and the average accuracy of wetland types has reached 92.6829% the kappa coefficient reaches 0.9098 in the test region.Which suggested that the multi-level classification method including the knowledge rules and GIS rules are effective to extracting the coastal wetland cover information.
Land use and land cover change is one of the hot issues in the study of global change,while surface temperature and vegetation are the important parameters to describe land cover characteristics.In this paper,TM satellite remote sensing images in 1999 and 2010 have been used to quantitatively analyze the urban thermal field and vegetation index of Fushun,provided theoretical and practical basis for the spatial layout and key construction of Fushuns construction of forest city.The results showed that,in the past 11 years (1999~2010),the average temperature of the thermal field of the city increased by 1.53 ℃,and the Urban Heat Island (UHI) concentratedly distributed in the built-up urban area of Fushun,as well as the Suzi River Valley and along the Heida highway,but the space distribution has been unprecedentedly compressed,distributed only in the built-up urban area.NDVI of Fushun edged down from 0.4764 in 1999 to 0.4756 in 2010.From the overall situation of vegetation coverage,the percentage of the area of high vegetation coverage is more than 60%,even more than 78%,whereas the percentage of the area of vegetation coverage below is very small,lower than 1.5%.From the variation of vegetation coverage,in the past 11 years,the percentage of the area of both high and relatively high vegetation coverage decreased by 3.22% and 2.31% respectively,and the percentage of the area of middle vegetation coverage increased by 4.94%,which,in total,shows that the citys ecological environment has been deteriorated.From the spatial change of vegetation coverage of the city,largest change area is the urban district,whose change is about 3 to 5 times more than the whole city.The change reasons of the thermal field and vegetation are:Firstly,the influence is from the warm and dry climate in the growing season.Secondly,the cropland and grassland decreased,while the land for construction increased rapidly.In addition,it has been influenled by the ecological construction of Fushun.
This paper introduces the image processing methods of Worldview-Ⅱ image data and the study on the interpreting of structure.By employing ETM+ and Worldview-Ⅱ remote sensing images,with geomorphic analysis,to carry out structural interpretation in Gaize area,west-central Tibet,China.It is the first time to do such big range of remote sensing interpreting on the Gaize area,where is at high altitude,and difficult to deploy the ground work in.The results suggested that the interpretation works have gotten the good results based on Worldview-Ⅱ remote sensing images.And according to the results,there are three types of fault structures developed in the area,i.e.E-striking thrusts,N-striking normal faults and NE- or NW-striking strike-slip faults,in response to the prevailing stress regime of N-S maximum stress and W-E minimum stress that results in the N-S contraction and W-E tension in Tibet.Remarkable geomorphic features have been controlled by the fault structures:① the Relacuo lake to the north of the Gaize town is developed on a graben bounded by N-S striking normal faults;② the Xiagacuo lake is formed on a bend-release basin as a result of the transtensional horsetail termination of a NW trending dextral strike-slip fault;③the fluvial plain to the north of Gaize is controlled by a NE-trending transtensional sinistral strike-slip fault.
Using satellites and ground synchronous observation method,preprocess Hyperion image and then extract corn thematic information,at the same time calculate the correlation between chlorophyll content and the true ground spectrum,its first-order differential form and spectral index of corn.The results showed that the crop chlorophyll content prediction index TCARI/OSAVI has the best correlation,which are 05694 and 05313.Use the feature to do the regression analysis with chlorophyll content,so that establish chlorophyll inversion model With the regression result to corn area of remote sensing image,obtain the spatial distribution of chlorophyll a and chlorophyll b contents.
Monitoring vegetation phenology is very important for many aspects,such as seasonal appearance of plant,crops production,global change,ecological study.Vegetation index is an excellent index for monitoring vegetation appearance.With the development of remote sensing,it has become a new way to extract vegetation phenology.We use the filter of Savitzky-Golay to rebuild the time-series of SPOT Vegetation NDVI,then we extracted the spatial patterns of vegetation phenology in Heihe river basin.The results show:Vegetation phenology information obtained using this method is in good agreement with the farming calendar of this region.Vegetation phenology have clear spatial patterns in Heihe river basin.Arctic-alpine meadow in the upper-stream have shortest growing season.While ,the oasis in the middle-stream have much longer growing season.In the middle-stream,human activities greatly influenced vegetation growth,vegetation phenology is in good agreement with the farming calendar.
There have been a great changes for the land use and land cover in Tianjin Binhai new area and Caofeidian region since 1980s.Based on four years (1984,2000,2006 and 2009) Landsat images,this paper analyzed land use change characteristics for the past 26 years in the two study areas.This study adopted the maximum likelihood classification and post-classification change detection methods to monitor the land use dynamic variation characteristics,which clarified the regional differences of land use change,and provided valid decision for sustainable land use.The results indicated that:① The pond was the major land use type in the two areas,especially in Caofeidian,where the pond area covered 60%~70% of the total land area.The total land area showed an increasing trend with land reclamation from sea area since 1980s;② the reduction of cultivated area and the increasing of construction sites are the main features of land use change in two areas,especially after 2000;③ in the Binhai new area,the center of land trend for construction sites had mores towards southwest,whereas the other land use types had migrates to northeast.In Caofeidian region,the center of land use types had obvious southward trends.
Along with the increasing development of urbanization,tidal flat is now serving as the most important resources of land reserves for coastal cities.As a sensitive belt of sea and land interaction,silt tidal flat is characterized as muddy surfaces,densely covered and frequently varied tidal creeks.Therefore,the traditional field observation has been restricted by the difficulty of access,however,the development of remote sensing techniques make it possible for the coastal investigator to monitor the dynamic changes of coastal zone at low cost and in an efficient way.This paper reviewed the current state of the use of remote sensing in estuaries and coastal tidal flat.Recent advances of four main application aspects including shoreline extraction,retrieval and analysis of elevation at mudflat,bathymetry and surface suspended sediment concentration retrieval are introduced.To date,the most common remote sensed techniques used in coastal zone can be classified into four categories:photogrammetry,satellite optical remote sensing,SAR as well as Lidar.Through systematical analyzing the mechanism,technical characteristics and advantages and shortages of the four categories techniques,the author finds that despite these considerable advances have been made,lack of suitable remote sensing data and not-perfect data processing methods are the remaining challenges to impede the improvement of survey accuracy in coastal zone.In order to improve this situation,it is to suggest that future studies should focus on the study of combination of different remote sensed information,hyperspectral data mining and data processing methods on SAR and Lidar data.
To get the four Stokes vectors and ocean surface fields,fully polarimetric microwave radiometer can adopt multi-channel digital correlation technology including the self-correlation and cross-correlation between the horizontal and vertical polarization signals.Fully polarimetric microwave radiometer is a new-type of microwave remote sensors.Digital correlation is the core part of the system.A novel digital correlation is introduced in this study.Four high-speed A/D converters are used to sample the signals of four channels with the results translated to multiplexers for decelerating.The latest Field-Programmable Gate Array (FPGA)-Virtex5 fabricated by Xilinx has been used to complete the correlation,meanwhile,the results are translated to PC in time.The new-type of correlator can process data with up to 5 GHz bandwidth.
A digital transceiver unit of VHF active phased array radars T/R module was introduced.Distributed high speed D/A and A/D were invoked to generate RF transmission signal for every antenna high speed,and to sample echo signal of every antenna,thus both transmission waveform and echo signal of antenna units could be processed independently.All digital units were connected to center control computer with embedded Ethernet.This digital unit design has great flexibility in radar signal processing,and it is high performance,high scalability and low cost.
Discussing the three storage models:storage based on traditional file,storage based on the relational table and storage based on XML,and analyzes their advantages and disadvantages.And then,it is a conclusion that,XML approaches to describe the raster metadata's hierarchy,complexity and object-oriented,and has good extensibility.Raster metadata because of its complexity and hierarchy.In the following sections,we design and implement the management model for raster metadata based on XML in BeyonDB.Finally this paper taked the DEM metadata in Earth System Science Data Sharing Platform as example to verify its extensibility,and it would be a reference for the research on managing massive remote sensing data in spatial database.
The recent development of Geographical Information Science has facilitated its application on meteorological information services at high frequency.As a new pattern of system architecture,Mashup means to collect and aggregate distributed data and services from internet,so as to develop a new application.Among numerous types of Mashup application,geographical information Mashup is the most popular one.This paper proposes to employ Google Earth API,a provider of geographical information Mashup,into meteorological information services,and illustrate the approach and framework for aggregating resources from Google Earth API and local meteorological database into a B/S system.In the end,the framework is detailed in an application case,three-dimensional geographical information system of meteorological disaster warning,which is featured by high visualization,high browsing speed and multi-user.
