The principle and scheme of the spatially modulated Fourier transform hyperspectral imager developed by authors for the Chinese Environment and Disaster Monitoring Small Satellite are introduced. The calculation of the main parameters and the key techniques of optics,mechanics,electronics,calibration and data reconstruction are discussed in detail. The first results of datacubes with some spectra obtained by the hyperspectral imager (called EDIS) in orbit are presented.
Information Extraction using Polarimetric Synthetic Aperture Radar (PolSAR) data has become hot research topics in remote sensing with the development of PolSAR systems.In this paper,a detailed description and analysis of the techniques of polarimetric information extraction methods is reviewed.On the basis,the development trend and application prospect of PolSAR are presented.Researchers in related areas could get a general idea of the latest development of the area in order to promote the domestic research and applications of the related techniques in the years ahead.
Since the sea satellites separated from the earth resource satellites,it had been well-developed for several decades and contributed a lot to strength to the marine monitoring and ocean studying.In the paper,the evolution process of seasats has been presented,including the characteristics and missions of the sea satellites and the payloads as well as the developing trend and so on.At the end,the paper puts forwards the referenced opinions for the analysis of the Chinese developing requirement and key technology.
With the rapid development of remote sensing and information extraction technology,it is possible to automatically update the geographic information.The road is important manmade object and is component of geographic information data.Road information exacted from remotely sensed imagery to update the GIS database has become a hot research spot for many years.This paper summarizes the course of development on road extraction from imagery,and review main methods of road extraction,template matching，knowledge method,Snakes model,dynamic programming,ridge and valley exaction method,morphological method,Hough transform,multi-scale method,method based on segmentation and other techniques for road exaction as well.The characteristics of various methods and insufficient of road extraction from remote sensing imagery were analyzed.Finally,subsequent studies were prospected.
Taking a localized area in Kunlun Mountain as an example,the digital elevation model (DEM) in the highly mountainous area is effectively generated with ERS-1/2 tandem radar interferometry.The accuracy of the achieved DEM is assessed statistically by taking SRTM DEM and USGS GTOPO30 DEM as the benchmark.The main reason affecting the accuracy of interferometry with ERS tandem radar is discussed.The experimental results show that ERS tandem radar interferometry can be used to successfully extract DEMs for highly mountainous areas.It is therefore recommended that ERS tandem radar interferometry might be applied to generate or update DEMs for the western parts of China.
The larger and highly variable microwave emissivity over land results in more difficulties to retrieve the precipitation and other atmospheric parameters over land. The research about microwave emissivity over land is still weak due to the complicated terrains in China. In the paper, the synchronous observation of infrared and visible scanner (VIRS) and microwave imager (TMI) on the Tropical Rainfall Measuring Mission (TRMM) satellite and one microwave radiation transfer model to retrieve the microwave emissivity over land of China were utilized in Jianghuai-Huanghuai region. Then, combining with the land cover type data derived from MODIS observations, the variation characteristics of microwave emissivity over different types of land cover in the middle region of China was further analyzed.
Results show that the microwave emissivity of crop land surface is smallest and its polarization difference is largest while forest emissivity is largest and its polarization difference is smallest among mainly 5 types of land cover in this region. In addition, the microwave emissivity over different types of land cover shows more significant variation in day and night time while less variation in seasons. For the error estimation of emissivity, the influences of land surface temperature (LST), microwave brightness temperature (TB) and relative humidity (RH) on microwave 22 and 85 GHz channels are quite obvious. For those channels with frequencies less than 85GHz, the influence of TB on estimation of emissivity is most obvious, then LST and RH. For high frequency 85GHz, the influence of RH on estimation of emissivity is most obvious, then TB and LST.
Quickly monitoring of cyanobacteria bloom in Taihu Lake is significant for supporting for emergency response plan , building the corresponding monitoring of remote sensing information system is one of most effective way.The system overall structure and system technical processes are introduced to build the system , and the key techniques used are explored.System configuration and singleton soft mode are adopted to implement system architecture based menu form, cyanobacteria bloom spatial distribution information is automatically extracted from pretreated image data that are proceeded with automation, while the inversion model methods to obtain cyanobacteria bloom are applied to model remote sensing image,eventually remarkable results in monitoring cyanobacteria bloom in Lake Taihu was achieved.
Based on the measured data,the MODIS LSE product and 1 scene of Landsat TM thermal infrared band(TM6)images of Honghe wetland,which was obtained on May 15 ,2008,the corresponding data of surface temperature were retrieved with three different methods(thermal radiance transfer equation ,mono-window algorithm carried out by Qin Zhihao,mono-window algorithm carried out by Jimёnez-Muoz & Sobrino).The retrieved data are compared and analyzed.Validation analysis was conducted by comparisons of corrected and uncorrected data including NDVI,LSE,LST estimated with the different methods.The results show that the data estimated by thermal radiance transfer equation are highly similar to that estimated by mono-window algorithm by Qin Zhihao.Therefore,when the in situ atmospheric profile data are unavailable,the mono-window algorithm by Qin Zhihao can be used to estimate the data of surface temperature from one thermal infrared band of Landsat TM images,and the precision of the retrieved data of surface temperature is acceptable.
This paper studied the automatic extraction of linear form in remote sensing image of molybdenum polymetallic deposit in Liaoxi area by this flow direction: linear extension enhancement,edge detection,Binarization by choosing a cutoff value,transition from raster to vector,building a topology,removing the disturbing information,extraction the linear form.The validity of extracted data was analyzed by the relationship between length and frequency of linear form,the relationship between azimuth and frequency of linear form and the structure intensity analysis.The relationship between structural linear form and deposit was studied by weight of evidence; the results showed that optimal ore-forming structure intensity is between 4 and 7.
Traditional way to monitor biomass changes is to use linear or nonlinear model from TM/ETM data.In this paper we discuss the neural network algorithms(NNA) to retrieve wetland biomass from multi-polarization(HH and VV) backscattering values using ENVISAT ASAR data.Two field measurements were carried out concomitant to the acquisition of ASAR images in this area through the hydrological cycle.Training data of the network are generated by MIMICS model which is often used in the forest.We modify the model to make it available on the wetland system.NNA retrieval results are validated with experimental data.The inversion results show that the NNA is capable of performing the retrieval with good accuracy.Finally,the trained neural network is used to estimate the overall biomass of the Poyang Lake and make the map of biomass distribution in April,July and November.
Atmospheric correction is necessary to retrieve the real surface reflectance of the surface objects and eliminate the distortions and noises to the spectrum caused by the presence of the atmosphere.6S (Second Simulation of the Satellite Signal in the Solar Spectrum) model is a widely used atmospheric correction model.However,great errors exist for the model if an average value of elevation or aerosol optical thickness (AOT) is used for the correction of the image covering a wide and complex area.Taking elevation or AOT as input parameters,an atmospheric correction method is proposed in this paper based on 6S model.The histogram of the corrected reflectance, NDVI and the spectral characteristics of a variety of surface objects from Guangzhou were compared with the original ones.The results show that this method is valid and in high correction precision,which were simple,applicable and could be used for atmospheric correction of remote sensing image covering the regions with similar climate conditions.This method can be applied in similar circumstances for references.
Cloud base height as an important cloud macrophysical parameter, plays an important role in energy exchanges between the cloud-layer and the surface. Traditional measurements of cloud base height are mainly based on conventional data,and retrieval of cloud base height with satellite data by taking a passive remote sensing approach has not been adopted in China. Firstly, the retrieval principle, method and feasibility of cloud base height with MODIS visible infrared data are described,and the truth value on the basis of airplane measurements in northwestern China, compared with MODIS water clouds base height data. The preliminary results show that MODIS CBH retrieval algorithm is feasible to water clouds and between MODIS CBH retrieval results and the measurements from 3 airplane flights show that the mean error is about 249.4 meters.
Remote sensing information extraction of wetland resource is one of the most important aspects in wetland research that need to meet definite accuracy and efficiency.Based on SPOT5 image,thematic information extraction of typical wetland was studied by carrying out pixel-based supervised classification and object-based classification in study area,and DEM data was combined with the information of object-oriented classification to explore ways to improve the accuracy of classification.The results showed that the information extraction based on objects and DEM can effectively improve the accuracy of remote sensing image classification.
With the accelerating process of urbanization,the technology of Remote Sensing(RS) can supply the direct,accurate and synchronous information for the change detection of urban land use.Ontology is a definite description of conceptualization.It can be showed closer to cognitive model and easier to be understood and shared; it can be also operated by the computer's formal language to express a tangible goal in the field of the concept and its implication semantics.As a result,with the existed researches analyzed and learned,〖JP3〗the thought of Ontology and Semantic are introduced to the expression of the RS images.Moreover,semantic model and interpretation framework of RS images for urban field based on Ontology are built up in this paper.Then the semantic model in the processing procedure of urban RS images was formed to improve the accuracy and efficiency of RS technology in urban field.
There is a Jiang-huai Watershed between the Yangtze River region and the Huaihe River region.According the history books' records,there was a canal that connected the Yangtze River and the Huaihe River.But the position is not fully ascertained.Form history records,remote-sensing image processing and field investigations,we concluded that Caocao River was the part of the Jianghuai Ancient Canal.Study of the ancient canal will be a clue to the comprehend the connection of the human activities and environmental transition.
Image fusion is a very important research field in remote sensing.Recently developed contourlet transform can offer a much richer set of direct ions and shapes,and thus it is more effective than wavelet in capturing smooth contours and geometric structures in images.A novel method of fusing panchromatic and multispectral remote sensing images is proposed based on contourlet transform.Using the laplacian pyramid(LP)analysis to capture the low frequency information of images,and directional filter bank(DFB)to obtain the high frequency information of images,and using an image fusion scheme based on arithmetical average and plus-power to construct contrast pyramid.Fusion images were obtained through inverse contourlet transform.A laplacian pyramid and directional filter bank(PDFB)are given in this article.On one hand,with the proposed scheme,the contourlet transform as a new mathematical tool is introduced to remote sensing image fusion area.On the other hand,the algorithm is used QuickBird image experimentation.Besides,using information entropy,distorted tolerance,difference index,correlation coefficient,standard difference etc to evaluate and analyze the fusion results.The experimental results show that the proposed method can effectively retain spectral information.It can also improve spatial resolution and spatial information of multispectral images.
In order to inhibit the image noises effectively,a novel algorithm for noise suppression is proposed based on the wavelet transform in this paper.Firstly,the image edges are detected by the wavelet transform and the potential positions of noises are determined.Secondly,according to the histogram distribution of wave image,a threshold value is determined,sea echo signal points are eliminated and the noise points are obtained.Finally,according to the similar property values of sea echo,the property values of determined noise points are substituted with the adjacent signal points and the noise are filtered.Experiments on the wave images indicate that the noise suppression effect for the proposed algorithm perform better than the traditional wavelet domain hard threshold and soft threshold method.So we can obtain the sea echo signal more correctly and more precisely by using the proposed algorithm and the filtered sea echo signal can satisfy for wave analysis.
High resolution remote sensing image acquired by CBERS\|02B consists of 3 chips of TDICCD image.For the space structure of the TDICCD,3 chips of TDICCD image have overlapped horizontally and shifted vertically.In this paper,a new image mosaic method of processing high resolution remote sensing image based on the space structure of the TDICCD and the pixel relativity is proposed,and scene precision reaches sub-pixel.
Combining the features of position and shape,the method of detecting the airport shelter in remote sensing images is proposed in this paper.Firstly,the Mathematics Morphology to extract the skeleton of airport road networks was introduced in preprocessing step.Then topological relationship of the net is employed to locate the End Road of shelter targets,which can indicate the position well.In succession,contour sequence moments are used as salience features to extract building shapes.On that basis,the fusion detection of shelters can be achieved.The experiment is carried out with high resolution satellite images of airport; the results show that this method can recognize the shelters in airport area accurately.
A new method combined Non-negative Matrix Factorization (NMF) with Projected Gradient (PG) is proposed for hyper-spectral image classification.Projected Gradient method demonstrates much faster convergence than the popular multiplicative update approach in the iteration process of two sub-problems from NMF thus effectively maintains higher classification accuracy than traditional methods; RBF neural network achieves higher accuracy and faster classification process compared to BP network.The new method combines the advantages of the above two,applying PGNMF for feature extraction and RBFNN as classifier.The experiment shows that compared to traditional NMF and PCA,PGNMF-RBF has higher accuracy for classification and less time consumption.The classification accuracy for 6 classes reaches 83.34%.This paper demonstrates PGNMF-RBF an effective and promising method in hyper-spectral image classification.
In this paper,structure and functions of a Calibration Hot Target for Spaceborne Microwave Radiometer (the frequency range from 10 GHz to 90 GHz) is presented.Material selecting,structure designing of absorber,thermal designing as well as temperature measuring and controlling are also described and absorb rate and performance testing results the temperature are presented.The data of ground and orbit operation shows that the Calibration Hot Target accorded with Microwave Radiometer design.
3D GIS could describe our world better than 2D GIS, but still has some shortage. In some cases we need to use 2D GIS and 3D GIS by turns. Thus one solution is proposed: to implement the 3D GIS and integrate 2D GIS functions into it.In the end this solution was succeeded in applying to develop a real application system.
With the development of computer technology,workflow technology plays a much more important role in modern organization management.The Web-based workflow technology introduced into surveying and mapping management field can help realizing automation,coordinating of business process of surveying and mapping authority,and making the business information shared as more as possible.This paper presents a framework of workflow application system and the related model which consists of three components,organization model,process definition model,process execution model.The application cases based on this model is also introduced in this paper.
In this paper,a web-based system of remote sensing information extraction was developed by combinating IDL and ASP.NET technique. The IDL language calling the ENVI secondary development library realize the extraction of RS information. The data transmission mechanism between the C# and IDL was analysed with several program examples. The visualization of RS data and the extraction of RS information were realized in this way. Meanwhile,the RS data and the extraction information can be downloaded from the system.
