This paper proposes a regional algorithm to estimate sea surface temperature (SST) in the East China Sea has been developed using MODIS data aboard Terra and the coefficients of the algorithm were ascertained using MODTRAN 4.0 code and TIGR profiles.The East China Sea's 24 profiles were chosen from TIGR database to input the MOTRAN4 code to calculate the at sensor apparent brightness temperatures in MODIS band 20,29,31 and 32 under 21 observation angles (from 0 to 65 degree) and the coefficients were obtained from the 3,528 samples using the least square method.The preliminary results show a good agreement between SSTs estimated by the proposed algorithm for Terra MODIS data and MODIS SST products.The comparison of the SSTs estimated by the proposed algorithm with concurrent in situ data showed an accuracy of about 1K.With observation angles increase the accuracy deduced from 0.68K to 1.16K.The accuracy of the proposed algorithm was better than that used in MOD28.Our future work would be conducted to collect more profiles and in situ data and improve the accuracy of our algorithm in large observation angles.
The risk level of forest fire depends not only on weather,topography,human activities,socio-economic conditions,but also closely related to the types,growth,moisture content,and quantity of forest fuel on the ground.How to timely acquire information on the dynamics of growth and moisture content of forest fuel and climate in the whole country is critical to national-level forest fire risk forecasting.The development and application of Remote Sensing (RS),geographic information system (GIS),databases,Internet,and other modern information technologies has provided- an important technical means for macro-regional forest fire risk forecasting.Quantified forecasting of national-level forest fire risk was studied using Fuel State Index (FSI) and Background Composite Index (BCI).The FSI was estimated using MODerate resolution Imaging Spectroradiaometer (MODIS) data.National meteorological data and other basic data on distribution of fuel types and forest fire risk rating were standardized in ArcGIS platform to calculate BCI.The FSI and the BCI were used to calculate the Forest Fire Danger Index (FFDI),which is regarded as a quantitative indicator for national forest fire risk forecasting and forest fire risk rating,shifting from qualitative description to quantitative estimation.The major forest fires occurred in recent years was taken as examples to validate the above method,and results indicated that the method can be used for quantitative forecasting of national-level forest fire risks.
To generate 3D information from the image sequence of the normal UAV(Unmanned Aerial Vehicle) loading camera,a reconstruction method is proposed.At the first step,the key frame selecting from the sequence,the robust features extracting and corresponding of multi-images of sequence are accomplished.At the second step,two views which are far away enough and sharing lots of correspondences are selected.With the correspondences the RANSAC algorithm estimates the fundamental matrix robust and then the more accurate correspondences with less outliers are gotten,which are called as inliers.Basing on the calibrated camera parameters,the motions R and T of the view is computed by decomposition of the fundamental matrix,and then it is optimized with the correct correspondences.At last,3D reconstruction is realized by the method of triangle communicating.Experiment results show that the algorithm is efficient and it improves the robustness and accuracy of the reconstruction.
Vegetation includes all plant communities that cover the earth surface.And vegetation fraction is the most important index to scale the status of the vegetation of the region so the vegetation is the composition and the function body of ecological system.Vegetation fractions in different districts of Wuhan were calculated based on remote sensing images (TM images and ETM+ images) in 1988,1991,1996 and 2002 by employing method for dimidiate pixel model,and the vegetation fraction maps of different periods were generated to analysis the temporal change of vegetation fraction of Wuhan area.The results showed that,the vegetation fraction changed much from 1988 to 2002; the average vegetation fraction of the whole area was decreased from 58.41% to 50.45%,especially in Jiangxia district and the central district.From 1996 to 2002 is the period which vegetation fraction decreased the most sharply in this period.From 1991 to 1996 the vegetation fraction was lightly increased in the whole study area.Analyzing spatial changing characteristics in the whole study area we can see that,the whole area was in the decreasing moment,especially in Jiangxia district and the central district,this was the result of urban development,and led to the malign development of the environment,worthy of all aspects of attention.
Suspended soil is one of the main water color elements which affect inland water optical properties.In these years,many methods and models are developed by scholars to reverse soil concentration.These methods or models all use immobile characteristic spectral positions.However,soil characteristic spectral positions move when soil concentration changes.So,using immobile characteristic spectral positions to reverse soil concentration must bring some error.In this article,in order to obtain higher precision,the author brings forward a new method of using dynamic apex to reverse soil concentration.
Spectral and temporal information can improve crops classification precision greatly.In this paper,4 multi-temporal TM & SPOT images were selected on Youyi farm in Heilongjiang province.We used the NDVI as a new band information by extracting the NDVI information on the correspond time.By analyzing the spectral and time feature of the objects on each band,we designed a decision tree classified arithmetic.Finally,after series value division and mask management,the areas and distributions of dadou,yumi and shuidao were successfully remotely sensed with an overall accuracy of 98.67% .
To take Wuhu in Anhui province for example.Firstly,the author analysed the water body in Wuhu and the spectral characters of the earth's surface,then,summarized every class separability of the water information and the earth's surface in every band of ASTER Remote Sensing Image,after repeated experiments and analysis constructed the extracting model of water body which based on threshold of bands and relation of spectrum:B2>B3,B1+B6<127,B3+B4<54 and B3<24.In the end,the author compared and evaluated the conclusion of extracting model of water body with the conclusion of unsupervised classification,supervised classification and NDVI.The result of experiment indicated that this method is feasible and more simple,but higher demands were needed in the selected samples of the analysing process of spectral characters.
This paper takes the color photography picture and large-scale terrain map from Northeast University as data source,and gains the DOM data and DEM by using VirtuoZoNT3.5.After pretreatment,these data can have the same coordinate system.By using 3D GIS software Skyline Terrasuite,we overlay DOM to DEM structuring the vein coming to show 3D circumstances and the building roof 3D surface.Also by making use of a digital camera to collect the side vein of buildings,we can achieve 3D landscape of city Visualization.The paper discus above-mentioned method process,and give some experience summary.
This report assesses the effectiveness of different resolutions for estimations on vegetation cover in urban area using Landsat-7 ETM+ and Quickbird data.The Normalized Difference Vegetation Index (NDVI) data are first generated from these two types of data in Beijing area.It shows that a finer imagery can distinguish a smaller areas,thus Quickbird image is better for the urban area.However,for a larger area or a homogenous vegetation cover,these is little difference.Landsat ETM image is more appropriate for a larger area due to its lower cost and more bands when compared with the Quickbird imge.
This paper deals with locating the synthetic targets precisely and dynamically.Based on experiments,authors analyze common methods such as filtering,edge detection,sub-pixel edge localization and central localization and compare them according to precision and time efficiency.Furthermore,the performance of moment operators is improved.More importantly,the paper presents a scheme applied to the baseline determination of dual- antenna InSAR.The new scheme consists of target matching,segmentation,noisy filtering,edge coarse localization,sub-pixel localization and central localization.The aim of 0.05 pixel' accuracy and 50ms' period is achieved.The experiments indicate that the algorithm proposed is anti-noise outstandingly and more applicable to the complicated circumstance of the outer space.
New method for automatic geometric rectification based on image matching in remote sensing image is proposed,which can solve the problem of lower-precision and time-consumption in traditional manual geometric rectification.First,the pictures contained ground control points (GCPs) are gained in the remote sensing image which has been processed with basic geometric correction method.Secondly,the accurate matching between remote sensing image and GCPs pictures are found.Then,the outliers of GCPs are detected.Finally,the remote sensing image is precisely corrected by the GCPs.Also in this paper,a new multicriterion image matching algorithm is proposed to detect precise matching.The experimental results demonstrate the robustness and effectiveness of the proposed automatic geometric rectification method.
The fused image of ETM+ and SPOT-5 Pan is a suitable data source for geohazard detection because it has abundant spectral and spatial textural information.However,the spatial resolution of SPOT-5 Pan is much higher than that of ETM+ multi-spectral images,a suitable fusing method should be selected to fuse SPOT-5 Pan with ETM+ images to obtain a fused image with high spatial and spectral resolutions.In this paper,a comparison has been made using various fusing methods,including IHS,Brovey,PCA and Gram-Schmidt transformation methods.Subjective appraisal and horizontal spectral profile have been adopted to assess the quality of the fused images.It is concluded that PCA and Gram-Schmidt transformation methods are suitable for fusing SPOT-5 Pan and ETM+ images,and that it would be better for ETM+ spectral bands to be fused with ETM+ Pan image,and then fused with SPOT-5 Pan image.
We propose an algorithm which optimizes the way of choosing quality threshold according to the distribution of the residues.All the pixels of the wrapping phase figure are classified by this threshold into two types,high quality pixels and low quality pixels,and given different weights and then unwrapped.Experimental results show that the proposed algorithm has the advantages of less information loss,clearer guide line,fewer manual works,and its precision is superior to some of the conventional algorithms such as the branch-cut algorithm.
We proposed an algorithm of SAR speckle denoising method based on combination of statistic model of complex wavelet coefficients and significant estimation of noise variance.This method first employs a logarithmic transformation to change the multiplicative speckle into additive noise,then logarithmic image is processed by Dual-Tree Complex Wavelet Transform,and the model,which is based on statistical distribution for the complex wavelet coefficients of SAR image,is set up.Under such prior distribution,Maximum A Posteriori(MAP) estimator is used to restore the wavelet coefficients from the noisy observations to achieve the goal of filtering noise.Experiment results show that the method can remove the noise while preserving significant image details and obtain the good performance.
This article basing on the similarity of bands width between CBERS02 and Landsat5 and according to the theory of cross calibration put forward (present) using landsat5 data assistant CBERS02 data atmospheric correction（ATC）.The exactly method is by liner regression gained regress coefficient of the band1、2、3、4 between CBERS02 and TM5,and then calculated radiance calibration coefficient,finally in the ERDAS ATCOR2 model modified parameter of landsat4_5 atmospheric correct module achieved atmospheric correct of CBERS02 data in the ATCOR2 model.The result of experiment show that this method feasible.After atmospheric correct,enhanced image contrast,improved image precision and restored image quality.
In the methods of improving the classification precision of remote sensing images,adding textural information as an expanded eigenvector into feature space is a pretty useful method.In this paper,the author extract texture using spatial connections between geo-objects,then put it into the classification process.This experiment shows a nice result.Through the problems encountered in this experiment,we discussed the appropriate scope of this methodology.
According to the different method of I/Q demodulation,the receivers of the synthetic aperture radiometer have two configurations,which are referred to as I/Q down-conversion and I/Q demodulation after down-conversion.It is analyzed that whether or not the mirror-image is produced when the synthetic aperture radiometer,with the two receiver configurations respectively,images the targets at single-sideband and double-sideband mode.The results show that the mirror-image is produced when the synthetic aperture radiometer with I/Q demodulation after down-conversion receivers configuration images the targets at double-sideband mode,not produced at the other cases.Through the signal analysis in frequency domain,the mirror-image is produced because the minus frequency components of the RF input signals are mixed into the analytic IF output signals when the RF input signals are processed by the receivers.At last,the comparison between the single-sideband and double-sideband mode of synthetic aperture radiometer and the radiant point-source imaging simulations,which prove the results of mirror-image analysis,are carried out.
Fully polarimetric radiometer plays an important role in measuring and researching of the ocean surface wind field.Fully polarimetric radiometer can get target's all polarization information by measuring the full set of the Stokes parameter,which is an useful implement of the measuring of the ocean surface wind field.There are two main types of the fully polarimetric radiometer:polarization combining radiometer and correlation radiometer.This paper focuses on the correlation radiometer.At last,we discuss the calibration of the fully polarimetric radiometer.
Integrated Modeling Environment is mainly used for the rapid realization of model integration,enhancement of the authenticity of modeling and model predictive analysis capabilities.IME is the point of model disassembling and reassembling in the final analysis,focusing on how to modularize the existing model and reassemble the appropriate module together in the support of the modeling environment.This paper discusses the development method of IME prototype based on plugins and establishes a visual integrated modeling environment,in which we can implement the composition and connection of the hydrology and water resources model,and generates new model through graphical operation.
The technology of component software has been one of mainstreams in the development of software technologies today.It is also one of the hotspots of the Geographic Information System (GIS).Component GIS would be an important direction in the development of GIS in future.In this paper a query system for segmental map-tables of relief maps in China was developed based on ComGIS technologies.The segmental map-tables of relief maps were made according to the regulation of dividing-map and map-coding of national basic scale relief maps.Firstly the data with generate format were made and then the original generate data were converted into Shapfile data by using the predominant spatial analysis function of Arcview3.3 of GIS tools.Finally,spatial database of the different scale relief maps in China was created.On the base of the spatial database,the object oriented VB (Visual Basic6.0) develop-platform and MO (MapObjects2.2) component were adopted to compile the thematic geographic information system software-query system on segmental map-tables of relief maps in China.
It is important that government knows social and economic information of region for government decision-making to develop.This paper uses Components GIS based on MapObjects to develop social and economic information system of Zhangye city,taking Zhangye city in Gansu province as study area.Through social and economic information system developed in paper Guests could not only use kinds of basic functions of GIS but also browse and search the visualized and imagewise social and economic information,including maps of economic indexes and synthetic economic analysis.It can give reference of social and economic development to the governors for decision-making to develop.
Remotely-sensed monitoring for algal blooms is one of the important subjects of remote sensing application.With the development of almost 30 years,many algorithms for detection of algal blooms based on satellite data were developed by scholars both at home and abroad.The history of satellite remote sensing detection for algal blooms is reviewed,the remote sensing monitoring algorithms of several sensors are summarized,and their performance and application range are analyzed.Finally,the challenge of remotely-sensed monitoring for algal blooms is discussed,and the prospect of remotely-sensed monitoring for algal blooms is proposed.
