Recently,applications from atmosphere,ocean and land soil moisture have required higher and higher spatial resolution for passive microwave remote sensors.However,if we use the conventional technology,once the spatial resolution reaches a certain level,the small resolution cell will limit the sensitivity of the brightness temperature measurement due to very short integration time at each of the cell.In this paper,a new technology,so called interferometric radiometry or synthetic aperture radiometry,is summarized.While the basic principle is introduced,the authors tried to explain it in a different way from the point of view that every target or distributed scene has characters in their frequency domain pictures.What the new technology does is,in fact,not to measure the scene in its original spatial domain but to measure it in its frequency domain by a sampling device called two-element interferometer.From this point of view,the new technology appears more systematic and clear to understand.While the imaging systems are summarized,the authors emphasize more on the 2-D clock rotation sampling system with associated image retrieval algorithm,called the Pseudo Polar Grid Method,which both were developed by the authors.
Atmospheric aerosols affect the climate change and air pollution significantly.But it is difficult to study the particles distribution,the chemical composition,etc,due to the indetermination of aerosol source and distribution in atmosphere.Therefore,the development of aerosol investigation depends on monitoring methods.The remote sensing from space had provided a new way to understand the regional air pollution better,and the information and data from satellite observations filled up the shortcoming of those from ground observations with limited spatial coverage.Especially,the aerosol data from MODIS are useful to the research on global and regional climate.At present,the dominating method for retrieval optical depth of aerosols over land is to combine the ground monitoring data and MODIS data.Based on the dense dark vegetation method of estimating the optical depth over land surface from MODIS data,the high quality products of aerosol optical depth distribution were obtained at coastland in Southeast China.The optical thickness of inversions estimated from the sun photometer on the ground at the same time as the pass of the satellite was used to validate the retrieval from satellite data.The two data series fit very well and have high correlations,which proved that the reasonable inversions optical thickness has been obtained.Some pictures are shown which described the aerosol optical depth (AOD) distribution at coastland in Southeast China,and the characteristic of aerosols is descripted.
With emerging and prevailing of the new remote sensing images that have traditional classification methods based on pixels and spectral information of images has been not adapted to new data.Using the method of object-oriented and multi-level segmentation technique,This paper classified QuickBird remote sensing images of Heishiding Nature Reserve in Guangdong Province.The results showed that compared to traditional pixel-based classification methods,multi-level classification method based on objects can get the more accurate classification results,the more clearly classification boundary and the more uniform internal homogeneity.
Taking Shanghai region as the study areas,by using thermal infrared data of multi-sources polar orbit meteorological satellite,the research selected 264 preprocessed images to couple with the synchronous air temperature data gathered from 52 weather stations and then built two kinds of air temperature retrieval models changed with seasons and times.Results showed that the stable models for retrieving the air temperature could be constructed based on large numbers of samples from multi-sources remote sensed data,and furthermore the retrieval precision could be improved by using a field-measured data to modified the model.
Three Gorge possesses the characters of complicated terrain,frequent geologic disasters and full-grown vegetation and soil.In the paper we made analysis of lithology with a remote sensing image aiming at the area of Three Gorge,proposed a gradual concept grid algorithm,built three sorts of guideline sets of spectrum,texture and vegetation index and mined the associated rules of the lithology in T1j2.
Taking Fengqiu county which locate along lower reaches of the Yellow River as study area,the land use and landscape pattern change from 1990 to 2000 as well as its driving factors were analyzed using remote senseing,geographic information system technic,and canonical correlation methold.The results showed as follow: rural residential area and constructed land increased 2 934.87hm2 while other types of land use decreased,particularly cultivated land and water body respectively decressed 1 084.81 hm2、1 717.92 hm2.The agricultural landscape pattern is well stable with the mareix of dry land and paddy field which is always near 80% of total area.On the other hand,agricultural structure is simple and landscape diversity is low.The driving factors of land use and landscape pattern change are mainly agricultural society and economic such as population and grain production.
Based on the Landsat TM/ETM images of Xi′an in 1988,2002 and 2007,the built-up land information were extracted,the built-up land map overlaying using GIS technology,as a result ,the sprawl information and data were obtained.The sprawl data were subset by the maining road traffic map and administrative boundaty,sprawl information of inner express way around city and the district of outside suburb were obtained.This paper analyzed the city sprawl by using growth intensity index,relatively built-up land transformation rates and fractal dimension model.The research results indicates that the area of built-up land increased from 151 796 493.8m2 to 365 180 608.0m2 during the period from 1988 to 2007,which increased for 2.4 times;the sprawl of urban district concentrate on the area between the second circular road and express way around city,meanwhile the built-up land area inner the second circular road increased more slowly.The sprawl times of Chang′an district among the outside suburb districts is greatest,which expanded 7.39 times for its area from 1988 to 2007.The Lintong district and Yanliang district are lower.The fractal dimension of urban district and outside suburb district in Xi′an tend to increased in the period of 1988 to 2002,the edge of city tend to be conplexity,however,the fractal dimension decreased in the period of 2002 to 2007.The relatively built-up land transformation rates in outside suburb district is higher than urban district.The future develop trend of Xi′an is that the sprawl in urban district to be slowly while outside suburb district scale will be increase.
The earthquake occurred in the county of Wenchuan,Sichuan province on May 12th,2008 has brought huge loss in both property and lives.Road is the lifeline which is very important for disaster relief and people's life after the earthquake.Thus,it becomes one of the most significant tasks for monitoring the situation of road damage.This study selects Beichuan which was destroyed seriously in the earthquake as the study area.Utilizing high spatial resolution remote sensing images before and after the earthquake,this study recognizes roads based on object-oriented image classification technology.In addition,it extracts the sections of damaged road using two approaches,one of which is overlaying the roads extracted from images acquired before the quake with the images after the quake,while the other is applying change detection to the roads extracted from images before and after the quake.Result of this study has already submitted to correlative departments of ministry of communications and provided timely and scientific basis for the disaster relief.This pilot study shows the methods mentioned above is feasible to road damage extraction based on high-resolution airborne image and satellite images.However,further study should be done in the near future.
We select our study area of Honghe National Nature Reserve and three surrounding farms located in Sanjiang Plain in the northeast of China.Supported by the high resolution image , the authors interpret three periods' remote sensing images of this area to quantify dynamically changed information of six classes of landscape (marsh , river & pool , forest , paddy field , dry land , other types).By means of GIS methods , they analyze the changing process of this area and contrasted the classes of landscape in the middle of 70's and those in recent years with the development of local agricultural activities.In conclusion , this study shows that all kinds of landscape have experienced severe change , especially the changing process of paddy field and dry land.In addition , different changing processes occurred in four areas.Among them , sharpest decrease in wetland area has taken place in Qianfeng farm which is the earliest developed one in this area.Although a series of strict measures have been adopted , Honghe National Nature Reserve has gone through wetland degradation to some extent as a result of the space-narrowed environmental habitat and the influence of surrounding farms.
This paper is focused on Weihe River in Shaanxi Province.With conventional monitoring data of Weihe River in Shaanxi and SPOT-5 data in the same period obtained,the remote sensing data are preprocessed to set up a BP neural network model and RBF neural network model to reverse concentrations of CODcr,NH3-N,DO,CODmm.The result of experiment shows that artificial neural network used for inversing water quality parameters was effective,because artificial neural network is nonlinear,its retrieving results were much better than linear regression model.
A feasible object-oriented farm water extraction method is proposed.This approach includes the following steps.First,a multi-resolution image segmentation method combining spectral and shape features is implemented to extract image parcels.Second,a set of parcel features including spectral,shape,spatial relationships are obtained for the succeeding analyses.Third,the whole water areas and then the polygonal water areas and linear water areas are extracted with multi-feature analyses.In the last step,the farm waters are extracted by eliminating polygonal water area and linear water areas.Our method is validated with experimental analyses.
Through the MODIS sea ice remote sensing monitor principle and the sea ice inversion method, extracts sea ice element and estimates the sea ice area.Using 2004~2007 year winter MODIS remote sensing phantom, and unifies the meteorological data of the 14 weather stations on the Liaodong bay, studies the relationship of Liaodong Bay sea ice and temperature.The results show that: Liaodong Bay area of winter sea ice and temperatures have a significant negative correlation and the correlation of -0.815, by the regression equation between the two can forecast future trends in sea ice area.
Images of SPOT in 2000, 2003 and CBERS-1 in 2006 as the data sources, have been used for this study. Based on a series of image pre-processing by using the technology of RS and GIS, urban built-up area of the central of Chongqing city was extracted, as well as the speed and the spatial-temporal features of urban expansion was analyzed.The results obtained show that,urban built-up area have increased 111.14 km2, 10.48% of the annual growth rate during the 2000~2006 period. The north and northeast direction were the leading orientation of urban expansion, accounted for 60% of the total expansion area.The erosion of arable land is most prominent.The built-up area expansion and the spatial-temporal features were mainly attributed to the economic development, the proper policies of local governments and the urban planning, natural and geographical environment, as well as the development of traffic infrastructure.
The outside calibration for the Dual-antenna Airborne InSAR was researched by 3D reconstruction model.The error model based on sensitivity equations was educed by differentiating InSAR imaging equations based on adopting Sensitivity Equations.Then the biases of interferometric parameters were solved by several accurate Ground Control Points(GCPs). The calibrated interferometric parameters were calculated by iteration method.And the accurate Digital Elevation Model (DEM) was reconstructed.A set of InSAR data was adopted to do calibration experiments,which was derived by the Airborne InSAR system researched independently by Institute of Electronics,Chinese Academy of Sciences.The experimental results show that this algorithm is efficient.
The reason why the goals of true ortho rectification can not be achieved by the replacement of digital elevation model (DEM) with digital surface model (DSM) directly is discussed at first,then the primary workflow of true ortho rectification is discussed. Aiming at automatically detecting the occlusion area of buildings,its key technical matter,a solution based on z-buffer algorithm is proposed. Experimental test using ADS40 three line images shows that related algorithms put forward in this paper is correct.
To get accurate Ortho-SAR image,it is important to keep the same precision for GCP and DEM data in the process of Ortho-rectification.How to select reliable Ground Control Point (GCP) and control the precision of Ortho-model is discussed in this paper.The conclusions are drawn by comparing different Ortho-rectification process which was using Fine1 to Fine5 mode Radarsat-1 SAR images of same region and 140 GCPs gotten by GPS surveying.Some advices for processing SAR image Ortho-rectification are given at last.
In this article,taking Hengqin island as experiment region,Normal image fusion algorithms (HIS transform,Brovey transform,PCA transform,wavelet algorithm,SFIM transform and PANSHARP transform) are used to fuse the multispectral image of CBERS-02 and panchromatic image of SPOT5.In order to analyze each band of fused images and find the best fusion method by criterion,four quantitative indexes such as the average value,the entropy,the correlation coefficient,the standard difference and the gradient are computed and analyzed.Based on the PANSHARP-fused image,the land use categories are extracted by support vector machine classifier,the total classify precision is 82.55% and Kappa index value is 0.7358.The results show that by fusing the multispectral image of CBERS-02 and panchromatic image of SPOT5,both spatial and spectral resolutions can be improved,and the fused images are of wide application in various aspects such as land use monitoring and evaluation.
CBERS-02B is the first generation transmission type land resource remote sensing satellite,the sensor of which can acquire panchromatic band wave data with resolution of 2.36m.Based on the remote sensing image fusion technology,this paper fuses the SPOT-5 multispectral data of 10m resolution and the panchromatic data of CBERS-02B and SPOT-5 using multi-method.After the evaluation and comparison of the fused image spatial texture,several characteristic parameter values are got.Based on the visual evaluation and quantitative analysis,fusion image of CBERS\|02B is better than that of SPOT-5 image on spatial texture.So,the panchromatic data of CBERS-02B is high resolution data with high quality and wide prospect of application.
Based on the theory of interferometric synthetic aperture radar (INSAR),6 ENVISAR ASAR radar images from 2003 to 2007 are used to generate the coherence maps of coastal area in the middle Jiangsu Province,on different spatial scales with a resolution of 20m and 80m,respectively.The coherence features of typical urban and rural objects in the study area are analyzed.Result shows that ① the average coherence at low resolution is lower than that at high resolution,however,the former coherence contrast is higher than latter; ② the effect of spatial scale on coherence in obvious for small objects,but for objects with a large area,it is less obvious.This research result can be used to improve the accuracy of land use classification and also can help selecting the high coherent points (HCPs) which are necessary in the retrieval of ground deformation.
A method combined with automated morphological endmember extraction (AMEE) and support vector machines (SVMs) is proposed to solve sub-pixel problem.Based on morphological principle,AMEE method which integrates spatial and spectral information to select endmembers is able to provide a relatively good characterization of general landscape conditions.SVM method can be combined with pairwise coupling to output probabilities as the abundance fractions of targets.The experiments show that the method can provide better result of abundance estimation as compared with other methods.
Along with the development of satellites and sensors technology,remote sensing technology has been applied to survey and detection of gas and oil resource,acting a more and more important role.This article introduces the hydrocarbon microseepage model of gas and oil reservoirs,figuring out that hydrocarbon seeped from reservoirs can lead to abnormity of hydrocarbon concentration,oil slicks and microorganism which lives for hydrocarbon.Taking north part of South China Sea as example,we introduce three remote sensing methods of oil and gas offshore:① Calculating SST by infrared band.② Detecting oil slicks by SAR(Synthetic Aperture Radar).③ Detecting concentration of microorganism on sea surface by ocean color remote sensing,due to abnormity of sea surface spectrum led by increasing of microorganism which lives for hydrocarbon.Finally,this article brings forward some prospects for the remote sensing development of gas and oil offshore.
