Using MODIS surface albedo (MOD43B3 ) , vegetation indices (MOD13A 2 ) , land cover (MOD12Q 1) and land cover products during the year 2000～ 2005, the spatial and temporal distribution of surface albedo over Beijing region are investigated. Temporal variation surface albedo during 2000～ 2005 is calculated, and the relationship between the NDVI and surface albedo is checked. The results show that the surface albedo is lower in northwest mountainous area (0. 11) than in southeast plain (0. 15). The albedo over Beijing urban area ( 0. 12) is nearly equal in summer and autumn. The albedo over the Yongding River basin demonstrates high value (0. 18) for its lower vegetation cover. According to the topography and vegetation cover around Beijing area, we also find that the NDVI is negatively related to the surface albedo, and the data show that the surface albedo is descending in most part of Beijing during the six years, but ascending in mountainous areas and the urban area.
Positioning river bank is very important for channel surveying and gauging , which has significant meaning infresh water navigation, hydraulic and hydroelectric engineering building , water resource exploitation and so on. On the basis of currentr esearch on river extraction from satellite imagery and the application of deformable template model in computer vision, the paper puts forward an active contour model to extract river bank from high resolution satellite imagery . The model can take both spectrum and shape character into account and is tested on QuickBird images with 0. 6m spatial resolution in Yibin City ,Sichuan province. Rivers extracting from Landsat TM imagery and small scale maps or manual river sketch are input as the initial estimate of river bank, and these contours will be shaped as the river bank in the QuickBird image using the model. About 70 percent of the total points in the final contour locate within two-pixel distance from the accurate position, and above 90 percent are situated within five-pixel distance when the initial contour is close to the river. The result points out that introducing the mature technology in compute vision research field is very promising for feature extraction from high-resolution satellite imagery.
It is an important aspect for remote sensing applications to detect LUCC using multi-platform images and GIS auxiliary data. In the paper, the thematic information is extracted by the software eCognition which principle is object-oriented fuzzy classification. During the process of extracting thematic information, the multitude of the additional information which can be derived based on image objects: tone,shape, texture, area, context and information from other GIS layers beyond the pure spectral information.The method is more accurately than traditional classification one.In the paper, through deriving the thematic information of XingShan County using Landsat TM in 2002 and other GIS data, we find that cultivated land and forest land are two major land-used types, then obtaining the classification result of 1992 through superposing the vector layer of 2002 with remote sensing image of 1992, and dynamic change matrix of 10 years from 1992 to 2002 of XingShan County by the mathematic rule. Analyzing the dynamic matrix, forest land area expands, construction land increases and but cultivated land reduces. The economic development and the construction of Three Gorges Projects are two main factors that lead to the changes. There is firm function to the weak ecological environment of Three Gorges region to a certain extent because of the increase of the forest land area.
Regional or global land surface temperature can only be got by remote sensing technology, which is a very important parameter in many applications. L and surface temperature retrieval is a hot and difficult problem in the research of thermal infrared remote sensing, in which atmospheric correction, temperature and emissivity separation must be considered. Many research have been developed in recent years,which can be classified to 5 categories including single band method, split-window method, multi-bands temperature and emissivity separation methods, multi-angles retrieval method, and combination of multi-angles and channels, but these methods have both advantages and disadvantages. How to improve retrieval precision and models applicability are the future development trends for land surface temperature retrieval,and synthetic application of multiinformation by theory combined with experiment methods is the inevitable request.
Urban heat island is one of the most important research Contents in city environment and climate.Land surface temperature and air temperature is associated, we can get land surface temperature by remote sensing data, and it becomes one of the most important ways to research urban heat island. In this text , based on MODIS data , we calculate two important parameters: the surface emissivity and the atmospheric transmit tance, then the land surface temperature of Nanjing is calculated by means of a split-window method. Based on different temporal MODIS data, the four temporal land surface temperature scenes were contrasted, it shows the area , distribution and intensity of heat island of Nanjing , the research result shows that urban heat island effect is very serious in Nanjing city .
This research analyzes the correlativity, effect and distribution of green and thermal island of Shanghai city in recently years. By using meteorological and resources satellite data as themain information sources, combining weather and green belt observation data, adopting synchronous or quasi-synchronous observations on satellite and land, developing multifactor GIS spatial analysis patterns, the research reveals the accommodation and effects between greenbelt and air temperature of the city. The result provides the scientific foundation abou trationality plan for the governments.
Based on radar backscattering turbulence model of ocean surface caused by wave-current interaction, For weak ocean current , it simplifies the model and calculates the radar backscattering coefficient ' s turbulence caused by weak ocean current . It analyzes the relationships between the results and current field, current amplitude, wind speed, wave-current angle, radar wave band and radar incidence angle.Then it gives the turbulence characteristics. Thus this paper will provide valuable help for studying the detecting capability of radar for ocean surface current .
Due to effects of atmosphere and optical subsystem , detector and electronic subsystem in imaging system , there is degradation in imaging process. The degradation of imaging system induces imagery blur.The ability to acquire information from blurred image is debased The technique of image restoration can improve imagery quality, so it can enhance the ability to acquire information from restored image. According to the requirement of image restoration technique, high precision modulate transfer function (MTF) of imaging system is the base of high-quality imagery restored. Since there are differences of MTF between different remote sensors and at different period of same remote sensor, it is important to acquire MTF of imaging system in-flight. The paper presents systematically a in-flight measurement technique of remote sensor MTF, which is called knife edge technique. In the technique, we first analyze its principle and its requirement on targets in images, then introduce in detail several key techniques including sampling method line by line in image, registering line pixels with shif ted knife method and fitting method to acquired knife edge. After introducing the technique of image restoration based on imaging system’MTF,the paper shows the improved image on the bases of experiment. The result appears imagery quality is imp roved obviously.
As frequency divided multiplex accessis widely adopted in communication satellite system, strict frequency spectrum limits on modulator is mandated. In a wideband/ narrowband compatible communication system, bandwidth of modulated signal is variable for different coderate applications. A time-varying interpolating pulse shaped FIR is designed to provide a large coderate dynamic range and anagile coderate adjustment required by airborne remote sensing data real-time transmission system in this paper . It is implemented and optimized for FPGA, which results in a low costdigital IF transmitter that meets the performance of the system designing.
Based on the echo model of SAR , An advanced SAR raw data frequency-domain simulation method is introduced, and the time-frequency-domain simulation method of SAR raw data based on complex scenarios is presented. The formulae of the advanced SAR raw data frequency-domain simulation are deduced in detail, and the process of the complex scenario raw data simulation is shown. The results and conclusions of the simulation experiments show that the advanced SAR raw data time-frequency-domain simulation method can greatly improved the speed and accuracy of the simulation. The results and conclusions also manifest the validity of the complex scenario raw data simulation method.
Image segmentation is the basis of pattern recognition and the first step for extracting the objects automatically from image using computer. This is significant for the application and analysis of remote sensing images. These years, with an increasing amount of high resolution imager y of high quality provided,some effective segmentation methods are required for the related geoscience applications of high resolution images. However, for the unique characteristics of high resolution image, classic image segmentation methods cannot be satisfied. The methods for segmentation using in the application and analysis of remote sensing images are overviewed and analyzed. Considering the characteristics of high resolution image, the technical difficulties of segmentation for high resolution remote sensing image are analyzed, and the problems of the traditional pixel-based methods are given. Afterward, mathematic morphology method, OOA( Object Oriented Analysis) and some other methods are illustrated. These methods, which have more advantages for high resolution image segmentation, can make good use of the object s' at tributes such as tone, texture and geometry. Finally, the future development of image segmentation technology using in application and analysis of remote sensing images is put forward.
With ten scape ETM+ at the middle of Tibet , this study composed above dataset artificially and mosaicking for the resultant image. It carried out the optimization processing for mosaicking gap in order to convenient classification. This wo rk also super imposed administration boundary on the image, along with image's classification inside the boundary and statist ical analysis for classification.
The Development of Spatial Database in 21st Century provides significant new capacity for managing large volumes of image and gridded raster data in RDBMS. This paper induces the architecture and data model of GeoRaster objects in Oracle Spatial 10g and make an analysis on general application pattern using GeoRaster objects and a brief introduction on ETL , a middlew are for GeoRaster objects access and management.
This paper presents a multi-sensor image registration approach based on Hausdorff distance.Firstly, close contours of images are extracted through bottom -hat filter and threshold. Secondly Hausdorff distances between the longer contours of different maps are calculated, and contour pairs with small enough Hausdorff distance are deemedmatching contours pairs. Then the consistency checking succeeds by relative distance ratio histogram clustering based on center of contours. Finally accurate contour pairs are obtained so that image transformation parameters are attained by applying LSM in in terrelated parts. Considering speckle noise of SAR images and distortion due to multi-sensor images being taken at different time, extracted contours of SAR and optical images differ to certain extent. As Hausdorff distance allows large contour difference, the approach presented in this paper can register images of wide translational and distortional range.
The dynamic monitoring of farmland to forests project need launch into much money and in general the result of manual monitoring has a low precision. According to the requirement project monitoring ,discuss the monitoring technology of remote sensing from the sides of data sources selection, process and application. Moreover, the paper compares the new technology with conventional method and concludes that remote sensing will have a broad using in dynamic monitoring of farmland to forests project . At last ,the paper points out that fusion of multi-source data and new information extraction technology of remote image are the important developing direction of this technology in the future.
