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Search Results: 1 - 10 of 74408 matches for " GUO Hua-dong "
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The inversion method study of sub-canopy soil moisture estimation using repeat pass SIR-C PolInSAR data

LI Xin-wu,GUO Hua-dong,LI Zhen,CHEN Quan,

遥感学报 , 2009,
Abstract: From repeat pass SIR-C L band polarimetric SAR interferometric data and fully maximum likelihood inversion decomposition model of PolInSAR, a method for sub-canopy soil moisture estimation using repeat pass SIR-C PolInSAR data is proposed. At the same time, the potential and validity of fully maximum likelihood inversion decomposition model of PolInSAR for sub-canopy soil moisture inversion is investigated. Firstly, from the random oriented volume over ground two layer coherent scattering model and the statistical characteristics of Pol-InSAR coherency matrix, the fully maximum likelihood inversion decomposition model is used to reconstruct or recover the surface polarimetric coherency matrix with volume scattering components significantly removed; then, from recovered surface polarimetric coherency matrix, co-HH, VV and cross-HV polarization backscattering coefficient are obtained, and the sub-canopy soil moisture are inverted from Oh and Dihedral scattering model. At last, Compared the inversion result with the field measurement and the climate data of hetan region from 1951 to 2006, the preliminary result indicates that the proposed method based on fully maximum likelihood inversion decomposition model has enough high inversion accuracy, if the new spaceborne or airborne polarimetric SAR interferometric data with synchronously spaceborne or airborne-ground measurement will be acquired, the validity and accuracy of proposed inversion method will be further investigated and validated.
Developing National Earth Observing System for"Digital Earth"

GUO Hua-Dong,Yang Chong-Jun,

遥感学报 , 1999,
Abstract: This paper describes the concept and the important sig nificance of the"Digital Earth". It is pointed out that the earth observing t echnology is the key issue of the"Digital Earth". It has been suggested that China should develop the national earth observing system. The system should cons ist of three parts, i.e., information acquisition, information processing and in formation application. The development of earth observation technology, in the f irst priority, have been discussed in the article. The national earth observing system could have a great contribution for the Digital Earth.
Digital Earth and Earth Observation

CHEN Shu-peng,GUO Hua-dong,

地理学报 , 2000,
Abstract: 在21世纪到来之际,人类向“数字地球”这一地球信息科学新领域发起了挑战。这是在信息社会、知识经济、可持续发展时代背景下,由空间科学、信息科学、地球科学和环境科学的相互交融,在全球及区域尺度上的一次大整合、大聚焦。是面向21世纪地球系统科学思维模式的开拓大跳跃。对地观测技术系统的蓬勃发展,是“数字地球”的不可缺少的基础。数字地球的发展,离不开对地观测技术系统的支撑。
DEM generation and accuracy analysis on rugged terrain using ENVISAT/ASAR multi-angle InSAR data

LI Xin-wu,GUO Hua-dong,LI Zhen,

遥感学报 , 2009,
Abstract: With the successful implementation of ERS-1/2 tandem and SRTM project, InSAR has been wildly used for topographic mapping; in addition, the new global topographic mission such as TanDEM-X project is ongoing. In this paper, firstly, the impact of incidence angle on interferometric SAR DEM generation is detailed investigated from theoretical viewpoint; then, from the ENVISAT/ASAR multi-angle interferometric SAR data, the three DEMs of IS2, IS3 and IS4 swath images are generated using EvlnSAR software of EarthView; finally, the impact of layover and foreshortening on DEM accuracy at different incidence angle are compared and analyzed from quantitative and qualitative viewpoints using SRTM DEM with 90m horizontal resolution and digital topographic DEM with 1 : 50000 scale. The results indicate that : (1) the impact of incidence angle on DEM generation is significant and large differences exist in the result DEMs due to radar layover and foreshortening at different incidence angle. For example, the difference is over 6m between the DEMs extracted from IS2 and IS4 swath images. So, the incidence angle must be strictly selected when using InSAR for DEM generation in the mountain area. (2) The decorrelation is significant with the 35-day temporal, which is in prejudice of the overall DEM accuracy evaluation. If the data with large incidence angle and no temporal decorrelation is obtained, the further study and analysis will be implemented from more general quantitative and qualitative viewpoints.
Measuring the Change of Soil Moisture with Vegetation Cover Integration Passive and Active Microwave Data

LI Zhen,Guo Hua-dong,SHI Jian-cheng,

遥感学报 , 2002,
Abstract: Soil moisture is a highly variable component in land surface hydrology and plays a critical role in agriculture and hydrometeorology. It also plays an important role in the interactions between the land surface and the atmosphere, as well as the partitioning of precipitation into runoff and ground water storage. Two basic microwave approaches are used to measure soil moisture, one is passive which is based on radiometry and the other is active and uses radar. Both approaches utilize the large contrast between the dielectric constant of dry soil and water. Two systems are complementary. The passive microwave systems include frequent coverage, low data rates, and simpler data processing, but with poor resolution . In the case of the active microwave systems, the advantages include high resolution, but this comes at the expence of higher data rates and more complex processing. In this study, we showed the estimation of soil moisture with vegetation cover integrated passive and active microwave data.A total backscattering amoumt for a vegetated surface include volume, surface, and surface-volume interaction scattering terms. The direct volume scattering is considered to be controlled mainly by vegetation; surface scattering term is controlled by soil dielectric component and roughness. The backscattering model here is based on without surface-volume interaction scattering terms. Im attempt to use active microwave remote sensors in estimation of soil moisture, we are mainly facing two major problems: effects of surface roughness and vegetation cover. For a given sensor, we assume the roughness under the condition of no change during data acquisitions. The main problem for retrieval surface dielectric properties is separate the volume scattering item from total backscattering.With the time-serial soil moisture map from L band passive microwave radiomerty, the Electronically Scanned Thinned Array Radiometer (ESTAR)at Southern Great Plains 1997(SGP'97), we calculated the surface reflectivity with 800m resolution. The volume scattering items at 800m resolution can be derived using multi-temporal resample calibration Radarsat SAR and surface reflectivity data. Weighting the ratio of NDVI at different resolution from NOAA/ANHRR and TM, the surface reflectivity wity 50m resolution can be estimated according to the total backscattering and volume scattering , then soil moisture be mapped at 50m resolution. The deriving results showed the same trend of soul moisture change comparing with the field measurement.
Digital Earth GRID

XUE Yong,WANG Jian-qin,GUO Hua-dong,

遥感学报 , 2004,
Abstract: Digital Earth will be a multi resolution, four dimensional virtual representation of our planet that enables a person to explore and interact with the vast amounts of natural and cultural information gathered about the Earth. It needs Interactive 3 D visualisation, display and navigation through immersed and non immersed environments; it also needs high performance computation to create derived information and model simulations on demand, storage and real time access to very large, multi resolution datasets, fusion of satellite imagery and other geo referenced data sources of diverse content, satellite and terrestrial broadband networks for high data rate transmission, interaction, and collaboration, standards and metadata for interoperability among and access to differing geo spatial databases are inevitable. Digital Earth concept becomes an international cooperative program instead of merely one country's initiative. So far, Grid technique is the best solution for Digital Earth. Digiatl Earth can only be done through the interaction of people, heterogeneous computing resources, information systems, and instruments, all of which are geographically and organizationally dispersed. Earth observation includes information acquisition, processing and applications. Information acquisition provides a vast amount of spatial adta for building the fabric resource infrastructure. Information processing means that spatial information processing middleware is used with distributed large, secure grid computing resources for real time processing of all kinds of spatial data. With the help of GIS, we are currently working on the development of core middleware for Earth observation data processing and applications. The results will be available soon.
Effect of Forest Types Discrimination Using Multifrequency and Multipolarization Imaging Radar Images

LIAO Jing-juan,GUO Hua-dong,SHAO Yun,

中国图象图形学报 , 2000,
Abstract: The paper presents the results of discrimination and classification of Three North shelter forests using shuttle imaging radar (SIR-C/X-SAR) data in Yichuan count, Shannxi province. The forest is divided into three types coniferous, deciduous and mixed forest. The backscatter coefficients of three forest types are extracted from the SIR-C/X-SAR data, and the effect of the forest types discrimination is analyzed using multifrequency and multipolarization.
Studies on Rice Backscatter Signatures in Time Domain and Its Applications

SHAO Yun,GUO Hua-dong,FAN Xiang-tao,LIU Hao,

遥感学报 , 2001,
Abstract: Rice monitoring and production estimation has special significance to China, as rice is the staple grain and accounts for 42% of the crop production for this country. Radar remote sensing is appropriate for monitoring rice as cultivated areas are most often cloudy and rainy. SAR is anticipated to be the dominant remote sensing data source with high resolution in tropic and sub_tropical regions. It also provides re_visit schedules suitable for agricultural monitoring. This paper presents the results of a study examining the backscatter behavior of rice as a function of time using multi_temporal RADARSAT data set acquired in 1996 and 1997. A rice_type distribution map was produced, showing 4 types of rice with different life spans ranging from 80 days, to 120_125 days. The life span of a rice crop has significant impact on yield, as well as the taste and quality of the rice. The rice production of three counties and two administrative regions, totaling 5000 square kilometers, are estimated in this study. The accuracy was found to be 91%, providing confidence that multi_temporal RADARSAT data is capable of rice monitoring and production estimation. Based on the studies carried out in the Zhaoqing test site since 1993, it is suggested that rice production estimations require three radar data acquisitions taken at 3 stages of crop growth season. That is at the end of the seedling development period, in the ear differentiation period, and at the beginning of the harvest period. Alternatively, if multi_parameter radar data is available, data acquisitions may reduce to only two. That is at the end of the seedling period, and at the beginning of the harvest period. This paper also proposes a pilot scenario for operational rice monitoring and production estimation.
Speckle Suppression Using the Empirical Mode Decomposition

HAN Chun-ming,GUO Hua-dong,WANG Chang-lin,

遥感学报 , 2002,
Abstract: An effective algorithm for suppressing speckle in synthetic aperture radar(SAR)images utilizing the empirical mode decomposition(EMD)method is presented in this paper.The EMD was proposed by Norden E Huang et al .,with which any complicated data set can be decomposed into a finite and often small number of intrinsic mode functions.Contrary to almost all previous methods,this new method is intuitive,direct,a posterior and adaptive,with the basis of the decomposition based on,and derived from,the data.So EMD is quite suitable for analyzing nonlinear and non_stationary data.A line of digital SAR images can be decomposed into a series of modes whose characteristic space scale defined by the space lapse between the extrema is different.The speckle noise is defined by the mode whose space scale is not more than 4.The SAR speckle suppression is implemented by smearing short space scale component in the spatial domain via the EMD.As the EMD is one_dimensional method,we use EMD in the following way.First we process each horizontal row of pixels,then process each column pixel of image. EMD is based on and derived from the data,thus it is adaptive and can preserve the edge information.Application to SAR images has shown that the performance of the algorithm is satisfactory in both smoothing and edge preservation.
Applications of remote sensing technique in archaeology: a review

DENG Biao,GUO Hua-dong,WANG Chang-lin,NIE Yue-ping,
邓 飚

遥感学报 , 2010,
Abstract: Remote sensing technique is able to quickly detect the distribution of the sites above and below the ground, and plays a constructive role in the present archaeological work, so it becomes an important tool for archaeological investigations. This article presented the fundamental principles of the remote sensing technique in detection of sites, and then listed comprehensively the general methods used and some successful applications, and finally reviewed the its functions, constraints and future development.
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