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4th ISPRS geospatial Week 2019

作者： Feng, R. Li, X. Shen, H. School of Resource and Environmental Sciences Wuhan University China School of Remote Sensing and Information Engineering Wuhan University China Collaborative Innovation Center of Geospatial Technology Wuhan University China Key Laboratory of Geographic Information System Ministry of Education Wuhan University China

Mountainous remote sensing images registration is more complicated than in other areas as geometric distortion caused by topographic relief, which could not be precisely achieved via constructing local mapping functions in the feature-based framework. Optical flow algorithm estimating motion of consecutive frames in computer vision pixel by pixel is introduced for mountainous remote sensing images registration. However, it is sensitive to land cover changes that are inevitable for remote sensing image, resulting in incorrect displacement. To address this problem, we proposed an improved optical flow estimation concentrated on post-processing, namely displacement modification. First of all, the Laplacian of Gaussian (LoG) algorithm is employed to detect the abnormal value in color map of displacement. Then, the abnormal displacement is recalculated in the interpolation surface constructed by the rest accurate displacements. Following the successful coordinate transformation and resampling, the registration outcome is generated. Experiments demonstrated that the proposed method is insensitive in changeable region of mountainous remote sensing image, generating precise registration, outperforming the other local transformation model estimation methods in both visual judgment and quantitative evaluation. © Authors 2019.

关键词： Optical flows

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Improved calibration method of the airborne polarimetric SAR

Improved calibration method of the airborne polarimetric SAR

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2011 3rd International Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2011

作者： Ming, Feng Hong, Jun Zhang, Lintao Institute of Electronics Chinese Academy of Sciences Beijing 100190 China Key Laboratory of Geo-spatial Information Processing and Application System Technology CAS Beijing 100190 China National Key Laboratory of Microwave Imaging Technology Beijing 100190 China Graduate University of the Chinese Academy of Sciences Beijing 100039 China

ISBN: (纸本)9788993246179

The PolSAR system must be calibrated before obtain effective polarimetric information. The airplane attitude is unstable during the PolSAR measurement, which will impact the polarimetric calibration precision. This paper improved the polarimetric calibration method proposed by Whitt considering the impact of airplane attitude. The improved method is proved by polarimetric experiment using a PolSAR system developed by IECAS(Institute of electronics, Chinese Academy of Sciences). © 2011 KIEES.

关键词： Calibration

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Extreme environmental risk assessment of Tibetan Plateau based on ArcGIS 5

Extreme environmental risk assessment of Tibetan Plateau bas...

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5th International Conference on Geoscience and Remote Sensing Mapping, ICGRSM 2023

作者： Wang, Xia Jin, Sunmei Yang, Xiaoying Li, Lin Qinghai Provincial Key Laboratory of Geospatial Information Technology and Application Qinghai Xi'ning810001 China Qinghai Geographic Information Industry Development Co. LTD. Xining810001 China School of Geographical Science Qinghai Normal University Qinghai Xi'ning810001 China

ISBN: (纸本)9781510672789

The Qinghai-Tibet Plateau's harsh natural environment poses a significant risk to life, making environmental risk assessment crucial for developing comprehensive risk prevention measures. In order to establish the Extreme Environment Index (EEI) zone for the Qinghai-Tibet Plateau, a geographically weighted regression model was utilized in this study. Various natural factors, such as altitude, relief degree of the land surface, land cover index, temperature-humidity index, river network density index, human comfort, wind-chill index, and absolute oxygen content, were carefully chosen for analysis. The research findings reveal a range of EEI scores between 0.37 and 4.39 across the Tibetan Plateau, signifying a gradual intensification of environmental extreme conditions from the southeast to the northwest regions. The Changtang plateau stands out as the most environmentally extreme region, covering the largest area on the Qinghai-Tibet Plateau. This area is characterized by numerous mountains, which contribute significantly to its proportion. On the other hand, the zone with relatively milder environmental extremes encompasses the river valleys along the plateau's periphery and the Hengduan Mountains. Among these areas, the Tibet-South Valley stands out as having the least extreme environmental conditions, occupying the smallest geographical area. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Regression analysis

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A METHOD OF AIRBORNE INSAR DEM RECONSTRUCTION IN LAYOVER AREAS

A METHOD OF AIRBORNE INSAR DEM RECONSTRUCTION IN LAYOVER ARE...

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IEEE International Geoscience and Remote Sensing Symposium

作者： Fangfang LI Bing HAN Xue LIN Donghui HU Chibiao DING Key Laboratory of Geo-Spatial Information Processing and Application System Technology Chinese Academy of Sciences

ISBN: (纸本)9781467311601

The layover phenomenon of SAR imaging arises when different height contributions collapse in the same range-azimuth resolution cell, due to the presence of strong terrain slopes or discontinuities in the scenarios. Because of the phase discontinuities, for single baseline interferometric SAR, it is difficult to recover the accurate unwrapped phase in layover areas by traditional phase unwrapping methods. In this paper, according to the phase characteristic of layover areas, we propose a new method to retrieve unwrapped phase based on local frequency estimate. It can avoid the unwrapping error resulted from the phase jump at the edge of layover areas. As a result, relative accurate DEM of layover areas can be reconstructed, which is beneficial to afterward geocoding in InSAR topographic mapping.

关键词： SAR interferometry Layover Interferometric phase DEM reconstruction Local frequency estimate phase step resolution cell local frequency Synthetic aperture radar discontinuities Phase indium Radar polarimetry Geocoding Topographic Mapping Reconstructions PHASE LAG CHARACTERISTIC

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Generation of 12th order harmonic mode-locking in a Nd-doped single-mode all-fiber laser operating at 0.9μm

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Chinese Optics Letters 2023年第1期21卷 97-103页

作者：张斌李平刘兆军李明刘靖赵浩旭胡琼宇陈晓寒 Center for Optics Research and Engineering Key Laboratory of Laser&Infrared SystemMinistry of EducationShandong UniversityQingdao 266237China School of Information Science and Engineering Shandong Provincial Key Laboratory of Laser Technology and ApplicationShandong UniversityQingdao 266237China

Based on the Nd-doped single-mode fiber as the gain medium,an all-fiber 12th harmonic mode-locked(HML)laser operating at the 0.9μm waveband was obtained for the first time,to the best of our knowledge.A mandrel with a diameter of 10 mm was employed to introduce bending losses to suppress mode competition at 1.06μm,which resulted in a suppression ratio of up to 54 *** 1st–12th order HML pulses with the tunable repetition rate of 494.62 kHz–5.94 MHz were obtained in the mode-locked laser with a center wavelength of∼904 *** addition,the laser has an extremely low threshold pump power of 88 *** the best of our knowledge,this is the first time that an HML pulse has been achieved in a 0.9μm Nd-doped single-mode all-fiber mode-locked laser with the advantages of low cost,simple structure,and compactness,which could be an ideal light source for two-photon microscopy.

关键词： Nd-doped fiber laser harmonic mode-locking bending loss nonlinear polarization rotation low repetition rate

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An advanced 2-D spectrum for high-resolution and MEO spaceborne SAR

An advanced 2-D spectrum for high-resolution and MEO spacebo...

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2009 Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2009

作者： Huang, Lijia Qiu, Xiaolan Hu, Donghui Ding, Chibiao Key Laboratory of Spatial Information Processing and Application System Technology China Institute of Electronics Chinese Academy of Sciences 19 Beisihuanxi Road Beijing 100190 China Graduate University of Chinese Academy of Sciences Beijing 100039 China

ISBN: (纸本)9781424427314

In this paper, an advanced range equation is presented for high-resolution and medium-earth-orbit (MEO) synthetic aperture radar (SAR). Besides an additional linear component, this new equation has a similar formalism to conventional hyperbolic range equation (CHRE), so is called the advanced hyperbolic range equation (AHRE). Incorporating with this additional linear coefficient and the other two parameters, the cubic Taylor series expansion of AHRE has exactly the same value as which of the actual range history. Furthermore, a two-dimensional (2-D) spectrum based on AHRE is derived, which is useful for developing efficient SAR algorithms. Simulations validate AHRE and show its advantages in high-resolution and MEO spaceborne SAR cases. ©2009 IEEE.

关键词： Synthetic aperture radar

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Effect of land prices on the spatial differentiation of housing prices:Evidence from cross-county analyses in China

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Journal of Geographical Sciences 2018年第6期28卷 725-740页

作者： WANG Shaojian WANG Jieyu WANG Yang Guangdong Provincial Key Laboratory of Urbanization and Geo-simulation School of Geography and PlanningSun Yat-sen UniversityGuangzhou 510275China Guangdong Open Laboratory of Geospatial Information Technology and Application Guangzhou Institute of GeographyGuangzhou 510070China

This study analyzes the spatial patterns and driving forces of housing prices in China using a 2,872-county dataset of housing prices in *** theoretical perspec-tives on housing demand,supply,and market,are combined to establish a housing price model to explore the impact of land prices on housing *** relative impacts of land prices on housing prices at different administrative levels are then analyzed using the geo-graphical detector ***,the influencing mechanism of land prices on housing prices is *** main conclusions are as follows.(1)Housing prices have a pyra-mid-ranked distribution in China,where higher housing prices are linked to smaller urban populations.(2)Land prices are the primary driver of housing prices,and their impacts on housing prices vary over different administrative *** be specific,the effect of land prices is the strongest in the urban districts of provincial capital cities.(3)The internal influ-ence mechanisms for land prices driving housing prices are:topographic factors,urban con-struction level,the agglomeration degree of high-quality public service resources,and the tertiary industrial development *** urban land supply plan(supply policies)is the in-trinsic driver that determines land prices in cities;through supply and demand,cost,and market mechanisms,land prices then impact housing prices.

关键词： housing prices land prices influencing factors spatial differentiation county unit China

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What Drives the Decadal Variability of Global Tropical Storm Days from 1965 to 2019?

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Advances in Atmospheric Sciences 2022年第2期39卷 344-353页

作者： Yifei DAI Bin WANG Weiyi SUN Key Laboratory of Meteorological Disaster of Ministry of Education and Earth System Modeling CenterNanjing University of Information Science and TechnologyNanjing 210044China International Pacific Research Center University of Hawaii at ManoaHonoluluHI 96822USA Department of Atmospheric Sciences School of Ocean and Earth Science and TechnologyUniversity of Hawaii at ManoaHonoluluHI 96822USA Key Laboratory for Virtual Geographic Environment.Ministry of Education State Key Laboratory Cultivation Base of Geographical Environment Evolution of Jiangsu ProvinceJiangsu Center for Collaborative Innovation in Geographical Information Resource Development and ApplicationSchool of Geography ScienceNanjing Normal UniversityNanjing 210023China

The tropical storm day(TSD)is a combined measure of genesis and *** reflects tropical cyclone(TC)overall activity,yet its variability has rarely been studied,especially *** we show that the global total TSDs exhibit pronounced interannual(3-6 years)and decadal(10 years)variations over the past five-to-six decades without a significant *** leading modes of the interannual and decadal variability of global TSD feature similar patterns in the western Pacific and Atlantic,but different patterns in the Eastern Pacific and the Southern Indian *** interannual and decadal leading modes are primarily linked to El Ni?o-Southern Oscillation(ENSO)and Pacific Decadal Oscillation(PDO),*** TSDs-ENSO relationship has been steady during the entire 55-year period,but the TSDs-PDO relationship has experienced a breakdown in the 1980 *** find that the decadal variation of TSD in the Pacific is associated with the PDO sea surface temperature(SST)anomalies in the tropical eastern Pacific(PDO-E),while that in the Atlantic and the Indian Ocean is associated with the PDO SST anomalies in the western Pacific(PDO-W).However,the PDO-E and PDO-W SST anomalies are poorly coupled in the 1980 s,and this"destructive PDO"pattern results in a breakdown of the TSDs-PDO *** results here have an important implication for seasonal to decadal predictions of global TSD.

关键词： tropical storm days(TSDs) interannual and decadal variations El Ni?o-Southern Oscillation Pacific Decadal Oscillation(PDO)

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REMOTE SENSING IMAGE COMPRESSION BASED ON DOUBLE-SPARSITY DICTIONARY LEARNING AND UNIVERSAL TRELLIS CODED QUANTIZATION

REMOTE SENSING IMAGE COMPRESSION BASED ON DOUBLE-SPARSITY DI...

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IEEE International Conference on Image Processing

作者： Xin Zhan Rong Zhang Dong Yin Anzhou Hu Wenlong Hu Department of Electronic Engineering and Information Science University of Science and Technology of China Hefei 230027 China Key Laboratory of Geospatial Information Processing and Application System Technology Chinese Academy of Sciences Beijing 100190 China

ISBN: (纸本)9781479923427

In this paper, we propose a novel remote sensing image compression method based on double-sparsity dictionary learning and universal trellis coded quantization (UTCQ). Recent years have seen a growing interest in the study of natural image compression based on sparse representation and dictionary learning. We show that using the double-sparsity model to learn a dictionary gives much better compression results for remote sensing images, the texture of which is much richer than that of natural images. We also show that the compression performance is improved significantly when advanced quantization and entropy coding strategies are used for encoding the sparse representation coefficients. The proposed method outperforms the existing dictionary-based image coding algorithms. Additionally, our method results in better rate-distortion performance and structural similarity results than CCSDS and JPEG2000 standard.

关键词： Dictionary learning image compression remote sensing universal trellis coded quantization

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Improve spaceborne SAR geometric accuracy using DORIS

Improve spaceborne SAR geometric accuracy using DORIS

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IET International Radar Conference 2009

作者： Jiayin, Liu Wen, Hong Yueguan, Lin Key Laboratory of Technology in Geo-spatial Information Processing and Application System Institute of Electronics Chinese Academy of Sciences Beijing 100190 China National Key Laboratory of Microwave Imaging Technology Institute of Electronics Chinese Academy of Sciences Beijing 100190 China Graduate University Chinese Academy of Sciences Beijing 100190 China

ISBN: (纸本)9781849190107

The paper analyzes the effects of the orbit position errors in terms of the geometric accuracy of the space-borne SAR based on the range-Doppler method. The paper gives the simulation experiment results of the space-borne SAR geometric accuracy using DORIS, GPS and MADRAS. The results show the space-borne SAR geometric accuracy is 1 meter using DORIS, 80 meter higher than using MADRAS, and 50 meter higher than using GPS.

关键词： Geometry

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