基于奇异值分解的遥感图像鲁棒水印算法探讨     

侯翔  杨辉 《测绘科学》2015,40(7)

针对遥感图像的安全保护问题,文章提出了一种基于DCT-SVD和最近区间量化的鲁棒水印算法,将遥感图像进行分块,选择视觉掩蔽效应好的纹理子块作为嵌入区域,根据混合变换后的系数在各自所属区间上的位置,将系数进行最近区间量化来嵌入水印信息;利用密钥即可实现水印的提取,不需要原始遥感图像参与。实验结果表明,该算法对加噪、滤波、旋转、缩放、随机剪切、JPEG压缩等攻击均具有较强的鲁棒性,可有效保护遥感图像的安全。  相似文献   

昆承湖水质状况遥感监测与空间特征分析   总被引：2，自引：0，他引：2  

何磊  童玲  李玉霞 《测绘科学》2015,40(4):58-62

针对镇域水资源常规的监测方法不能满足对水质适时、大尺度的监测评价要求等问题,该文以江苏常熟辛庄镇昆承湖为例,分析叶绿素a(Chl-a)和悬浮物(SS)浓度值与水体归一化反射光谱、一阶微分反射光谱特征的关系,运用PEARSON法分析两者之间的相关性,确定Chl-a和SS的敏感波段,利用Chl-a和SS敏感波段归一化光谱反射值和实测浓度数据建立了水质参数反演模型。采用同时相ETM遥感数据对水质参数(叶绿素a和悬浮物)浓度进行遥感定量反演,并根据反演结果分析镇域水体污染空间分布特征。结果表明,对水质参数几个最大正(负)相关的光谱值进行波段组合处理可以提高反演精度,并且模型反演值和实测浓度值之间误差较低。通过对叶绿素、悬浮物等水质参数反演实现了对昆承湖水体污染状况的快速、准确和动态的信息获取和评价,有效地实时监测镇域水体在空间和时间上的变化状况和特性。  相似文献   

Land quality index assessment for agricultural purpose using multi-criteria decision analysis (MCDA)     

Tarun Kumar 《国际地球制图》2015,30(7):822-841

In this study, an attempt has been made to apply Remote Sensing (RS) and geographic information system (GIS) to determine land quality for agriculture purpose using analytic hierarchy process technique. In this study, various thematic layers were used like organic matter content, soil texture, soil depth, soil pH, soil P, soil K, geomorphology, run-off potential, slope and land use/land cover to assess the land quality index of the study area for the agriculture purpose which were generated in the RS and GIS environment. The study area can be divided into four zones, viz. high quality, moderately quality, marginally quality and low quality according to their suitability of land quality for agriculture purpose. It was found that about 39.09, 31.24, 20.41 and 9.26% of the study area falls under high quality zone, moderately quality, marginally quality and low quality zone, respectively, for agricultural purpose.  相似文献   

Remote sensing and geophysical survey applications for delineating near-surface palaeochannels and shallow aquifer in the United Arab Emirates     

Samy Ismail Elmahdy  Mohamed Mostafa Mohamed 《国际地球制图》2015,30(7):723-736

This study integrates remote sensing data and geoelectrical dipole–dipole resistivity to delineate near-surface palaeochannels and shallow aquifer in the northern part of Abu Dhabi Emirate, United Arab Emirates. The shuttle imaging radar images and shuttle radar topographic mission DEM were used to delineate near-surface palaeochannels visually based on the contrast between bright and dark tone and automatically using the eight-direction flow model. The delineated palaeochannels were validated by comparing the textural features evident from advanced land observing satellite-phased array type L-band synthetic aperture radar images and determining whether these patterns were different. Field observation and geoelectrical dipole–dipole resistivity method was used to define the depth of palaeochannels and lithology of the shallow aquifer. The remote sensing and geophysical investigations in the UAE, including the study area, indicate the presence of buried palaeochannels with south-west and north-west flow directions from Oman Mountain. The study area can be of economic importance to the local population.  相似文献   

An assessment of chlorophyll-a concentration spatio-temporal variation using Landsat satellite data,in a small tropical reservoir     

Tatenda Dalu  Timothy Dube  P. William Froneman  Mwazvita T.B. Sachikonye  Bruce W. Clegg  Tamuka Nhiwatiwa 《国际地球制图》2015,30(10):1130-1143

Traditional approaches to monitoring aquatic systems are often limited by the need for data collection which often is time-consuming, expensive and non-continuous. The aim of the study was to map the spatio-temporal chlorophyll-a concentration changes in Malilangwe Reservoir, Zimbabwe as an indicator of phytoplankton biomass and trophic state when the reservoir was full (year 2000) and at its lowest capacity (year 2011), using readily available Landsat multispectral images. Medium-spatial resolution (30 m) Landsat multispectral Thematic Mapper TM 5 and ETM+ images for May to December 1999–2000 and 2010–2011 were used to derive chlorophyll-a concentrations. In situ measured chlorophyll-a and total suspended solids (TSS) concentrations for 2011 were employed to validate the Landsat chlorophyll-a and TSS estimates. The study results indicate that Landsat-derived chlorophyll-a and TSS estimates were comparable with field measurements. There was a considerable wet vs. dry season differences in total chlorophyll-a concentration, Secchi disc depth, TSS and turbidity within the reservoir. Using Permutational multivariate analyses of variance (PERMANOVA) analysis, there were significant differences (p < 0.0001) for chlorophyll-a concentration among sites, months and years whereas TSS was significant during the study months (p < 0.05). A strong positive significant correlation among both predicted TSS vs. chlorophyll-a and measured vs. predicted chlorophyll-a and TSS concentrations as well as an inverse relationship between reservoir chlorophyll-a concentrations and water level were found (p < 0.001 in all cases). In conclusion, total chlorophyll-a concentration in Malilangwe Reservoir was successfully derived from Landsat remote sensing data suggesting that the Landsat sensor is suitable for real-time monitoring over relatively short timescales and for small reservoirs. Satellite data can allow for surveying of chlorophyll-a concentration in aquatic ecosystems, thus, providing invaluable data in data scarce (limited on site ground measurements) environments.  相似文献   

浅析地理国情基础数据采集中的问题     

江京亚 《测绘与空间地理信息》2015,(5):73-76

地理国情普查是把握本国国情、国力的一项重大调查.国情基础数据作为地理国情普查的根本,提供了认识和把握国情,评估和增强国力的重要信息.本文主要介绍了地理国情普查内业采集基础数据建库流程,总结了采集过程中应遵循的规则,提出了作业中遇到的情况和处理办法.  相似文献   

模拟退火机制下优化离散粒子群的端元提取算法     

刘飞  杨可明  魏华锋  孙阳阳  史钢强 《测绘与空间地理信息》2015,(7):37-40

针对离散粒子群优化(Discrete Particle Swarm Optimization,DPSO)端元提取算法初始种群质量差、收敛性能低且易于陷入局部最优,本文将模拟退火算法引入到DPSO的不同阶段,模拟退火算法能以一定的概率接受和舍弃新状态,使种群内粒子渐趋有序、达到平衡,收敛到全局最优,有效避免了搜索陷入局部最优。因此,该算法不仅保持了DPSO的全局组合优化特点,克服了初始种群质量差、易陷入局部最优等缺点,而且还提高了收敛速度和端元提取精度。  相似文献   

基于遥感影像的城市用地变化监测方法研究     

刘丹丹  常慧娟  刘发明 《测绘与空间地理信息》2015,(10):101-103

利用遥感技术进行动态变化监测是地理国情监测的重点研究内容之一,动态监测技术方法较多,笔者在对已有方法探讨的基础上,基于World View-2及资源三号遥感影像,提出了一种城市用地变化信息检测的多波段主成分分析方法。该方法通过线性变换生成互不相关的波段组合,对多波段主成分分析后的影像采用直方图统计法进行阈值分割,再经过滤波处理,去除干扰信息。研究结果表明,采用该方法提取两期遥感影像上的变化信息,可以实现动态变化监测。  相似文献   

基于多源多时相遥感数据的秋季菜田监测与分析——以北京市大兴区为例     

梁建平  王大山  赖科霞  李龙龙  范楠楠  陈婷  鲁艳丽 《测绘与空间地理信息》2015,(10):25-27

根据北方蔬菜种植生育期特点,选择7~8月份的高分1号(GF1)融合影像、10月份的16 m宽覆盖的GF1影像以及8月份Rapid Eye融合影像,结合耕地本底数据开展提取秋季菜田信息的技术流程研究,并对2013年和2014年大兴区秋季菜田进行了动态监测,同时结合气象等数据分析其时空分布规律和变化原因。  相似文献   

浅谈高原高寒地区遥感影像判读技巧     

张晓莉  田璐  陈宜军 《测绘与空间地理信息》2015,(12):102-104

以西藏怒江流域高原高寒地区为背景,对利用高分辨率遥感影像进行判读时经常遇到的几方面问题,运用实例分析的方法,给出了解决问题的思路,为以后的工作和类似区域遥感影像的判读提供了参考依据。  相似文献