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ETM+影像IHS融合算法改进及其土地覆盖分类实验比较 总被引：5，自引：2，他引：3
在总结PCA、IHS融合算法优缺点的基础上,发展了一种改进的IHS融合算法。利用HPF、Brovery、PCA、IHS及改进的IHS融合算法对ETM+全色和多光谱影像进行了融合实验。通过定性、定量分析比较融合影像的质量,并分别对融合后影像和原始影像进行土地覆盖非监督分类实验。选取原始影像和非监督分类精度最高的一种融合影像进行监督分类实验与比较,发现无论是非监督分类还是监督分类,改进的IHS融合影像精度均较高。 相似文献
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针对IHS融合法的融合影像相对于原多光谱影像光谱扭曲严重、小波变换融合法运算量大的缺点,依据影像成像时传感器像素间的对应关系,提出应用遥感影像空间分辨率比值关系对影像进行分块,采用离散余弦变换与IHS变换相结合的融合方法进行多光谱影像与全色影像融合,以提高遥感影像的应用能力。仿真实验表明,该方法融合结果的光谱保持性与小波变换方法相近,均优于IHS变换融合影像,对全色影像空间信息集成能力稍弱,但计算效率明显改善,适合于对大数据量的遥感影像融合。 相似文献
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鉴于IHS变换的融合影像存在光谱扭曲问题,而灰色关联度对图像边缘检测具有局限性,该文将基于灰色绝对关联度的灰色关联分析与IHS变换相结合进行影像融合。采用灰色绝对关联度检测高分辨率影像的边缘点和非边缘点,基于边缘信息确定高分辨率影像和IHS变换后的亮度分量在组合中的权值,最后通过IHS反变换实现影像加权融合。应用该算法分别对多源遥感影像进行融合处理,在提高空间分辨率的同时能够很好地保持多光谱影像的光谱信息,优于传统的IHS融合方法和基于灰色关联度的IHS融合算法。 相似文献
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基于小波变换和局部相关系数改进IHS变换的图像融合方法 总被引：3，自引：0，他引：3
为得到分辨率高、光谱畸变小的融合图像,该文根据图像处理理论和小波变换的时频局部 特性,采用Quickbird数据,对多光谱波段经IHS变换的I分量和全波段图像分别进 行小波分解,用全波段图像经小波分解得到的高频系数替换I分量小波分解的高频系数, 替换时根据图像的地物光谱特性引入局部相关系数进行有选择的高频替换.经过IHS反变换得到空间分辨率高且没有光谱畸变的融合图像. 相似文献
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遥感信息融合（Fusion）是目前遥感应用领域的一个热点问题。高分辨率的全色影像与多光谱彩色低分辨率的遥感数据叠加，可以最大限度地利用不同分辨率、不同光谱信息和不同时相分辨率的遥感信息。融合中对同一地区长江流域秭归段的TM4、3、2多光谱和TM8高分辨率的遥感影像采用了IHS变换、分辨率（主成分分析）融合方法进行了数据融合，并对不同的融合方法所得到的融合影像进行目视和统计特征的分析与评价。 相似文献
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提出一种基于差值权重和快速傅立叶变换的影像融合方法--DWF,对"北京一号"小卫星的全色和多光谱影像进行融合.该算法根据卫星影像的成像过程,通过傅立叶变换获取全色影像的高频、低频信息和多光谱影像在HIS颜色空间中分量的低频信息,由这3种信息通过基于差值权重的决策计算获得融合影像的空间信息.实验采用PCA、GS、DWF以及基于小波的HIS变换的融合方法,结果表明DWF方法优于其他融合方法,比较适合于"北京一号"卫星的全色与多光谱影像融合. 相似文献
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以SAR与SPOT多光谱影像为数据源,通过几何校正、辐射定标、降噪等数据预处理,选取PCA(Principal Component Analysis)、BT( Brovey Transform)、WT( Wavelet Transform)和HPF( High-Pass Filtering)4种方法进行融合实验,并对融合后数据以及原SPOT多光谱数据进行道路提取研究.结果表明:基于PCA和HPF方法所提取的道路特征明显,纹理清晰,错分和漏分现象不明显,道路信息效果较好;WT方法提取效果次之;BT道路提取效果相对较差;4种方法经融合后数据提取道路精度均高于原始SPOT多光谱数据,最优方法提取道路精度错分率较SPOT多光谱高达29.4％,道路提取精度相对较差的BT方法较SPOT多光谱错分率高出18％. 相似文献
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《地理与地理信息科学》2016,(2)
针对现有遥感图像融合算法存在的光谱失真及空间细节丢失的问题,提出一种非下采样Shearlet变换(NSST)与稀疏表示(SR)相结合的图像融合算法。该算法利用NSST多尺度、多方向及平移不变的特性对全色图像与多光谱图像亮度分量进行变换分解,并根据稀疏表示能够有效捕捉图像结构特征的特点,对低频分量采用基于结构相关性的稀疏表示加权融合规则,从而减少光谱失真,对高频分量则利用基于改进的拉普拉斯能量和的方法,以保留细节信息,最后通过NSST与IHS逆变换得到融合图像。实验以WorldView-2不同场景下的影像为数据源,与传统的IHS、AIHS、IHS-WV、IHS-WV-SR、IHS-NSST融合方法进行对比,结果表明:新的算法不论在视觉上还是指标参数上都得到了有效提高,光谱分辨率和空间分辨率更接近于融合参考图像。 相似文献
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利用微机和基于栅格数据的软件系统,采用主成分分析(PCA)详细分析了浙江省南部飞云江下游地区TM多波段数据的信息特征,从中找出了适合于假彩色合成和土地利用分类的最佳波段组合;利用PCA结果,进一步结合较为新颖二图象增强方法-彩色空间变换(IHS变换),讨论了TM图象PCA变换和IHS变换相互结合的优势,为研究区遥感信息的应用提供了新的技术途径;通过对TM图象信息特征分析和图象增强处理,进行了土地利用自动分类的试验.对研究区的土地利用空间结构进行了分析,并针对一些具有区域特点、专题信息进行了提取和分析,提出了一些可供当地政府决策参考的区域发展建议. 相似文献
10.
基于MODIS 数据的长江三角洲地区土地覆盖分类 总被引：9，自引：0，他引：9
长江三角洲地区是我国经济最发达的地区之一, 人类活动对自然环境产生了很大影响。为了研究该地区人类活动与生态环境的相互作用, 利用250 m 分辨率MODIS 数据进行土地 覆盖制图研究, 采用的主要数据为增强型植被指数EVI 数据、反射率数据和DEM 数据。通过基于时间序列的滤波方法消除EVI 的噪声, 通过PCA 变换压缩数据量, 并计算均质度来表征空间维的纹理信息, 构造了一个综合性的分类数据矩阵, 依据高分辨率影像选取了训练区, 采用最大似然法进行分类, 并采用缓冲区分析技术进行分类修正, 得到长江三角洲地区的土地覆盖分类结果。利用高分辨率影像解译信息对分类结果进行了精度评价, 并将分类结果与 MODIS 土地覆盖产品进行了对比, 精度分析表明分类结果很好的反映了研究区的土地覆盖信息, 显示了本研究分类方法与技术处理在实践中的可行性及250 m 分辨率EVI 时间序列数据在区域尺度土地覆盖分类方面的优势与潜力。 相似文献
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《The Professional geographer》1988,40(4):471-499
Books reviewed in this article: USA, Eine Geographische Landeskunde , Vol. I, Der Grossraum in Strukturellem, Wandel, 3rd Ed. Helmut Blume . Introduction to Remote Sensing . James B. Campbell . The Sounds of People and Places: Readings in the Geography of American Folk and Popular Music . George O. Carney , ED. Development and Underdevelopment . John Cole . Mobility and Employment in Urban Southeast Asia: Example from Indonesia and the Philippines . Michael A. Costello , Thomas R. Leinbach , AND Richard Ulack . Soviet Asia: Economic Development and National Policy Choices . Leslie Dienes . The Third World City . David Drakakis -Smith . Scholars' Guide to Washington, DC for Cartography and Remote Sensing Imagery (maps, charts, aerial photographs, satellite images, cartographic literature and geographic information systems). Ralph E. Ehrenberg . Population and Development in the Third World . Allan AND Anne Findlay . The Early Mapping of Hawaii . Gary L. Fitzpatrick . Energetics of Physical Environment: Energetic Approaches to Physical Geography . K. J. Gregory , ED. Wildland Recreation: Ecology and Management . William E. Hammitt and David N. Cole . Agricultural Commercialization and Government Policy in Africa . J. Hinderink AND J. J. Sterkenburg . The Dynamics of American Housing . James W. Hughes AND George Sternlieb . Thailand: Buddhist Kingdom as Modern Nation State . Charles F. Keyes . Resolving Locational Conflict . Robert W. Lake , ED. Lands at Risk in the Third World: Local-level Perspectives . Peter D. Little and Michael M. Horowitz , EDS. Nathaniel Southgate Shaler and the Culture of American Science . David N. Livingstone . Regions: The Economics and Politics of Territory . Ann R. Markusen . Wetlands . William J. Mitsch and James G. Gosselink . Historical Geography: Progress and Prospect . Michael Pacione , ED. Loess and Periglacial Phenomena . Marton P$eacsi and Hugh M. French , EDS. Regional Management of Metropolitan Floodplains, Experience in the United States and Abroad . Rutherford H. Platt , ED. Human Cartography: Mapping the World of Man . Janos Szegö . Atlas of Great Lakes Indian History . Helen H. Tanner , ED. The Botany of Mangroves . P. B. Tomlinson . Urban Spatial Traffic Patterns . Rodney Vaughan . The Night After … Climatic and Biological Consequences of a Nuclear War . Yevgeni Velikhov , ED. Industrial Geography . H. D. Watts . Dictionary of Quotations in Geography . James O. Wheeler and Francis M. Sibley . Vermont Townscape . Norman Wiliams , Jr. , Edmund K. Kellogg and Peter M. Lavigne . 相似文献
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P. Guilizzoni A. Marchetto A. Lami N. G. Cameron P. G. Appleby N. L. Rose Ø. A. Schnell C. A. Belis A. Giorgis L. Guzzi 《Journal of Paleolimnology》1996,15(3):245-264
A palaeoecological study of an oligotrophic alpine lake, Paione Superiore (Italy), provided a record of historical changes in water quality. Historical trends in lake acidification were reconstructed by means of calibration and regression equations from diatoms, chrysophycean scales and pigment ratios. The historical pH was inferred by using two different diatom calibration data sets, one specific to the alpine region. These pH trends, together with the record of sedimentary carbonaceous particles and chironomid remains, indicate a recent acidification of this low alkalinity lake.Concentration of total organic matter, organic carbon, nitrogen, biogenic silica (BSiO2), chlorophyll derivatives (CD), fucoxanthin, diatom cell concentration and number of chironomid head capsules increased during the last 2–3 decades. When expressed as accumulation rates, most of these parameters tended to decrease from the past century to c. 1950, then all except P increased to the present day. A marked increase in sedimentary nitrogen may be related to atmospheric pollution and to the general increases in output of N in Europe. High C/N ratios indicate a prevailing allochthonous source of organic matter.Finally, the increase in measured air temperature from the mid-1800's appeared to be related to lake water pH before industrialization: cold periods generally led to lower pH and vice-versa. The more recent phenomenon of anthropogenic acidification has apparently decoupled this climatic-water chemistry relationship. 相似文献
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K. F. Walker I. G. Dunn D. Edwards T. Petr H. Z. Yang 《International Journal of Salt Lake Research》1995,4(3):169-222
Quinghai Hu is a large, high-altitude, saline lake in north-western China, and supports a fishery based on an endemic species of naked carp (snow trout). The fish take seven years to attain maturity and a marketable weight of 300 g, and have a lifespan of 14–21 years under the present fishery regime. They seasonally migrate from the lake to spawn over the gravel beds of inflowing rivers, but these areas have been reduced by weirs and irrigation diversions and recruitment may have declined. The population may have been affected also by a 1.85-m fall in the lake level over the past 30 years, and by associated changes in salinity. The fishery was opened to large-scale exploitation in 1958. Yields declined sharply (max. 28,523 tonnes, 1960) as the larger, older fish were removed, and then more slowly (min. 2523 tonnes, 1983). Since 1987 the fish factory has been limited to an annual quota of 1200 tonnes, taken by a fleet of four pair trawlers. Another 800 tonnes are taken by licensed fishermen, mainly using gill nets, and perhaps 1000 tonnes are taken illegally. The estimated total catch in 1992 was 3000 tonnes. New trawlers introduced in 1989–90 substantially increased the factory's catch per unit effort, and in 1990 the quota was virtually filled in one month in a zone within 20 km of the factory. Although this could suggest that the stocks will be conserved if the quota is retained, at least half of the catch in 1989–92 consisted of immature individuals. Trawling operations recently were suspended following a further decline in the catch after 1992. While the new trawlers are capable of a major increase in effort, neither the changing environment, the fish stocks or the present markets favour intensified pressure. Gillnets may provide better control over the minimum size limit and may cause less damage than trawling. Other options to improve the viability and profitability of the fishery include improvements in handling, processing and marketing. Failure to develop the fishery may encourage attempts to introduce exotic fish, at some risk to survival of the local species. 相似文献
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Chironomidae (Diptera) remains in surficial lake sediments from the Canadian Cordillera: analysis of the fauna across an altitudinal gradient 总被引：3，自引：0，他引：3
The altitudinal distribution of Chironomidae (Diptera) in the southern Canadian Cordillera was analyzed by means of head capsules preserved in surficial sediments of 30 lakes. Taxa characteristic of late-glacial deposits of southern, coastal British Columbia are extant at high elevations, particularly in the Rocky Mountains, and in large, deep, low-elevation lakes. Many chironomid taxa common at low elevations in the southern Canadian Cordillera were not found in alpine and upper subalpine lakes. These faunal differences are probably climatically related. The differences in fauna between high and low-elevation lakes parallel differences between arctic and temperate lakes. 相似文献
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MATT K. MATSUDA 《Geographical review》2007,97(2):230-243
ABSTRACT. Narratives concerning Pacific Ocean territories are often historically derived from European and American mainland visions of great, empty oceans dotted with deserted and uninhabited islands. However, research by indigenous and outlander scholars, along with struggles for political and cultural autonomy in the Pacific, has brought attention to vital island communities and 6has raised questions about a Pacific‐island way of understanding the world. This understanding is traced through scholarly and artistic engagements with history, island‐community studies, and navigational philosophies and is framed by a growing theoretical literature on epistemologies of place from the disciplines of geography and oceanography. 相似文献
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Precipitation is an important component of global water and energy transport and a major aspect of climate change. Due to the scarcity of meteorological observations, the precipitation climate over Tibet has been insufficiently documented. In this study, the distribution of precipitation during the rainy season over Tibet from 1980 to 2013 is described on monthly to annual time scales with meteorological observations. Furthermore, four precipitation products are compared to observations over Tibet. These datasets include products derived from the Asian Precipitation-Highly-Resolved Observational Data(APHRO), the Global Precipitation Climatology Centre(GPCC), the University of Delaware(UDel), and the China Meteorological Administration(CMA). The error, relative error, standard deviation, root-mean-square error, correlations and trends between these products for the same period are analyzed with in situ precipitation during the rainy season from May to September. The results indicate that these datasets can broadly capture the temporal and spatial precipitation distribution over Tibet. The precipitation gradually increases from northwest to southeast. The spatial precipitation in GPCC and CMA are similar and positively correlated to observations. Areas with the largest deviations are located in southwestern Tibet along the Himalayas. The APHRO product underestimates, while the UDel, GPCC, and CMA datasets overestimates precipitation on the basis of monthly and inter-annual variation. The biases in GPCC and CMA are smaller than those in APHRO and UDel with a mean relative error lower than 10% during the same periods. The linear trend of precipitation indicates that the increase in precipitation has accelerated extensively during the last 30 years in most regions of Tibet. The CMA generally achieves the best performance of these four precipitation products. Data uncertainty in Tibet might be caused by the low density of stations, complex topography between the grid points and stations, and the interpolation methods, which can also produce an obvious difference between the gridded data and observations. 相似文献
20.
Jean-Claude Plaziat 《Journal of Paleolimnology》1993,8(2):163-169
Potamids generally live in estuaries, lagoons, and along protected sea shores. However, their ability to colonize intracontinental lakes has been underestimated due to non- or misidentifications. Potamides conicus, the only present lacustrine Potamid currently found in North Africa, belongs to a lagoon-type (thalassoid) malacofauna, dominated by the Cardium Cerastoderma glaucum: this fauna occurs in association with Foraminifera (especially Ammonia beccarii) and Ostracoda (Cyprideis gr. Torosa). Potamids have been found 250 to 900 km from the nearest sea shore: passive dispersal (probably through birds) is the primary dispersal mechanism. Shell morphology and ornamentation can be used to characterize life environment (lacustrine versus marine) but not distance from sea shore. The presence of Potamid-Foraminifera fauna in the fossil record has been interpreted as providing evidence for a sea connection (e.g., gulfs, lagoons). However, more recent paleoecological studies have demonstrated that such assemblages span an ecological gradient from freshwater to hypersaline lacustrine environments. Thus, the occurrence of modern Potamids in lacustrine (in addition to maritime) environments has important implications for Quaternary and Tertiary paleogeographic investigations. Lacustrine Potamids have been recorded from the European Tertiary (France, Spain) and from the Sahara Holocene. More research is required for the better understanding of the distribution and ecology of Potamids in modern and fossil lakes of other continents.This publication is the fifth of a series of papers presented at the Conference on Sedimentary and Paleolimnological Records of Saline Lakes. This Conference was held August 13–16, 1991 at the University of Saskatchewan, Saskatoon, Canada. Dr Evans is serving as Guest Editor. 相似文献