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1.
由于遥感数据越来越丰富,不同传感器获取的影像数据在几何、光谱和空间分辨率等方面存在着一定的局限性和差异性。全色波段和多光谱影像融合得到的影像,兼有全色波段的高空间分辨率和多光谱影像的高光谱分辨率特性,可以满足影像解译的需求,而且融合后更能突出影像的某些特征:如土地利用变化和森林覆盖的变化等等。本文主要是介绍遥感影像融合的基本原理、融合后影像的评定和分析,并且将以主成份影像融合、IHS变换与直方图匹配法的遥感影像融合,进行以南昌市部分地区Quickbird全色影像和多光谱影像的融合实验分析。 相似文献
2.
高光谱遥感是高光谱分辨率遥感的简称,它是在电磁波谱的光学波段,主要包括可见光、近红外、短波红外和热红外波段范围,获取许多非常窄的光谱连续影像数据的技术.高光谱遥感的出现是遥感界的一场革命,它使本来在宽波段遥感中不可探测的物质在高光谱遥感中能被探测,其巨大意义已经得到世界范围内的公认,相对于可见光和短波红外,在热红外谱段进行高光谱遥感研究具有独特优势. 相似文献
3.
基于改进遗传算法的高光谱图像波段选择 总被引：3，自引：0，他引：3
在对地观测领域,高光谱图像得到了广泛应用,但存在数据量大、波段间相关性高等问题. 针对以上问题分析了已有的波段选择方法,提出了基于信息量及类间可分离性准则的遗传算法对高光谱图像进行波段选择:构造波段互相关系数矩阵进行子空间划分;利用联合熵作为组合信息量的标准,Bhattacharyya距离作为类间可分离性标准,构造遗传算法的适应度方程,改进了遗传算法中的选择算子. 最后用AVIRIS图像对提出的算法进行试验,并利用最大似然分类法对最优波段组合进行分类,总体分类精度达到94.24%,Kappa系数达到0.94. 相似文献
4.
在遥感技术中,测定地面上不同物体的光谱反射特性,对选择传感器的最佳工作波段起了十分重要的作用,这说明遥感图像上的信息与地物反射光谱之间是有密切联系的。因此为了对图像作更准确的分析和判读,测定不同地物的光谱反射特性也是重要的。当测得了反射光谱数据后,如何应用于判读,必须解决光谱反射特性与图像密度之间的对应关系。目前我们尚未见到有关这方面工作的报道。 相似文献
5.
QuickBird遥感影像的融合及在农业园区底图制作中的应用研究 总被引：4，自引：0，他引：4
应用比值变换、IHS变换、主成分变换和合成比值变量变换等4种影像融合方法对QuickBird多光谱和全色遥感影像进行融合,并利用偏差指数、平均梯度等指标对融合效果进行定量评价;运用最佳指数因子确定参与成图的多光谱影像的波段．研究结果表明,合成比值变量变换法的融合效果最佳;最优波段组合为431,并在此基础上建立了地物判读分析依据,用于QuickBird遥感影像目视解译;采用容差格网矢量化技术进行遥感影像的屏幕矢量化,制作了1：2000比例尺农业园区底图。 相似文献
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7.
以柑橘树冠层光谱为例,通过对HJ-1A星HSI传感器所采集的柑橘高光谱遥感数据与ASD便携式手持光谱仪所采集的地面实测柑橘冠层光谱进行比较,旨在探究HJ-1A星高光谱数据反演柑橘光谱的可靠性与适用性。结果表明:ASD与HSI数据的柑橘光谱反射率存在差异,尤其在红光波段和近红外波段有显著差异;ASD数据的光谱反射和吸收特征都较HSI数据明显;ASD与HSI数据的柑橘光谱变量特征也存在差异,尤其是黄光波段微分值造成的光谱变量差异最明显。因此,在进行小区域尺度柑橘光谱研究时不宜采用HSI测得的柑橘冠层反射光谱数据,但通过适当地改进HSI数据预处理方法,在大区域尺度上HSI数据能较为准确地表现柑橘光谱吸收、反射、红边等特征,可以应用于柑橘植被指数的反演研究。 相似文献
8.
在对海量高光谱遥感图像数据库进行挖掘的过程中,容易出现数据缺失与噪声干扰的情况,导致传统主元分析方法由于依据数据差异特征进行挖掘,无法实现海量高光谱遥感图像数据库的高效挖掘,提出一种时空二维联合的海量高光谱遥感图像数据库挖掘方法,分析了海量高光谱遥感图像数据库的挖掘原理,将数据库与背景结合起来,获取最佳分组次数,依据所提方法的基本原理,采用Apriori算法对高光谱遥感图像层与层之间的关系进行处理,按照顺序对由查询方案引起的候选数据存储空间的干扰进行消除,引入空间维度,完成各种监测点的层次划分,采用适应度函数对所提方法的效率进行改进,避免陷入局部最优解,从而实现海量高光谱遥感图像数据库的高效挖掘。实验结果表明,所提方法具有很高的挖掘效率和精度。 相似文献
9.
长春南湖水体透明度高光谱定量模型研究 总被引：2，自引：0，他引：2
透明度是衡量水质优劣、评价湖泊富营养化的一个重要指标，高光谱遥感可有效反演透明度，较好解决了常规遥感中出现的问题。本研究利用野外高光谱仪在长春南湖夏季进行了反射光谱测量和同步水质采样分析，通过分析水体透明度与其高光谱反射率之间的相关关系，尝试采用多种半经验算法建立透明度高光谱定量模型，并进行了验证。结果表明：1）单波段、波段比值和一阶微分反演模型，确定性系数皆在0.74以上，RMSE小于透明度极值差，因此皆可以用于反演透明度；2）模型精度从高到低依次为：一阶微分模型、单波段模型和波段比值模型。该定量模型的建立，为今后利用成像光谱数据在南湖进行透明度大面积遥感反演研究提供了研究基础和科学依据，对内陆水体透明度反演也有一定的借鉴意义。 相似文献
10.
阐述了雾的辐射特性及遥感监测的基本原理。借助具有高光谱分辨率的MODIS数据,对雾与其他背景（地表、水体、云）的光谱特性进行分析比较,得到有利于夜间雾检测的波段。利用分析结果给出多通道综合阈值法检测大雾的流程,并用此方法进行了个例分析。 相似文献
11.
A research group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol-a chemical found in the skins of red grapes in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said. 相似文献
12.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
13.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
14.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
15.
Active biological molecules functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery disease diagnosis therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction. 相似文献
16.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
17.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
18.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
19.
Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment. 相似文献
20.
Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献