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基于Landsat-8的遥感影像分类研究 总被引:1,自引:0,他引:1
遥感影像分类在专题信息提取、地表动态监测以及专题地图制作等应用中具有重要作用,传统的分类方法可以分为监督分类和非监督分类,因算法成熟、操作简单,这两类方法仍然是当前使用较广泛的分类方法,但从理论、过程以及使用范围条件上二者都不相同,各有其优缺点。鉴于这种现状,本文采用Landsat-8 OLI焦作地区遥感数据分别基于监督与非监督中的各种算法进行土地覆盖分类,并对分类结果进行比较分析和精度评价,以期为实际工作中根据不同需求选取适当分类器提供依据。研究结果表明:监督分类中最大似然法分类精度相对较高,漏分错分最少,总体分类精度达到87.152%;非监督分类中ISODATA算法从聚类效果、漏分错分以及计算时间上综合分析要优于K-均值分类;另外,不同分类算法对不同地物类型的解译效果不同。 相似文献
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基于SOM神经网络的城市土地覆盖遥感分类研究 总被引:1,自引:0,他引:1
土地覆盖及其变化的研究作为区域及全球环境变化研究所需的极为重要的地表参数,是遥感应用分析的主要内容之一。以往所采用的遥感分类方法主要针对侧重于土地社会属性的土地利用类型的分类研究且很难获得理想的精度。本文在非监督的自组织映射神经网络的基础上进行了一定的改进,构建了有监督的神经网络模型,以湖南省长沙市主城区的土地自然属性为侧重点,对其土地覆盖进行分类。实验结果表明:利用本文所使用的方法得到的分类结果,其总体精度和Kappa系数均高于传统的分类方法得出来的分类结果。 相似文献
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SPOT4-VEGETATION中国西北地区土地覆盖制图与验证 总被引:13,自引:0,他引:13
利用SPOT4 VEGETATION的遥感数据产品生成的NDVI与NDWI植被指数时间序列图像集 ,通过ISODATA非监督分类方法 ,编制中国西北地区土地覆盖图。以TM影像人工解译结果作为真实值 ,通过对西北五省共计 47个均匀分布且异质性强的 2 5km× 2 5km样本区内的土地覆盖类型及其面积进行统计分析 ,修正了SPOT4 VEGETATION的土地覆盖分类系统 ,建立了各省验证结果的样本统计直方图并计算其回归系数。结果表明SPOT4 VEGETATION中国西北地区土地覆盖图在总体上具有较高的准确性。影响遥感数据自动分类精度 ,造成土地覆盖误判的原因主要来源于两个方面 :即异物同谱和混合像元问题。对于前者通过叠加各种辅助数据如DEM等可以降低误判的机率 ;对于后者运用混合像元分解的各种算法可以提高分类精度 相似文献
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ISODATA算法是遥感影像非监督分类的典型算法之一。在进行非监督分类前,需要对遥感影像进行必要的处理,影像增强就是其中最为重要的步骤之一。本文通过对ISODATA算法和影像增强算法的阐述,分析了影像增强算法与非监督分类结合的方式和局限性。并通过实验分析了常用影像增强算法对非监督分类结果的影响,科学合理的选择适当的影像增强算法来提高非监督分类的可靠性。 相似文献
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自组织神经网络在遥感影像分类中的应用研究 总被引:5,自引:0,他引:5
竞争学习网络与Kohonen神经网络相比,由于不考虑邻域神经元,其网络结构相对简单。采用这种简化的网络结构,并对其学习算法进行改进,用最大、最小距离法设置的初始聚类中心来代替随机初始中心。实验结果表明,用改进的竞争学习网络对遥感影像进行非监督分类,在分类精度和效率上都有较大的提高。 相似文献
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土地资源是一个国家或地区赖以生产和发展的重要物质基础,利用3S技术和数字化测绘技术对土地资源进行定期调查与动态监测,逐渐成为人们加强对土地资源的合理利用问题研究的重要手段。以1∶5万湖北省武汉市、陕西省韩城市土地覆盖/土地利用图的制作为试验样本,利用遥感和数字图像处理领域的前沿技术——基于Erdas Imagine 8.4的非监督分类、监督分类,辅以人工干预方法,以遥感影像数据(Landsat 7)为数据源,对土地资源的定期调查与快速监测的工艺流程与方法进行了较为深入的研究探讨。 相似文献
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人工免疫网络是受免疫网络理论的启发建立的用于数据处理的一种人工免疫系统。同时免疫系统是进化的,通过不断调节系统内细胞的数量和种类适应外界环境。提出的进化人工免疫网络借鉴免疫网络和进化的思想,是用于遥感影像分类的监督算法。算法通过一个学习过程,得到能够表示训练数据特征的网络细胞,然后利用这些网络细胞进行分类。实验表明进化人工免疫网络是遥感影像分类的有效工具。 相似文献
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《ISPRS Journal of Photogrammetry and Remote Sensing》1999,54(5-6):305-316
This paper describes the development of a 1-km landcover dataset of China by using monthly NDVI data spanning April 1992 through March 1993. The method used combined unsupervised and supervised classification of NDVI data from AVHRR. It is composed of five steps: (a) unsupervised clustering of monthly AVHRR NDVI maximum value composites is performed using the ISOCLASS algorithm; (b) preliminary identification is carried out with the addition of digital elevation models, eco-region data and a collection of other landcover/vegetation reference data to identify the clusters with single landcover classes; (c) re-clustering is performed of clusters with size greater than a given threshold value and containing two or more disparate landcover classes; (d) cluster combining is performed to combine all clusters with a single landcover class in one cluster, and all other clusters into one mixed cluster; and (e) supervised classification is used to carry out post-classification of the mixed cluster generated in the previous step by using the maximum likelihood algorithm and the identified single landcover classes of the previous step as training data. The classification is based on extensive use of computer-assisted image processing and tools, as well as the skills of the human interpreter to take the final decisions regarding the relationship between spectral classes defined using unsupervised methods and landscape characteristics that are used to define landcover classes. 相似文献
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Although multiresolution segmentation (MRS) is a powerful technique for dealing with very high resolution imagery, some of the image objects that it generates do not match the geometries of the target objects, which reduces the classification accuracy. MRS can, however, be guided to produce results that approach the desired object geometry using either supervised or unsupervised approaches. Although some studies have suggested that a supervised approach is preferable, there has been no comparative evaluation of these two approaches. Therefore, in this study, we have compared supervised and unsupervised approaches to MRS. One supervised and two unsupervised segmentation methods were tested on three areas using QuickBird and WorldView-2 satellite imagery. The results were assessed using both segmentation evaluation methods and an accuracy assessment of the resulting building classifications. Thus, differences in the geometries of the image objects and in the potential to achieve satisfactory thematic accuracies were evaluated. The two approaches yielded remarkably similar classification results, with overall accuracies ranging from 82% to 86%. The performance of one of the unsupervised methods was unexpectedly similar to that of the supervised method; they identified almost identical scale parameters as being optimal for segmenting buildings, resulting in very similar geometries for the resulting image objects. The second unsupervised method produced very different image objects from the supervised method, but their classification accuracies were still very similar. The latter result was unexpected because, contrary to previously published findings, it suggests a high degree of independence between the segmentation results and classification accuracy. The results of this study have two important implications. The first is that object-based image analysis can be automated without sacrificing classification accuracy, and the second is that the previously accepted idea that classification is dependent on segmentation is challenged by our unexpected results, casting doubt on the value of pursuing ‘optimal segmentation’. Our results rather suggest that as long as under-segmentation remains at acceptable levels, imperfections in segmentation can be ruled out, so that a high level of classification accuracy can still be achieved. 相似文献
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基于ETM+制作土地利用覆盖图——以制作北京1:5万土地利用覆盖图为例 总被引:3,自引:1,他引:2
简要介绍了基于LANDSAT7 ETM+影像,采用计算机非监督分类、监督分类与人工解译相结合的方法制作土地利用覆盖图的过程和所采用的关键技术,给出了适用于规模化生产土地利用覆盖数据的工艺流程图。使用该方法制作的十一种分类要素的北京地区1:5万土地利用覆盖图,平均分类精度为84.85%,可以满足一般用户对土地利用覆盖图的要求。 相似文献
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针对高光谱影像分类面临的小样本问题,提出了一种深度少样例学习算法,该算法在训练过程中通过模拟小样本分类的情况来训练深度三维卷积神经网络提取特征,其提取得到的特征具有较小类内间距和较大的类间间距,更适合小样本分类问题,且能用于不同的高光谱数据,具有更好的泛化能力。利用训练好的模型提取目标数据集的特征,然后结合最近邻分类器和支持向量机分类器进行监督分类。利用Pavia大学、Indian Pines和Salinas 3组高光谱影像数据进行分类试验,试验结果表明,该算法能够在训练样本较少的情况下(每类地物仅选取5个标记样本作为训练样本)取得优于传统半监督分类方法的分类精度。 相似文献
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基于自适应共振模型的遥感影像分类方法研究 总被引:9,自引:1,他引:9
人工神经网络(ANN)是人视觉和服的基本功能的抽象、简化和模拟。在对遥感影像的综合解释应用中,与传统的统计方法和符号逻辑方法相比较,ANN更接近人对影像的视觉解译分析过程。自适应共振理论(ART)是一种自组织产生认知编码的神经网络理论,其自组织、反馈式增量学习机能,能兼顾适应性和稳定性,克服了一般神经网络学习速度慢、网络结构难以确定、局部最小陷阱等缺陷。以FUZZY-ART和ARTMAP为基础,提出基于ART遥感影像非监督和监督分类的一般模型,并以实际上土覆盖分类和城市结构信息提取为应用实例,通过与传统统计方法和一般ANN分类器相比较,ART具有正确率更同、学习速度快、自适应性等优点,是复杂数据分类和信息提取的有效工具。 相似文献
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自适应模糊规则分类方法及在TM土地覆盖分类中的应用研究 总被引:1,自引:1,他引:0
根据自组织网络和模糊逻辑推理,实现土地覆盖自适应模糊规则分类方法。该方法通过网络的节点和权值提取出模糊规则,调整网络中节点个数(即相应增加规则节点数)和权值向量,使模糊规则自动生成,并利用模糊逻辑推理,完成TM土地覆盖分类。对拒分类的像元,自适应增加K值使其可分。该方法所得分类精度及Kapp系数与最大似然分类方法结果相比分别提高了2.7%和2.9%;与自组织网络相比,总精度相差不大,而Kapp系数低1%。实验证明,如何提取和表示非光谱知识,从而解决类别混淆等问题,是提高自适应模糊规则分类性能的关键 相似文献
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I. K. Lur'ye 《地理信息系统科学与遥感》2013,50(3):255-261
Algorithms, designed for digital image processing in standard mainframe computers and representing sequential stages in a land-use classification procedure, are used to produce maps of agricultural crop types from multispectral satellite imagery. Pixel reflectance values are first grouped according to an unsupervised “rapid classification algorithm,” or data compression procedure. Mean reflectance values of the resulting classes then go into a supervised “sequential clustering algorithm” where classes are refined according to training value and other parameter inputs. The objective is to increase the accessibility of automated image interpretation while balancing classification accuracy and processing time. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1984, No. 4, pp. 63-69. 相似文献
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Automatic monitoring of changes on the Earth’s surface is an intrinsic capability and simultaneously a persistent methodological challenge in remote sensing, especially regarding imagery with very-high spatial resolution (VHR) and complex urban environments. In order to enable a high level of automatization, the change detection problem is solved in an unsupervised way to alleviate efforts associated with collection of properly encoded prior knowledge. In this context, this paper systematically investigates the nature and effects of class distribution and class imbalance in an unsupervised binary change detection application based on VHR imagery over urban areas. For this purpose, a diagnostic framework for sensitivity analysis of a large range of possible degrees of class imbalance is presented, which is of particular importance with respect to unsupervised approaches where the content of images and thus the occurrence and the distribution of classes are generally unknown a priori. Furthermore, this framework can serve as a general technique to evaluate model transferability in any two-class classification problem. The applied change detection approach is based on object-based difference features calculated from VHR imagery and subsequent unsupervised two-class clustering using k‐means, genetic k-means and self-organizing map (SOM) clustering. The results from two test sites with different structural characteristics of the built environment demonstrated that classification performance is generally worse in imbalanced class distribution settings while best results were reached in balanced or close to balanced situations. Regarding suitable accuracy measures for evaluating model performance in imbalanced settings, this study revealed that the Kappa statistics show significant response to class distribution while the true skill statistic was widely insensitive to imbalanced classes. In general, the genetic k-means clustering algorithm achieved the most robust results with respect to class imbalance while the SOM clustering exhibited a distinct optimization towards a balanced distribution of classes. 相似文献