【作者】 袁愈才；

【导师】 周晓光；

【作者基本信息】 中南大学 ， 地图学与地理信息系统， 2011， 硕士

【摘要】 由于全球变化对未来人类的生存环境产生长远影响,近几十年得到国际科学界的广泛重视。地表覆盖变化是全球变化研究的重要组成部分,其又包括地表覆盖变化检测、驱动力分析、更新制图等。其中地表覆盖变化检测是变化驱动力分析与更新制图的前提和基础。本文针对地表覆盖数据更新制图的应用需求,对基于像元的灰度差值法、比值法、NDVI差值法、PCA差异法四种方法进行地表覆盖变化信息提取方法的比较实验。主要工作如下：(1)单一变化信息提取方法的比较实验：应用上述四种变化信息提取方法对陕西省地表覆盖数据进行变化信息提取实验,比较了这四种方法的提取精度。实验结果表明,这四种方法在30m分辨率ETM/TM影像地表覆盖变化信息提取中,PCA差异法的变化检测精度最高。但总体来讲,四种单一方法的提取精度还是偏低的(使用者精度都低于80%)。(2)为了获得更好的变化信息提取效果,本文在单一变化信息提取方法的基础上分析了上述四种方法提取结果的相同和相异性。实验结果表明：灰度差值法与PCA差异法的提取结果较为相似(相同的变化像元达到了76.38%)。同时NDVI差值法与其它三种方法的提取结果相差较大。造成这种状况的主要原因在于各种方法对于不同的地表覆盖的敏感程度是不一样的,其中NDVI差值法对植被覆盖变化较为敏感,故其对植被覆盖的变化检测效果较好,但同时其对水体的变化较为迟钝,造成其对水体的变化检测效果不明显。(3)在分析四种方法的相同和相异性的基础上,进一步研究了四种方法的不同组合情况的提取效果,包括四种不同的组合方式：1)比值法与PCA差异法求并；2)NDVI差值法与PCA差异法求并；3)NDVI差值法、比值法、PCA差异法三种方法求并；4)先对差值法、比值法、PCA差异法三种方法进行求交,再将所得结果与NDVI差值法求并。实验结果表明,比值法、NDVI差值法、PCA差异法三种方法求并的组合方式所检测的结果中包含了四种单一检测方法所检测出的全部变化像元,但比四种方法的并大大降低了过度检测现象,这种组合方式的检测效果最好。更多还原

【Abstract】 Global change will affect human survival environment in the long-term, so it has gotten the extensive attention in the international scientific community in recent decades. Land cover change is an important component in the global change research, and it includes three aspects of contents:land cover change detection, driving force analysis, updating and mapping. Among them, land cover change detection is the premise and foundation. In this paper, image differencing, image ratioing, NDVI differencing and PCA differencing technique based on pixel are used for land cover change information extraction experiment. The main work is as follows.(1) Comparison between single change detection methods:Four methods which are mentioned in this paper are used to do change information extraction experiment for land cover of Shanxi province, and their extraction accuracy is evaluated. The results show that PCA differencing own highest change detection accuracy when four methods are used for land cover change information extraction experiment. But overall speaking, the accuracy of various single method is still low (user accuracy less than 80%).(2) In order to obtain better change information extraction effect, the sameness and dissimilarity of extraction results of four methods are analyzed in the basis of single change information extraction method. The results show that:differencing and PCA differencing have close extraction accuracy (the same change pixels reached 76.38%). At the same time, the extraction accuracy of NDVI differencing has greater difference compare with the other three methods. This situation is mainly due to a variety of methods has different degree of sensitivity for different surface cover. NDVI difference method is more sensitive to change of vegetation cover, so its change detection effect for vegetation is better. At the same time, NDVI differencing is relatively slow to change of water, so its change detection for water is ineffective.(3) In order to improve the change information extraction accuracy, combination of four methods to be applied according to evaluation results of the analysis of the sameness and dissimilarity. There are four different combination forms:1) The union of ratioing and PCA differencing; 2) The union of NDVI differencing and PCA differencing; 3) The union of NDVI differencing, ratioing and PCA differencing; 4) Firstly, calculate the intersection of differencing, ratioing and PCA differencing, and then calculate the union of the result and NDVI differencing. The results show that:the detection results which are generated by the union of image radioing, NDVI differencing and PCA differencing contain all the change pixels detected by four simplex methods. At the same time, this combination form reduces the over-detection phenomenon. So, the article argues that it is the best combination form.更多还原