建筑用地的急剧增加和耕地资源的迅速减少,使得土地利用动态变化监测显得尤为重要。遥感作为监测土地利用动态变化的一种有效手段,已经得到日益广泛的应用。但是建筑用地由于其光谱的异质性,而难以用简单的方法将它们从遥感影像中准确提取出来,遥感建筑用地指数(Index-based Built-up Index,IBI)是针对这一问题提出的。它的构建采用的是三个专题指数波段(SAVI植被指数、MNDWI水体指数、NDBI建筑指数),而不是影像的原始波段。由于这三个指数互为负相关,因此,可以有效地增强和提取遥感影像中的建筑用地信息。通过将IBI指数提取建筑用地的影像处理过程编成可自动执行的模块,并集成于大型的遥感商业软件中,使得影像数据处理和建筑用地信息提取时间大大缩短,提高了建筑用地信息增强和提取的效率。
The fast expansion of urban built-up land and accompanied sharp decrease in farm land have made timely monitoring of landuse changes become more important than ever before.The ability to monitor the built-up land dynamics in a cost-effective manner is highly desirable for local communities and decision makers alike.Fortunately,satellite remote sensing technique offers considerable promise to meet this requirement.Although the use of remote sensing technique in the monitoring of land use changes has become more and more popular and satellite imagery has been frequently used to discriminate built-up lands from non-built-up lands for the last few decades,the extraction of built-up land information from remote sensing imagery is still not an easy task due largely to the heterogeneous characteristics of the built-up land.Among many techniques developed for the extraction of built-up land information,the index-based built-up index(IBI) was created based on three existing thematic indices rather than original multispectral bands.The use of the three thematic indices-soil-adjusted vegetation index(SAVI),modified normalized difference water index(MNDWI) and normalized difference built-up index(NDBI)-greatly help the delineation of built-up land features in remote sensing imagery,because these three indices represent three major landuse components,which are vegetation,water and built-up land,respectively.Therefore,the IBI can significantly enhance built-up land information while suppressing background noise.Consequently,the built-up land can be effectively extracted from the IBI image with high accuracy.In order to quicken image processing,this built-up extraction technique has been programmed to form an easy-use module using the ER Mapper scripting language.The module was further integrated in the ER Mapper package by adding a button to the manual bar.This allows users to automatically perform the extraction procedure with high accuracy just in a few minutes.