Review on information extraction of hydrographic objects in the Three Gorges Reservoir area

摘要

As for the existent special condition that the width of tributaries in Yangtze River is mostly less than 28.5m,in this paper,the HLS color spatial threshold method,which is combined with the multispectral relation threshold method is used and testified to be quite effective to extract information of hydrographic objects.Compare this method with the two traditional information extraction methods of the water index threshold method and the multispectral relation threshold method.The experimental results have shown that the methods of the water index threshold method and the multi-spectral relation threshold method are superior to the the single-band analysis method.The first two methods can separate the similar spectral characters of shadows from hydrographic objects,and the latter is more accurate in shadow elimination.But those two traditional methods are both ineffective in extraction of small hydrographic objects.The HLS color spatial threshold method,however,is able to extract tributaries of Yangtze River,Consequently,the method used in this paper quite improves the effect of information extraction of hydrographic objects.