The Research Of Water Extraction Based On Spectral Area And IHS Transformation

In recent years, along with the climate change, the arid phenomenon which appeared frequently has caused humanity's interest in the use of water resource. Using the remote sensing phantom to renew the water body has already become the principal means of the water body monitor. At present, the methods of monitoring the water body using the remote sensing technique mainly have:the threshold value of single wave band, the law of the spectrum relevance, the exponential of water body and so on. However, in these methods, each sole method is very difficult to exhaustively extract the water body especially in some terrain complex region, it even more is unable to meet humanity's need.On the foundation of the predecessor, this article proposed one kind of spectrum relates method which was based on the area on spectrum using the prior knowledge of each farm's spectrum curve such as water,plant, settlement place,the farms in shadow, Road and industrial land. It unified the tiny water body extraction method that the predecessor had carried on to extract Changsha's water body and had obtained the good extraction effect. Finally, it had carried on the precision appraisal using the MAPGIS software to the water body extraction result, the main research work includes:(1)This article had analyzed each kind of model kind of spectrum rule and the nature, had carried on the element depuration to each farm class and the Classification processing, thus determined the background terrain feature type that affecting water body extraction, so,it is convenient for extracting water accurately.(2)This article carried on the analysis processing using ENVI and EXCEL software to each farm class, discovered each land group's reciprocity between the regional kind of wave bands, obtained every land group's curves in spectrum diagram. It discoveried that the water body basically is lower than other kind of spectrum value in 3,4,5,7 wave band's spectrum values through the analysis. The area that the spectrum curve and the wave band axis encircles is obviously smaller than the area which other background terrain feature encircles, then it obtained the method that using these four spectrum curve to carry on the integral to extract the water body.(3)The experiment proved that the small water body could not be obviously distinguished in the luminance value scope between other kinds as a result of the mix element's existence. The article used the brightness, the chromaticity, the degree of saturation in IHS to carry on the extraction to the tiny water body based on the predecessor's research.(4)It carried on the precision appraisal to the both large and tiny water body's extraction using MAPGIS and the ENVI software and carried on the statistics using the method of area similarity, simultaneously withdrawed the scope area that mistaking raises and leaking raises. It could appraise the extraction precision regardless of the vision or the data analysis.