Sargassum Extraction Using Remote Sensing Technology

Abundant Sargassum in the coastline of northern South China Sea present great ecological role and are worthy of exploration.Study on the method of extracting Sargassum using remote sensing technology is a fundamental work to investigate resource and constitute the protection and exploitation rule.In this paper,spectrum and image characters of Sargassum are studied.Four methods,single band,dual bands ratio,dual band difference and normalized differential vegetation index are used to extract Sargassum.The precision of extraction result is verified by IKONOS data.The results show that both in true color(TC) and false color(FC) synthesis image,it is yellow in color in Sargassum water.The bound line of Sargassum water in FC is more clearly than that in TC.TM4 presents largest difference between Sargassm and no Sargassum water,TM3 also shows small difference between Sargassm and no Sargassum water.All four methods can extract Sargassum from nature water.Among the four methods,normalized differential vegetation index presents highest precision compared to the results obtained from IKONOS data.