基于ENVISAT-MERIS数据的过火区制图方法研究

Studying on Burned Scar Mapping Using ENVISAT-MERIS Data

森林或草原在发生火灾后,过火区内的植被层在近红外波段的反射率通常要比健康植被低,利用光学遥感数据的近红外波段和红光波段可以探测出植被层的反射率在大气上界的明显变化。对过火区域的提取是利用卫星数据进行测算森林或草原火灾过火面积的关键技术之一。根据实验区内近年来发生的多次重特大森林或草原火灾,在对ENVISAT-MERIS数据中典型地物光谱特征进行分析的基础上,分别采用图像处理方法、植被指数法和面向对象的图像分析方法对过火区制图方法进行对比研究。研究结果表明,通过面向对象的图像分析方法获得的过火区域,可以较好地适用于过火区面积的估测,该方法是一项实现定量提取过火区域的行之有效的方法。

After forest fire or grass fire, the burned vegetation usually has a lower reflectance in the NIR- channel than they are healthy. The strong TOA （Top of Atmosphere） reflectance change can be detected in the NIR-channel and Red-channel of Optics Remote Sensing data over a vegetation layer. Extracting burned scar region is one key technique for calculating burned area of forest fire or grass fire by using satellite data. In this study,According to the records of many large forest fires or grass fires which have taken place in the experiment region in recent years,based on the spectral character analysis of typical objects in ENVISAT-MERIS （Medium Resolution Imaging Spectrometer Instrument） images,methodology of burned scar mapping has been studied. The extracting results have been compared by using image processing method, vegetation index method and object image analysis method. It shows that the results can be used directly to evaluate the burned scar area. It＇s an effective quantificational method by using object image analysis to extract burned scar region.