基于自适应NDVI阈值的青岛海域浒苔监测研究

发布时间：2018-04-16 07:33

本文选题：浒苔 + MODIS图像　；参考：《中国石油大学(华东)》2014年硕士论文

【摘要】：从2008年开始,连续几年来每年5至8月份青岛海域都爆发了大规模的浒苔灾害,浒苔大量繁殖时会过分消耗氧气,对海底其他生物的生长繁殖构成威胁,对近海养殖业造成不利影响;而且大面积浒苔漂浮于近岸海面,甚至漂移到海滩上,其腐烂后还会散发出恶臭味,严重影响沿海旅游业的发展。为了更好的满足浒苔预警监测的需求,卫星遥感技术因其具有宏观、快速、大范围监测等优势成为了浒苔灾害预警监测非常重要的手段。精确的浒苔遥感监测资料对于浒苔的打捞工作具有重要的指导意义,根据浒苔遥感监测示意图及覆盖面积统计图,可以针对性的展开打捞工作,在最短的时间内了解并控制浒苔灾害的发展态势,有助于浒苔的治理,而且利用遥感技术监测浒苔也是近年来学术研究的热点。本文首先搜集整理了青岛近海区域的MODIS图像,以及海表面温度等相关历史资料数据,并对遥感数据进行了消除Bowtie效应、几何校正、大气校正、陆地掩膜等预处理操作;然后利用野外地物光谱仪测量海水中浒苔的实际光谱曲线,分析浒苔不同波段所具有的光谱特性,浒苔的基本光谱特征表现为在蓝光波段和红光波段附近形成反射谷,在绿光波段形成反射峰,而在近红外波段反射率明显增大,形成高反射峰,这为利用遥感图像提取浒苔信息奠定了基础;之后分别利用最小距离分类、归一化植被指数法、基于混合像元分解的波谱角分类等图像分类方法,以及最小值点阈值法、迭代法、最大类间方差法等图像分割方法提取浒苔信息,在此基础上研究自适应归一化植被指数(NDVI)阈值的选取方法,既可以有效消除或减少云的影响,又可以方便针对多幅图像进行浒苔信息提取,提高工作效率;最后提取2008-2010年多时相青岛海域浒苔灾害信息,分析了青岛海域浒苔灾害的时空分布特征及影响浒苔大面积聚集的相关因素。总之,本研究的最终目的在于获取一种高效的基于遥感影像的浒苔信息提取方法,进而获取多时相的青岛海域浒苔灾害时空分布特征,分析浒苔爆发的影响因素,为今后浒苔的监测与治理提供一定的理论依据及技术参考。
[Abstract]:Since 2008, a large-scale Enteromorpha disaster has erupted in the Qingdao sea area from May to August every year for several years. The excessive consumption of oxygen during the mass propagation of Enteromorpha enteromorpha poses a threat to the growth and reproduction of other organisms on the sea floor.Moreover, a large area of Enteromorpha enteromorpha floats on the shore and even drifts to the beach, which will give off a bad smell after decaying, which will seriously affect the development of coastal tourism.In order to better meet the needs of early warning monitoring of Enteromorpha margin, satellite remote sensing technology has become a very important means for early warning and monitoring of Enteromorpha margin because of its macroscopic, rapid and large-scale monitoring advantages.Accurate remote sensing monitoring data of Enteromorpha enteromorpha has important guiding significance for salvage work of Enteromorpha margin. According to the map of remote sensing monitoring and statistical map of coverage area of Enteromorpha margin, the salvage work can be carried out pertinently.Understanding and controlling the development situation of Enteromorpha margin disaster in the shortest time is helpful to the management of Enteromorpha margin, and the monitoring of Enteromorpha margin by remote sensing technology is also a hot topic of academic research in recent years.In this paper, the MODIS images of Qingdao offshore area and the relevant historical data such as sea surface temperature are collected and collated, and the Bowtie effect, geometric correction, atmospheric correction, land mask and so on are eliminated from the remote sensing data.Then the actual spectral curves of Enteromorpha enteromorpha in sea water were measured by using the field ground object spectrometer, and the spectral characteristics of different bands of Enteromorpha margin were analyzed. The basic spectral characteristics of Enteromorpha margin were the formation of reflection valleys near the blue and red light bands.The reflection peak is formed in the green light band, but the reflectivity in the near infrared band increases obviously, which lays the foundation for extracting the information of Enteromorpha enteromorpha from remote sensing image, and then uses the minimum distance classification method to normalize the vegetation index method.Image classification methods based on mixed pixel decomposition, such as spectral angle classification, minimum point threshold method, iterative method and maximum inter-class variance method, are used to extract the information of Enteromorpha enteromorpha.On this basis, the selection method of adaptive normalized vegetation index (NDVI) threshold is studied, which can not only effectively eliminate or reduce the cloud effect, but also can conveniently extract the information of Enteromorpha enteromorpha for multiple images and improve the working efficiency.Finally, the disaster information of Enteromorpha enteromorpha in Qingdao sea area from 2008 to 2010 was extracted, and the spatial and temporal distribution characteristics of Enteromorpha enteromorpha disaster in Qingdao sea area and the related factors affecting the accumulation of Enteromorpha enteromorpha were analyzed.In a word, the ultimate purpose of this study is to obtain an efficient method for extracting the information of Enteromorpha margin based on remote sensing image, and then to obtain the temporal and spatial distribution characteristics of Enteromorpha enteromorpha disaster in Qingdao sea area, and to analyze the influencing factors of the outbreak of Enteromorpha margin.To provide a certain theoretical basis and technical reference for the monitoring and control of Enteromorpha enteromorpha in the future.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：X55;X87

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