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潮沟作为潮滩的主要地貌类型之一,以长江口九段沙为研究对象,利用2015年2月15日获取的Landsat 8分辨率为15 m的全色波段遥感数据为数据源,选取了3条发育不同的潮沟。首先利用顶帽变换来消除直接利用最大类间方差法对图像亮度背景不均匀不能准确分割的问题,然后通过最大类间方差法找到一个最佳的阈值使潮沟和背景之间方差最大,得到二值化图像;接着通过形态膨胀对断裂的潮沟进行连接,并用形态去除方法剔除非目标;最后对潮沟进行骨架化提取和去除短枝处理,得到完整的潮沟信息骨架图。采用视觉分析和定量分析对提取的潮沟信息进行精度评价。结果表明,最大类间方差法和数学形态学的结合对潮沟信息提取有较好的效果,平均准确度达到93.0%,遗漏误差和冗余误差分别为7.0%和0.5%。
As one of the main landform types of the tidal flat, taking the Jiuduansha of the Yangtze River estuary as the research object, using the data of Panchromatic band of Landsat 8 with a resolution of 15 m acquired on February 15, 2015 as the data source, 3 Different development of the tide groove. First, the top hat transform is used to eliminate the problem that the maximum variance between classes can not be accurately segmented due to the inhomogeneous brightness of the image, and then an optimal threshold can be found by the maximum variance between classes to maximize the variance between the trenches and the background. Then the morphological expansion is used to connect the fractured trenches, and the morphological removal method is used to eliminate the non-targets. Finally, the tidal channel is skeletonized and removed, and the complete tidal groove information skeleton map is obtained. Visual accuracy and quantitative analysis were used to evaluate the accuracy of extracted tide information. The results showed that the combination of maximum variance between classes and mathematical morphology had a good effect on extracting tide information, with an average accuracy of 93.0%, error of omission and redundancy error of 7.0% and 0.5% respectively.