基于Canny算子的海南陵水双潟湖岸线提取技术

RESEARCH ON A TECHNIQUE OF EXTRACTING COASTLINE SHORELINE INFORMATION EXTRACTION USING THE CANNY EDGE DETECTION OPERATOR FOR TWO COASTAL LAGOONS IN LINGSHUI, HAINAN PROVINCE

遥感影像海岸线提取是研究长周期海岸动力地貌演化的有效技术手段.本研究以海南陵水新村、黎安双潟湖海岸为研究区,在中值滤波、图像分割等图像处理技术基础上,采用Canny边缘检测算法,对Landsat OLI遥感影像进行瞬时水边线提取,并结合岸线类型和潮位数据进行潮位校正,获得准确海岸线.利用多时段岸线的距离偏差对岸线提取精度进行验证.结果表明,使用Canny算子结合潮位校正是一种可行的遥感影像海岸线提取方法,尤其是对于植被覆盖影响较小的海岸区域.

Extracting the shoreline information using remote sensing image is an effective technique for the study on long- term geomorphological evolution. In the present study, the studying area is located in Xincun and Li-An coastal lagoons in Lingshui, Hainan Province, ranging from latitude 18°22′N to 18°47′N and longitude 109°45′E to 110°08′E. Three-times Landsat OLI images, acquired on October 10, 2013, October 26, 2013 and December 29, 2013, respectively, were collected with a multispectral resolution 30m and panchromatic resolution 15m. Four tide gauge records, acquired in the Xincun entrance and bay, Li-An entrance and bay separately. Firstly, the Canny edge detection operator was applied to derive instantaneous shoreline positions, for two coastal lagoons areas, using the Landsat OLI remote sensing images. Subsequently, tidal correction was carried out, on the basis of the shoreline types and tide gauge records from 4 sites over the study area, to obtain the true shoreline positions. Finally, in order to evaluate the uncertainty of the analytical results, the shorelines for three satellite images were compared and the accuracy was calculated. The average accuracy of artificial shoreline, bedrock shoreline and sandy shoreline was calculated. Xincun lagoon were 87.11% , 100% and 51.55% and Li-An lagoon were 86.74% , 98.04% and 87.67% respectively. The results show that the technique using the Canny operator in combination with tidal correction is generally feasible, especially for the areas where there is thick vegetation cover.