地理研究 ›› 2015, Vol. 34 ›› Issue (4): 677-690.doi: 10.11821/dlyj201504007

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多目标珊瑚岛礁地貌遥感信息提取方法——以西沙永乐环礁为例

周旻曦1(), 刘永学2,3,4(), 李满春2,3,4, 孙超1, 邹伟1   

  1. 1. 南京大学地理与海洋科学学院, 南京 210023
    2. 南京大学中国南海研究协同创新中心, 南京 210023
    3. 南京大学江苏省地理信息技术重点实验室, 南京 210023
    4. 江苏省地理信息资源开发与利用协同创新中心, 南京 210023
  • 收稿日期:2014-10-25 修回日期:2015-01-22 出版日期:2015-04-10 发布日期:2015-04-10
  • 作者简介:

    作者简介:周旻曦(1991- ),男,江苏宜兴人,硕士,主要从事遥感图像处理与模式识别研究。E-mail: zhouminxi_103@hotmail.com

  • 基金资助:
    国家高科技研究发展计划(863计划)课题(2012AA12A406-1);国家自然科学基金项目(41471068, 41171325,41230751,J1103408);新世纪优秀人才支持计划(NCET-12-0264)

Geomorphologic information extraction for multi-objective coral islands from remotely sensed imagery: A case study for Yongle Atoll, South China Sea

Minxi ZHOU1(), Yongxue LIU2,3,4(), Manchun LI2,3,4, Chao SUN1, Wei ZOU1   

  1. 1. Department of Geographic Information Science, Nanjing University, Nanjing 210023, China
    2. Collaborative Innovation Center for the South China Sea Studies, Nanjing University, Nanjing 210023, China
    3. Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Nanjing 210023, China
    4. Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China
  • Received:2014-10-25 Revised:2015-01-22 Online:2015-04-10 Published:2015-04-10

摘要:

南海珊瑚岛礁资源极为丰富,实时、快速、高效、准确地获取大范围珊瑚岛礁地貌遥感信息具有现实意义。研究提出了一种双尺度转化下的模型与数据混合驱动的岛礁地貌信息提取框架,并设计了珊瑚岛礁地貌分类体系及相应技术流程:首先采用自上而下模型驱动的GVF Snake模型进行宏观地理分带的粗分割,然后采用自下而上数据驱动的云影极值抑制下多阈值OTSU分类算法进行微观地貌类型的精细分类,最终利用区域生长算法提取离散分布的暗沙、暗滩等浅水地貌单元。针对西沙永乐环礁利用CBERS-02B数据进行实验,精度验证表明:珊瑚岛礁地貌遥感信息提取方法总体精度优于经典数据驱动的监督分类算法,且具有抗噪能力强、顾及空间拓扑关系、自动灵活等特点。

关键词: 珊瑚岛礁地貌, 遥感, GVF Snake模型, 多阈值OTSU分割, CBERS-02B卫星

Abstract:

In the South China Sea, the vast ocean is dotted by hundreds of islands. It is meaningful to dynamically update precise geo-information of multi-objective coral islands in real time. Considering the poor spatial accessibility of these islands, remote sensing as a modern monitoring technique outstands the traditional time-consuming ground survey with relatively low expenses and high efficiency. This paper proposes a dual-scale transferred framework applying hybrid model-data driven technique for geomorphologic information extraction based on the 'ring-like' spatial structure of coral islands. Taking the sedimentary environment of each geographic zone and benthic detection capacity of CBERS-02B CCD image into account, we established a practical geomorphology classification system mainly based on 'geo-entity' and supplemented by subclass, i.e., 'geomorphologic structures'. To accord with the classification system, we developed a fully automatically geo-information extraction method for multi-objective coral islands: (1) outlines of first-class geomorphologic zones are delineated by applying top-down and model-driven GVF Snake model; (2) for sub-class geomorphologic structure within the first-class geomorphologic zones, down-top data-driven multi-threshold OTSU segmentation algorithm is applied after removing cloud and shadow areas; (3) region-growing algorithm restricted by gradient-neighborhood criterion is applied for external discretely distributed submerged sandy beaches and hidden shoals extraction. <br/> Experiment for Yongle Atoll (Xisha) based on CBERS-02B CCD images shows that the hybrid framework proposed in this paper outperforms the traditional data-driven supervised classification methods, and the overall accuracy is up to 88.89%, better than ML classification (77.49%) and SVM classification (82.16%). In comparison, this proposed method can delineate the regional geomorphologic heterogeneity under the premise of guarantee spatial continuity and completeness of geographic zones. Additionally, this method is robust to stripe noises, keeping geo-entity from being shattered. Furthermore, the top-down geographic zone segmentation provides the foundation for mining the spatial topological relationship between the ring-like zonation, so as to enhance the feature separability. Practically, this method is flexible and fully automatic, but the final classification result is dependent on key parameters setting, which calls relatively high standard for interpreter.

Key words: coral island geomorphology, remote sensing, GVF Snake model, multi-threshold OTSU segmentation, CBERS-02B satellite