基于机载雷达数字高程模型的地质灾害微地貌增强显示算法研究

    Research On Geo-hazard LiDAR Image Highlight Algorithm based on the Topographic Profile feature

    • 摘要: 我国植被茂密山区地质灾害发育多存在高位、高危、高隐蔽性的特点,利用机载雷达技术提取林下地形来开展植被茂密山区的地质灾害识别已成为行业主流,然而现有的DEM可视化技术对地质灾害微地貌刻画能力较弱,仍然存在地质灾害微地貌特征的误识别与漏识别的问题。针对该问题,提出了一种基于机载雷达数字高程模型的地质灾害微地貌增强显示算法(LIHA)。LIHA算法受到信号学对随机非平稳波谱信号处理的启发,提出将地形剖面这类随机波形数据当做信号处理,其基本思路为:首先将LiDAR获取的DEM数据进行地形剖面分割,对每个地形剖面进行地形曲线拟合与拟合前后的地形差分处理,并将差分后得到的微地貌地形特征曲线,通过一定系数放大并反算DEM地形剖面,遍历DEM栅格所有剖面及得到增强显示后的DEM数据。结合浙江青龙滑坡的微地貌分布发育情况,应用LIHA算法对滑坡DEM进行增强显示。增强结果表明LIHA算法受光线入射方向影响较小,可有效提高滑坡DEM上微地貌特征的可视性,更有利于遥感目视解译工作的开展;为地质灾害早期识别与微地貌特征解译提供了有效的技术支持。

       

      Abstract: China's densely vegetated mountainous regions are prone to frequent geo-hazards, and existing DEM visualization techniques are inadequate for depicting the micro-topography associated with these hazards. This paper proposes an enhanced display algorithm for micro-topography based on DEM terrain profile features. Inspired by the random unstable spectral signal processing, this algorithm proposes to treat terrain profiles as signals. The fundamental approach involves segmenting the DEM data obtained from LiDAR into terrain profiles, fitting terrain curves to each profile, and processing the differences between the fitted and original terrain curves. The micro-topographic features obtained from these differences are then amplified by a specific coefficient and used to reconstruct the DEM profiles. This process is applied to all DEM profiles to obtain the enhanced DEM data. The study selected one landslide area as research sites and applied the proposed algorithm to enhance the landslide DEMs. The results show that the enhancement algorithm proposed in this paper is less affected by the direction of sun light, which can effectively improve the visibility of micro-topographic features on the landslide DEM, and is more conducive to the visual interpretation of geo-hazards. The results demonstrate the algorithm's validity and provides effective technical support for the early identification and interpretation of micro-topographic features in geo-hazards.

       

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