基于地面激光的探地雷达图像地形校正方法

为消除地形起伏对探地雷达图像畸变和解译的影响,需进行地形校正处理。本文主要通过地面激光建立的数字高程模型(Digital Elevation Model,DEM)来实现探地雷达图像的地形校正。首先,利用激光点云构建高精度DEM,借助靶球标记的雷达测线起始和结束位置实现雷达图像与DEM上提取出相应的二维地形剖面之间的匹配。然后,选择测线上最高点所在的水平面为参考基准面,根据时间移位原理并结合线性插值法对雷达图像上各道数据的双程传播时间进行校正；最后,选择实例数据并以差分GPS采集的地形数据为标准,着重分析了不同分辨率DEM下提取出的地形剖面对地形校正效果的影响。结果表明利用激光点云建立DEM实现探地雷达图像地形校正的有效性,当DEM分辨率与探地雷达数据采集道间距相一致时,从DEM上提取出的地形剖面实现探地雷达图像地形校正的效果最佳。

Topographic correction of GPR image based on terrestrial laser scanning

In order to eliminate the influence of undulating terrain on GPR image distortion and interpretation,the topographic correction should be done. Digital elevation model(DEM)based on terrestrial laser was used to realize topographic correction of GPR image. Firstly,high-precision DEM was set up by laser point cloud,and the match of GPR images and two-dimensional topographic profile is carried out by initial and end position of radar survey line. Then,taking the plane of the highest survey line position as reference datum,the two-way travel time of each way data was corrected according to the time shift theory and linear interpolation method. Finally,taking differential GPS acquisition of terrain data as criterion,the influence of different resolution DEM terrain profile on terrain correction effect were analyzed. The results show that the topographic correction of GPR images based on DEM is effective. When DEM resolution is consistent with trace interval of GPR image,the topographic correction of GPR image by the extracted topographic profile from DEM is optimum.