利用机载LIDAR双次回波高程之差分类激光脚点

Airborne LIDAR points cloud classification based on difference of twice return pulse heights

机载LIDAR技术已经引起了测绘界的浓厚兴趣,有可能给测绘领域带来一场新的技术革命。机载LI-DAR技术的硬件设备在国外已相对成熟,而机载LIDAR的数据后处理算法仍然处于研究发展阶段,还有诸多问题没有得到解决,其关键之一就是机载LIDAR数据的滤波与分类。本文首先对已有的滤波分类方法进行了综合评价,并指出了各自的局限。然后提出利用两次回波信号的高程数据来实现对机载LIDAR数据的分类。首次分类后得到植被激光脚点点集和地面及房屋激光脚点点集。而房屋上的激光脚点要高出地面上的激光脚点数米之多,简单利用阈值法就可以进一步分类出房屋激光脚点和地面激光脚点。也可以先经过滤波处理将地面激光脚点去掉,然后利用两次回波信号的高程数据来分类自然植被激光脚点和人工地物激光脚点。实验证明所提方法简单有效,算法简单实用,特别适用于分类植被激光脚点。

Airborne LIDAR technology has attracted great attention in the community of geomatics recently,and it possibly brings a new revolutionary of technology in geomatics.The hardware of airborne LIDAR is matured oversea,while algorithm for LIDAR data processing is under developing and more effort should be made to resolve airborne LIDAR points cloud filtering and classification.Firstly,evaluation on the referenced methods of filtering and classification is made.As the shortcomings of these methods exist,a new airborne LIDAR footprint points classification based on twice return pulse heights is investigated.Using the proposed method,vegetation footprints can be removed firstly,after that,further classification should be down to classify the ground footprint and buildings footprint based on the threshold,because the height of the point on the building is higher than that on the ground.And also we can filter the ground points,and then using the proposed method to classify the vegetation points and building points.Test demonstrates that the method is simple and effective,especially for classifying the vegetation points.