倒排索引优化的波形激光雷达数据存储和访问  

Storage and access of full waveform Li DAR data of LAS1.3 format based on inverted index

作　　者：卢昊[1] 庞勇[1] 李增元[1] 

机构地区：[1]中国林业科学研究院资源信息研究所,北京100091

出　　处：《计算机工程与应用》2015年第16期243-247,共5页Computer Engineering and Applications

基　　金：国家高技术研究发展计划(863)(No.2012AA12A306)

摘　　要：LAS1.3格式是由美国摄影测量与遥感协会(ASPRS)制定的一种用于存储激光点云及其他相关信息的激光雷达交换数据格式,该版本支持激光雷达波形数据的存储,以适应全波形激光雷达的发展和应用。但由于其继承了LAS格式以点存储为中心的设计思路,波形数据仅作为附加部分挂接在点云数据上,故只提供了一种简单的映射方法实现波形数据访问,而无法直接体现出波形数据作为原始信息与回波点云的逻辑关系,因此在研究和实际应用中不便于波形数据的直接访问。设计实现了一种基于倒排索引的文件格式,建立了从波形数据到属于该束激光脉冲的点云的倒排映射关系,消除了LAS1.3文件中波形数据访问的无序性,也大大降低了波形数据处理过程中程序访问的复杂性。实验表明,新的索引文件组具有标准LAS1.3格式规范不具备的访问特性,可以增加波形数据的访问速度。LAS specification version 1.3 is an exchange data format published by American Society for Photogrammetry and Remote Sensing（ASPRS）for storing Li DAR point cloud and other corresponding information,which can storage full waveform data to accommodate the development of Li DAR hardware and data applications.As an upgrade of old version of LAS,LAS1.3 format still focus on the description of point cloud data and simply attach the waveform data to the end of point records to extend the information of laser pulse return,which only provides a simple mapping mechanism to access the waveform data and cannot depict the logical relationship between the laser points and waveform,making it inconvenient to make direct access to waveforms.To solve this problem,a new data format based on inverted index technique is implemented to build an inverted mapping from waveform data packet to associated laser points,which eliminates the disorder of waveform accessing in LAS1.3 specification and degrades the complexity of waveform processing in applications.The experiment shows that the data format has other new features that LAS1.3 does not have,which increases the accessing speed of waveform information.

关 键 词：倒排索引 激光雷达 LAS1.3 全波形 点云 存储优化 

分 类 号：TP702[自动化与计算机技术—检测技术与自动化装置]