一种适用于古建筑建模的全波形高光谱激光雷达设计与实现

A design and implementation of full waveform hyperspectral LiDAR for ancient architecture modelling

  • 摘要: 为了获取古建筑完整的空间结构、历史演进及其健康状态等特征信息,研制了一种全波形的高光谱激光雷达系统(HSL)。该系统同时获得目标的空间三维信息和光谱信息,用于古建筑空间和状态特征的建模。利用超连续谱激光器和声光可调滤波器(AOTF)作为发射单元,实现550~1050 nm的连续光谱波长范围内101个光谱通道采样,并利用5 GHz/s高速采集卡完成主波和回波全波形数据采集。设计了静态单点测试和zigzag单点扫描相结合的双模式分步扫描方案,保证三维空间和光谱信息的准确获取。在实验室环境下,对HSL系统反射率稳定性、信噪比以及扫描精度进行了分析测试。利用三维空间和超连续的高光谱信息对古建筑构件样本建模进行验证,并采用随机森林(RF)多分类方法实现不同古建筑构件木种材料的分类。结果表明,HSL系统能够同时获得空间三维信息和连续光谱信息,满足古建筑空间和状态特征建模的信息采集的需求。

     

    Abstract: To acquire multidimensional characteristic information of ancient architectures, such as spatial structure, historical evolution and health status, this paper developed a hyperspectral LiDAR (HSL) system that implemented continuous spectrum wavelength selection from 550 nm to 1050 nm by an acousto-optic tunable filter (AOTF). 5 GHz/s high-speed acquisition card recorded the full waveform, including the transmitted and the echo waveforms. A two-mode step scanning strategy, including static single-point testing and zigzag scanning mode, was designed to ensure the accurate acquisition of three-dimensional spatial information. The reflectivity stability, signal-to-noise ratio (SNR), and scanning accuracy tests were conducted in an experimental environment, which indicated that our HSL system was stable and reliable. The 3D reconstruction distribution of ancient building components was presented with a single wavelength quantized voltage value, and the component material classification was conducted by a random forest (RF) classifier with hyperspectral reflectance. The results show that the system can obtain reliable 3D spatial and supercontinuous spectral information, providing multidimensional feature data for ancient architecture modelling.

     

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