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基于光反馈自混合干涉效应的雷达激光器带宽测量方法
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作者 郭常盈 吴冉 《激光杂志》 北大核心 2018年第7期63-67,共5页
采用传统外差方法测量雷达激光器带宽时,由于一个调频周期内光程在102数量级上,显著高于光源的相干长度且外差计算过程较复杂,使雷达激光器带宽测量结果的精度较低。提出基于光反馈自混合干涉效应的雷达激光器带宽测量方法,采用光反馈... 采用传统外差方法测量雷达激光器带宽时,由于一个调频周期内光程在102数量级上,显著高于光源的相干长度且外差计算过程较复杂,使雷达激光器带宽测量结果的精度较低。提出基于光反馈自混合干涉效应的雷达激光器带宽测量方法,采用光反馈自混合干涉效应测量模型,获取雷达激光器外腔位移变化规律。根据该规律通过法布里-珀罗(F-P)共焦球面腔对雷达激光器带宽进行测量,透过峰与激光的最低频率重合时调控电压使得光电探测器不在输出内容,确保透过峰和调频激光的最高频率相同,此时施加电压值实现对雷达激光器调频带宽的测量。实验结果说明:所提方法测量的雷达激光器带宽结果精度较高,实际应用效果佳。 展开更多
关键词 光反馈 自混合 干涉效应 雷达激光器 带宽测量 共焦球面腔
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Urban tree species classification based on multispectral airborne LiDAR 被引量:1
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作者 HU Pei-Lun CHEN Yu-Wei +3 位作者 Mohammad Imangholiloo Markus Holopainen WANG Yi-Cheng Juha Hyyppä 《红外与毫米波学报》 北大核心 2025年第2期211-216,共6页
Urban tree species provide various essential ecosystem services in cities,such as regulating urban temperatures,reducing noise,capturing carbon,and mitigating the urban heat island effect.The quality of these services... Urban tree species provide various essential ecosystem services in cities,such as regulating urban temperatures,reducing noise,capturing carbon,and mitigating the urban heat island effect.The quality of these services is influenced by species diversity,tree health,and the distribution and the composition of trees.Traditionally,data on urban trees has been collected through field surveys and manual interpretation of remote sensing images.In this study,we evaluated the effectiveness of multispectral airborne laser scanning(ALS)data in classifying 24 common urban roadside tree species in Espoo,Finland.Tree crown structure information,intensity features,and spectral data were used for classification.Eight different machine learning algorithms were tested,with the extra trees(ET)algorithm performing the best,achieving an overall accuracy of 71.7%using multispectral LiDAR data.This result highlights that integrating structural and spectral information within a single framework can improve the classification accuracy.Future research will focus on identifying the most important features for species classification and developing algorithms with greater efficiency and accuracy. 展开更多
关键词 multispectral airborne LiDAR machine learning tree species classification
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