“句芒号”激光光斑质心提取方法与稳定性分析  

Laser Spot Centroid Extraction Method and Stability Analysis of“Gou Mang”

作　　者：万科 黎荆梅 韩启金[3] 李功伟 王宁 徐兆鹏 赵航[3] 马灵玲 Wan Ke;Li Jingmei;Han Qijin;Li Gongwei;Wang Ning;Xu Zhaopeng;Zhao Hang;Ma Lingling(National Engineering Laboratory for Satellite Remote Sensing Applications,Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100094,China;University of Chinese Academy of Sciences,Beijing 100049,China;China Centre for Resources Satellite Data and Application,Beijing 100094,China)

机构地区：[1]中国科学院空天信息创新研究院遥感卫星应用国家工程实验室,北京100094 [2]中国科学院大学,北京100049 [3]中国资源卫星应用中心,北京100094

出　　处：《光学学报》2024年第6期362-373,共12页Acta Optica Sinica

基　　金：国家重点研发计划(2023YFB3907705)。

摘　　要：根据句芒号足印影像特点,提出一种针对复杂背景噪声的激光光斑质心提取方法:基于灰度转换模型去除地物背景,结合距离约束、高斯滤波和大津阈值分割去除影像噪声,并利用灰度重心法计算质心坐标。使用所提方法对多种地物类型仿真光斑和实测光斑进行质心提取,结果表明:所提方法的质心提取均方根误差约为0.074 pixel,最大误差约为0.482 pixel,对句芒号光斑影像的适应性较好。对句芒号足印影像光斑开展了稳定性分析,结果表明,所有激光波束的光斑质心坐标的标准差小于0.34 pixel,激光器与光轴监视相机的相对几何关系较为稳定。所提方法可用于激光光斑质心提取及稳定性监测,对句芒号激光数据处理和应用有一定参考价值。Objective The first Terrestrial Ecosystem Carbon Monitoring(TECM-1)satellite—Gou Mang was successfully launched on August 4,2022 in China.TECM-1 satellite is equipped with a multi-beam LiDAR which is mainly used to obtain the elevation of land and forest.The mission of measuring the elevation of a forest requires both high-ranging accuracy and horizontal positioning accuracy.The multi-beams LiDAR on the TECM-1 satellite is concurrently equipped with an optical axis monitoring camera to obtain the footprint images,including the ground images and spot images.The centroid of the laser spot in the spot image can indicate the laser pointing angle,helping reduce the horizontal positioning errors.However,the laser spot is inevitably influenced by the background features in the spot image,and traditional centroid extraction methods are difficult to achieve ideal accuracy.Many scholars have made improvements based on traditional methods,and most of them apply noise reduction processing to the spot image,such as grayscale threshold constraint and image filtering.However,due to the influence of photography conditions and complex terrain,it is challenging for these relatively simple noise reduction methods to separate the laser spot from background noise.The centroid extraction accuracy still faces challenges in complex background scenarios.We report a laser spot centroid extraction method against complex background noise,which can effectively remove background noise from the spot image.It achieves better adaptability and higher accuracy than previous methods.We hope that our research can provide a certain reference value for the future processing and application of laser data collected by the TECM-1 satellite.Methods A set of footprint images collected by the TECM-1 satellite consists of the ground image and spot image and the spot image can be considered to be formed by the laser spot and surrounding background features.The ground image and spot image are geometrically aligned and exhibit noticeable brightness difference

关 键 词：遥感 足印影像 激光光斑 影像噪声 光斑质心提取 

分 类 号：P236[天文地球—摄影测量与遥感]