基于Photoscan软件测量城市行道树胸径的可行性  

A Feasibility Study to Measure the DBH of Street Trees Using Photoscan

作　　者：娄婧 梁陈涛 王慧梅 王文杰[2,3] Lou Jing;Liang Chentao;Wang Huimei;Wang Wenjie(College of Chemistry,Chemical Engineering and Resource Utilization,Northeast Forestry University,Harbin 150040,China;Northeast Institute of Geography and Agroecology,Chinese Academy of Science,Changchun 130102,China;College of Forestry and Biotechnology,Zhejiang Agriculture&Forestry University,Hangzhou 311300,China)

机构地区：[1]东北林业大学化学化工与资源利用学院,哈尔滨150040 [2]中国科学院东北地理与农业生态研究所,长春130102 [3]浙江农林大学林业与生物技术学院,杭州311300

出　　处：《中国城市林业》2023年第3期60-67,共8页Journal of Chinese Urban Forestry

基　　金：国家自然科学基金(31670699)。

摘　　要：行道树胸径的精确测量是城市森林管理的基础,如何利用网络街景大数据与摄影测量技术实现城市行道树测量是一个新兴领域。文章通过沿城市道路采集的数码图像,测试单相机采集方式结合Photoscan软件生成的点云模型完整度、模型生成耗时和模型测量准确度的潜力。结果表明:利用Photoscan生成完整可测量的三维模型,其采集数码图像的像素不应低于2048×1536或单株树木采集的图像不应小于4张,模型生成耗时随图像像素、数量线性增加(R2>099,P<0001),行道树周围环境影响点云模型的完整度,在公园、马路、幕布背景下,行道树模型完整率仅为30%,而背景为广告牌和灌丛时,可达到70%,Photoscan使用不同大小标尺时,测量值与实测值间相对误差多小于6%,标尺与树木胸径较为接近时,相对误差最小(<2%),模型中使用单标尺,Photoscan可以实现25棵树的测量,相对误差<4%,其中前10棵树的测量误差更小(<15%),目前街景图片尚不能用于构建点云模型,预期未来街景能与Photoscan结合实现单标尺多树木的测量。Precise measuring the diameter at breast height(DBH)of street tree is a basis for urban forest management,while utilizing big data from Street View Picture and Photographical measurement technology to measure street trees is a hot issue today.This paper uses digital images of trees collected along urban streets and tests the potential of the point-cloud model constructed by combining camera collection and Photoscan software in integrity,time consumption and measurement precision.The results show that Photoscan can be used to generate a complete and measurable point-cloud model,and the picture pixel should be no less than 2048∗1536 or at least 4 pictures for a single reconstructed tree stem.Time consumption is linearly related with picture pixel and the picture number utilized in point-cloud model(R2>099,P<0001).Surroundings of street trees also affect the integrity of reconstructed point-cloud model.In the case of parks,roads and curtains,the integrity is rather low(30%),and in the case of advertising boards and shrubs,it could be 70%.When Photoscan uses different sizes of standard,the relative errors reference to actual measurement is usually lower than 6%,when the tree DBH is similar to the standard,the precision could be improved to as low as<2%(relative error).Using a single ruler in the model,Photoscan can measure 25 trees with a relative error of<4%,among them,the measurement error of the first 10 trees is smaller(<15%).At the moment,street-view pictures cannot be used in point-cloud model construction.It is expected that Street View can be combined with Photoscan in the future to realize the measurement of multiple trees with a single standard inclusion.

关 键 词：城市行道树 街景照片测量 摄影测量技术 IMAGEJ Agisoft Photoscan PROFESSIONAL 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术] S687.1[自动化与计算机技术—计算机科学与技术]