《实时动态多功能双目立体摄影测树仪设计》（doi: 10.11975/j.issn.1002-6819.2018.22.008）是由刘金成、冯仲科等发表在《农业工程学报》34卷22期“ 农业装备工程与机械化”板块的学术论文，被美国The Engineering Index (EI)源刊检索。

      为了实现林木精准实时定位，满足森林资源调查中多因子精准计测的需求，本文设计研发了一种集单木像对解算和林分点云测量于一体的多功能、高精度、实时定位的实时动态（real - time kinematic, RTK）双目立体摄影测树仪，该仪器测量精度符合林业调查的精度要求，可在森林资源调查及精准林业工作中推广使用。

      《农业工程学报》为全国中文核心期刊，在最新版的《中文核心期刊要目总览》中位居“农业工程类”期刊榜首；2001年入选中国期刊方阵“双效”期刊；被中国科协主办的《中国学术期刊文摘》选为首批收录期刊；2009年入选“中国科协精品科技期刊工程项目”期刊；先后被美国工程索引（EI光盘版）、英国国际农业与生物中心（CAB International）、美国剑桥科技文摘(CSA)等15家检索系统、数据库收录。

Design of real - time kinematic multi-functional binocular stereo-photogrammetric dendrometer

Abstract: The construction of green ecological civilization is the key to ecologically sustainable development. The quick and accurate acquisition of multivariate forest resource factors is of great significance for the prompt understanding of forest ecosystem and its changing patterns. With the development of science and technology in the forestry survey, a variety of multifunctional dendrometers have been constructed, which basically solved the technical problems of forestry observation. However, there are still many deficiencies in existing forestry equipment, such as low integration degree, insufficient functions, high cost and low measurement accuracy. Currently, there is no dendrometer capable of obtaining accurate geographic location of trees. In this research, we designed a multi-function, high-precision and real-time positioning RTK (Real-Time Kinematic) binocular photogrammetric dendrometer. The main hardware components of the equipment included RTK module, CCD (Charge Coupled Device) image acquisition module, MEMS (Micro-Electro-Mechanical System) sensor position module, main control storage module-portable PDA (Personal Digital Assistant), while the auxiliary components included fixed cloud platform, lithium battery, and telescoping mast. The software was developed by a modular structure compiled in Android Studio 2.2 development environment based on the Java language. The equipment’s basic operating principle was based on multifunctional photogrammetry, GNSS (Global Navigation Satellite Systems) spatial positioning technology, trigonometric function principle, binocular photogrammetry principle and SfM (Structure from Motion) vision algorithm. The equipment had the capability to perform many functions such as the real-time position of trees, downsizing of sample trees in a forest stand, DBH (Diameter at Breast Height) measurement, tree height measurement, tree density measurement, and forest stand spatial structure parameter measurement. For the single tree measurement model, the real-time positioning of single trees, tree DBH and tree height measurement function was designed and implemented. And for forest stand measurement model, we proposed and implemented the “imitation route method”. The experiment was carried out on 30 test trees (including both coniferous and broad-leaved trees) of 4 different tree species we selected in Haidian district, Beijing, with single tree measurement mode. Our equipment measured the real-time tree position, DBH, and height of trees in the study area. This equipment had an advantage in measuring ancient trees, precious tree species, or trees that were difficult to measure manually. The results showed the accuracy of DBH measurement was 97.11%, and the accuracy of tree height measurement was 94.72%. To find the forest stand measurement, a relatively flat artificial forest in Haidian district of Beijing was selected as the experimental area, after considering the influence of topographic factors on measurement results. According to the terrain conditions, growth and distribution of trees, the scheme of "imitation route" was designed to obtain forest stand images. The pix4D commercial software was used for quick and accurate establishment of the three-dimensional point cloud model of the forest stand. Our results showed that the average DBH was 17.9 cm, while the average tree height was 18.26 m, density was 928 trees/hm², angular scale was 0.675, size ratio was 0.625, and mingling intensity was 0.200 ss. The accuracy in the measurement of the forest stand DBH was 97.18%, which was consistent with the measurement accuracy of 97.11% of the single tree measurement mode. The preliminary test verified that the RTK tree-meter had unique advantages in real-time measurement of the sample tree position and three-dimensional point cloud restoration of the stand. The forest stands investigation factors such as the position of trees, average DBH, average height, tree density and the spatial structure parameters of forest stand such as angle scale, size ratio and mixed degree were extracted efficiently, which had a positive effect on the research of small and medium-sized forest plots. The precision of this equipment was in the range specified in China's national forest resources continuous inventory technical regulations (2014 edition) and meets with the requirements of forest survey.

Keywords: forestry; measurements; design; RTK (real-time kinematic) tree measuring instrument; stereo-photogrammetry; point cloud; forest measurement; spatial positioning

引文格式：

刘金成，冯仲科，杨立岩，Abdul Mannan. 实时动态多功能双目立体摄影测树仪设计[J]. 农业工程学报，2018，34(22)：61－68.      doi: 10.11975/j.issn.1002-6819.2018.22.008  http://www.tcsae.org

 
Liu Jincheng, Feng Zhongke, Yang Liyan, Abdul Mannan. Design of real-time kinematic multi-functional binocular stereo-photogrammetric dendrometer[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2018, 34(22): 61-68. (in Chinese with English abstract) 

doi: 10.11975/j.issn.1002-6819.2018.22.008  http://www.tcsae.org