A stereo imaging system for measuring structural parameters of plant canopies
A stereo imaging system for measuring structural parameters of plant canopies
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DOI：
10.1111/j.1365-3040.2007.01702.x
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发表时间：
2007-10-01
影响因子：
7.3
通讯作者：
Rascher, Uwe
中科院分区：
文献类型：
--
作者：
Biskup, Bernhard;Scharr, Hanno;Rascher, Uwe
植物不断调整叶片方向以应对环境的波动，以在面对不同强度和入射方向的阳光时保持辐射利用效率。存在多种测量冠层结构参数（例如叶角分布）的方法。然而，直接方法往往是劳动密集型的，而间接方法通常提供林分水平的统计信息，而不是单个叶子的统计信息。我们提出了一种基于区域的双目立体系统，由市售组件组成，允许在野外条件下在单叶水平上对中小型冠层进行三维重建。单叶的空间方向是使用现代、完善的立体匹配和分割技术通过自动化过程计算的，这些技术适应了植物冠层的特性，提供了高空间和时间分辨率（角度测量精度约为+/- 5度，最大采样率为每秒三帧）。我们的方法的适用性在三个案例研究中得到了证明：（1）跟踪单个大豆的二面角，以监测显示不同频率和幅度的夜间和白天叶子运动； (2) 通过量化天顶小叶角度分布的变化来诊断大豆的干旱胁迫； (3)测量封闭大豆冠层天顶叶角分布的日程。
Plants constantly adapt their leaf orientation in response to fluctuations in the environment, to maintain radiation use efficiency in the face of varying intensity and incidence direction of sunlight. Various methods exist for measuring structural canopy parameters such as leaf angle distribution. However, direct methods tend to be labour-intensive, while indirect methods usually give statistical information on stand level rather than on individual leaves. We present an area-based, binocular stereo system composed of commercially available components that allows three-dimensional reconstruction of small- to medium-sized canopies on the level of single leaves under field conditions. Spatial orientation of single leaves is computed with automated processes using modern, well-established stereo matching and segmentation techniques, which were adapted for the properties of plant canopies, providing high spatial and temporal resolution (angle measurements with an accuracy of approx. +/- 5 degrees and a maximum sampling rate of three frames per second). The applicability of our approach is demonstrated in three case studies: (1) the dihedral leaflet angle of an individual soybean was tracked to monitor nocturnal and daytime leaf movement showing different frequencies and amplitudes; (2) drought stress was diagnosed in soybean by quantifying changes in the zenith leaflet angle distribution; and (3) the diurnal course of the zenith leaf angle distribution of a closed soybean canopy was measured.