ESTIMATION OF THE HEIGHT AND ANGLES OF ORIENTATION OF THE UPPER LEAVES IN THE MAIZE CANOPY USING STEREOVISION
ESTIMATION OF THE HEIGHT AND ANGLES OF ORIENTATION OF THE UPPER LEAVES IN THE MAIZE CANOPY USING STEREOVISION
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DOI：
10.1051/agro:19940305
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发表时间：
1994-01-01
期刊：
影响因子：
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通讯作者：
VALERY, P
中科院分区：
文献类型：
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作者：
IVANOV, N;BOISSARD, P;VALERY, P
已构建植被 3D 模型以允许进行各种模拟，例如传入辐射的拦截、辐射传输、遥感中的反射率模拟、植物功能研究和种间竞争。此类 3-D 模型的构建基于简单的几何假设和若干产生规则（例如，生长、分支）。它带来了两个问题：在田间采集大量关于叶子高度和方向角的数据；模型的验证及其在现场规模上的适用性评估。本文提出了一种基于立体视觉的 3D 采集和重建方法，即使用 2 个同步 CCD 或摄影相机采集数据。我们首先证明托斯卡尼的相机校准方法可以在现场的实际条件下使用。然后，我们将该方法应用于高的玉米冠层（2.50 m 高），因为该冠层允许在田间轻松进行控制测量。给出了叶子位置和方向的估计结果。该方法可以估计叶片和茎的特征点的 X、Y 和 Z 坐标。该方法提供叶片倾斜角度的能力被评价为相当好。由于隐藏区域的困难，仅重建属于上 4 层的叶子。我们讨论了这个问题，并展示了作物结构的辅助信息如何与立体视觉获得的数据互补。
3D models of vegetation have been constructed to allow various simulations, such as the interception of incoming radiation, radiative transfer, reflectance simulation in remote sensing, study of plant function, and interspecies competition. The construction of such 3-D models is based upon simple geometric assumptions and several production rules (eg, growing, branching). It poses 2 problems: the acquisition of a large amount of data on leaf heights and orientation angles in the field; and the validation of the model and assessment of its suitability on the scale of the field. This paper presents a method of 3D acquisition and reconstruction based upon stereovision, ie upon the acquisition of data using 2 synchronized CCD or photographic cameras. We first show that Toscani's method of camera calibration can be used under real conditions in the field. We then apply the method to a tall maize canopy (2.50 m high) because this canopy allows easy control measurements to be made in the field. Results on the estimation of position and orientation of the leaves are presented. This method allows the estimation of the X, Y and Z coordinates of characteristic points of laminae and stems. The ability of the method to provide inclination angles of the leaves was evaluated to be rather good. Only the leaves belonging to the 4 upper layers were reconstructed because of the difficulties due to hidden areas. This problem is discussed and we show how auxilliary information on crop structure may be complementary to data obtained from stereovision.