Laboratory of Geo-Information Science and Remote Sensing, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands.
Sensors (Basel). 2012 Dec 13;12(12):17358-71. doi: 10.3390/s121217358.
In this paper, a laboratory goniometer system for performing multi-angular measurements under controlled illumination conditions is described. A commercially available robotic arm enables the acquisition of a large number of measurements over the full hemisphere within a short time span making it much faster than other goniometers. In addition, the presented set-up enables assessment of anisotropic reflectance and emittance behaviour of soils, leaves and small canopies. Mounting a spectrometer enables acquisition of either hemispherical measurements or measurements in the horizontal plane. Mounting a thermal camera allows directional observations of the thermal emittance. This paper also presents three showcases of these different measurement set-ups in order to illustrate its possibilities. Finally, suggestions for applying this instrument and for future research directions are given, including linking the measured reflectance anisotropy with physically-based anisotropy models on the one hand and combining them with field goniometry measurements for joint analysis with remote sensing data on the other hand. The speed and flexibility of the system offer a large added value to the existing pool of laboratory goniometers.
本文描述了一种在受控照明条件下进行多角度测量的实验室测角仪系统。商用机械臂使在短时间内获取整个半球面的大量测量成为可能，这比其他测角仪快得多。此外，所提出的设置还能够评估土壤、叶子和小冠层的各向异性反射率和发射率特性。安装光谱仪可以进行半球形测量或水平平面测量。安装热像仪可以进行热发射的定向观测。本文还展示了这三种不同测量设置的实例，以说明其可能性。最后，提出了应用该仪器的建议和未来的研究方向，包括一方面将测量的反射率各向异性与基于物理的各向异性模型联系起来，另一方面将它们与野外测角仪测量相结合，以便与遥感数据进行联合分析。该系统的速度和灵活性为现有的实验室测角仪提供了很大的附加值。
