Sun Wei-Qi, Zhao Yun-Sheng, Tu Lin-Ling
Guang Pu Xue Yu Guang Pu Fen Xi. 2014 Sep;34(9):2495-9.
In the present paper, the slope gradient, aspect, detection zenith angle and plant types were analyzed. In order to strengthen the theoretical discussion, the research was under laboratory condition, and modeled uniform slope for slope plant. Through experiments we found that these factors indeed have influence on plant hyperspectral remote sensing. When choosing slope gradient as the variate, the blade reflection first increases and then decreases as the slope gradient changes from 0° to 36°; When keeping other factors constant, and only detection zenith angle increasing from 0° to 60°, the spectral characteristic of slope plants do not change significantly in visible light band, but decreases gradually in near infrared band; With only slope aspect changing, when the dome meets the light direction, the blade reflectance gets maximum, and when the dome meets the backlit direction, the blade reflectance gets minimum, furthermore, setting the line of vertical intersection of incidence plane and the dome as an axis, the reflectance on the axis's both sides shows symmetric distribution; In addition, spectral curves of different plant types have a lot differences between each other, which means that the plant types also affect hyperspectral remote sensing results of slope plants. This research breaks through the limitations of the traditional vertical remote sensing data collection and uses the multi-angle and hyperspectral information to analyze spectral characteristics of slope plants. So this research has theoretical significance to the development of quantitative remote sensing, and has application value to the plant remote sensing monitoring.
在本文中,分析了坡度、坡向、探测天顶角和植物类型。为了加强理论探讨,研究在实验室条件下进行,为坡面植物构建了均匀坡度模型。通过实验我们发现这些因素确实对植物高光谱遥感有影响。当选择坡度作为变量时,随着坡度从0°变化到36°,叶片反射率先增加后降低;当保持其他因素不变,仅探测天顶角从0°增加到60°时,坡面植物的光谱特征在可见光波段变化不明显,但在近红外波段逐渐降低;仅坡向变化时,当坡面朝向光照方向时,叶片反射率最大,当坡面背向光照方向时,叶片反射率最小,此外,以入射平面与坡面的垂直交线为轴,轴两侧的反射率呈对称分布;另外,不同植物类型的光谱曲线彼此之间有很大差异,这意味着植物类型也影响坡面植物的高光谱遥感结果。本研究突破了传统垂直遥感数据采集的局限,利用多角度和高光谱信息分析坡面植物的光谱特征。因此本研究对定量遥感的发展具有理论意义,对植物遥感监测具有应用价值。