基于分层理论与三维激光扫描的单木叶面积指数反演技术研究

Individual Tree LAI Inversion Technique Based on Stratification Theory and 3D Laser Scanning

以荔枝树、黑松、马尾松作为研究对象,采用LAI_-2200和Stonex X300三维激光扫描仪获取孤立冠层叶面积指数(LAI_g)、反演整体冠层叶面积指数(LAI_z),同时耦合分层理论,通过平面投影、轮廓提取、叶倾角矫正,得到分层叶面积指数(LAI_f);分析LAI_g、LAI_z、LAI_f三者间关系,验证单木LAI_反演精度。结果表明:单木叶面积分层垂直分布趋势与冠层叶片垂直分布轮廓趋势基本一致;荔枝、黑松和马尾松的LAI_z分别比LAI_f低75.78%、47.75%和18.21%;LAI_f与LAI_g具有极高的相关性,决定系数R2为0.992 3。因此,耦合分层理论与三维激光扫描技术的单木LAI_反演技术可以满足调查需求,为今后全方位多角度森林调查提供了重要的发展方向。

Taking Litchi chinensis, Pinus massoniana and Pinus thunbergii as objects. LAI-2200 and Stonex X300 were used to obtain Leaf Area Index of isolate canopy （ LAIg） , further to simulate Leaf Area Index of overall canopy （ LAIz ）. Simultaneously, the methods of planar projection, contour extraction and leaf angle correction were used to obtain Leaf Area Index of a layer （LAIf） coupled stratification theory. The simulation accuracy of Leaf Area Index of single tree were verified by analyzing correlation among LAIg, LAIz and LAIr. The results showed that the stratified vertical distribution of leaf area of single tree was consistent with the trend of vertical distribution profile of the canopy leaves. LAIz of L. chinensis, P. sthunbergii and P. massoniana were 75.78%, 47.75% and 18.21% low- er than LAIr of them, respectively. There were a very high correlation between LAIf and LAIs, of which the correla- tion coefficient R2 was 0. 992 3. Therefore, coupled stratification theory and the three-dimensional laser scanning technology meet the needs of the investigation, which can provide important development method to comprehensive and multi-angle forest survey.