基于三维点云的苹果树冠层光照分布模型研究

为给果园精细管理中果树修枝整形、果实品质评价以及果实产量估算等提供科学的理论依据和技术指导,以果园自然开心形苹果树为研究对象,基于果树三维点云结构,进行果树冠层空间光照分布建模研究。用三维点云重构技术和点云分割技术获取果树不同高度的点云分层,分别使用像素占比和Graham扫描算法计算各高度点云分层垂直投影的有效投影面积和占地面积及有效叶面积指数。以果树冠层不同高度层的有效叶面积指数为自变量,对不同高度层平均相对光照强度进行线性回归,获得果树冠层光照分布模型,并对模型进行验证。结果表明:所建果树冠层光照分布模型的校正决定系数R2c为0.924,校正均方根误差RMSEC为0.05,验证决定系数R2v为0.955,验证均方根误差RMSEP为0.04,相对分析误差RPD为4.91。该模型具有较高的预测精度和较强的预测能力。

Canopy light distribution modeling for apple trees based on the 3D point cloud

In order to provide theoretical foundation and technical guidance for pruning,fruit quality evaluating and fruit production predicting,the open center shaped apple tree was taken as research object,and its canopy light distribution model was explored based on apple tree''s 3D point cloud structure.3D point clouds reconstruction and the point cloud segmentation technology were used to get apple tree''s point cloud at different altitude layers,and the Pixel proportion and Graham scanning algorithms were used to calculate effective projection area of each layer and its covering area and the effective leaf area index of each layer.The apple tree canopy light distribution model was investigated between the actual illumination of each layer and its effective leaf area index.The model calibration and validation results showed that its calibration reached 0.924,and its root mean square error correction (RMSEC) was 0.05;its validation reached to 0.955,its root mean square error of prediction (RMSEP) was 0.04,and its relative percent deviation (RPD) was 4.91 indicating this model had high prediction precision and strong ability of prediction.