Abstract: Fruit tree architecture, changed by orchard pruning management, determines the internal light distribution and light interception efficiency, which affects fruit growth and development process in turn. Light distribution within fruit tree canopy is one of the important factors to optimize the tree architecture, and to improve the potential production and fruit quality. There were natural growth tree type and trimmed tree type used to analyze the effect of pruning on the canopy structure and light distribution for Wandao Myrica rubra. Multi‑view image sequence method was used to reconstruct the three‑dimensional (3D) structure for the tree canopy, combined with three‑dimensional radiation model and ray tracing algorithm to simulate the light distribution within the 3D canopy. The results showed that the multi‑view image method well reconstructed the canopy structure of Myrica rubra tree. There was satisfactory correspondence between acquired and measured tree canopy parameters, with the root mean squared error (RMSE) smaller than 19.3 cm. The natural growth tree had a more crowded structure, with relative concentrated leaves and more light interception at the top of the canopy. However, due to the occlusion of foliage and branches, the light interception in the middle and lower part was less. After pruning, the tree canopy height went to shorter and the branches went to looser and distributed more uniform. Due to the less occlusion of foliage and branches in the middle and bottom part, the overall leaf area increased by 16.3%. The light interception coefficient in the middle and bottom part was higher than that of the natural growth tree type. Pruning management in the orchard increased the ability of light interception by 15.8%. This study could be further used to analyze the effect of different tree type, caused by pruning management, on the canopy light distribution and light interception, which provides data reference for intelligent decision‑making of fruit tree pruning equipment.

Key words: Wandao Myrica rubra tree, multi?view images, 3D reconstruction, canopy structure, light distribution, radiation model

摘要： 果树冠层形态结构决定其冠层内部的光分布情况，果园修剪管理通过改变冠层内微环境进而影响果树的生长发育和光截获能力，最终影响果实产量和品质形成。以晚稻杨梅果树自然生长与修剪管理两种树型结构为研究对象，采用多视角图像序列法重建杨梅树冠层三维结构，结合三维辐射模型和光线追踪算法定量模拟冠层内光分布规律。结果表明，多视角图像序列法可以较好地重建杨梅树冠层形态结构，果树主要形态参数模型提取值与人工实测值之间具有较好的一致性，均方根误差RMSE<19.3 cm。自然生长树型结构较为紧凑，叶片相对集中，光截获量大多集中于冠层顶部，中下部由于枝条叶片的遮挡，截获光照较少。修剪后，果树矮化，枝条分布松散均匀，尤其冠层中下部枝条叶片遮挡较少，整体叶面积较自然生长树型增加16.3%，中下部光截获系数高于自然生长树型。修剪管理使得晚稻杨梅的叶片光截获能力提高15.8%。可用于定量分析不同修剪方案形成的树型结构对果树冠层光分布和光截获量的影响，为杨梅果树整形修剪装备智能化决策提供数据参考。

关键词: 晚稻杨梅, 多视角图像, 三维重建, 冠层结构, 光分布, 辐射模型