“V”字形苹果幼树二维图像的分形特征

Fractal Characteristics of Two-dimensional Images of Young Apple Trees Trained to V-shaped Configuration

果树的树体结构对树木的生长和生产力具有极为重要的影响。然而目前对幼树树形特征的研究和评价较少。2009-2011年,采用计盒维数和Photoshop图像处理技术,调查不同方位及不同品种两年生"V"字形苹果幼树二维图像的分形维数与分形特征。从"V"字树形整体水平上看,果树侧视图的分形维数按品种排序为富红早嘎>红盖露>玉华早富>长富2号>丽嘎啦>烟富6号,变化范围为1.650～1.700;正视图的分形维数按品种排序为红盖露>玉华早富>丽嘎啦>烟富6号>富红早嘎>长富2号,变化范围为1.583～1.631;正视和侧视图总体分形维数按品种排序为红盖露>玉华早富>丽嘎啦>富红早嘎>长富2号>烟富6号,变化范围为1.620～1.660。从"V"字形树的局部特征看,树体由东边和西边树组成。6个品种东边和西边苹果树侧视图的分形维数分别为1.593～1.683和1.645～1.720;正视图的分形维数分别为1.548～1.627和1.568～1.657。"V"字形苹果树东边树的二维图像正视和侧视分形维数都比西边树小。因此,果树二维图像的分形维数随着方位和品种而变化,可以表征不同品种及不同方位树体结构特征,并可用来指导幼树的整形修剪。

The architectures of fruit trees are very important to their growth and productivity. Howev- er, there have been few reports on the research and assessment of the architectures of V-shaped-con- figured young apple trees. The fractal dimension of two-dimensional images of 2-year-old apple trees with this configuration with different cultivars at different orientations were investigated employing box-counting and Photoshop image processing technology during 2009-2011. On the whole level, the fractal dimensions of trees ranged from 1. 650-1. 700 for side views and from 1. 583-1. 631 for front views and the ranking order was Honggailu〉Yuhua Early-maturing Fuji〉Li Gala〉Yanfu No. 6〉 Fuhong Early-maturing Gala〉Nagafu No. 2 and Fuhong Early-maturing Gala〉 Honggailu〉Yuhua Early-maturing Fuji〉Nagafu No. 2〉Li Gala〉Yanfu No. 6 respectively. The total fractal dimensions of front views and side views ranged from 1. 620--1. 660 and the ranking order was Honggailu〉Yu- hua Early-maturing Fuji〉Li Gala〉Fuhong Early-maturing Gala〉Nagafu No. 2〉Yanfu No. 6. On the partial level, the tree configuration was composed of eastern and western trees. The fractal dimensions of side views ranged from 1. 593--1. 683 for eastern trees and from 1. 645--1. 720 for western trees. The values of front views ranged from 1. 548--1. 627 and from 1. 568--1. 657 respectively. The values of front and side views of eastern trees were both smaller than western trees. Hence, the frac- tal dimensions of two-dimensional images of apple trees trained to V-shaped configuration differed and varied with their cultivars and picture-taking directions, and could be employed to evaluate the struc- tural characteristics of young trees with different eultivars at different orientations, and to guide train- ing and pruning.