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浙江大学学报（农业与生命科学版）
Journal of Zhejiang University (Agriculture and Life Sciences)  2018, Vol. 44 Issue (6): 748-754    DOI: 10.3785/j.issn.1008-9209.2017.07.131
    
Geometrical parameter calculation of excised wheat leaves based on image analysis
ZHANG Wanhong* 
(Institute of Soil and Water Conservation, Northwest A & F University, Yangling 712100, Shaanxi, China)
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Abstract  Aiming at some deficiency of geometrical parameter calculation in plant leaves at present, we proposed a computational method suitable for measuring area, length, width and perimeter of excised wheat leaves. Wheat image was segmented under a certain background by histogram algorithm. Leaf area was calculated by statistical image number method, and leaf perimeter was calculated on the distance between adjacent pixels of the blade edge. Leaf length and width were measured by improved minimum enclosing rectangle. Then the calculated results were compared with the measured values, and statistical analysis was carried out. The results showed the calculated results were close to the measured values. The root mean square error (RMSE) values for area, length and width of wheat leaves were 0.49 cm2, 0.57 cm and 0.04 cm, respectively. The coefficient of determination (R2) for area, length and width of wheat leaves were 0.99, 0.97 and 0.96, respectively. The differences in RMSE values were close to 0 and R2 values were close to 1, and the calculated results and the measured values were insignificant, indicating that the improved algorithms for measuring area, length, width and perimeter of wheat leaves are not influenced by wheat leaf shapes, suitable for different conditions, reliable and practicable.

Key words： wheat leaf      image segmentation      leaf area      leaf perimeter      leaf length      leaf width     
Published: 25 November 2018
CLC:  S 24  
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ZHANG Wanhong
Cite this article:

ZHANG Wanhong. Geometrical parameter calculation of excised wheat leaves based on image analysis. Journal of Zhejiang University (Agriculture and Life Sciences), 2018, 44(6): 748-754.

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http://www.zjujournals.com/agr/10.3785/j.issn.1008-9209.2017.07.131     OR     http://www.zjujournals.com/agr/Y2018/V44/I6/748


基于图像法的离体小麦叶片几何参数计算

针对目前植物叶片几何参数计算中的一些不足，提出适用于离体小麦叶片叶面积、叶长、叶宽和周长的计算方法。首先使用直方图阈值法对特定背景下小麦图像进行分割；然后采用统计像素数法计算小麦叶面积，采用叶片边缘相邻像素间距离的方法计算周长，使用改进后的最小外接矩形法计算叶长和叶宽；最后对计算结果与实测值进行比较，并使用统计分析方法对计算结果进行检验。结果显示，计算值接近实测值，叶面积、叶长和叶宽的均方根误差（root mean square error, RMSE）分别为0.49 cm2、0.57 cm、0.04 cm，决定系数（R2）分别为0.99、0.97、0.96。RMSE值接近于0、R2值接近于1，以及计算值与测量值之间存在的较小差异，表明改进后的叶长和叶宽算法的计算结果不受小麦叶片形状的影响，方法普适性好，且叶长、叶宽、叶面积和周长算法对相应参数的计算结果准确度高。

关键词： 小麦叶片,  图像分割,  叶面积,  叶周长,  叶长,  叶宽 
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[2] ZHANG Wanhong, LIU Wenzhao. Image segmentation method of plastic-film corn canopy[J]. Journal of Zhejiang University (Agriculture and Life Sciences), 2017, 43(5): 649-656.
[3] Lü Tengfei, Zhou Wei, Sun Yongjian, Zhu Yi, Yan Fengjun, Yang Zhiyuan, Ma Jun. Effects of different transplanting seedling ages and nitrogen managements on plant type of indica hybrid rice.[J]. Journal of Zhejiang University (Agriculture and Life Sciences), 2015, 41(2): 169-178.