基于分形维数的梗丝形态差异性评价方法

Method for evaluation of morphological difference between cut stems based on fractal dimension

为对梗丝形态差异性进行评价,通过测量单一形态梗丝周长、面积并采用"小岛法"计算其分形维数及形态指数,以叶丝形态为标准,选取梗丝与叶丝分形维数及形态指数的差异为指标,建立梗丝形态差异性系数模型及评价方法并验证分析。结果表明:(1)单一形态梗丝拟合方程决定性系数R^2均达到0.850,且均方差及残差均较小,表明"小岛法"可准确计算其分形维数。(2)梗丝形态具有分形特性且不同形态梗丝分形维数具有明显差异,随着分形维数逐渐增大梗丝形态越来越不规则。(3)所建梗丝形态差异性系数模型■,决定性系数R^2达到0.948,F检验达到显著水平表明回归模型具有统计学意义,且模型经验证准确可靠。(4)初步建立了一种梗丝形态差异性评价方法,以差异性系数e为指标,梗丝形态间差异性小(e≤0.491);较小(0.491<e≤0.813);适中(0.813<e≤1.189);较大(1.189<e≤1.565);大(e>1.565),该方法可通过定量指标实现对梗丝形态差异性的定性分析。

To evaluate the morphological difference of cut stems, fractal dimension and morphological index were calculated by slit island method through measuring perimeter and area of single morphological cut stems. Taking the morphology of cut tobacco as standard, a model and evaluation method for morphology difference of cut stems were established. Analysis was verified by taking the difference of fractal dimension and morphological index of the cut stem and cut tobacco as indexes. Results showed that:1) determinant coefficients of fitting equations of single morphological cut stems all reached 0.850, with mean square error and residual error were both smaller. This indicates that the slit island method can accurately calculate its fractal dimension.2):the morphology of cut stems possessed fractal characteristics and there was significant difference in fractal dimension among cut stems of different morphologies. With the increase of fractal dimension, the morphology of cut stems became more and more irregular. 3):difference coefficient model of morphology of cut stems was proved to be accurate and reliable (Ye=4.825XDi-D'-1.149XK-K'+0.320, with determinant coefficient reaching 0.948. F test reached significant level, indicating that the regression equation was of statistical significance. 4):method for evaluating morphology difference of cut stems was established preliminarily. By taking difference coefficient e as an index, there was no difference (e≤0.491), small difference (0.491 <e≤0.813), moderate difference (0.813 <e≤1.189), relatively large difference (1.189<e≤1.565), large difference (e>1.565) between morphology of cut stems. Qualitative analysis of morphology difference of cut stems can be realized by means of quantitative indexes.