土壤样本分形几何特征的图像分析方法

土壤水分的持留与水分和溶质的运移,在很大程度取决于土壤孔隙的几何性质,而用数字图像处理方法能够较准确地加以识别。本文采用面积法和周长法分别计算了土壤样本图像的孔隙分形维数和多重孔隙轮廓线分形维数,并分析了它们同土壤质地之间的关系。结果表明,土壤孔隙空间在一定尺度范围内才存在明显的分形特征,土壤质地越细(粘粒含量越高)分形维数越大。与周长法相比较,用面积法计算的孔隙分形维数对土壤质地更为敏感。

ON FRACTAL GEOMETRY CHARACTERISTICS OF SOIL SAMPLE IMAGES

Water retention, water flow and solute transport in soil, to some extent, depend on geometric characteristics of the soil pore, which can be accurately identified with the digital image analysis method. In this article, pore fractal dimensions and multiple pore outline fractal dimensions of some soil sample images are calculated with the area method and circumference method, separately. And the relationship between those fractal dimensions and soil texture is discussed. The results show that obvious fractal features can be found only of soil pore spaces of a certain scale. The finer the soil texture (or the higher the clay content), the higher the value of the fractal dimension. Comparatively, the pore fractal dimension calculated with the area method is more sensitive to soil texture than with the circumference method.