Fractal texture analysis of bread crumb digital images

A fractal texture analysis technique was applied to bread crumb digital images. Fractal dimensions obtained from several methods (fractional Brownian motion, frequency domain, relative differential box-counting, morphological fractal, mass fractal and random walks methods) were investigated in order to determine their capability to accurately describe the surface roughness of bread crumb images or the visual appearance of bread crumb in meaningful terms. A total of 500 bread crumb images of different porosity and grain quality were analysed. It was found that bread crumb appearance could be effectively quantified by the fractal dimension of its digital image. Correlations of fractal dimensions with mean cell area, standard deviation of cell area and void fraction were variable for the fractal methods. While the mass fractal method measured better crumb heterogeneity, other methods quantified coarseness, cell-cell wall ruggedness and cell wall tortuosity. A vector comprising fractal dimensions would objectively depict crumb grain and would allow comparisons between different bread crumb images.