Fractal Dimension and Lacunarity of Psoriatic Lesions — A Colour Approach —

Fractal measures like fractal dimension and lacunarity are widely-used for the analysis of textures, or any images with self-similar content. However, all the existing approaches are defined for one dimensional signals or binary images with extension to grey-scale images. We propose a colour approach, derived from the existing probabilistic algorithm for the computation of the fractal dimension and lacunarity. We used this approach for the evaluation of the skin lesions, in case of psoriasis. We show that there is correlation between the severity of a psoriatic lesion and the fractal dimension, when we compare two lesions of the same person. Lacunarity can be used as a complementary tool to interpret the results and distinguish between two lesions with the same fractal dimension. We discuss the results and then draw the conclusions. Key-Words: fractal dimension, lacunarity, colour images, texture, psoriasis, skin lesions