Fractal anisotropy measurement of bone texture radiographs

This communication presents a method to estimate the fractal anisotropy. This method consists in estimating the H(θ) parameter of an anisotropic fractional Brownian field depending on the direction θ. We have tested this method on synthetic isotropic and anisotropic images. Results are of good quality. Then, it was applied to bone radiographic images described by their anisotropy, non stationary, and textured character. 109 images (70 controls and 39 osteoporosis cases) were examined. Results show the efficiency of the method to discriminate the two populations. Moreover they show that the structural organization of bone is more anisotropic for the osteoporotic cases than for control cases in accordance with the natural evolution of bone tissue linked to osteoporosis.