Image analysis techniques for determining the fractal dimensions of rock joint and fragment size distributions

Knowledge of the fractal dimensions of the spatial distribution and geometry of a system of rock joints, and of the distributions of the sizes and shapes of rock fragments provides a powerful tool for prediction of these variables in situations where they cannot be measured. The authors use active stereo image analysis techniques which require projection of a planar laser beam on to the conveyor belt, muck pile or rock face; then use a solid-state video camera plus frame grabber to capture images of the light stripe, now distorted by the rock joints and fragments, on to a computer where the data are rapidly analysed to produce x,y,z coordinates for all points scanned by the laser and cameras. They construct a 3D image for the surface scanned by the laser and camera and determine rock joint orientations and distributions and fragment size distributions from this image. -from Authors