Mineral quantification by digital image analysis: I. A semi-automatic method

摘要

X-ray element maps and back-scattered electron images obtained in a scanning electron microscope with energy dispersive X-ray detection were analysed using digital image processing. This method is a useful tool for quantifying mineral mixtures, texture and porosity over a wide range, and in samples involved in petroleum research. The method is illustrated by a study of three artificial mineral mixtures, embedded in epoxy resin, with 0.001 - 1 mm grain size. The samples were examined in a SEM-EDX and noise was removed from the X-ray maps by applying suitable median filters. The images were then binarised and combined (boolean and/or arithmetic operators) or even quantified directly. Deviation of the values obtained from theoretical values was very low. The higher the number of areas studied (i.e., maps) in the samples, the lower the variation of data from the true value.