Comparison between different image acquisition methods for grain-size analysis and quantification of ceramic inclusions by digital image processing: how much similar are the results?

This paper focuses on the statistical comparison between the abundance and grain-size distribution of inclusions in pottery, determined by digital image process on images acquired using different methods (crossed-polarized light optical microscopy, back-scattered scanning electron microscopy (SEM) and microchemical mapping also under SEM). The results clearly indicate that the acquisition method deeply affects the absolute quantification, resulting in highly underestimated values for crossed-polarized light images with respect to those obtained from the microchemical mapping. Besides absolute quantification, the grain-size distribution shows some small differences among acquisition methods both in mean and variance values although frequency distributions and cumulative curves of inclusions show some similarities regardless of the acquisition method. Differences in terms of abundance and grain-size distribution of inclusions on the same sample are here analyzed and related to the limitations of each acquisition method.