Size and shape analysis of sedimentary grains by automated dynamic image analysis

The application of Automated Dynamic Image Analysis (ADIA) for measuring the size and shape of sedimentary grains is presented. This technique determines the size and shape of a large number of particles (typically 5,000 to 50,000 or greater) in the size range between 10 to 1,500 mu m. ADIA measurements are carried out using a RapidVue particle analyzer. The size and shape of particles are obtained by analyzing digital images. Each image is composed of shapes representing two-dimensional projections of particles. The analysis yields the area and perimeter of each particle cross-section, which are transformed into size-independent shape values. The analysis of such a large number of particles results in a very small statistical variation of the results, ca. 0.3% for 50,000 particles. Since operator selection of images does not enter the measurement procedure, the risk of bias caused by subjective sample selection is eliminated. ne combination of ADIA with a two-dimensional Kolmogorov-Smirnov test, allows the identification of similarities and differences between sedimentary grains.