WHEN MAKING A QUALITATIVE EXAMINATION OF A MICROSTRUCTURE, the interpretation of the structure is to a high degree based on the knowledge and experience of the observer. In quantitative metallography/materialography the constituents in the microstructure are measured to provide more reliable data for materials engineering and quality control purposes. Typical microstructural measurements include the length, width, and area of features or the relative amount of a structure or phase. The application of stereological principles enables two-dimensional measurement data extracted from metallographic/materialographic specimens to provide accurate information about three-dimensional structures increasing the usefulness and importance of quantitative microstructural analysis. It can be tedious to implement quantitative methods. Digital image analysis equipment and software have been developed as tools to automate the collection and reporting of quantitative data.