Stereology, or the quantitative evaluation of microstructures

SUMMARY A general survey is presented of the basic equations of stereology, that is, the quantitative relationships that exist between quantities measured on the two‐dimensional plane of polish or section and the magnitudes of microstructural features that occur in three‐dimensional space. A new and important branch of stereology concerns the quantitative relationships between structures in a thin foil and their projected images. Basic equations are given in the absence of overlap and truncation; then overlap and truncation corrections are indicated for simple cases. The methods of determining the size distribution of particles or grains are outlined. Finally, other important parameters are described, such as the mean free distance and the mean intercept length. The subject of stereology is not completely new to some, but there are still many experiments to be run and methods to be perfected. It is hoped that microscopists dealing with microstructures will be encouraged to apply quantitative methods in their work in order to advance our knowledge in this fascinating field.