COMPUTER-AIDED QUANTITATIVE MICROSCOPY

Microscopy of materials specimens can provide important quantitative information about microstructures that can be related to processing history and composition on the one hand, and to properties and service performance on the other. Simple visual observation of images is not adequate to extract the important parameters, and is easily confused by the natural variability of the structure and the unfamiliarity of looking at three-dimensional structures in two-dimensional sections. Stereological tools to relate the two- and three-dimensional parameters are well developed. The use of computers makes it practical to perform image processing to extract the parameters and to carry out the appropriate calculations. The steps may be broken down for convenience into acquisition of images, processing of the gray-scale (or color) information, discrimination to select the features of interest, editing to correct defects, measurement of either feature-specific or global parameters, and interpretation. Examples of each are shown using a variety of materials specimens, using images from light and electron microscopes.