Image analysis is the qualitative or quantitative characterization of two- or three-dimensional digital images. In its simplest form, image analysis is the manual measurement of an image using a scaled ruler. This is a time-intensive way to generate data associated with an image, and it is not in the scope of this chapter (see Optical Microscopy 〈776〉). Image analysis is primarily a size and shape analysis and yields data that are complementary to many other techniques such as laser diffraction and sieve analysis.