Measurements that can be performed on each of the individual features in images can be grouped into four general classes: brightness (including color values and param-eters such as density that are related to brightness), location (both absolute position and relative to other features present), size, and shape. Within each class, quite a variety of different specific measurements can be made, and there are also a variety of different ways to perform the operations. Most image analysis systems offer at least a few measures in each class. Users find themselves at some time or another having to select from several different measurement parameters. The problem is frequently to decide which of the measured parameters is most useful or appropriate for solving a particular problem.