An overview of present computer techniques of partitioning continuous-tone images into meaningful segments and of characterizing these segments by sets of "features" is presented. Segmentation often consists of two methods:boundary detection and texture analysis. Both of these are discussed. The design of the segmenter and feature extractor are intimately related to the design of the rest of the image analysis systemÂ¿particularly the preprocessor and the classifier. Toward aiding this design, a few guidelines and illustrative examples are included.