Picture Segmentation And Description

Descriptions of the structure of a picture or scene generally refer to objects or regions in the scene. Thus, to construct a description, it is generally necessary to segment the scene into meaningful parts. When the parts have gray levels (or colors) that lie in different ranges, this is easy to do by simple thresholding, or by edge detection using simple differencing operations. When the parts differ in texture, rather than in gray level, the thresholding and edge detection approaches can be generalized to work in a variety of cases; the basic approach involves preprocessing and averaging prior to the thresholding or differencing step. This approach is based on the assumption that textural differences between regions are generally associated with differences in the average values of some simple local property. Examples of segmenta-tions obtained by these methods will be given.