On Symmetry

Symmetry, in the sense of repetitive spatial arrangements, takes many specific forms that we encounter routinely, usually recognize visually, and have some difficulty in quantifying. As there are many types of symmetry, some of them partial or imperfect, so there are many measurement approaches. Some of these consider only the outline or boundary of an object, others include the interior structure, some apply to an entire image, while others operate on individual objects. Examples of the various classes of symmetry and several methods for analysis are presented.