Representation

A pattern is a physical object or an abstract notion. If we are talking about the classes of animals, then a description of an animal would be a pattern. If we are talking about various types of balls, then a description of a ball (which may include the size and material of the ball) is a pattern. These patterns are represented by a set of descriptions. Depending on the classification problem, distinguishing features of the patterns are used. These features are called attributes. A pattern is the representation of an object by the values taken by the attributes. In the classification problem, we have a set of objects for which the values of the attributes are known. We have a set of classes and each object belongs to one of these classes. The classes for the case where the patterns are animals could be mammals, reptiles etc. In the case of the patterns being balls, the classes could be football, cricket ball, table tennis ball etc. Given a new pattern, the class of the pattern is to be determined. The choice of attributes and representation of patterns is a very important step in pattern classification. A good representation is one which makes use of discriminating attributes and also reduces the computational burden in pattern classification.