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1.2 Pattern Similarity and PR Tasks 3

Assessing the similarity of patterns is strongly related to the proposed pattern
recognition task as described in the following.

1.2.1 Classification Tasks
When evaluating the similarity among objects we resort to feutures or attributes
that are of distinctive nature. Imagine that we wanted to design a system for
discriminating green apples from oranges. Figure 1.1 illustrates possible
representations of the prototypes "green apple" and "orange". In this discrimination
task we may use as obvious distinctive features the colour and the shape,
represented in an adequate way.

Figure 1.1. PossiL., :epresentations of the prototypes "green apple" and "orange".

Figure 1.2. Examples of "red apple" and "greenish orange" to be characterized by
shape and colour features.