Visual recognition and categorization on the basis of similarities to multiple class prototypes

One of the difficulties of object recognition stems from the need to overcome the variability in object appearance caused by pose and other factors, such as illumination. The influence of these factors can be countered by learning to interpolate between stored views of the target object, taken under representative combinations of viewing conditions. Difficulties of another kind arise in daily life situations that require categorization, rather than recognition, of objects. Although categorization cannot rely on interpolation between stored examples, we show that knowledge of several representative members, or prototypes, of each of the categories of interest can provide the necessary computational substrate for the categorization of new instances. We describe a system that represents input shapes by their similarities to several prototypical objects, and show that it can recognize new views of the familiar objects, discriminate among views of previously unseen shapes, and attribute the latter to familiar categories.