Clustering is the task of grouping objects into different groups, referred to as clusters. Different clustering methods have their own way of choosing which objects belong to which clusters. One commonality is that similar objects tend to be in the same cluster. A distance function determines what is considered similar and what is not. The most common distance function is the Euclidean Distance, which uses a straight line between two points in Euclidean space as a basis for the distance.

Dubey et al. \cite{dubey2013infected} proposed using K-Means clustering to segment the infected part of an apple.