Critical scale for unsupervised cluster discovery

Abstract

This paper addresses the scale-space clustering and a validation scheme. The scale-space clustering is an unsupervised method for grouping spatial data points based on the estimation of probability density function (PDF) using a Gaussian kernel with a variable scale parameter. It has been suggested that the detected cluster, represented as a mode of the PDF, can be validated by observing the lifetime of the mode in scale space. Statistical properties of the lifetime, however, are unclear. In this paper, we propose a concept of the 'critical scale' and explore perspectives on handling it for the cluster validation. © Springer-Verlag Berlin Heidelberg 2007.