Unsupervised change detection in the feature space using kernels

In this paper we propose an unsupervised approach to change detection by computing the difference image directly in the feature spaces. The resulting difference kernel, that is a combination of kernels computed on the coregistered and radiometrically matched input images, is used to train a nonlinear partitioning algorithm. In order to apply the kernel k-means, issues related to the initialization and to the tuning of parameters (e.g. the Gaussian RBF bandwidth) are considered. To validate the proposed unsupervised algorithm, two multitemporal VHR remote sensing images are used.