sentences:  In application to image segmentation, spectral clustering is known as segmentation-based object categorization.Given an enumerated set of data points, the similarity matrix may be defined as a symmetric matrix formula_1, where formula_2 represents a measure of the similarity between data points with indices formula_3 and formula_4.The general approach to spectral clustering is to use a standard clustering method (there are many such methods, "k"-means is discussed below) on relevant eigenvectors of a Laplacian matrix of formula_1.