A method and an apparatus for processing an image generate a first vector of a first number dimension for the image from a first number of points of the image based on topological information of the first number of points, and the first vector for the image is invariant to rotation and scaling in creating the image. The first number of points may be locations of a set of rotation and scaling invariant feature points for the image, and the generated first vector may be a graph spectrum of a pair-wise distance matrix generated from the first number of points of the image.