Patent ID: 7630526

Claim:
A method of representing an image using one or more processors to process signals corresponding to the images, the method comprising: segmenting, using a processor, the image into component images; transforming, using a processor, the component images into the frequency domain; deriving, using a processor, a plurality of feature vectors using the transformed component images in the frequency domain, wherein said plurality of feature vectors has a grand mean, and wherein each feature vector belongs to a class with the feature vectors in a class having a class centroid; and generating and outputting descriptor data representative of the image, the generation of the descriptor data comprising performing, using a processor, at least one stage of discrimination transformations using a discrimination transformation matrix generated by forming a first matrix from the differences between the class centroids of the plurality of feature vectors and the grand mean of the plurality of feature vectors, forming a second matrix from the differences between said plurality of feature vectors and their respective class centroids; forming a third matrix by performing a singular value decomposition of the first matrix and taking the first q left singular vectors corresponding to the q largest singular values, wherein q is a first dimension value; forming a fourth matrix by performing a singular value decomposition to the product of the transpose of the third matrix and the second matrix, and taking the left singular vectors corresponding to the r smallest non-zero singular values, wherein r is a second dimension value, and forming the product of the third matrix and the fourth matrix to generate the discrimination transformation matrix.