Patent ID: 6920231
Filing Date: 2005-07-19
Classification: G06K

Abstract:
1. A method of constructing a vector space in which a data sample relating to an object may be encoded, comprising: providing a raw matching score between each of a plurality of basis sample elements and each of a plurality of data samples in a first sample database; the samples in the first sample database being out-of-sample with respect to the basis sample elements; constructing a sample space from the raw matching scores, the sample space being defined by a basis set of sample modes, by generating a covariance matrix for the basis elements from the raw matching scores; and determining the eigenvectors and eigenvalues of the covariance matrix, the eigenvectors specifying the sample space modes; generating a rotation matrix, based on the eigenvectors of the covariance matrix, the rotation matrix mapping raw matching scores into sample space scores; and truncating the sample space by eliminating a subset of the sample space modes, the eliminated modes generally having the lowest eigenvalues, by determining a sample space score between each of a plurality of data samples in a second sample database and each of the sample space modes, the samples in the second sample database being out-of-sample with respect to the basis sample elements and the samples in the first sample database; and selecting a cut-off for eliminating a subset of sample space modes based on the distribution of said sample space scores for each of the sample space modes, the distribution being indicative of how well a sample space mode is able to discriminate between samples.