Patent ID: 7680337
Filing Date: 2010-03-16
Classification: G06K

Abstract:
1. A process for identifying one or more materials in a scene by determining a subset consisting of a number N of members, denoted as endmembers, of a data set of spectral vectors, denoted as spectra, such that the endmembers may be taken in positive linear combinations to approximate the remaining spectra of the data set, comprising: a. gathering image data of the scene with a sensor; b. providing a data set comprised of a plurality of spectra from the image data; c. defining an error metric dependent on a vector difference between two spectra in the data set; d. selecting a first spectrum from the data set as the first endmember; e. for each spectrum in the data set, determining an initial weighting factor of the first endmember, such that f. selecting as a new endmember the spectrum from the data set whose residual generates the largest error metric; g. designating the new endmember as the currently-considered endmember; h. for each spectrum in the data set, i. for each of the endmembers selected prior to the currently-considered endmember, identifying the trial revised weighting factors that are negative, and determining revised weighting factors and revised residuals such that the revised weighting factors are non-negative and the revised residuals generate a smallest error metric; j. designating the revised weighting factors as weighting factors and the revised residuals as residuals; k. repeating steps f, g, h, i and j for all or a subset of spectra in the data set one or more times, until a total of N endmembers have been determined.