1. A method for selecting spectral bands for material classification in which material classification uses multi-spectral BRDF (bidirectional reflectance distribution function) slice images captured under multiplexed illumination, the method comprising: analysis of a database of labeled training material samples within a multi-class classification framework, captured using a large number of spectral bands, so as to select a subset of spectral bands, wherein the number of selected spectral bands in the subset is smaller than the large number of spectral bands, wherein the selected spectral bands in the subset have a significant aptitude for distinguishing between different classifications of materials, and wherein the significant aptitude for distinguishing between different classifications of materials comprises an aptitude such that accuracy of material classification using the selected spectral bands in the subset are comparable to accuracy of material classification using the large number of spectral bands.