0957-4174/$ see front matter 2011 Elsevier Ltd. A doi:10.1016/j.eswa.2011.08.165 ⇑ Corresponding author. Tel.: +39 0547 339121; fax E-mail addresses: [email protected] (L. Nanni), (S. Brahnam), [email protected] (A. Lumini). Presented in this paper is a novel feature extractor technique based on texture descriptors. Starting from the standard feature vector representation, we study ...

G-Frames in Hilbert spaces are a redundant set of operators which yield a representation for each vector in the space. In this paper we investigate the connection between g-frames, g-orthonormal bases and g-Riesz bases. We show that a family of bounded operators is a g-Bessel sequences if and only if the Gram matrix associated to its denes a bounded operator.