%0 Journal Article %@ 1070-9908 %A Rusu, Cristian %A Dumitrescu, Bogdan %A Tsaftaris, Sotirios A. %D 2014 %F eprints:1917 %I IEEE %J IEEE Signal Processing Letters %K Dictionary learning; Shift-invariant learning; Sparse representations %N 1 %P 6-9 %T Explicit Shift-Invariant Dictionary Learning %U http://eprints.imtlucca.it/1917/ %V 21 %X In this letter we give efficient solutions to the construction of structured dictionaries for sparse representations. We study circulant and Toeplitz structures and give fast algorithms based on least squares solutions. We take advantage of explicit circulant structures and we apply the resulting algorithms to shift-invariant learning scenarios. Synthetic experiments and comparisons with state-of-the-art methods show the superiority of the proposed methods.