Department of Information Engineering, University of Padova, via Gradenigo 6B, 35131 Padova, Italy.|Department of Information Engineering, University of Padova, via Gradenigo 6B, 35131 Padova, Italy.|Department of Information Engineering, University of Padova, via Gradenigo 6B, 35131 Padova, Italy.|Department of Information Engineering, University of Padova, via Gradenigo 6B, 35131 Padova, Italy.