Fig. 13

The feature extraction for the one-class classification based on the estimation of the reference templates via \(\mathcal {D}_{{\textrm{t}} \hat{\textrm{t}}}\) and \(\mathcal {D}_{\textrm{t}}\) and the printed codes via \(\mathcal {D}_{{\textrm{x}} \hat{\textrm{x}}}\) and \(\mathcal {D}_{\textrm{x}}\) terms