Figure 9

Importance of model estimation when compared to a blind authentication test. ROC curves comparing different degrees of knowledge about the opponent channel while the true opponent printing process model has parameters (σ = 40,m _b = 40, and μ _w = 160). ‘True model’: the receiver knows exactly this model, ‘Blind model’: the receiver uses arbitrarily his printing process to model it, and ‘Est. model’: the receiver estimates the opponent channel using N _o = 2,000 observations.