Fig. 19From: Image life trails based on contrast reduction models for face counter-spoofingClusters from 60-natural spectral descriptors and 60 print spectral descriptors. N S = 1 (which means only one random scan was generated per image statistic) and scan parameters were: Image-statistic or patch size W × W , W = 21 and walk length (complete) covering full image-statistic, L = W2Back to article page