Fig. 9From: Unsupervised learning approach to automation of hammering test using topological informationFourier spectrums of a the computed model, b a non-defective sample and c a defective sample from the 15° delamination test block. The model’s spectrum bears more similarities to the non-defective spectrum than to the defective spectrum: the correlation distance between the model and the non-defective sample was 0.10 whereas it was 0.33 for the defect sampleBack to article page