Multivariate image analysis for inspection of multilayer films

The potential and effectiveness of near-infrared (NIR) hyperspectral imaging was investigated for rapid and nondestructive spectral-spatial inspection of functional multilayer films. A series of film samples having different combinations of layers were used to demonstrate the sensor performance. Multivariate Image Analysis (MIA) was applied to NIR hyperspectral images of unprinted multilayer films with different compositions to distinguish them regarding absence/presence of particular layers. Since printing of commercial brands on the films may interfere with product inspection, the ability of MIA to detect the presence of the functional layer (barrier) in spite of film surface printing was also assessed. The results show that the proposed MIA approach is successful at classifying multilayer films, even in the presence of printing.