Fig. 5: Classification results for concealed chemical samples.

a Schematic illustration of chemical classification through a visibly opaque paper cover; the explosive samples were hidden, i.e., remained undetected under visible illumination. b Ground truth labels and model predictions after spatial majority voting for KNO₃, PETN, RDX, and TNT. c Confusion matrix summarizing the classification performance for the concealed explosive samples. d Sample pictures with and without concealment, and our network predictions for a scenario involving multiple types of concealed chemicals within the same field of view. Note that the models were trained exclusively on uncovered samples