Fig. 1. Explosive powder surface contamination remote detection by NIR reflection

Fig. 2. Spectral feature aliasing of NQ and chemical fiber cloth base

Fig. 3. Diagram of explosive powder surface contamination remote detection based on NIR reflectance spectroscopy

Fig. 4. Reflectance spectra of samples

Fig. 5. Factor scores of model

Fig. 6. Correction score image and recognition result of CL-20
(a): Correction score of CL-20; (b): Recognition result after threshold discrimination overlayed on Infrared image

Fig. 7. Removing glares and shadows
(a): Glares and shadows in the original image; (b): Scores image after glares and shadows removed

Fig. 8. Comparison of spectra between RDX and the noise
(a): Reflectivity spectra; (b): Pretreated spectra

Fig. 9. Classification result of multi-explosive powder surface contamination
(a): AP; (b): CL-20; (c): NQ; (d): RDX; (e): TATB; (f): Fireworkers and firecrackers