Objective Color Classification of Ecstasy Tablets by Hyperspectral Imaging

Authors


  • Supported in part by the Netherlands Organization of Scientific Research (NWO) and the Technology Foundation STW (MCGA: AGT07547).

Additional information and reprint requests:

Gerda Edelman, M.Sc.

Department of Biomedical Engineering & Physics

Academic Medical Center

University of Amsterdam

P.O. Box 22700

1100 DE, Amsterdam

The Netherlands

E-mail: g.j.edelman@amc.uva.nl

Abstract

The general procedure followed in the examination of ecstasy tablets for profiling purposes includes a color description, which depends highly on the observers' perception. This study aims to provide objective quantitative color information using visible hyperspectral imaging. Both self-manufactured and illicit tablets, created with different amounts of known colorants were analyzed. We derived reflectance spectra from hyperspectral images of these tablets, and successfully determined the most likely colorant used in the production of all self-manufactured tablets and four of five illicit tablets studied. Upon classification, the concentration of the colorant was estimated using a photon propagation model and a single reference measurement of a tablet of known concentration. The estimated concentrations showed a high correlation with the actual values (R2 = 0.9374). The achieved color information, combined with other physical and chemical characteristics, can provide a powerful tool for the comparison of tablet seizures, which may reveal their origin.

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