  The campaign against drug abuse is fought by all countries, most notably on
ATS drugs. The technical limitations of the current test kits to detect new
brand of ATS drugs present a challenge to law enforcement authorities and
forensic laboratories. Meanwhile, new molecular imaging devices which allowed
mankind to characterize the physical 3D molecular structure have been recently
introduced, and it can be used to remedy the limitations of existing drug test
kits. Thus, a new type of 3D molecular structure representation technique
should be developed to cater the 3D molecular structure acquired physically
using these molecular imaging devices. One of the applications of image
processing methods to represent a 3D image is 3D moments, and this study
formulates a new 3D moments technique, namely 3D Hahn moments, to represent the
3D molecular structure of ATS drugs. The performance of the proposed technique
was analysed using drug chemical structures obtained from UNODC for the ATS
drugs, while non-ATS drugs are obtained randomly from ChemSpider database. The
evaluation shows the technique is qualified to be further explored in the
future works to be fully compatible with ATS drug identification domain.
