Classification of prepaid cards based on multivariate treatment of data obtained by X-ray fluorescence analysis Minemasa Hida, Toshiyuki Mitsui Forensic Science International Volume 119, Issue 3, Pages 305-309 (July 2001) DOI: 10.1016/S0379-0738(00)00459-X
Fig. 1 XRF spectrum of a real turnpike card. Mo tube, 45kV, 4μA. Forensic Science International 2001 119, 305-309DOI: (10.1016/S0379-0738(00)00459-X)
Fig. 2 Relationship between Ti/Mo and Fe/Mo in 200 subway cards. (■): Group I; (□): Group II; (•): Group III; (○): Group IV; (▴): Group V; (▵): Group VI; (♦): Group VII. Forensic Science International 2001 119, 305-309DOI: (10.1016/S0379-0738(00)00459-X)
Fig. 3 Relationship between Ti/Mo and Fe/Mo in 32 turnpike cards. (□): counterfeit I; (▵): counterfeit II; (♦): real I; (•): real II; (○): white card. Forensic Science International 2001 119, 305-309DOI: (10.1016/S0379-0738(00)00459-X)
Fig. 4 Dendrogram of 200 subway cards. I–VII: Group I–VII. Forensic Science International 2001 119, 305-309DOI: (10.1016/S0379-0738(00)00459-X)
Fig. 5 Relationship between 1st and 2nd PCS for 200 subway cards. (■): Group I; (□): Group II; (•): Group III; (○): Group IV; (▴): Group V; (▵): Group VI; (♦): Group VII. Forensic Science International 2001 119, 305-309DOI: (10.1016/S0379-0738(00)00459-X)
Fig. 6 Relationship between 1st and 2nd PCS for 32 turnpike cards. (□): counterfeit I; (▵): counterfeit II; (♦): real I; (•): real II; (○): white card. Forensic Science International 2001 119, 305-309DOI: (10.1016/S0379-0738(00)00459-X)