BIOMETRIC SYSTEM U.S. Army Sgt. Donald Armstrong explains a biometric scanning system to Deputy Defense Secretary Ashton B. Carter during a training exercise to counter improvised explosive devices, or IEDs, on Fort Campbell, Ky., June 20, 2012. Armstrong is assigned to the 101st Airborne Division. SHARE: Download: Full Size (0.07 MB) Credit: VIRIN: 012724-T-IJW20-676.jpg Photo Gallery