When it comes to patrolling the mean streets of post-Saddam Iraq, American soldiers could benefit from an extra set of eyes. Since major combat ended in April, more than 40 American soldiers have been killed by Iraqi insurgents armed with hidden weapons and explosives. In many cases, such as Sunday's attack when a soldier was killed while waiting to buy a drink, the assailants often strike from among crowds of people. But keeping soldiers and others safe from assassins hidden in a crowd may eventually become a bit easier. Rick Blum, a professor of electrical and computer engineering at Lehigh...