A used bullet tells many tales. The grooves and striations it picks up as it blasts down a gun barrel can link weapons to crimes and help prosecutors put criminals behind bars.
But the stories have always been two-dimensional. Until now.
New ballistics-imaging technology, developed by a Rockville, Maryland, engineering firm with funding from the Justice Department, lets forensic scientists capture a fired bullet’s distinctive markings in 3-D for the first time.
The technology, which was featured at the 2006 National Institute of Justice conference here Tuesday, works by projecting white light through a special microscope onto a bullet or its casing. The depth of the marks determines the intensity of the reflected light, which is recorded by a camera.
A computer then generates a 3-D image of, say, a Remington 9-mm slug or a Winchester .44-caliber Magnum round for researchers to pore over. Previously, forensic examiners were limited to flat photos of bullets and casings taken from different angles. But the wrong orientation of the photos can throw off the analysis: An examiner may end up comparing striations from different sides of the bullets. Not with the new technology.
"The 3-D representation is like a cross section," said Benjamin Bachrach, a vice president at Intelligent Automation, which developed the technology under grants from the Justice Department and the National Science Foundation. "The other way is an indirect representation."
The increase in microscopic precision could be a potential breakthrough for crime labs around the country. Already the technology has allowed scientists at the National Institute of Standards and Technology, or NIST, to create "golden bullets," clones of a standard slug that has been fired. With a golden bullet, crime labs can calibrate their imaging equipment to a single set of striations. This makes it easier to share data.
By Luke O’Brien
wired.com