NIST launches 3-D ballistics research database

In crime dramas, detectives track down criminals by analyzing striations left on bullets and matching them to the rifled grooves inside gun barrels, typically using nothing more than a microscope. In real life, however, the process is far from straightforward.

Matches can be blurred by a number of things. Guns made at the same time may have extremely similar grooving, and an individual gun's barrel can change over time -- both of which can confuse less-sophisticated analyses.

To bring ballistics analysis into the big data age, the National Institute of Standards and Technology opened a 3D Ballistics Research Database for to law enforcement use on July 7. The new database will provide statistical foundations using an open-source-developed algorithm to more reliably link bullets to the guns that fired them. The new database helps vastly narrow down those nuances and differences by harnessing algorithms derived from a growing library of three-dimensional images of bullets.

To start the database, Xiaoyu Alan Zheng, a mechanical engineer who conducts forensic science research at NIST, said he asked forensics and law enforcement conferences to test-fire every 9-mm firearm in their reference collection. He said that 9 mm is known to be the most commonly used in the commission of crimes.

Zheng told FCW in an email that NIST will host the database at its facilities, but is relying on outside sources to expand its library of bullet profiles, according to an email Zheng sent FCW, a sister site to GCN.

"NIST will continue to collect, measure and enter new test fires contributed from laboratories across the U.S. In addition, participating agencies will have the ability to upload data into the database themselves," Zheng said. "One of those agencies is the FBI, and we anticipate that a large portion of the database's growth will come from the FBI's firearm reference collection."

Zheng said the FBI's firearm reference collection consists of thousands of firearms, but the law enforcement agency is planning to multiply those references by a factor of six by using six different brands of ammunition per firearm to generate the test fires. "FBI will upload their measurement data onto the NBTRD as well as providing physical test fires to NIST."

According to NIST, after labs complete the test fires, they sent the bullets and cartridge cases to the agency, along with data on the gun that fired it. At NIST's lab, technicians scanned the samples using a microscope that produces a high-resolution, 3-D topographic surface map, which produces a virtual model of the physical object itself.

The surface maps produce more detailed comparison data than the two-dimensional images traditionally used to match bullets.

NIST said its new database is open access, and the data in it is freely available to researchers. Similar databases already in use, such as the National Integrated Ballistics Information Network, are proprietary and contain sensitive information. Researchers can't download bulk data from other databases for use in statistical studies.

"As far as uploads are concerned, the database is secure and protocols are in place to ensure data quality control," Zheng said. When data is submitted, he explained, the database administrator uses a program to check scanned data files and strip out any extraneous metadata, leaving only the 2D image or 3D topography data. Once the data is live on the server, only the database administrator has access to modify those files, Zheng said.

This article was first posted on FCW, a sister site to GCN.