Marked for Life: Tattoo Matching Software to Identify Suspects (4/15/2010)

Tattoo matching software has many law enforcement and investigative uses.

When a criminal's face is masked, police have to search for other identifying markers. Many law enforcement agencies and correctional facilities keep a database of tattoos and scars that can be used to identify disguised suspects captured on surveillance cameras. However, searching a computerized tattoo database isn't as simple as flipping through a few photographs.

Most databases catalogue thousands of images using text-based descriptions and have text-based search functions. This complicates the task of finding the correct image, as descriptions in the database may not be consistent or easily determined. If the suspect's tattoo shows a snake entwined around a rose stem, for example, one person might search for the term "rose," while another might look under "snake."

A technological advance simplifies the search process by comparing crime scene images of tattoos to those in law enforcement databases. TattooID, a software program developed at Michigan State University, uses the principles employed in computerized fingerprint matching technology, said Anil Jain, a distinguished professor in the University's Department of Computer Science and Engineering.

TattooID identifies distinctive image features, called keypoints. Keypoints are places where pixel values undergo some stable transitions, such as a color change or a boundary between two parts of an image. TattooID compares those points to images in existing law enforcement databases to find the closest matches.

The automated process is able to effectively identify similar tattoos in law enforcement databases and avoid the difficulties that can arise from a text-based search, according to Eric Hess, senior biometric product manager for MorphoTrak, Inc., which plans to launch a commercial version of the TattooID software in 2011. "By using technology to analyze the patterns, we can actually remove the variability of the human and how we interpret that image ourselves," he said.

MorphoTrak acquired TattooID in late 2009. Michigan State University developed the software with funding from the Federal Bureau of Investigation (FBI) Biometric Center of Excellence (BCOE). The U.S. Army Research Office and the National Science Foundation Center for Identification Technology Research provided seed funding for the project, which began two years ago.

Michigan State University researchers used nearly 64,000 photographs of tattoos from the Michigan State Police database to develop TattooID. Many law enforcement agencies photograph tattoos and scars as part of the booking process. Soft biometrics such as tattoos offer a way for police to identify a suspect or a homicide victim when fingerprints cannot be used, according to Jain.

The technology would help police in situations where a suspect provides a false name, according to Inspector Greg Michaud, assistant division commander of the Michigan State Police Forensic Science Division. In addition, tattoo-matching technology could help medical examiners identify bodies. "What it does is provide the capability to search tattoos against a known database, resulting in additional possible clues as to the identity of the individual," he said.

Tattoo databases also can help police and corrections officers investigate gang activity, according to Hess. Certain tattoos, such as the Latin Kings' five-pointed crown, are associated with a specific gang. Police can identify suspected gang members and gain valuable information by observing tattoos. Teardrop tattoos, for example, can signify that the person killed a rival when they were in prison. TattooID's visual matching capabilities are not limited to tattoos.

Police can use the technology to track graffiti and match gang symbols. This offers another way to investigate gangs, according to John Manzo, supervisor of the FBI BCOE Innovative Sciences & Identification Technologies group. "[TattooID] will provide state-of-the-art tools that will change the way law enforcement identifies victims and suspects," he said.

In a similar vein, the FBI is expanding its Integrated Automated Fingerprint Identification System to include other biometric capabilities. This system, Next Generation Identification, will have databases for tattoos, iris scans, mug shots, and other biometric data, as well as improved fingerprint matching capabilities. TattooID will make it easier for police to use existing tattoo databases to identify individuals. "We believe that this will be a very valuable technology … to make available to other law enforcement agencies in the country," Hess said.

Original Paper:

www.cse.msu.edu/rgroups/biometrics/Publications/SoftBiometrics/Jainetal_TattooCBIR_ICIP09.pdf

Note: This story has been adapted from a news release issued by Michigan State University

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