We've all seen facial biometrics in the movies where a security camera picks out a terrorist subject or supposed perpetrator, reads their face and maps out a facial recognition identifier for law enforcement. It’s really flashy, cool and fast. Does it work that way? Well, yes and no. Let’s start at the beginning.
Security and Biometrics
Biometrics needs to perform two functions: identify and verify. In order to satisfy an identification it must work against records in a database, which it can search through for results, such as mugshots that are used by police. This comparison is called a "one to many" search and presents a best match result. Verification, on the other hand, is a system that relies on input from the user, generally via the password or another form of identity. This would be a "one to one" search, such as would be done with a computer allowing someone access using a private code.
Did You Know?
The police in Tampa Bay, Florida, used Indentix’s facial recognition software to screen at Super Bowl XXXV in January 2001. The search was for potential terrorists and criminals in attendance. The results? The system found 19 people with pending arrest warrants. Facial recognition is often able to operate with the used of surveillance cameras or closed circuit television (CCTV).
Better Than People
The software algorithms are generally better than people estimations. People are very good at recognizing people they know from surveillance film. With unfamiliar faces, however, not so good. The reasons for this are believed to be that people just aren’t good at it and they have a short attention span. To test this point, a British study used trained supermarket cashiers to screen shoppers. The shoppers were of four types. One had a shopping card with a recent photo, another had a card with modifications to their photo such as a minor hairstyle change or the addition of glasses. A third shopper’s card was issued that was actually of a different person who resembled them somewhat, and, finally, a shopper was issued a card where the only similar characteristic was the same sex and race as the shopper.
When the various cards were presented to the checkout clerks, more than half of the fraudulent cards were accepted. The breakdown was as follows. 34 percent of the cards that did not look like the shopper were accepted, 14 percent of the cards where the appearance had been altered were accepted, and 7 percent of the unchanged cards were rejected by the clerks. Time plays a factor too, as a human being's ability to detect critical signals drops rapidly after the start of a task, so that within 35 minutes their focus to task drops significantly.
A London borough uses a CCTV system, German Federal Police use it at a fully automated border station at an airport, Australia also has a system called SmartGate, and casinos and United States law enforcement agencies employ systems. It’s also been used at highly publicized trials, and to ensure fair counts for elections in Mexico.
The IAFIS (Integrated Automated Fingerprint Identification System) has an Interstate Photo File of 9,695,672 photos for over 5,629,772 records. The U.S. Department of State operates one of the largest face recognition systems in the world with more than 75 million photographs, and it is actively used for visa processing.
Results Are Weaker
The results of biometric facial recognition are still weaker and less efficient than the other methods, but police like it because it doesn’t require aid or consent from the test subject, and it can be installed in public places.
Faces Are Public
How do you feel about having your image captured, however? There is some controversy, but the privacy issue raised here is not protected by the U.S. Constitution. Under current law, the type of facial recognition used by law enforcement to monitor public places is legal because according to the United States Supreme Court, a person does not have a reasonable expectation of privacy because the physical characteristics used, such as one’s facial characteristics, voice, and handwriting, are constantly exposed to the public.
A newly emerging trend, claimed to achieve previously unseen accuracies, is three-dimensional face recognition. This technique uses 3-D sensors to capture information about the shape of a face. You may also see technology developed as a security measure at ATMs, where a webcam image would be compared to a photo card.
When Madeleine McCann disappeared at Praia de Luz in Portugal, the British police asked visitors at the Ocean Club Resort to provide any photographs they may have taken in an attempt to identify the abductor of the missing child as part of the investigation, as some modern cameras have a focus and measure component.
Hey, even Facebook has a program that identifies faces in photos and allows you to tag other people you may know. I’m just saying, it’s going to be everywhere.