Know a friend with an unusual prowl, prance, strut, or swagger? Turns out, everyone’s walk may be different. A new tool called “gait recognition” analyzes body shapes and movements. It can identify people by their strides—even when their faces are hidden. But the walk-watching trend is raising concerns about privacy and how far biometric technology will go.
Biometrics is the term for measuring unique physical characteristics. Retina scans, fingerprint analysis, and DNA matching are types of biometrics. Of course, God doesn’t need biometrics to know His creation. He formed each body. (Psalm 139:13-16) So He knows everyone’s eyeballs, hands, genes . . . and gaits.
Why would anyone want to identify a walk? Gait recognition can help detect certain behaviors. It can find people who are acting suspiciously: Is she taking short strides because she’s carrying something too heavy in her purse? Is he circling the same area over and over because he’s planning a crime? Gait recognition can also help spot elderly or injured people in distress.
Scientists in Japan, the United Kingdom, and the United States have been researching gait technology for over a decade. In China, police already study strides.
Huang Yongzhen is CEO of Watrix, a technology company. Watrix’s system can identify people from up to 165 feet away, even with their backs turned or faces covered. First, the software extracts a person’s silhouette from video. It analyzes the movement. Then it makes a model of the person’s walk. The program can search through an hour of video in about 10 minutes. It can analyze ordinary surveillance camera footage, like those at a bank, a concert venue, or an amusement park.
Shuffles, wobbles, waddles—nothing tricks this software, says Huang: “Gait analysis can’t be fooled by simply limping, walking with splayed feet, or hunching over, because we’re analyzing all the features of an entire body.” That includes looking at whole-body movements, not just feet.
Most biometrics require someone to give physical data purposefully. Gait recognition does not. People can be monitored without their consent. That invasion of privacy makes some people uncomfortable with gait recognition technology.
So far, gait recognition software isn’t as good as facial recognition. But at 94% accuracy, it works pretty well. “Everybody knows you can be recognized by your face,” gait expert Mark Nixon says. But he says, “We believe you are totally unique in the way you walk.”