SAN FRANCISCO — A watchful eye has arrived on San Francisco's bar scene but not to keep you in check. It just wants to check you out.
An app launched this weekend that will scan the faces of patrons in 25 bars across the city to determine their ages and genders. Would-be customers can then check their smartphones for real-time updates on the crowd size, average age and men-to-women mix to decide whether the scene is to their liking.
The Austin, Texas-based makers of SceneTap say it doesn't identify specific individuals or save personal information. But in a city known for loving libations and civil liberties, a backlash erupted from bar-goers who said before cameras were switched on that they would boycott any venue with SceneTap installed.
SceneTap's ability to guess how old people are and whether they're men or women relies on advances in a field known as biometrics. A camera at the door snaps your picture, and software maps your features to a grid. By measuring distances such as the length between the nose and the eyes and the eyes and the ears, an algorithm matches your dimensions to a database of averages for age and gender.
SceneTap chief executive officer Cole Harper, 28, says the app doesn't invade patrons' privacy because the only data it stores is their estimated ages and genders and the time they arrived — not their images or measurements.
"Nothing that we do is collecting personal information," he said. "It's not recorded; it's not streamed; it's not individualized."
Whether the company's promises are comforting or SceneTap still seems creepy, it seems to indicate a near future when any camera-equipped smartphone will be able to recognize faces.
Already the iPhone's camera app will highlight a person's face with a green box before the picture is snapped. And Apple's iPhoto software tries to recognize the faces of people in pictures to categorize photos automatically by who's in the shot.
Facebook also uses facial recognition software that tries to identify any friends in a photo a user uploads.
SceneTap's San Francisco debut came the same day Facebook went public. Privacy experts say social media has played a major role in making it easier to attach a face to a name.
"Ten years ago if I walked down the street and took a picture of someone I didn't know, there was little I could do to find out who that person was. Today it's a very different story," said Lee Tien, a staff attorney with the Electronic Frontier Foundation, who focuses on surveillance technology and privacy.
Tien said facial recognition technology has advanced so that having your picture taken potentially offers up the same degree of identifying information as giving someone your fingerprints. Computer programs can break down high-resolution images in minute detail to identify the distinctive features of individual faces.
Those patterns, rather than the images themselves, make possible the tracking of individuals even without knowing who they are. In theory, a program could also match that pattern to identifiable online images such as a Facebook profile picture.
But along with the images being deleted nearly as soon as they're snapped, SceneTap's sensors aren't sophisticated enough to recognize individual faces, Harper said. Detecting basic characteristics like gender and age takes much less digital work than identifying individuals, he said.
He argues SceneTap doesn't come close to intruding on personal privacy the way many other technologies already do. Bars already have video cameras that record customers' every move, creating an archive that could, for example, be subpoenaed in court.
SceneTap is already in use in six other cities across the country, including Chicago and several college towns.