In early April, Engadget posted a story confirming a rumour that Facebook would be using facial recognition to suggest the names of friends who appeared in newly uploaded photos. You'd be allowed to opt out of tagging, and only friends would be able to tag each other in albums. Nevertheless, a commenter beneath the story quipped: "Awesome! Now I can take pictures of cute girls at the grocery store or at the park, upload them and Facebook will tell me who they are! (I'm pretty sure that's not [how] it works but I'm sure it will get there.)"
The commenter's confidence says a lot: facial recognition may be just one more way for Facebook to push the visual part of the social graph (photos of us) toward being more public and far less private.
Facebook has a history of asking for forgiveness after the fact instead of asking for permission in advance, and its new face-recognition feature could become the latest example of a seemingly innocuous development morphing into a serious threat to the privacy of our (visual) data. And as usual, some Facebook users will like the convenience of the new features so much that they will forget the privacy trade-off altogether, or just choose not to worry about it.
Features you didn't know you had
As it stands, Facebook's current feature uses facial recognition technology to pick out faces in your photos. Once you've uploaded your album, Facebook will take you to a new screen where you can enter the name of each person below their face. Sometimes (depending on your privacy settings and the clarity of the photo), Facebook will go a step further: if a face matches one you previously tagged in another album, Facebook may suggest that person's name for you.
Facebook quietly added the feature to the Privacy Settings, allowing users to disable the peppy-sounding 'Suggest photos of me to friends' option. Most Facebook users probably don't know that the extra privacy setting is there.
Technological advances in the past 10 years are making it possible for computers to match images and names with impressive accuracy. Though every company using the technology handles it a little differently, the president of Applied Recognition, Ray Ganong, shared some insight into how his company's product Fotobounce gets the job done: "We scan each image as a bitmap and look for potential face images that qualify. We try to see the two eyes, and based on the eye location we reorient the face and then generate a digital signature, based on that face."
Many builders of facial recognition technology base their matches on 'faceprints' of people, where an engine synthesises information using many photos of the same person from different angles or with different lighting to make a more accurate match. Given that Facebook users had uploaded 60 billion photos by the end of 2010, the prospects for accurate facial recognition on the social network are better now than ever before.
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