A lawsuit filed by three Illinois residents under the auspices of the state's Biometric Information Privacy Act can proceed, US District Court Judge James Donato said.
"The court accepts as true plaintiffs' allegations that Facebook's face recognition technology involves a scan of face geometry that was done without plaintiffs' consent," he said in the ruling.
It appeared that legislators in Illinois passed the act to address emerging biometric technology such as Facebook face-recognition software at issue in the case, according to the judge.

Facebook had argued in a motion to dismiss that analyzing uploaded photographs did not qualify as biometric data and that the Illinois law did not apply.
The leading social network had modified its terms of service to state that California law applies, but timing and circumstances permit the application of the Illinois act in the suit, the 24-page ruling said.

The suit accuses Facebook of unlawfully collecting and storing biometric data taken from faces in pictures "secretly and without consent" for a feature that lets people "tag" friends by name at the social network.
Lawyers for the plaintiffs contend that Facebook is violating Illinois law because biometric identifiers in the form of facial geometry are gathered, stored and then used for tagging suggestions at the California-based social network without permission.

The suit, which seeks unspecified damages, comes as Internet titans such as Facebook, Google, and others are investing heavily in artificial intelligence to better recognize, understand and cater to users of online offerings.