Google has responded to privacy concerns about people being recognized from Google StreetView map images, and begun deploying new face-blurring technology to mask their identity. So those blurry faces you see aren’t an accident, or the result of the subjects having drunk too much the night before.

Google has frequently come under fire from privacy advocates, for issues as diverse as the duration for which it keeps search histories to alleged invasions of privacy by publishing thousands of street-level photographs of United States’ cities. Indeed, one couple – the Borings of Pittsburgh, PA – have sued Google for publishing on Street View pictures of their house.

Responding to these complaints, Google have made it easy for anyone to flag Street View images if you think them inappropriate, revealing, or sensitive. The images are then reviewed, and if needed, removed.

Google has taken a further response to these concerns with the release of new technology that scours the Street View image database, identifies faces, and blurs them, masking their identity. The capability is being tested in Manhattan, with plans to roll it out more broadly across the other cities covered by Street View.

While face detection can be used to determine from a larger photograph what constitutes a human face (for example on a person, an advertising billboard, or a large TV screen), face recognition can extract salient features from the detected face, sometimes regardless of lighting, hair style, colouring or head gear, and by searching a database of known faces identify the individual precisely. How useful for surveillance that would be. Hmm. Searching huge databases. Classification. Ranking. Sound like anyone we know? Like, maybe, Google? No, they wouldn’t be evil, would they?