Here’s some face recognition fun. There’s a site called riya.com that I’ve been playing with. Basically, you upload photos to the site a bit like Flickr except the site runs face recognition software: it picks faces out of the photos: you label them (eg, Dad). Then you can upload more photos and search for "Dad": the software performs face recognition on the photos you’ve uploaded. It didn’t work perfectly, but I thought the fact that it worked at all was quite interesting.
Face recognition, especially at a distance, hasn’t worked terribly well historically. Certainly the Hollywood-SciFi version is a long way off. In practical deployments, trying to match faces in a population hasn’t worked at all. A system installed a Keflavik airport in Iceland — not primarily aimed at terrorists but at drug dealers, missing children and so on — never matched a single wanted person. I remember a few years ago there was a much-discussed case in Florida, where the police turned off a similar system after just two months because it produced so many false identifications. As in the case of CCTV in town centres, face-scanning cameras might make us feel safer, but they wouldn’t necessarily make us safer.
If anyone has any experience with 1:n face recognition systems that have had more success, perhaps you could share them with us.