I have a very large photo gallery with thousands of similar people, objects, locations, things. The majority of the people in the photos have their own user accounts and avatar photos to match. There are also logical short lists of people potentially in the photo based on additional data available for each photo. I allow users to tag photos with their friends and people they know but an automated process would be better.

I've used photo tagger/finder from face.com integrating with Facebook photos and the Google Picasa photo tagger for personal albums also does the same thing and is exactly what I'm looking to do.

Is there a PHP script, API for Google Picasa, face.com or other recognition service or any other open source project that provides server-side facial recognition and/or grouping photos by similarity?

Examples: As you can see, various photo sharing sites offer the feature, but are there any that provide an API for images stored on my own server or something extensive enough to link into my own gallery and tagging system?

• viewdle - Face recognition/Tagging for video
• PHP - Face detection in pure PHP
• Xarg
• OpenCV
• Face.com - app for finding and tagging photos in Facebook
• Google Picasa - photo sharing
• TeraSnaps - photo sharing site
• Google Portrait - photo grouping from Google Image results
• FaceOnIt - Video face recognition
• PittPatt - Detection, Recognition, Video Face Mining
• BetaFace
• ChaosFace - Real-time Face Detector