A while back I thought it would be a good idea to implement face detection in Gallery2, based on a similar feature in Facebook. I downloaded the OpenCV computer vision toolkit and ran the facedetect sample app against a collection of 60 photos from my gallery, some with no faces, others with a single face, still others with multiple faces, faces in profile, etc. No matter which training file I used, the face detection was horribly unreliable. I would estimate 10% of actual faces were detected, and of all the faces reported by the tool, maybe 5% were actual faces.

This was pretty disappointing, so I uploaded the same corpus of photos to Facebook to see how well it did with them. Imagine my surprise when it didn’t detect any! The face detection I was seeing on my sister’s profile was due to manual tagging of the photos from within the upload applet, and was not driven by computer vision algorithms. That explains that.

I still think a similar feature in Gallery would be nice, but with the CV aspect removed it doesn’t seem quite so fun.