Tuesday, February 03, 2009

Family Resemblance

Yesterday, I installed the new version of iLife '09 on my computer. This is Apple's photo management and editing software for the Mac, and the new version includes a truly incredible feature based on face recognition technology. You can select pictures from your photo library and tag faces in the pictures. The software then searches your library and finds other pictures that it selects as candidate matches for the tagged faces. There is an interface for viewing all of the candidate pictures, confirming correct matches, and correcting pictures that have been mis-tagged.

I am an amateur photographer with a photo library of over 30,000 pictures, going back to the advent of digital cameras. I have a studio in my basement where I take portrait shots, and I'm often lugging around my camera bag with all my lenses - especially to the kids' events at school. Finding particular pictures has been very hard, but Apple has made it easier with the last few upgrades to iPhoto, including categorizing pictures into Events, keyword searches, and smart libraries. This face recognition technology takes organizing photos to a new level.

One of the most interesting and entertaining properties that I've discovered in iPhoto '09 comes from pictures that are tagged incorrectly by the software. The most common mistake is tagging someone as his/her sibling. There must be something in the face recognition algorithm that picks up on family resemblances that are not perceived by humans. For example, as luck would have it, my brother and I look nothing alike. (In this case it is his good fortune.) We've been told that our entire lives. But, in several instances the software confused our faces. Similarly, my father and his brothers were mis-tagged as each other. In fact, the two people that the software seems the most confused about are my older daughter and my son. I found this a bit surprising because my son has a twin sister, and I have not seen an instance yet where one of the twins was tagged as the other. However, my older daughter and my son seem to provide the biggest challenge to the tagging feature.

I've noticed two factors that contribute to the accuracy of the face recognition - the number of pictures I have of someone, and the number of times I manually tag them. So, it's not surprising that the most collisions occur between relatives. Still, I observed few instances of two people being tagged as each other where there was no blood relation. Siblings on the other hand seem to throw iPhoto face recognition for a loop.

What was surprising to me was that I was not tagged as either of my parents by the software, despite the fact that people tell me I look like my mother. In fact, I saw very few instances of parents tagged as their children or vice versa. I'm very curious about the face recognition algorithm and about the family resemblance properties that iPhoto '09 exposes as a side effect.

Apple has taken what I believe to be a revolutionary step in photo organization, and for once, the bugs, or more accurately, the deficiencies in the software, namely mistakes in the tagging algorithm, actually provide the most fun.