Two faces are better than one: Face recognition in group photographs

Face recognition systems classically recognize people individually. When presented with a group photograph containing multiple people, such systems implicitly assume statistical independence between each detected face. We question this basic assumption and consider instead that there is a dependence between face regions from the same image; after all, the image was acquired with a single camera, under consistent lighting (distribution, direction, spectrum), camera motion, and scene/camera geometry. Such naturally occurring commonalities between face images can be exploited when recognition decisions are made jointly across the faces, rather than independently. Furthermore, when recognizing people in isolation, some features such as color are usually uninformative in unconstrained settings. But by considering pairs of people, the relative color difference provides valuable information. This paper reconsiders the independence assumption, introduces new features and methods for recognizing pairs of individuals in group photographs, and demonstrates a marked improvement when these features are used in joint decision making vs. independent decision making. While these features alone are only moderately discriminative, we combine these new features with state-of-art attribute features and demonstrate effective recognition performance. Initial experiments on two datasets show promising improvements in accuracy.