Understanding Images of Groups of People

Just as birds naturally space themselves on a wire (Upper Left), people position themselves in a group image. We extract contextual features that capture the structure of the group of people. The nearest face (Upper Right) and minimum spanning tree (Lower Left) both capture contextual information. Among several applications, we use this context to determine the gender of the persons in the image (Lower Right).


In many social settings, images of groups of people are captured. The structure of this group provides meaningful context for reasoning about individuals in the group, and about the structure of the scene as a whole. For example, men are more likely to stand on the edge of an image than women. Instead of treating each face independently from all others, we introduce contextual features that encapsulate the group structure locally (for each person in the group) and globally (the overall structure of the group). This “social context” allows us to accomplish a variety of tasks, such as such as demographic recognition, calculating scene and camera parameters, and even event recognition. We perform human studies to show this context aids recognition of demographic information in images of strangers.

Andrew Gallagher
Tsuhan Chen

A. Gallagher, T. Chen, "Understanding Images of Groups of People," IEEE Conference on Computer Vision and Pattern Recognition 2009.



author = {A. Gallagher and T. Chen},

title = {Understanding Images of Groups Of People},

booktitle = {Proc. CVPR},

year = {2009},


The Images Of Groups Dataset
We introduce the dataset for researchers interested in images of groups of people that was used in this work.
The data associated with these images is provided for academic research only (non-commercial). I believe this is the first publically available dataset of group images with faces marked with age and gender.

Please cite my paper paper if you use this collection.