Understanding Interactions and Guiding Visual Surveillance by Tracking Attention

The central tenet of this paper is that by determining where people are looking, other tasks involved with understanding and interrogating a scene are simplified. To this end we describe a fully automatic method to determine a person's attention based on real-time visual tracking of their head and a coarse classification of their head pose. We estimate the head pose, or coarse gaze, using randomised ferns with decision branches based on both histograms of gradient orientations and colour based features. We use the coarse gaze for three applications to demonstrate its value: (i) we show how by building static and temporally varying maps of areas where people look we are able to identify interesting regions; (ii) we show how by determining the gaze of people in the scene we can more effectively control a multi-camera surveillance system to acquire faces for identification; (iii) we show how by identifying where people are looking we can more effectively classify human interactions.