GPU-Accelerated Human Detection Using Fast Directional Chamfer Matching

We present a GPU-accelerated, real-time and practical, pedestrian detection system, which efficiently computes pedestrian-specific shape and motion cues and combines them in a probabilistic manner to infer the location and occlusion status of pedestrians viewed by a stationary camera. The articulated pedestrian shape is approximated by a mean contour template, where template matching against an incoming image is carried out using line integral based, Fast Directional Chamfer Matching, employing variable scale templates (hybrid CPU-GPU). The motion cue is obtained by employing a compressed non-parametric background model (GPU). Given the probabilistic output from the two cues, the spatial configuration of hypothesized human body locations is obtained by an iterative optimization scheme taking into account the depth ordering and occlusion status of individual hypotheses. The method achieves fast computation times (32 fps) even in complex scenarios with a high pedestrian density. Employed computational schemes are described in detail and the validity of the approach is demonstrated on three PETS2009 datasets depicting increasing pedestrian density.