There are barrier detection systems for automobiles. We cannot use the same systems for pedestrians, because of the limitation of camera placements, size, weight and power-consumption. We develop a barrier detection system for pedestrians. This paper proposes a single camera barrier detection system for pedestrians and discusses the implementation and the experiments in real environments. The proposed system is extension of classical single camera barrier detection system for cars. Our experiments shows the performance and the problems in barrier detection system using images.