The laser line object detection method in an anti-collision system for powered wheelchairs

Abstract

The residents in long term care facilities with cognitive impairment and mobility disability need an anti-collision system on their powered wheelchairs to prevent them from causing other seniors to fall. Because of the severe consequence of falling, the detection method of the anti-collision system must be very reliable. However, many object detection techniques tend to miss targets that are unfavourably oriented or have certain surface properties. This research evaluated an uncommon method: laser line object detection (LLOD). The LLOD system projects an invisible infrared laser line onto the ground, and reads the resulting image via a camera. By analyzing the laser line in the image, the system can identify whether objects are in the target area. A pilot LLOD system was designed and installed on a powered wheelchair. The results of the evaluation experiments showed that the LLOD system can detect almost all obstacles with different orientations and materials, and produced a high detection rate on favourable flooring surfaces.