Appling Lidar-based obstacle detection and wireless image transmission system for improving safety at level crossings

The safety issue of level crossings has been concerned persistently in our society. Several function requirements such as high detection probability, low false alarm rate and short warning latency should be taken into account in order for precise and reliable detection at level crossings. In this paper, modern technologies, including Lidar and digital wireless image transmission, are used in a safety control system. The Lidar is an acronym for "LIght Detection And Ranging", or for "Laser Imaging, Detection and Ranging". When an obstacle intrudes the level crossing and is detected by the high resolution Lidar sensor, the real-time images from surveillance cameras will be transmitted through wireless channel to the receiver installed at drive's cab on the incoming train. Therefore, the driver of the train can judge if the train has to be stopped immediately or just slowed down. Two important modules, the Lidar sensor and the wireless transmitter will dominate the performance figures of this system. To validate the detection capability in the practical situations, several testing scenarios were conducted, including various obstacles such as bicycles, motorcycles, vehicles, and different weather conditions, such as sunny day and rainy day. Furthermore, field tests are also done by installing the system at a real level crossing. The result shows that the transmission time of streaming images is less than three seconds, which proves the feasibility of our design.