6. Method to detect passengers approaching vehicles using vehicle side cameras

Safety confirmation on the platform when a train departs has been done visually by the train crews. In anticipation of the future shift to one-man operation even for a long set of trains, it is required to automate the safety confirmations on platforms. Therefore, we have developed a method to automatically detect the approach of passengers to vehicles by attaching cameras to the side of the vehicles and analyzing the images from the cameras, and thus confirm the safety of the platform when the train departs.

Four cameras are mounted at both ends of the vehicle, front, rear, left and right, per vehicle. At the time of departure, the system detects persons by analyzing images from two cameras on the platform side and estimates where the person is standing on the platform by making station equipment such as Braille blocks as markers and using a coordinate transformation technique called projective transformation (Fig. 1). If the estimated position of the person is judged to be too close to the vehicle, the crews are notified by sound and light. By processing 10 frames of images in a second, it is possible to give notification of any approach in real time. As a result of an evaluation using a prototype device incorporating the developed method, we confirmed that no person was overlooked irrespective of day or night, that the maximum detection error of the person's position was about 20 cm, which is about a half of that of Braille blocks with inward lines, and that it was accurate enough not to overlook a person outside the blocks (Figs. 2 and 3).

This method can be utilized to support the safety confirmation by the driver in one-man operation, as well as for safety confirmation on platforms in future automatic operation. We will expand the detectable targets to include wheelchairs, baby strollers, and running-in passengers and create a system to ensure the safety of all on platforms.