An Experimental Study on Localization of Other Ships with Onboard Stereo Cameras

An automatic lookout system is very important to realize autonomous navigation of ships. Many kinds of sensors such as radar, GNSS (Global Navigation Satellite System), IMU (Inertial Measurement Unit) and AIS (Automatic Identification System) are required for the autonomous navigation system. In addition to that, visual sensors are very useful to recognize the situation around the own ship. In particular, stereo cameras can provide the distance information of the surrounding objects such as other ships, buoys, breakwaters, bridges and other obstacles. This paper proposes a novel method to calibrate a wide baseline stereo camera system to measure 3D locations of long-distance targets. An experiment measuring locations of other ships using onboard stereo cameras indicates that distances to the other ships can be measured within an error of 10 % for 1,000 meters ahead and 20 % for 2,000 meters ahead.