ABSTRACT
Concerning the problem of collision accident between large cetaceans and vessels, it is expected to identify the critical season and species of large cetacean in some courses of hydrofoils off Japan water and also to technically improve the Under Water Speaker (UWS) for repellent of cetaceans. However, it is necessary to take measures of not only repellent of cetacean but also actively cetacean avoidance. The UWS is one of the countermeasures for cetaceans to give way. For the safety navigation of hydrofoils, as part of these studies, we are envisaging an alert system triggered by the whale detection using infrared camera (thermography). Because any cetaceans are of air-breathing animals, they come to the surface inevitably in regular interval and their blow or body parts appear at the sea surface. In this system, we aim at these objects as detection cue by using infrared camera.
