Quadrotor Vision-based Localization for Amphibious Robots in Amphibious Area

Considering imaging qualities and air-water medium changes, the localization of multiple amphibious robots in GPS-denied outdoors is a great challenge. This paper presents a vision-based localization approach for multiple amphibious robots in amphibious environment using a quadrotor hovering over the head of robots. In terms of the circular shape observed by the quadrotor on land, a shape and color-based detection method is designed to identify robots. An improved Hough transform was used to speed up the shape detection of our robot. Then we use the color information to identify different robots. In water, ASRobot is able to realize multiple motion with different configurations of legs. Therefore, in view of different shapes generated by different configurations, a multiple size-varying template matching method is utilized to recognize different robots in water. On account of the refraction of rays, the vision-based localization model was built in amphibious environment. Finally, experiments of localization were conducted, and the results verified the feasibility of the proposed vision-based localization approach for ASRobots.