Résumé
This paper introduces a new visual odometry method for underwater vehicles. It is based on images grabbed by a monocular video camera, and aided by inertial and pressure measurements. This approach offers several advantages. Firstly, it is compact and runs very fast, even with limited computational resources. This allows to embed it on very small vehicles. Secondly, and probably most importantly, the method is able to estimate online the scale factor of the observed scene, thanks to the combined measures of a low-cost IMU and a pressure sensor. The paper ends with an experimental validation onboard the Leonard underwater vehicle.