Sensor fusion technique for cable following by autonomous underwater vehicles

A sensor fusion technique is proposed for autonomous underwater vehicles (AUVs) to track underwater cables. The work presented is an extension of the vision based cable tracking system proposed by that authors (1997, 1998) and Balasutiya (1998). The focus of this paper is to solve the two practical problems encountered in vision based systems; namely: 1) navigation of AUV when cable is invisible in the image, and 2) selection of the correct cable (interested feature) when there are many similar features appearing in the image. The proposed sensor fusion scheme uses deadreckoning position uncertainty with a 2D position model of the cable to predict the region of interest in the image. This reduces the processing data increasing processing speed and avoids tracking other similar features appearing in the image. The proposed method uses a 2D position model of the cable for AUV navigation when the cable features are invisible in the predicted region. An experiment is conducted to test the performance of the proposed system using the AUV "Twin-Burger 2". The experimental results presented in this paper show how the proposed method handles the above mentioned practical problems.