In the last years visual odometers have been improved considerably, but there is
still a certain lack of robustness and reliability when used to navigate Autonomous Underwater
Vehicles (AUV) in complex underwater scenarios, such as habitats colonized with Posidonia
oceanica or Zostera noltii. The work presented in this paper goes one step beyond the current
solutions, improving a state of the art approach to be applied in underwater applications. Tests
conducted with real marine visual data grabbed in waters of the Balearic Islands from a bottom-looking camera installed on an AUV, show the progress in the vehicle displacement estimation and its viability to be used online.