In the underwater domain, we are quite limited as to the types of sensors we can use to understand our surroundings. Cameras (backed by a decent image processing algorithm) are the most inexpensive and reliable way to achieve this. Maelstrom has three cameras in total. Two of the cameras are internal and used for navigation, one camera is external and used for visual servoing.

The two internal cameras are PointGrey Blackflys. One camera faces forward and the other faces downward. These camera feeds are used to navigate and align to the next task. Sometimes it is enough to only use these two cameras for a given task. If manipulation is involved, a third camera is required to monitor the grabbing action.

The third external camera was adapted from a security camera by CCTV Camera World. This camera is unique because it is a special IP camera that is made to be submersible and allows us the flexibility to mount it outside of our main watertight housing. With this flexibility, we are able to mount the camera right next to our manipulator system to get a clear view of the task the bot is interacting with.

Additionally, this camera can be unmounted from the vehicle and submerged in a static location in our testing pool to get a third-person view of the robot while it’s in operation. This provides better insight to what is actually going on under the water, since it is difficult to see from the surface.