Purpose of Review
This review provides an overview of the current state of the art in Underwater Human-Robot Interaction (U-HRI), which is an area that is quite different from standard Human-Robot Interaction (HRI). This is due to several reasons. First of all, there are the particular properties of water as a medium, e.g., the strong attenuation of radio-frequency (RF) signals or the physics of underwater image formation. Second, divers are bound to special equipment, e.g., the breathing apparatus, which makes, for example, speech recognition challenging, if not impossible. Third, typical collaborative marine missions primarily requires a high amount of communication from the diver to the robot, which accordingly receives a lot of attention in U-HRI research.
Recent Findings
The use of gestures for diver-to-robot communication has turned out to be a quite promising approach for U-HRI as gestures are already a standard form of communication among divers. For the gesture front-ends, i.e., the part dealing with the machine perception of individual signs, Deep Learning (DL) has become to be a very prominent tool.
Summary
Human divers and marine robots have many complementary skills. There is hence a large potential for U-HRI. But while there is some clear progress in the field, the full potential of U-HRI is far from being exploited, yet.