We present a vision-based control and interaction framework for mobile robots, and describe its implementation in a legged amphibious robot. The control scheme enables the robot to navigate, follow targets of interest, and interact with human operators. The visual framework presented in this paper enables deployment of the vehicle in underwater environments along with a human scuba diver as the operator, without requiring any external tethered control. We present the current implementation of this framework in our particular family of underwater robots, with a focus on the underlying software and hardware infrastructure. We look at the practical issues pertaining to system implementation as it applies to our framework, from choice of operating systems to communication bus design. While our system has been effectively used in both open-ocean and closed-water environments, we perform some quantitative measurements with an effort to analyze the responsiveness and robustness of the complete architecture.