This book deals with mobile robot autonomous navigation in natural (unstructured outdoor) environment. This is a very difficult task and we propose an appropriate but not avoidably complex solution using a vision based perception system and a behaviour based (re)action system. Since we could not use a real robot and for general testing purpose, we developed a real mono camera based vision acquisition system and a virtual acting 3D environment for mobile robot navigation. We developed a virtual environment called «VIMRINNE» (Virtual Interface for Mobile Robot Instant Navigation in Natural Environment) which provides a framework for study, experimentation and development of mobile robot applications in 3D VR. This work includes the following contributions: The definition of a software architecture allowing modularity, extensibility, and near real time processing; We will demonstrate the capabilities of our project through some experiments and evaluations that show the interest of our approach. We are convinced that this work will constitute a good basis in the building of a robust 3D virtual interface for mobile robot outdoor navigation.