Minimally Invasive Surgery (MIS) has become a promising option for a great number of surgical interventions. Due to even further minimization of collateral surgical trauma and quicker recovery, Natural Orifice Transluminal Endoscopic Surgery (NOTES) procedures emerge as the next generation of MISs. However, the main disadvantage of those innovative methods is that diagnosis and intervention is solely based on the inspection of the image sequence provided by a monocular CCD camera. Distortion, inhomogeneous illumination and the limited field of view complicate depth perception and therefore navigation of the instruments and demand a high amount of expertise and experience. The surgeon's decisions are always based on his subjective perception. Hence, a method to objectively measure and visualize the three dimensional operating environment is necessary to overcome this difficulty. The project is based at the Chair of Robotics and Embedded Systems, MITI Group at TUM Medical Center "Rechts der Isar" and the Pattern Recognition Lab at University Erlangen.