Apparatus for automatically controlling the position of a device in a cavity includes a light emitter and light sensors disposed in a distal end of the device for determining the position of the distal end within the cavity. When the device is inserted into the cavity, light is emitted from the emitter...http://www.google.de/patents/US4292961?utm_source=gb-gplus-sharePatent US4292961 - Apparatus for automatically controlling the position of endoscopes or similar devices in a cavity
