The process comprises the steps of creating three reference points at an object and taking a tomogram of the object such that the three reference points define a first set of positional data in the tomogram. The object is then non-rigidly placed on a support for operation thereupon by an instrument which...http://www.google.se/patents/US5186174?utm_source=gb-gplus-sharePatent US5186174 - Process and device for the reproducible optical representation of a surgical operation
