Automatic Positioning of a Surgical Microscope

A procedure for interactive navigation of a fully motorized surgical microscope is presented. This procedure uses preoperative MRT-or CT-images to generate a 3D-model of the patient which then acts as the basis for navigation during surgery. The relation between tracking system, microscope and 3D-model is established using a simple calibration method based on the Horn [Ho87] algorithm. It enables positioning the microscope by defining target points either directly on the patient using an optical marker or on his 3D-model. After reaching the target position the microscope focuses automatically by calculating the focus score of the current field of view as function of the working distance. Thus, not only the surgeon will be discharged from positioning the microscope but he can also continue his work almost immediately. Manual interaction becomes unnecessary.