Abstract: The invention relates to a registration method for determining position and orientation of an object in relation to a position detection system, wherein the method comprises the steps of capturing an image of a surface of an object with an image sensor unit comprising at least one motion sensor and/or at least one position sensor, determining a capturing position of the image sensor unit in a coordinate system of the position detection system by processing motion sensor signals provided by said motion sensor and/or position signals provided by said position sensor, photogrammetrically generating a surface model of the object from the captured image, and transforming the photogrammetrically generated surface model into the coordinate system of a position detection system.

Abstract: The invention relates to a surgical instrument with an instrument handle, an instrument shank connected to the instrument handle, an instrument tip with a work point, which instrument tip is connected to the instrument shank, and a first locator arranged on the instrument handle or the instrument shank. During a use of the surgical instrument, the instrument shank can be deflected, e.g. on account of transverse forces, at least between the first locator and the work point. A second locator is arranged at a distance from the first locator and, by comparison with the latter, closer to the work point, wherein the second locator is designed to detect five degrees of freedom.