Abstract:
A data processing method for determining the relative orientation of an object coordinate system of an anatomical object in a global co-ordinate system, comprising the steps of: acquiring a reference direction dataset representing a first reference direction of a line between a first anatomical landmark of a reference object and a second anatomical landmark of the reference object, and a second reference direction of a line between a third anatomical landmark of the reference object and a fourth anatomical landmark of the reference object, wherein the first and second reference directions are given in a reference coordinate system and the reference object corresponds to the anatomical object; acquiring an object direction dataset representing a first object direction of a line between the first anatomical landmark of the anatomical object and the second anatomical landmark of the anatomical object, and a second object direction of a line between the third anatomical landmark of the anatomical object and the fourth anatomical landmark of the anatomical object, wherein the first and second object directions are given in the global co-ordinate system and the landmarks of the anatomical object correspond to the landmarks of the reference object; calculating the orientation of the reference co-ordinate system relative to the global co-ordinate system which results in the best match between each of the reference directions and the respectively corresponding object direction; and—using the orientation of the reference co-ordinate system in the global co-ordinate system as the relative orientation of the object co-ordinate system.
Abstract:
The present invention relates to a method for determining the spatial position of objects, in particular objects, comprising the steps of: —acquiring first position data which comprise first position information describing the spatial position of an object (2) within a first co-ordinate system (A); —acquiring first transformation data which comprise first transformation information describing a transformation of the object's position from the first co-ordinate system (A) into a second co-ordinate system (B); —acquiring, on the basis of the first position data and the first transformation data, second position data which comprise second position information describing the spatial position of the object (2) within the second co-ordinate system (B); —acquiring second transformation data which comprise second transformation information describing a transformation of the object's position from the second co-ordinate system (B) into an inertial co-ordinate system (I); —determining, on the basis of the second position data and the second transformation data, inertial position data which comprise inertial position information describing the spatial position of the object (2) within the inertial co-ordinate system (I). The present invention also relates to a program which, when running on a computer (4), cause the computer (4) to perform the method steps of the method described above and/or to a program storage medium on which the program is stored and/or to a computer (4) comprising such a program storage medium and/or to a signal wave, in particular a digital signal wave, carrying information which represents the program. The present invention also relates to a tracking system for determining the spatial position of objects, in particular medical objects, comprising: —a sensor array (1) which is configured to determine the spatial position of at least one tracking marker attached to an object (2); —an inertial sensor array (3) which is attached to said sensor array; and —a computer (4).
Abstract:
A data processing method, performed by a computer, for determining a leg length difference and a leg offset difference of a patient's leg including a femur connected to a pelvis, comprising the steps of: —determining a first landmark vector between a femoral landmark and a second landmark at a first point in time; —determining a second landmark vector between the femoral landmark and the second landmark at a second point in time which is later than the first point in time; —calculating an orthogonal projection of the first landmark vector into a sagittal plane and using the direction of the orthogonal projection of the first landmark vector into the sagittal plane as a leg length direction; —calculating a direction which is perpendicular to the sagittal plane and using this direction as a leg offset direction; and —calculating the leg length difference in the leg length direction and the leg offset difference in the leg offset direction from the first landmark vector and the second landmark vector.