Patent ID: 6652142
Filing Date: 2003-11-25
Classification: A61B

Abstract:
A method of calibration for constructing three-dimensional models from images acquired by a tomography system comprising means for detection and means for providing a radiation source which can move with respect to the means for detection, comprising:placing a set of markers in the field of the source; processing the positions of the projections of the markers onto the images acquired so as to deduce from this the position of the source at the time of the acquisitions, the markers being carried on the same support; determining the positions of the source during various acquisitions and the values of conversion parameters which, for all the markers and acquisitions, minimize an overall error that is a function of the distances between the theoretical position of the projection of each marker onto the image resulting from an acquisition and its actual position in the image; fixing the markers with respect to the support; and processing the positions of the projections of the markers onto the images acquired so as to deduce from this the position of the markers in space wherein the positions of the projections of the markers onto the images acquired are processed so as to deduce from this conversion parameters which characterize a rigid displacement of the markers between their assumed initial position and a position adopted by the markers following a displacement.