Registering coordinate systems on an image is carried out by positioninga calibration jig having at least two collinear marker quadruplesthat are opaque to an imaging modality. Collinear quadruples are detectedon an image of the jig and respective image cross ratios of thecollinear quadruples are computed. Candidate lines are established byassociating at least one collinear marker quadruple and at least one collinearimage quadruple that have matching cross ratios. Respective registrationsof the calibration jig with the image are performed using pairsof the candidate lines. One of the registrations is selected, wherein theselected registration has a residual that is smaller than a predeterminedvalue.
