IMAGE DISTORTION CORRECTION AND ROBUST PHANTOM DETECTION

摘要

The invention relates to Method for detecting a phantom, comprising the steps of: arranging a phantom (20) with respect to an object, the phantom (20) comprising a plurality of first calibration fiducials (Mi1, Mi2, Mi3) in a first plane, acquiring at least one image of said object by means of an x-ray apparatus (3), such that the image contains projections of the object as well as projections (IMi1, IMi2, IMi3) of at least three first calibration fiducials (Mi1, Mi2, Mi3), detecting the projections (IMi1, IMi2, IMi3) of the at least three first calibration fiducials (Mi1, Mi2, Mi3) in said at least one image, and establishing a correspondence between the 2D image coordinates (lx, ly) of said projections (IMi1, IMi2, IMi3) of the at least three first calibration fiducials (Mi1, Mi2, Mi3) and the 3D coordinates (x, y, z) of said at least three first calibration fiducials (Mi1, Mi2, Mi3) in a local coordinate system of the phantom (20) for computing the projection matrix (P) or at least an element of the projection matrix (P) at least up to a scale factor (α), which projection matrix relates said 2D image coordinates (lx, ly) to said corresponding 3D coordinates (x, y, z) in a local coordinate system of the phantom according to α[lx, ly,1]T=P[x,y,z,1]T. Further, the invention relates to a method for building a statistical model, particularly for image distortion correction, as well as to a fiducial device and a mobile phantom.

主权项

1. A Method for detecting a phantom, comprising the steps of:
arranging a phantom with respect to an object, the phantom comprising a plurality of first calibration fiducials (Mi1, Mi2, Mi3) in a first plane, acquiring at least one image of said object by means of an x-ray apparatus, such that the image contains projections of the object as well as projections (IMi1, IMi2, IMi3) of at least three first calibration fiducials (Mi1, Mi2, M13), detecting the projections (IMi1, IMi2, IMi3) of the at least three first calibration fiducials (Mi1, Mi2, Mi3) in said at least one image, and establishing a correspondence between the 2D image coordinates (Ix, Iy) of said projections (IMi1, IMi2, IMi3) of the at least three first calibration fiducials (Mi1, Mi2, Mi3) and the 3D coordinates (x, y, z) of said at least three first calibration fiducials (Mi1, Mi2, Mi3) in a local coordinate system of the phantom for computing the projection matrix (P) or at least an element of the projection matrix (P) at least up to a scale factor (α), which projection matrix (P) relates said 2D image coordinates (Ix, Iy) to said corresponding 3D coordinates (x, y, z) in a local coordinate system of the phantom according to α[Ix, Iy, 1]T=P[x,y,z,1]T.