C-arm calibration method for 3D reconstruction

A C-arm calibration method for 3D reconstruction in an imaging system comprising an imaging source and an imaging plane, said method utilizing a planar transformation for relating voxels in a voxel space and pixels in said imaging plane, and comprising the steps of:

• defining a source coordinate system in reference to said imaging source;
• defining a normal plane in said voxel space, not including the origin of said source coordinate system and being substantially normal to an optical axis from said source to said imaging plane;
• defining a relationship between said source coordinate system and another coordinate system, herein referred to as a world coordinate system, by transformation parameters;
• identifying pixel location coordinates for a respective pixel corresponding to each voxel by utilizing a planar to planar transformation;
• storing a value of a filtered image at said respective pixel location;
• and
• accumulating contributions corresponding to a plurality of image projections so as to thereby reconstruct said each voxel;
• dividing said voxel space into a plurality of planes parallel to said normal plane;
• back projecting an image of a plurality of pixels on said image plane onto a set of coplanar voxels defining one of said plurality of parallel planes;
• and
• defining a relationship in said source coordinate system between each of said plurality of pixels and corresponding ones of said coplanar voxels so as to obtain a 2-dimensional mapping between points on said one of said plurality of parallel planes and pixels on said image plane.