Quasar > Medical image Processing > CT reconstruction

CT reconstruction


An overview of the different functions and classes:

adjoint_dd_fanbeam_projectionAdjoint Ray-based forward Distance-Driven projection (sinogram domain -> image domain)
adjoint_fanbeam_projectionadjoint ray-based fanbeam projection using nearest neighbor/linear interpolation. (sinogram domain -> image domain).
adjoint_parabeam_projectionComputes the adjoint of the parallel beam projection (sinogram domain -> image domain). The adjoint is not the same as the backward projection, however a reconstruction can be obtained using e.g. the conjugate gradient algorithm.
bpf_parabeam_reconstructionReconstruction using backprojection filtration algorithm
cg_dd_fanbeam_reconstructionReconstruction using conjugate gradients - distance driven projections and
cg_fanbeam_reconstructionReconstruction using conjugate gradients - naive forward and adjoint projections and
cg_parabeam_reconstructionIterative reconstruction of parallel beam CT data using the conjugate gradients method Uses the projectors and
fan2paraRegridding from fan-beam to parallel-beam. This is useful for comparing to the FBP reconstruction.
fbp_design_reconstruction_filterDesign of a FBP reconstruction filter in the frequency domain
fbp_parabeam_predict_noisevarianceComputation of the noise variance of the reconstructed image for the FBP algorithm.
fbp_parabeam_reconstructionReconstruction using filtered backprojection algorithm
forward_dd_fanbeam_projectionRay-based forward Distance-Driven projection: a reimplementation of the Distance-Driven algorithm of De Man, although with a simplification: (image domain -> sinogram domain) One first important detail is the projection normalization (because the sum of the weights of the rays that go through a point is not necessarily 1). Here, we perform the normalization directly in the image domain, prior to the forward projection. We can call this a PRE-normalization. Correspondingly, in the adjoint projector , the normalization is performed in image domain, AFTER the projection.
forward_fanbeam_projectionray-based forward projection using nearest neighbor/linear interpolation (image domain -> sinogram domain). A naive implementation.
forward_parabeam_projectionComputes a forward parallel beam projection (image domain -> sinogram domain)