The linogram method for image reconstruction from projections applied to fan-beam projection data

The linogram method is compared to the fan-beam filtered backprojection method. Fan-beam filtered projection data are assumed. It is shown that the image quality is comparable for the two methods. The linogram method has the complexity O(N²log N), compared to the complexity O(N³) for the fan-beam algorithm. A more careful investigation gives the computation cost in FLOPS (floating point operations) for the linogram method and the fan-beam filtered backprojection method. For example the linogram method is nine times faster than the fan-beam filtered backpropagation method for an image size of 1024