| dc.description.abstract | In a previous paper a technique was  developed for finding reconstruction  algorithms for arbitrary ray-sampling  schemes. The resulting algorithms use a  general linear operator, the kernel of which  depends on the details of the scanning  geometry. Here this method is applied to the  problem of reconstructing density  distributions from arbitrary fan-beam data.  The general fan-beam method is then  specialized to a number of scanning  geometries of practical importance. Included  are two cases where the kernel of the general  linear operator can be factored and rewritten  as a function of the difference of coordinates  only and the superposition integral  consequently simplifies into a convolution  integral. Algorithms for these special cases of  the fan-beam problem have been developed  previously by others. In the general case,  however, Fourier transforms and convolutions  do not apply, and linear space-variant  operators must be used. As a demonstration,  details of a fan-beam method for data  obtained with uniform ray-sampling density  are developed. | en_US |