The Shepp-Logan phantom

The development of reconstruction algorithms is greatly eased by using standard phantoms with know properties. A well known example is the Shepp-Logan phantom containing ellipsis with different absorption properties, that resembles the outline of a head. An image of the phantom is shown below (click on the image to see the full version).

A Matlab function has been made, that can generate projection data for this phantom. The file shepp_logan.m can be found at the ftp-server in the directory:

It is possible to generate images of different sizes and vary the number of projections generated. Instruction are found by writing help shepp_logan at the Matlab prompt.

The ideal Shepp-Logan phantom image can be generated using the command shepp_logan_image.m. Instruction are found by writing help shepp_logan_image at the Matlab prompt. An ideal Shepp-Logan phantom image can also be found at (Note: 2 Mbyte file): https://courses.healthtech.dtu.dk/22485/files/ct_programs//files/ct_programs/ideal_shepp_logan_image.mat.