Shepp–Logan phantom
The Shepp–Logan phantom is a standard test image created by Larry Shepp and Benjamin F. Logan for their 1974 paper "The Fourier Reconstruction of a Head Section". It serves as the model of a human head in the development and testing of image reconstruction algorithms.
Definition
The function describing the phantom is defined as the sum of 10 ellipses inside a 2×2 square:| Ellipse | Center | Major Axis | Minor Axis | Theta | Gray Level |
| a | 0.69 | 0.92 | 0 | 2 | |
| b | 0.6624 | 0.874 | 0 | −0.98 | |
| c | 0.11 | 0.31 | −18° | −0.02 | |
| d | 0.16 | 0.41 | 18° | −0.02 | |
| e | 0.21 | 0.25 | 0 | 0.01 | |
| f | 0.046 | 0.046 | 0 | 0.01 | |
| g | 0.046 | 0.046 | 0 | 0.01 | |
| h | 0.046 | 0.023 | 0 | 0.01 | |
| i | 0.023 | 0.023 | 0 | 0.01 | |
| j | 0.023 | 0.046 | 0 | 0.01 |