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 |
