Friedrich-Alexander-Universität
Friedrich-Alexander-Universität
Stanford Radiology

Flower Artifact

The flower artifact

This artifact can be observed when using the algebraic resoconstruction technique.
It does not show the correct reconstructed phantom but rather a shaded circle that becomes edgy with increasing iteration. Its appearance reminds of a flower.

Explanation for the artifact

The original phantom
The recostruction after 50 iterations

The ART algorithm iterates the sinogram with specific angles. If the angle increases too much in each iteration the geometry does not hold and instead of the correctly reconstructed image we get these flowers. This occurs for example when the angle is not correctly converted from degrees to radians. After correction, the phantom is correctly reconstructed as shown on the right.

Authors

Anja Jäger, Tilmann Hübner, Karoline Kallis, Hamidreza Moghada, Yixing Huang, Andreas Maier