X-ray spectrum estimation for accurate attenuation simulation.

Purpose: To estimate detected x-ray spectra from transmission measurements of known attenuators that allow to accurately simulate the transmission in unknown attenuators.

Methods: Starting from the established spectrum estimation method using the truncated singular value decomposition (TSVD) we extended the algorithm by incorporating prior knowledge about the statistical nature of the transmission data and about high-frequency spectral components like characteristic peaks. Thereby our proposed approach requires only minimal prior knowledge, namely the energy positions of characteristic peaks or k-edges, which are typically well-known.

Model-based sphere localization (MBSL) in x-ray projections.

The detection of spherical markers in x-ray projections is an important task in a variety of applications, e.g. geometric calibration and detector distortion correction.