Fig. 2.

Root-mean-square deviations (RMSDs) of the estimated SPRs based on the AED phantom for all VMI energies / energy pairs as well as for the low- and high-energy spectra/bins (indicated by L and H, placed in grey boxes). The triangular heatmaps (a-e) show RMSDs following the Saito method applying two energies, and the lines (f) show RMSDs following the HLUT method applying a single energy. The energy / energy pair selected for further evaluations is indicated with a blue box. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)