Fig. 5

Result of robustness against the addition of noise. The noise in the X-ray absorption spectroscopy (XAS) or electron energy-loss spectra (EELS) spectroscopy is modelled as Gaussian noise. The signal-to-noise (S/N) ratio is defined as the ratio between the peak height of the true spectrum and the standard deviation of the noise. a Similarity of the spectra with Gaussian noise. Pearson's correlation coefficient (PCC) showed excellent robustness against the addition of noise. b Simulated Mn2+ XAS spectra with Gaussian noise