In this experiment, with the purpose of showing potential performance, we first varied the parameters for each smoothing method and selected the qualitatively best results. We evaluated the quality of denoising performance by considering the following conditions: first, whether the spectra are smoothed sufficiently to observe peaks at correct energies that correspond to those of C, O, and Si, which compose the sample, while are not overly smoothed without overlaps; second, whether false peaks appear. We will see that this second condition prominently characterizes, especially for carbon peaks, the difficulty of the direct application of wPCA and the existing smoothing techniques compared in the experiment. We will also conduct a qualitative evaluation of the denoised images at the true peak energies of the three elements by measuring the similarity against the corresponding region of interest (ROI) images (integrated images over a certain energy region around each peak).