Figure 4

Spectral plots and grey scale plots of the region 7000-7500 of the Wine dataset. The spectrum region before and after alignment by different methods (indicated at the bottom) was visualised as a spectral overlay (top) (multiple spectra overlaid in specific color for each spectrum) and as a two-dimensional grey-scale plot (bottom) (x axis: resonance frequency, y axis: spectrum index, lighter zones correspond to peaks).