Figure 5

Processing by PCA-LDA of the ATR-FTIR and Raman spectral datasets for categories: 1983–1984 and 2012–2013.
(A) Pre-processed ATR-FTIR spectral dataset. (B) Scores (DF1 × DF2) plot calculated by PCA-LDA. (C) Loadings plot derived from PCA-LDA. (D) Prepossessed Raman spectral dataset. (E) Scores (DF1 × DF2) plot calculated by PCA-LDA. (F) Loadings plot derived from PCA-LDA.