Figure 3

(a) Enlarged lignin peak region (1580–1630 cm⁻¹) for all plant species: red for ferns, black for monocots and blue for eudicots. (b) The logistic regression plot of the test set providing insights into the classification performance and accuracy of the LDA model. (c) The performance evaluation of the LDA model. LDA distinguishes among the three distinct plant types, with an accuracy of 81% in the test set when only the lignin region is considered. (d) The confusion matrix for the LDA model for the lignin region.