Prediction model of the hardness of waterlogged archaeological wood based on NIR spectroscopy

Heritage Science

Table 7 Hardness model results for WAW based on NIR spectra in the 1000–2100 nm range

Mathematical treatment	Calibration set			Validation set				Factors
Mathematical treatment	R²c	RMSEC	SEC	R²v	RMSECV	SECV	RPD	Factors
–	0.93	3.55	3.56	0.89	4.42	4.44	3.03	11
MSC	0.94	3.38	3.39	0.90	4.31	4.33	3.11	10
SNV	0.94	3.16	3.17	0.88	4.59	4.60	2.93	12
1st	0.96	2.61	2.62	0.88	4.73	4.73	2.85	7
2nd	0.93	3.49	3.50	0.82	5.73	5.75	2.34	5
1st + MSC	0.97	2.39	2.40	0.89	4.43	4.45	3.02	7
1st + SNV	0.97	2.40	2.41	0.87	4.67	4.68	2.88	7
2nd + MSC	0.93	3.57	3.58	0.84	5.45	5.47	2.46	4
2nd + SNV	0.95	3.04	3.05	0.84	5.49	5.51	2.44	5

Factors Opt. number of factors, MSC Multiple Scattering Correction, SNV Standard Normal Variate, 1st First Deviation, 2nd Second Derivative, R²c Coefficient of determination of calibration, RMSEC Mean Squared Error for Calibration, SEC Standard Error of Calibration, R²v Coefficient of determination of cross-validation, RMSECV Mean Squared Error for Cross-Validation, SECV Standard Error of Cross-Validation, RPD Ratio Performance of Deviation for Cross-Validation