Table 4.

Optimal wavelengths selected by 2nd derivative spectra and the PCA loadings of sample set 1 and 2 using pixel-wise spectra.

Methods	Sample Set 1		Sample Set 2
	Number	Wavelengths (nm)	Number	Wavelengths (nm)
2nd derivative spectra	19	507.12, 519.44, 528.07, 556.54, 587.64, 598.87, 606.38, 617.65, 646.56, 657.92, 687.02, 707.36, 717.55, 729.04, 749.52, 759.78, 770.06, 780.36, 801.01	19	507.12, 519.44, 528.07, 536.72, 556.54, 586.39, 598.87, 606.38, 617.65, 646.56, 657.92, 685.76, 707.36, 729.04, 749.52, 758.5, 770.06, 780.36, 801.01
PCA loadings	14	439.89, 529.31, 549.1, 555.29, 627.69, 637.75, 676.88, 679.42, 681.95, 698.45, 745.67, 757.21, 758.5, 950.13	16	439.89, 526.84, 545.38, 549.1, 551.57, 587.64, 598.87, 620.42, 675.62, 676.88, 688.29, 698.45, 745.67, 754.65, 757.21, 950.13