In the PLS-DA, the categorical variable of the normal egg was
set to 0, and that of the blood-spot egg was set to 1, and the
threshold was ±0.5. If the prediction value of normal eggs was
lower than 0.5 or higher than 0.5, the judgement failed. If the
prediction value of blood-spot eggs was lower than 0.5 or high
than 1.5, the judgement failed. After comparisons, the multiple
scattering correction (MSC) and first derivative were chosen
as pre-processing methods. Three different wavelength
ranges were chosen and compared for PLS-DA performance.