Use of ATR-FTIR Spectroscopy and Chemometrics for the Variation of Active Components in Different Harvesting Periods of Lonicera japonica

Table 1

Definition of six scaling methods.

Scaling method	Definition
UV	The variable j is centered and scaled to “unit variance,” which means that the base weight is computed as the reciprocal of the standard deviation of variable j computed around the mean (sdj)
UVN	Similar to UV, the variable is not centered, which means that the standard deviation is computed around zero
Par	Between no scaling and UV scaling. The variable j is centered and scaled to Pareto variance, which means that the base weight is computed as 1/sqrt (sdj)
ParN	Similar to par, however, the variable is not centered
Ctr	A column-wise centering to transform values varies around zero
Freeze	The scaling weight of the variable is frozen and will not be recomputed as observations in the work set change or the variable metric is modified