BUCHI NIRCal - Manual (Page 72)

NIRCal 5.5 Software Manual
72 NIRCal 5.5 Manual, Version A
Parameter
Range from ...
to ...
The first and the last spectra index.
Block select ...
leave ... Number of selected and left out spectra per block.
Amount ... % Amount of selected spectra in %.
3.3.5 Spectra Data Set
Samples of known characteristics, both chemical and physical are used to generate calibrations.
Measurement conditions should remain constant for all samples using the full spectrum range. Several
sample from different batches should be collected for a robust calibration and each samples should be
analysed in the laboratory with the classical method. Only acceptable samples can be used for the
calibration. The measured spectra are normally divided into two sets.

Calibration Spectra (spectra selected for the calibration) C-Set, about 2/3 of all measured
spectra (min. 3). Only the C-Set spectra are used for the calculation of the principal
components and the calibration limits.
Generally, the calibration spectra should contain all “extreme information” to define the limits
of acceptance. For quantitative calibration the spectra with the highest and lowest property
values always belong to the calibration spectra.

Validation Spectra, about 1/3 of all measured spectra selected for the internal validation V-
Set.
Only if a calibration treats the validation spectra equally to the calibration spectra, the settings
are considered as OK
NOTE
These two groups of spectra should be:

independent from each other: all spectra of one sample should belong to the same set;

no overlapping allowed.
It is possible to leave out some spectra from the C- and from the V-Set, these spectra are in the
Unused Set = U-Set:
C-Set + V-Set + U-Set = All Spectra
The U-Set is visible in the calibration results, but will not influence the calibration and validation results
e.g. will not be taken for the Q-Value calculation. The calibration protocol is stored within the
calibration.
C- and V-Set can be selected by the user in different ways:

in the NIR-Explorer,

in the Property table.

in the graphic