Number of points in each sub-model for filtering with Derivatives or Savitzky-Golay (Q816)

The information in this article applies to:

SIMCA^®

Summary:

When applying derivatives as spectral filter, the number of points in each sub-model can be selected. By default the number of points is set to 15 as a general valid setting. Depending on the data application, the spectral resolution and optical bandwidth it may be advantageous to change the number of points.

Some advice on this change:

• Theoretically one can say that the window (number of points) should be in the order of, or smaller than, the nominal width of non-noise features which should not be smoothed.
• Practical experience with data from a NIRS6500 instrument (Foss) showed that a window size of 5-9 points for 1st Derivatives and 7-11 point for 2nd Derivatives worked well.