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

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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:

  • Teoretically 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. 
Date modified: Jan 29, 2015
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