Smoothing

The ‘Smoothing FWHM’ window

The user may apply Gaussian smoothing to noisy spectra using the ‘Spectrum→Smoothing...’ menu option, as below.

The ‘Spectrum→Smoothing...’ menu option opens the ‘Smoothing FWHM’ window (shown below), in which you may enter the full-width at half maximum (FWHM) of the smoothing Gaussian function to be applied to the spectrum.

Please note:

• Smoothing may be cleared by entering a FWHM value of 0, or no text.
• The smoothing of the spectrum is updated live as you type, so you can immediately see the effect on the spectrum of different smoothing full widths at half maximum.
• If the text entered in the window cannot be parsed as a valid FWHM value, the text field background will turn a pale red colour.
• If multiple spectra are loaded (see loading multiple spectra), all spectra will be smoothed with the same FWHM. To use different smoothing settings for each spectrum, please see Smoothing multiple spectra, below.

Smoothing units

Note that the units for the full width at half maximum of the smoothing Gaussian function is displayed in the title of the ‘Smoothing FWHM’ window (“meV” in the above example). If you would like to specify the FWHM in different units, you may do so by typing the units after the value. OpticalFit supports smoothing units of channels (“ch”), electron volts (“eV”, with scalar prefixes, e.g. “meV”, “keV”), nanometres (“nm”), and inverse centimetres (“cm-1”).

Smoothing multiple spectra

If multiple spectra are loaded (see loading multiple spectra), but you don't wish to smooth them all equally, you may individually set the smoothing FWHM for each spectrum using the ‘Smooth FWHM’ column in the ‘Spectrum options’ window (shown below), which is opened using the ‘Spectrum→Spectrum options...’ menu option.

The ‘Smooth FWHM’ column in the ‘Spectrum options’ window behaves in the same way as the ‘Smoothing FWHM’ window (see above), except that each spectrum may have a different FWHM value (in different units, if desired), or may have no smoothing applied (i.e. FWHM not set).

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