Reduce noise by smoothing spectra
Use Smooth in the Process menu to remove random noise and improve the shape of your spectrum. Smooth uses the Savitzky-Golay algorithm.
There are two types of smooth operations available:
- Automatic smooth: An automatic smooth often gives a satisfactory result and is faster than a manual smooth.
- Savitzky-Golay smooth: Manually set the number of points used in the algorithm. Using more points results in a greater degree of smoothing.
These images show the result of applying the most aggressive Savitzky-Golay smoothing to a noisy spectrum. This is a closely zoomed portion of the spectrum to more easily show the difference.
Be careful when smoothing spectra with real sample peaks that are narrow, since these features are also smoothed. Smoothing degrades the effective spectral resolution of the data and can remove ("smooth out") small spectral features.
In general, it is better to measure the sample with more scans and a better resolution instead of using Smooth. Smoothing is applied to the currently selected spectrum and does not create a new, resulting spectrum.
Desktop interface
❖ To apply automatic smoothing
- Open your spectrum in the Spectra view.
- With your spectrum selected, go to Process > Smooth Spectrum > Automatic.
The smoothing is applied automatically. View the measurement history to undo the smoothing.
❖ To apply Savitzky-Golay smoothing
- Open your spectrum in the Spectra view.
- With your spectrum selected, go to Process > Smooth Spectrum > Savitzky-Golay.
- Set the number of smooth points to use in the Savitzky-Golay algorithm. The number of smooth points is used to set the size of the moving window used in the algorithm. Using more points causes more smoothing.
- Click Save.
Touchscreen interface
❖ To apply automatic smoothing
- Open your spectrum in the Spectra view.
- With your spectrum selected, go to Spectral Smoothing > Automatic.
The smoothing is applied automatically. View the measurement history to undo the smoothing.
❖ To apply Savitzky-Golay smoothing
- Open the measurement.
- Open the main menu and select Spectral Smoothing > Savitzy-Golay.
- Set the number of smooth points to use in the Savitzky-Golay algorithm.
- The number of smooth points is used to set the size of the moving window used in the algorithm. Using more points causes more smoothing.
- Select Save.