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Compare smoothing window sizes on a Raman spectrum

This example shows how the smoothing window size changes the balance between noise reduction and signal distortion on a Raman spectrum.

import spectrochempy as scp

Prepare a noisy spectrum

dataset = scp.read("ramandata/labspec/SMC1-Initial_RT.txt")
region = dataset[:, :400.0]
region += 200 * scp.random(region.shape)
region.name = "noisy spectrum"

prefs = scp.preferences
prefs.figure.figsize = (8, 4)
_ = region.plot()

Moving-average smoothing

smoothed = {size: region.smooth(size) for size in (3, 7, 11)}

Compare the results. Larger windows remove more noise but can also flatten narrow features:

for size, smoothed_region in smoothed.items():
    _ = scp.plot_compare(
        region,
        smoothed_region,
        title=f"Moving-average smoothing (size={size})",
    )

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Savitzky-Golay smoothing

sg = scp.Filter(method="savgol", size=7, order=2)(region)
_ = scp.plot_compare(region, sg, title="Savitzky-Golay smoothing (size=7, order=2)")

This ends the example. Uncomment the next line to display the figures when running the script directly with Python.

# scp.show()