Smoothing
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Smoothing is applied to reduce noise in the trace signals. During the smoothing step for each data point a local mean value (a running average) is calculated out of the surrounding data points and the point itself.

The smoothing width defines the number of data points considered for calculating the local mean values. The greater the smoothing width is, the more the trace data is flattened.

For example, a smoothing width value of 20 will calculate a mean value for the actual data point position out of the actual data point itself, 10 data points to the left and 10 data points to the right of this data point.

Tab. 1. Influence of wrong smoothing settings on the final data
Setting
Effect
If the smoothing width value is too large
... the peak data will be washed away.
If the smoothing width value is too small
... the noise is not efficiently removed. This may result in a detection of noise fluctuations as peaks.


Tab. 2. How does the processed data looks like if different smoothing values are applied?
Description
Graphics
Raw data

The image to the right shows a close up of raw trace data. Two local maxima (peaks) are visible.

Note, that there are two problems:
The trace curve runs in a zigzag manner and the peaks are sitting on a background noise.
graphic
Smoothing width set to 2

Here a smoothing width value of 2 has been applied.

The zigzag Pattern is still clearly visible. So the noise fluctuations are not efficiently removed. The smoothing width value is too low.

Too low!
graphic
Smoothing width set to 6

With zigzag is weaker but still present. This data could be used for peak detection.
It would be better to adjust a little bit greater smoothing width value.

Good!
graphic
Smoothing width set to 24

The zigzag almost completely vanished but the peaks remain clearly visible. This seems to be the best adjustment of the smoothing width value.

Best!
graphic
Smoothing width set to 50

Here the smoothing width value is too great. The peaks are washed away! So you will loose valuable information.

Too high!
graphic
Smoothing width set to 100

The same as above: Smoothing width value is too great. The peaks are eliminated!

Much too high!
graphic