[2/3] Fastgraph: Remove SPES artifacts using EMD

[chinmaychinara91]

This PR is the 2nd part required for Fastgraph. It involves cleaning the data for any artifacts.

Prerequisite: Follow steps in PR #913

Remove SPES artifacts

Linked to process_remove_spes_artifacts and it involves removing SPES artifacts and slow drifts using the Empirical Mode Decomposition (EMD) based filtering.

The GUI

Inputs

• Stimulation event: The stimulation event around which to remove the artifacts (here, STIM)
• EMD cutoff frequency (in Hz): Self explanatory
• Time to account for artifact (in ms): The duration of the actual stimulation artifact itself, starting at the stimulation event. Used to set the main artifact span inside the interpolation window (here, 5 ms).
• Time on either side of the artifact to spline with (in ms): How much clean signal to take from before and after that artifact window so the spline has anchor points to interpolate across the bad segment (here, 3 ms).

Steps to use

1. Follow steps as in PR [1/3] Fastgraph: Customize SPES blocks (Nihon Kohden) #913 .
2. Drag the loaded stimulation blocks into the Process1 tab. For e.g. SB A13-A14 4 (#1) .
3. Click on Run > Stimulation > Remove SPES artifacts.
4. Fill in the values as seen in the GUI figure above. Click Run.

It creates new stimulation block e.g. SB A13-A14 4 (#1)_emd. The results can be seen as under.

Associated PRs

1. [1/3] Fastgraph: Customize SPES blocks (Nihon Kohden) #913
2. Plot Fastgraphs (3rd PR) - TO BE ADDED

@jcmosher @Nastaranlotfi @yashvakilna