How to create indices for specific parts of signal to keep

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Hi
So i have this signal as shown in the plot, this is currently a 50000x1 vector. I would like to extract only the parts where the amplitude increases, these correspond to the extraction and retraction of a piston rod with a 1s dwell time. I know i can do it manually from looking at the plot and find the indices, but i have 40 different signals and would thus like a automatic process for this.
I would like to find the point where each extraction and retraction cycle starts and ends so i can remove the other parts.
thanks for all help.
  10 Comments
dpb
dpb on 14 Feb 2021
" The signal i attached is actually a shortened version where i took the mean of each 1000 datapoints..."
That's a moving-average filter right there. From the looks of the data, that's probably pretty good first cut. You might want to consider using median instead of mean to preserve the absolute magnitude since the mean will have somewhat of a constricting effect on the range of the observations as well as smoothing.
Jørgen Fone Pedersen
Jørgen Fone Pedersen on 14 Feb 2021
Thanks for your answers and tips. I had no idea it was a moving average filter it was called actually.
It seems to be working fine now, I will try with the median also to see how much of a difference it makes.

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