how to untilt my graphed data?

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cocopuffs
cocopuffs on 20 Apr 2015
Commented: Star Strider on 22 Apr 2015
Hello guys.
So I had some respiratory flow rate vs. time. I needed to find to graph volume of ventilation vs. time so I took the running integral of the flow rate data. However, taking this running integral results in volume data that is tilted. I need to untilt the data before analyzing it but I was unsure how to do it. The help would be greatly appreciated. I used cumtrapz to integrate the flow rate data.
Also, I attached an image of the graph as it may help.

Accepted Answer

Star Strider
Star Strider on 20 Apr 2015
It looks as though you are integrating a constant as well as your data. I don’t have your data so I can only suggest possible approaches.
The easiest approach would be to subtract the mean of ‘flow_data’ from ‘flow_data’ before you do the integration.
A more complicated approach would be to use a highpass or bandpass filter on the integrated data to eliminate the descending baseline.
  8 Comments
Star Strider
Star Strider on 22 Apr 2015
As always, my pleasure!

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More Answers (1)

Chad Greene
Chad Greene on 20 Apr 2015
What about detrend?
  1 Comment
cocopuffs
cocopuffs on 20 Apr 2015
Yes I tried it, but results is similar to subtracting the mean.

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