Remove drift from signal

How do I remove the drift from this signal? I want the "flat" lines in beginning and the end to be at the same level.

[Image Analyst]

You forgot to attach a screenshot or data, so until you read this link about all I can suggest is to use polyfit and subtract the fitted/smoothed signal.

[captainmariah]

Sorry, I forgot to click upload. Image added and attached the data here.

[captainmariah]

Tried with code:

opol = 1;
[p,s,mu] = polyfit(t1,phase1,opol);
f_y = polyval(p,t1,[],mu);
dt_phase1 = phase1 - f_y;
plot(t1,dt_phase1,'.');

Is there a way to only take the baseline into account for the slope?

[Star Strider]

We need to have your time vector as well, since that is required to write code specific to your data. Add that, and upload the .mat file.

[Image Analyst]

Exactly what/where do you consider the baseline to be? Can you draw it on there?

[Star Strider]

There seems to be an integrated square-wave pulse in the centre half of the data. What are your data and how are you acquiring and initially processing them?

[captainmariah]

Image shows what I meant with baseline. Baseline 1 and Baseline 2 are suppose to be at same level, but I had a drift in my measurement (signal = intensity). I want to remove the drift without distorting (changing) the amplitude of my bump.

What I am interested of here is the amplitude of this "bump" and the response time.

Many thanks!

Answer 1

[Star Strider]

Use the detrend function.