Hi everyone - I need some help in figuring out how best to do a baseline determination then subtract it out leaving just the peaks. My data is profilometry measurements across a substrate surface. As you can see in the chart below the substrate surface is fairly straight but not lying flat on the scanner table. I am looking for an easy method to identify the linear baseline then subtract it from the raw data thus leaving the four peaks with essentially a zero/horizontal)baseline. Then I can use the Peak Detector to identify the peaks and their locations so I can make additional calculations (mostly peak area and average peak height).
Any suggestions on how to best go about this?
Solved! Go to Solution.
Your baseline does not look linear, you probably need at least quadratic polynomial (or higher).
So just select all the non-peak values and fit them to a polynomial, then subtract the polynomial. Can you attach some typical data file?
Attached is a sample scan of data and my first attempt at applying a filtering routine. I don't think I'm usign this correctly becuase I cannot seem to flatten out the baseline without gross distortion of the peaks.
Can either suggest where I'm going wrong here?
Wow, this is nothing short of awesome! I have no idea what this small tight routine does, but it certainly seems to have solved my problem perfectly. It's an elegant solution. You must be a mathematician or a physicist. Thank you!!
This is an interesting topic to me, I would like to correct a baseline to zero for some data so that later I can determine the area of just the peak, and not the peak and its baseline. I have entered the data into altenbach's block diagram (thanks!) well enough to see the raw data (scan data) but the front panel doesnt return anything for baseline or baseline corrected. I will try to decipher what could be wrong on my end but am also submitting for anyone's consideration, thanks so much. Pic attached.