spread sheet file to the formula loop

[GerdW]

Hi KK,

is there a reason to start with a new thread for the very same problem?

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@KK54321 wrote:

My final spectrum looks good, and i am able to reduce the noise, but still background is present in the final spectrum.

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Your paper mentions a "High Pass Filter" (and gives specific implementation details), but you use a different filter…

That may be one reason for "unexpected" results!

Btw. why don't you cleanup your VI using the AutoCleanup tool? (After doing so delete the unused functions in the block diagram!)

[KK54321]

Hi GerdW,

Thank you for your reply. I have done the noise filtering using FFT and works fine, I have used a cosine tapered window to multiply with FFT. Now I have to remove the background using a polynomial fit. I have found one NI discussion about this and got a vi which does this. I have copied the vi to my FFT Vi, it removes the background but in wavelength data only. My final data after FFT will be in wavenumbers, here its not able to do I have adjusted the numbers accordingly still did not work. Is there any method in Labview to remove background of a spectrum automatically by estimating the standard deviation. Because in the present vi i have to choose wavelength range where there is no peaks and fit with a >4th order polynomial, instead I want to do this automatically. I have attached the VI and data file.

Here are the steps steps attached VI,

1. It loads the wavelength vs intensity data

2. background correction using polynomial fit

3. feed the background corrected spectra to interpolation vi

4. then add 700000 zeros

5. zero pad

6. FFT

7. multiply FFT and cosine tapered window

8. IFFT.

Thank you

KK