base line correction of a non uniformly spaced spectral data points

Hi all, Need help in performing baseline correction of a non-uniformly spaced spectral data points.

My values in X column are not equally spaced. I have 22k data points. Initially, they are spaced by 0.02 and finally it reaches to 0.06 units and fluctuate within 0.01 to 0.06. 'msbackadj' function in matlab is unable to execute as a stepsize is not constant.

thank you in advance

Answer 1

[Luuk van Oosten]

Dear Abdul Kalam,

You could resample your non-uniform spaced spectral data to obtain uniform spaced spectral data.

I am guessing your spectra with non-uniform X axis has some kind of Y value associated with it; you can use the msresample function, which allows you to get uniform spaced data.

See the documentation

[abdul kalam]

Dear Luuk van Oosten,

I have tried 'msresample' but still the data points are not equally spaced. step size is still increasing from 0.0089 to 0.06. I am providing a .txt file. It has wavelength in first column and intensity in second column.

kindly look into this.

[Luuk van Oosten]

Are you sure you set the value for uniformity to 'TRUE'? The default value (if not specified) of 'Uniform' is 'FALSE (i.e. your spectrum is not uniformly resampled). Example: If you do the following

[Xout, Intensitiesout] = msresample(X, Intensities, N)

Your resampled signal is still not uniform, because you did not specify that you wanted it uniform. Use the following instead:

[Xout, Intensitiesout] = msresample(X, Intensities, N, 'Uniform', 1)