MATLAB: How to use msbackadj without error

background reductioninterpolationMATLABmsbackadj

I am trying to reduce the background on a Raman spectrum. I have two 1011×1 doubles. One is wavelength and the other is intensity. When I try the command

YB = msbackadj(Wavenumber, Intensity)

I get the following errors:

Error using griddedInterpolant
Interpolation requires at least two sample points in each dimension.
Error in interp1 (line 161)
        F = griddedInterpolant(X,V,method);
Error in msbackadj (line 296)
        b = interp1(Xpt+Xw/2,WE(1:numWindows),X(:,nnss),regressionMethod);

Any help would be appreciated.

Best Answer

Hello,

The problem seems to be that my data was in reverse order. As in the wavenumber went from highest to lowest. Using the flip() function on my data corrected the error.

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MATLAB: How to use resolve griddedinterpolant error in the msbackadj in bioinformatics toobox

Hi,

The problem is that your variable MZ does not span a large enough range for the default algorithm options of msbackadj. The algorithm needs to be able to analyze multiple shifting windows of data. The default window size is 200 separation units. I am guessing your MZ data does not have a range of at least 200 separation units, leading to the error you see.

In MATLAB R2015a and later, msbackadj gives a warning and tries to proceed anyway. However, in all versions, the best thing for you to do would be to change the algorithm options WindowSize and StepSize to values that are more appropriate for your data. For example, it looks like your data has a range of 25 separation units. Perhaps it would make sense to break your data into 5 windows of 5 separation units each. Try the following:

   yb= msbackadj(MZ,a,'WindowSize',5,'StepSize',5);

Best Answer

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