MATLAB: Trouble with spikes.

scriptspikes

Hi all.
I've got a matrix called "turb" 2112×2688, which contains many outliers values. What I need is to remove those outliers values, and I tought about the folowing statistical method:
  1. Find the mean and standart deviation values of which one of the 2688 columns;
  2. Use two alternatives: Remove all the values in the column higher than it's respective mean value and Remove all the values in the column higher than it's respective standart deviation value;
  3. Replace these removedvalues with NaN.
Using the mean value of the matrix as a whole wouldn't fit well for my result, because the given mean value is too low and would remove too many components of the matrix, that's why using the mean value of which column fits better.
If anyone could give me any advice of how could I start building up this kind of script, I would be really thankfull!!
Regards, Paulo Beiral.

Best Answer

Here you can see the power of Matlab. What you want can be in a few short lines of code:
x=rand(2112,2688);
avg=mean(x);%or explicitly: avg=mean(x,1)
%sd=std(x);%or explicitly: sd=std(x,1)
L= x<=avg;%for R2016b and later
%L=bsxfun(@le,x,avg);%for R2016a and earlier
x(L)=NaN;
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