Finding mean of matrix excluding 0
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goyanks1989
on 13 May 2016
Commented: Image Analyst
on 13 May 2016
I have a 4 1200x1200 matrixes which includes numerous 0 values, lets just call them 'a' 'b' 'c' and 'd'
How do i find the mean of each individual point in the matrix (that is a+b+c+d), while ignoring the 0 values?
Thank you for the help!
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Accepted Answer
Star Strider
on 13 May 2016
If I understand correctly what you want to do, this will work:
a = randi([0 5], 10);
b = randi([0 5], 10);
c = randi([0 5], 10);
d = randi([0 5], 10);
abcd = cat(3, a, b, c, d); % Concatenate Along 3rd Dimension
abcd(abcd == 0) = NaN; % Set Zeros To ‘NaN’
mean_abcd = mean(abcd, 3, 'omitnan'); % Use 'omitnan' Argument And Take ‘mean’ Across 3rd Dimension
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More Answers (1)
Image Analyst
on 13 May 2016
You mean the mean at each location, like (a+b+c+d)/(# non-zeros)? How about
counts = (a~=0) + (b~=0) + (c~=0) + (d~=0);
theMeans = (a+b+c+d) ./ counts;
theMeans is a 1200-by-1200 matrix where each value is the mean of up to 4 values. If all 4 values are 0 then the value there is a nan.
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Image Analyst
on 13 May 2016
They are not all uint16 - some must be different. Cast all to double and then do it.
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