matrix normalization in matlab
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hi.. i want normalize a matrix (129 x 128)..please help me with matlab codes
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Thorsten
le 30 Jan 2013
To normalize a matrix such that all values fall in the range [0, 1] use
Anorm = (A - min2(A))/(max2(A) - min2(A));
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DGM
le 11 Déc 2022
Modifié(e) : DGM
le 11 Déc 2022
There ./ is not needed here, since the denominator is a scalar.
That said, there is no function called min2() or max2(), nor can I find evidence that there were functions by those names which have since been removed. Maybe they used to be part of one of the toolboxes.
Alternatively, you could do:
Anorm = (A - min(A(:)))/(max(A(:)) - min(A(:)));
or you could do
Anorm = (A - min(A,[],'all'))/(max(A,[],'all') - min(A,[],'all'));
though the latter option wouldn't have worked circa 2013
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Matt J
le 30 Jan 2013
You need to decide how you want to define the amplitude of the matrix first. Maybe you want this
normalized = A/norm(A);
or maybe this
normalized = A/max(abs(A(:)))
3 commentaires
Jan
le 30 Jan 2013
Please, jenifer, we have asked you to define "normalization" exactly. It wastes time if we guess what you mean.
Jing
le 30 Jan 2013
You can use 'normc' or 'normr' for normalization. 'c' or 'r' stands for columns or rows that you want to normalize.
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DGM
le 11 Déc 2022
A = 1:6
B1 = normalize(A,'range') % default range is [0 1]
B2 = normalize(A,'range',[-1 2]) % but you can specify any range
B3 = normalize(A,'zscore','std') % zero-center and scale to have std=1
B4 = normalize(A,'norm',2) % normalize by vector p-norm (default p=2)
2 commentaires
Sinan Islam
le 3 Août 2024
The normalize function in matlab either works on columns or rows. We want a function that normalizes the matrix as a whole. We are not looking for normalizing features or observations. So the calculation must be made on global minimum and global maximum of the matrix. Thats why we flatten the matrix into one vector before doing any calculation.
DGM
le 3 Août 2024
As others have mentioned, "normalize" is a terribly vague word. If the goal is to rescale the entire array with respect to global statistics, then yes, reshaping the array is one way to do so.
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