matrix normalization in matlab

hi.. i want normalize a matrix (129 x 128)..please help me with matlab codes

Answer 1

[Thorsten]

To normalize a matrix such that all values fall in the range [0, 1] use

Anorm = (A - min2(A))/(max2(A) - min2(A));

[moahaimen talib]

*how can i normalize the dwt2 coefficients *

[Irawati Roy]

You missed a dot before the division operation for a 2d matrix

[DGM]

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

Answer 2

[Matt J]

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(:)))

[Jan]

Or perhaps "normalization" means a range of [0,1]?

[jenifer]

ya... but how can i get a single value from whole matrix...

[Jan]

Please, jenifer, we have asked you to define "normalization" exactly. It wastes time if we guess what you mean.

Answer 3

[Jing]

You can use 'normc' or 'normr' for normalization. 'c' or 'r' stands for columns or rows that you want to normalize.

Answer 4

[DGM]

Since R2018a, you can use normalize() to perform normalization in various different ways.

A = 1:6

A = 1×6

1 2 3 4 5 6

B1 = normalize(A,'range') % default range is [0 1]

B1 = 1×6

0 0.2000 0.4000 0.6000 0.8000 1.0000

B2 = normalize(A,'range',[-1 2]) % but you can specify any range

B2 = 1×6

-1.0000 -0.4000 0.2000 0.8000 1.4000 2.0000

B3 = normalize(A,'zscore','std') % zero-center and scale to have std=1

B3 = 1×6

-1.3363 -0.8018 -0.2673 0.2673 0.8018 1.3363

B4 = normalize(A,'norm',2) % normalize by vector p-norm (default p=2)

B4 = 1×6

0.1048 0.2097 0.3145 0.4193 0.5241 0.6290