normalized data -1 to 1

how to normalized data for the scale -1 to 1?

Answer 1

[Walter Roberson]

dmin = min(data(:));
dmax = max(data(:));
scaled_data = (data - dmin)./(dmax - dmin) * 2 - 1;

or more simply,

scaled_data = mat2gray(data) * 2 - 1;

Multiply by 2 and subtract 1 is a very convenient mapping from [0 1] to [-1 1]