pad matrix to a particular size

I have a matrix M of size m x n

m and n may or may not be equal - M can be rectangular or square matrix - where m and n are less than 150,

I wanted to resize M to 150 x 150 by padding border with zeros, such that the m x n will come in the center

M_resized = padarray(M,[x y],0,'both');

how to compute value for x and y such that i can use the same line of code for any matrix,

or is there any another way to do?

Answer 1

[Image Analyst]

You can use the 'pre' and 'post' options to pad each side with the desired number of zeros.

Or use this "trick"

g = ones(150, 150); % Original matrix is 150 x 150
[rows, columns] = size(g);
m = 153
n = 152;
rowsPre = floor((m - rows)/2)
collsPre = floor((n - columns)/2)
% Pad it out with 334 rows top and bottom,
% and 281 columns left and right.
P = padarray(g, [rowsPre, collsPre], 0, 'both');
whos P  % Originally 152x152 padded with zeros all around.
% Not the size we want yet.  We want 153x152
% Here comes the "trick" to expand out the lower right corner with zeros.
P(m, n) = 0;
whos P  % Now 153 x 152

Answer 2

[David Hill]

assuming m and n are both even.

M_resized=padarray(M,[(150-size(M,1))/2 (150-size(M,2))/2],0,'both');

[Elysi Cochin]

what if both are odd or any one value is odd

say 71 x 100

or 97 x 97

or 63 x 89