help regarding indexing matrix in image processing

i am working on quincux matrix for image sampling. i want to make the alternate elements zero of rows of a given matrix such that for each odd row the row starts with zero and for each even rows the second starting element is zero.

example:- given matrix is

[1 2 3 4 5;
6 7 8 9 1;
1 3 6 7 4;
2 9 7 8 5;
5 6 7 8 3]

result required is:-

[0 2 0 4 0;
6 0 8 0 1;
0 3 0 7 0;
2 0 7 0 5;
0 6 0 8 0]

Answer 1

[Michael Haderlein]

I think there are dozens of possibilities, I just thought about this particular one:

if mod(size(m,1),2)==0
 m=[m;nan(1,size(m,2))];
end
m(1:2:end)=0;
if isnan(m(end,2))
 m=m(1:end-1,:);
end

Please note that there must not be NaNs in the matrix. If there are NaNs, this code must be little modified. Tell me in this case.