matrix correlation in different directions

Hey,

I would like to write a function thats gets two matrices and a direction (x-axis (o degrees)\yaxis (90 degrees)\diagonal (45 degrees)) and calculates the correlation in that direction.

for example, if I have matrices A and B, then

C = direction_corr(A,B,angle)

will give the correlation between the rotated matrices. So 0 is the regular correlation and 45 will give:

C=[sum(A(end,1)*B(1,end)),sum(A(end-1:end,1:2).*B(1:2,end-1:end),'all')...]

the 0 and 90 cases are easy, but I'm not sure what to do about the diagonal case. If i use imrotate it interpolates pixels and give me a wrong result.

Thanks in advence,

Oded