How to find correaltion coeffient for two image regions?

I have 2 5-by-5 image regions. I want to find out correlation coefficient between them. Formula is- Denote the pixel intensity at location x as I(x),and W(x) as the 5-by-5 neighboring area centered at x, the correlation coefficient between the two pixel locations is computed as:

Answer 1

[Dishant Arora]

doc corr2