Matrix extraction from image

I want to extract a matrix 5*5 Matrix from 256*256 image ... Then I have to do some modification in the 5*5... Then I apply the same modification in every 5*5 block of 256*256... How to do it...

Answer 1

[KSSV]

Refer here: https://in.mathworks.com/matlabcentral/answers/362262-i-have-a-32-32-matrix-i-want-to-take-mean-of-each-4-4-so-that-the-matrix-is-reduced-to-8-8-array#answer_286773