Merging a mask into a larger matrix

I have a 2D binary mask of size 200x200. I want to merge this mask into a matrix of size 775x640.

[Doug Hull]

What does it mean to merge these masks?

Answer 1

[Walter Roberson]

Matrix(J:J+199,K:K+199) = Mask;

Or possibly you mean something like

Matrix(J:J+199,K:K+199) = Matrix(J:J+199,K:K+199) .* Mask;