MATLAB: Is there is a way I can select the minimum value from a matrix, and replace all numbers surrounding this minimum value (3 cells) by a specific number

Question

I want to select this minimum value cell, and anything within a radius of ‘less than or equal to’ three cells to be replaced with a specific number such as 99 (including the selected minimum cell).

I have uploaded a pdf of what i am trying to accomplish. Sorry for any inconvenience and thank you.

Answer 1

[~,imin]=min(x(:));             % location of min (linear
[im,jm]=ind2sub(size(x),imin);  % convert to subscripts
x(im-1:im+1,jm-1:jm+1)=99;      % set a square around that location