If I understand well and if you want to keep it simple with an explicit for loop, what you want to do is something like that I guess:
element=find(blender >= 120);
NewMatrix = zeros(21, length(element));
for ii = 1:length(element)
k = element(ii);
r = max(1, k-10) : min(length(blender), k+10) ; % Range of indices +/- 10
% limited to valid ids.
NewMatrix(1:length(r),ii) = blender(r); % Store blender on the
% valid range; next
% elements left to 0.
end
Cheers,
Cedric
