size_strel = 3;
nl = 12*size_strel;
nc = 8*size_strel;
imfreezones(size(imbin,1),size(imbin,2))=false;
strel = true(nl,nc)
for l=1:(size(imbin,1)/nl)
    for c=1:(size(imbin,2)/nc)
        teste = imbin((nl*(l-1))+1:(nl*l),(nc*(c-1))+1:(nc*c))& strel(:,:);
        if sum(teste(:))==0
            imfreezones((nl*(l-1))+1:(nl*l),(nc*(c-1))+1:(nc*c))=true;
        end
    end
end
figure(1), imshow(imfreezones)
figure(2), imshow(imbin)