function [BGR] = swap_RB_dumb(RGB)
BGR = RGB;
    for i1 = 1:size(BGR, 1)
        for i2 = 1:size(BGR, 2)
            BGR(i1, i2, 1) = RGB(i1, i2, 3);
            BGR(i1, i2, 3) = RGB(i1, i2, 1);
        end
    end
end