    CImg<T>& blur_patch(const float sigma_s, const float sigma_r, const unsigned int patch_size=3,
                        const unsigned int lookup_size=4, const float smoothness=0, const bool is_fast_approx=true) {
      return blur_patch(*this,sigma_s,sigma_r,patch_size,lookup_size,smoothness,is_fast_approx);
    }
    CImg<T>& blur_patch(const float sigma_s, const float sigma_r, const unsigned int patch_size=3,
                        const unsigned int lookup_size=4, const float smoothness=0, const bool is_fast_approx=true) {
      return blur_patch(*this,sigma_s,sigma_r,patch_size,lookup_size,smoothness,is_fast_approx);
    }