Convolution product
===================

.. code:: cpp

    template <typename Img>
    concept bool Image_with_Neighborhood_and_Extension =
        Image<Img> &&
        Neighborhood<Img> &&
        Extension<Img>;

    template <
        Image_with_Neighborhood_and_Extension Img,
        Zippable<Img::neighborhood_type, Convol_Values>
    >
    Image convolution_product(const Img& ima, const Convol_Values& convol_values) {
        auto ima_res = copy(ima);

        for(auto [&pix_res, pix] : zip(ima_res.pixels(), ima.pixels())) {
            pix_res.val() = accumulate(
                zip(pix.neighborsWithSE(), convol_values),
                Img::value_type{},
                [](auto init_val, auto&& zipped_pixel) {
                    auto [neighbor, conv_scalar] = zipped_pixel;
                    return init_val + neighbor.val() * conv_scalar;
                }
            );
        }

        return ima_res;
    }