Function test_integral_image

dlib/test/image.cpp:896–940

    template <typename T, typename pixel_type>
    void test_integral_image (
    )
    {
        dlib::rand rnd;

        array2d<pixel_type> img;
        integral_image_generic<T> int_img;

        int_img.load(img);
        DLIB_TEST(int_img.nr() == 0);
        DLIB_TEST(int_img.nc() == 0);

        // make 5 random images
        for (int i = 0; i < 5; ++i)
        {
            print_spinner();
            img.set_size(rnd.get_random_16bit_number()%200+1, rnd.get_random_16bit_number()%200+1);

            for (long r = 0; r < img.nr(); ++r)
            {
                for (long c = 0; c < img.nc(); ++c)
                {
                    img[r][c] = (int)rnd.get_random_8bit_number() - 100;
                }
            }

            int_img.load(img);
            DLIB_TEST(int_img.nr() == img.nr());
            DLIB_TEST(int_img.nc() == img.nc());

            // make 200 random rectangles
            for (int j = 0; j < 500; ++j)
            {
                point p1(rnd.get_random_32bit_number()%img.nc(), rnd.get_random_32bit_number()%img.nr());
                point p2(rnd.get_random_32bit_number()%img.nc(), rnd.get_random_32bit_number()%img.nr());
                rectangle rect(p1,p2);
                DLIB_TEST(int_img.get_sum_of_area(rect) == sum(subm(matrix_cast<T>(mat(img)), rect)));
                rect = rectangle(p1,p1);
                DLIB_TEST(int_img.get_sum_of_area(rect) == sum(subm(matrix_cast<T>(mat(img)), rect)));
            }

        }


    }

    void test_filtering2(int nr, int nc, dlib::rand& rnd)
    {