Accord.Tests.Imaging.IntegralImage2Test.tiltedIntegral C# (CSharp) Method

        private static int[,] tiltedIntegral(byte[,] img)
        {
            int val = 0;
            int[,] expected = new int[img.GetLength(0) + 2, img.GetLength(0) + 2];
            for (int i = 2; i < img.GetLength(0) + 2; i++)
            {
                for (int j = 0; j < img.GetLength(1) + 2; j++)
                {
                    int sum = val;

                    for (int k = 0; k < img.GetLength(0); k++)
                    {
                        for (int l = 0; l < img.GetLength(1); l++)
                        {
                            if (k - l <= i - j + 1 &&
                                k + l <= i + j - 2)
                                sum += img[k, l];
                        }
                    }

                    expected[i, j] = sum;
                }
            }
            return expected;
        }