Accord.Imaging.RansacHomographyEstimator.distance C# (CSharp) Method

        private int[] distance(MatrixH H, double t)
        {
            // Compute the projections (both directions)
            PointF[] p1 = H.TransformPoints(pointSet1);
            PointF[] p2 = H.Inverse().TransformPoints(pointSet2);

            // Compute the distances
            for (int i = 0; i < pointSet1.Length; i++)
            {
                // Compute the distance as
                float ax = pointSet1[i].X - p2[i].X;
                float ay = pointSet1[i].Y - p2[i].Y;
                float bx = pointSet2[i].X - p1[i].X;
                float by = pointSet2[i].Y - p1[i].Y;
                d2[i] = (ax * ax) + (ay * ay) + (bx * bx) + (by * by);
            }

            // Find and return the inliers
            return Matrix.Find(d2, z => z < t);
        }