const double sfilter[6][6] =
{{0.280,  0.236, 0.075,  0.004, -0.055, -0.006},
 {0.236,  0.160, 0.066, -0.017, -0.046, -0.005},
 {0.075,  0.066, 0.009, -0.043, -0.027, -0.003},
 {0.004, -0.017,-0.043, -0.032, -0.010,  0.001},
 {-0.055,-0.046,-0.027, -0.010, -0.002, 0.0003},
 {-0.006,-0.005,-0.003, -0.001, 0.0003,    0.0}};

const double tfilter[4] =
{0.44407, 0.33614, 0.12500, -0.08614};