private Vector3 StandardDeviation()
{
Vector3 mean = Vector3.zero;
for (int x = 0; x < accel_array.Count; x++)
mean += accel_array[x];
mean /= accel_array.Count;
Vector3 ret = Vector3.zero;
for (int x = 0; x < accel_array.Count; x++)
{
Vector3 d = accel_array[x] - mean;
ret += new Vector3(d.x * d.x, d.y * d.y, d.z * d.z) / accel_array.Count;
}
ret.x = Mathf.Sqrt(ret.x);
ret.y = Mathf.Sqrt(ret.y);
ret.z = Mathf.Sqrt(ret.z);
return ret;
}