Smoothness Penalty P=1T∑t=1T((xt+1−xt)−(xt−xt−1))2(xt+1−xt)2+(xt−xt−1)2P=\frac{1}{T} \sum_{t=1}^T \frac{\left(\left(x_{t+1}-x_t\right)-\left(x_t-x_{t-1}\right)\right)^2}{\left(x_{t+1}-x_t\right)^2+\left(x_t-x_{t-1}\right)^2}P=T1t=1∑T(xt+1−xt)2+(xt−xt−1)2((xt+1−xt)−(xt−xt−1))2 From this we get nice properties such as enforced angle smoothness enforced constant velocity partly enforced noise cancellation