Figure 8.

An illustration of the combined forward-backward prediction: To allow a robust estimation that exploits the motion characteristics, we use higher-order approximations of the central differences. Here, we predict the location of $v_{i,t-1}$ based on the previous and the following three frames. The red line connects the joint locations used for forward prediction (Equation (6)) and the blue lines connect the joint locations used for backward prediction (Equation (7)).