Evaluation parameters of Model 3 (the hybrid model) with different pixel sizes. The bottom x-axis represents the downsampling factor of the velocity field in the validation set, and the top x-axis is the corresponding pixel scale at different downsampling factors. The definition of the evaluation metrics (RMS E, MAE, CC, and S S IM) can be found in the main text. RMS E and MAE have units of pixel per frame (PPF). CC and S S IM are unitless.