“…The solid, thin, blue line in each plot marked "oracle prior" shows results from running QBF-2 with a best-case-scenario prior, centered on the average ground truth spin for that spin type, with Λ = (−10, −10, −10). We show mean orientation and spin errors (to regressed ground truth), and also spin classification accuracy using the MAP estimate of spin type (out of 12) given the current spin belief 6 . The results clearly show that QBF-2 does the best job of identifying and tracking the ball rotations on this extremely challenging dataset, achieving a classification rate of 91% after just 30 video frames, and a mean spin (quaternion) error of 0.17 radians (10 degrees), with an average of 6.1 degrees of logo axis error and 6.8 degrees of logo angle error.…”