SMASH: Physics-guided Reconstruction of Collisions from Videos

摘要

Collision sequences are commonly used in games and entertainmentrnto add drama and excitement. Authoring even two body collisionsrnin the real world can be difficult, as one has to get timing andrnthe object trajectories to be correctly synchronized. After tediousrntrial-and-error iterations, when objects can actually be made torncollide, then they are difficult to capture in 3D. In contrast,rnsynthetically generating plausible collisions is difficult as it requiresrnadjusting different collision parameters (e.g., object mass ratio,rncoefficient of restitution, etc.) and appropriate initial parameters. Wernpresent SMASH to directly read off appropriate collision parametersrndirectly from raw input video recordings. Technically we enable thisrnby utilizing laws of rigid body collision to regularize the problemrnof lifting 2D trajectories to a physically valid 3D reconstruction ofrnthe collision. The reconstructed sequences can then be modifiedrnand combined to easily author novel and plausible collisions. Wernevaluate our system on a range of synthetic scenes and demonstraternthe effectiveness of our method by accurately reconstructing severalrncomplex real world collision events.