Unsupervised Intuitive Physics from Visual Observations

Abstract

While learning models of intuitive physics is an active area of research, current approaches fall short of natural intelligences in one important regard: they require external supervision, such as explicit access to physical states, at training and sometimes even at test time. Some approaches sidestep these requirements by building models on top of handcrafted physical simulators. In both cases, however, methods cannot learn automatically new physical environments and their laws as humans do. In this work, we successfully demonstrate, for the first time, learning unsupervised predictors of physical states, such as the position of objects in an environment, directly from raw visual observations and without relying on simulators. We do so in two steps: (i) we learn to track dynamically-salient objects in videos using causality and equivariance, two non-generative unsupervised learning principles that do not require manual or external supervision. (ii) we demonstrate that the extracted positions are sufficient to successfully train visual motion predictors that can take the underlying environment into account. We validate our predictors on synthetic datasets; then, we introduce a new dataset, Roll4Real, consisting of real objects rolling on complex terrains (pool table, elliptical bowl, and random height-field). We show that it is possible to learn reliable object trajectory extrapolators from raw videos alone, without any external supervision and with no more prior knowledge than the choice of a convolutional neural network architecture.

S. Ehrhardt and A. Monszpart—Contributed equally.