Unsupervised Object Keypoint Learning using Local Spatial Predictability
Authors: Anand Gopalakrishnan, Sjoerd van Steenkiste, Jürgen Schmidhuber
Venue: ICLR 2021 Spotlight
Keywords: unsupervised representation learning, object-keypoint representations, visual saliency
Abstract: We propose PermaKey, a novel approach to representation learning based on object keypoints. It leverages the predictability of local image regions from spatial neighborhoods to identify salient regions that correspond to object parts, which are then converted to keypoints. Unlike prior approaches, it utilizes predictability to discover object keypoints, an intrinsic property of objects. This ensures that it does not overly bias keypoints to focus on characteristics that are not unique to objects, such as movement, shape, colour etc.  We demonstrate the efficacy of PermaKey on Atari where it learns keypoints corresponding to the most salient object parts and is robust to certain visual distractors. Further, on downstream RL tasks in the Atari domain we demonstrate how agents equipped with our keypoints outperform those using competing alternatives, even on challenging environments with moving backgrounds or distractor objects.