Learning Space-Time Semantic Correspondences
This addresses fine-grain video understanding for applications like activity coaching and sports analysis, but it is incremental as it builds on existing benchmarks and tasks.
The paper tackles the problem of predicting space-time semantic correspondences between videos, proposing a new task and finding that a joint space-time approach outperforms decomposed methods.
We propose a new task of space-time semantic correspondence prediction in videos. Given a source video, a target video, and a set of space-time key-points in the source video, the task requires predicting a set of keypoints in the target video that are the semantic correspondences of the provided source keypoints. We believe that this task is important for fine-grain video understanding, potentially enabling applications such as activity coaching, sports analysis, robot imitation learning, and more. Our contributions in this paper are: (i) proposing a new task and providing annotations for space-time semantic correspondences on two existing benchmarks: Penn Action and Pouring; and (ii) presenting a comprehensive set of baselines and experiments to gain insights about the new problem. Our main finding is that the space-time semantic correspondence prediction problem is best approached jointly in space and time rather than in their decomposed sub-problems: time alignment and spatial correspondences.