Papers › Unsupervised Space-Time Network for Temporally-Consistent Segmentation of Multiple Motions

Unsupervised Space-Time Network for Temporally-Consistent Segmentation of Multiple Motions

1 Jan 2023CVPR 2023 1archive 2025-07-28

Etienne Meunier, Patrick Bouthemy

Motion segmentation is one of the main tasks in computer vision and is relevant for many applications. The optical flow (OF) is the input generally used to segment every frame of a video sequence into regions of coherent motion. Temporal consistency is a key feature of motion segmentation, but it is often neglected. In this paper, we propose an original unsupervised spatio-temporal framework for motion segmentation from optical flow that fully investigates the temporal dimension of the problem. More specifically, we have defined a 3D network for multiple motion segmentation that takes as input a sub-volume of successive optical flows and delivers accordingly a sub-volume of coherent segmentation maps. Our network is trained in a fully unsupervised way, and the loss function combines a flow reconstruction term involving spatio-temporal parametric motion models, and a regularization term enforcing temporal consistency on the masks. We have specified an easy temporal linkage of the predicted segments. Besides, we have proposed a flexible and efficient way of coding U-nets. We report experiments on several VOS benchmarks with convincing quantitative results, while not using appearance and not training with any ground-truth data. We also highlight through visual results the distinctive contribution of the short- and long-term temporal consistency brought by our OF segmentation method.

PaperPDFCode

Code

etienne-meunier-inria/GeneraUnet officialmentioned in paperpytorch report

Repository list and official/mentioned flags are the archive's, frozen 2025-07-28. Reachability, where shown, is from one Syntology probe window (2026-09-16 to 2026-09-18); repositories not probed show nothing. GitHub stars are not tracked.

Code Syntology ran Syntology

Not run by Syntology. Nothing on this page verifies that the listed code works.

Tasks

Motion SegmentationOptical Flow EstimationSegmentation

Results from the paper archive 2025-07-28

No leaderboard rows for this paper in the archive.

Methods

VOS

Report a problem or propose a change · a person checks every report against the paper or source before anything changes; decisions are listed on /corrections