SWEM: Towards Real-Time Video Object Segmentation with Sequential Weighted Expectation-Maximization

Matching-based methods, especially those based on space-time memory, are significantly ahead of other solutions in semi-supervised video object segmentation (VOS). However, continuously growing and redundant template features lead to an inefficient inference. To alleviate this, we propose a novel Sequential Weighted Expectation-Maximization (SWEM) network to greatly reduce the redundancy of memory features. Different from the previous methods which only detect feature redundancy between frames, SWEM merges both intra-frame and inter-frame similar features by leveraging the sequential weighted EM algorithm. Further, adaptive weights for frame features endow SWEM with the flexibility to represent hard samples, improving the discrimination of templates. Besides, the proposed method maintains a fixed number of template features in memory, which ensures the stable inference complexity of the VOS system. Extensive experiments on commonly used DAVIS and YouTube-VOS datasets verify the high efficiency (36 FPS) and high performance (84.3\% $\mathcal{J}\&\mathcal{F}$ on DAVIS 2017 validation dataset) of SWEM. Code is available at: https://github.com/lmm077/SWEM.

PDF Abstract CVPR 2022 PDF CVPR 2022 Abstract
Task Dataset Model Metric Name Metric Value Global Rank Result Benchmark
Semi-Supervised Video Object Segmentation DAVIS 2016 SWEM (val) Jaccard (Mean) 87.3 # 40
F-measure (Mean) 89.0 # 40
J&F 88.1 # 41
Speed (FPS) 36 # 12
Semi-Supervised Video Object Segmentation DAVIS 2017 (val) SWEM Jaccard (Mean) 74.5 # 45
F-measure (Mean) 79.8 # 49
J&F 77.2 # 49
Semi-Supervised Video Object Segmentation DAVIS (no YouTube-VOS training) SWEM FPS 36.0 # 5
D16 val (G) 88.1 # 2
D16 val (J) 87.3 # 4
D16 val (F) 89.0 # 2
D17 val (G) 77.2 # 6
D17 val (J) 74.5 # 6
D17 val (F) 79.8 # 6
Semi-Supervised Video Object Segmentation MOSE SWEM J&F 50.9 # 14
J 46.8 # 14
F 54.9 # 15

Methods