FAST3DIS: Feed-forward Anchored Scene Transformer for 3D Instance Segmentation

Fuente: arXiv
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Auteurs principaux: Li, Changyang, Huang, Xueqing, Chng, Shin-Fang, Zhan, Huangying, Yan, Qingan, Xu, Yi
Format: Preprint
Publié: 2026
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author Li, Changyang
Huang, Xueqing
Chng, Shin-Fang
Zhan, Huangying
Yan, Qingan
Xu, Yi
author_facet Li, Changyang
Huang, Xueqing
Chng, Shin-Fang
Zhan, Huangying
Yan, Qingan
Xu, Yi
contents While recent feed-forward 3D reconstruction models provide a strong geometric foundation for scene understanding, extending them to 3D instance segmentation typically relies on a disjointed "lift-and-cluster" paradigm. Grouping dense pixel-wise embeddings via non-differentiable clustering scales poorly with the number of views and disconnects representation learning from the final segmentation objective. In this paper, we present a Feed-forward Anchored Scene Transformer for 3D Instance Segmentation (FAST3DIS), an end-to-end approach that effectively bypasses post-hoc clustering. We introduce a 3D-anchored, query-based Transformer architecture built upon a foundational depth backbone, adapted efficiently to learn instance-specific semantics while retaining its zero-shot geometric priors. We formulate a learned 3D anchor generator coupled with an anchor-sampling cross-attention mechanism for view-consistent 3D instance segmentation. By projecting 3D object queries directly into multi-view feature maps, our method samples context efficiently. Furthermore, we introduce a dual-level regularization strategy, that couples multi-view contrastive learning with a dynamically scheduled spatial overlap penalty to explicitly prevent query collisions and ensure precise instance boundaries. Experiments on complex indoor 3D datasets demonstrate that our approach achieves competitive segmentation accuracy with significantly improved memory scalability and inference speed over state-of-the-art clustering-based methods.
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id arxiv_https___arxiv_org_abs_2603_25993
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle FAST3DIS: Feed-forward Anchored Scene Transformer for 3D Instance Segmentation
Li, Changyang
Huang, Xueqing
Chng, Shin-Fang
Zhan, Huangying
Yan, Qingan
Xu, Yi
Computer Vision and Pattern Recognition
While recent feed-forward 3D reconstruction models provide a strong geometric foundation for scene understanding, extending them to 3D instance segmentation typically relies on a disjointed "lift-and-cluster" paradigm. Grouping dense pixel-wise embeddings via non-differentiable clustering scales poorly with the number of views and disconnects representation learning from the final segmentation objective. In this paper, we present a Feed-forward Anchored Scene Transformer for 3D Instance Segmentation (FAST3DIS), an end-to-end approach that effectively bypasses post-hoc clustering. We introduce a 3D-anchored, query-based Transformer architecture built upon a foundational depth backbone, adapted efficiently to learn instance-specific semantics while retaining its zero-shot geometric priors. We formulate a learned 3D anchor generator coupled with an anchor-sampling cross-attention mechanism for view-consistent 3D instance segmentation. By projecting 3D object queries directly into multi-view feature maps, our method samples context efficiently. Furthermore, we introduce a dual-level regularization strategy, that couples multi-view contrastive learning with a dynamically scheduled spatial overlap penalty to explicitly prevent query collisions and ensure precise instance boundaries. Experiments on complex indoor 3D datasets demonstrate that our approach achieves competitive segmentation accuracy with significantly improved memory scalability and inference speed over state-of-the-art clustering-based methods.
title FAST3DIS: Feed-forward Anchored Scene Transformer for 3D Instance Segmentation
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2603.25993