URoPE: Universal Relative Position Embedding across Geometric Spaces

Fuente: arXiv
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Main Authors: Xie, Yichen, Meng, Depu, Peng, Chensheng, Hu, Yihan, Herau, Quentin, Tomizuka, Masayoshi, Zhan, Wei
Format: Preprint
Published: 2026
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author Xie, Yichen
Meng, Depu
Peng, Chensheng
Hu, Yihan
Herau, Quentin
Tomizuka, Masayoshi
Zhan, Wei
author_facet Xie, Yichen
Meng, Depu
Peng, Chensheng
Hu, Yihan
Herau, Quentin
Tomizuka, Masayoshi
Zhan, Wei
contents Relative position embedding has become a standard mechanism for encoding positional information in Transformers. However, existing formulations are typically limited to a fixed geometric space, namely 1D sequences or regular 2D/3D grids, which restricts their applicability to many computer vision tasks that require geometric reasoning across camera views or between 2D and 3D spaces. To address this limitation, we propose URoPE, a universal extension of Rotary Position Embedding (RoPE) to cross-view or cross-dimensional geometric spaces. For each key/value image patch, URoPE samples 3D points along the corresponding camera ray at predefined depth anchors and projects them into the query image plane. Standard 2D RoPE can then be applied using the projected pixel coordinates. URoPE is a parameter-free and intrinsics-aware relative position embedding that is invariant to the choice of global coordinate systems, while remaining fully compatible with existing RoPE-optimized attention kernels. We evaluate URoPE as a plug-in positional encoding for transformer architectures across a diverse set of tasks, including novel view synthesis, 3D object detection, object tracking, and depth estimation, covering 2D-2D, 2D-3D, and temporal scenarios. Experiments show that URoPE consistently improves the performance of transformer-based models across all tasks, demonstrating its effectiveness and generality for geometric reasoning. Our project website is: https://urope-pe.github.io/.
format Preprint
id arxiv_https___arxiv_org_abs_2604_18747
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle URoPE: Universal Relative Position Embedding across Geometric Spaces
Xie, Yichen
Meng, Depu
Peng, Chensheng
Hu, Yihan
Herau, Quentin
Tomizuka, Masayoshi
Zhan, Wei
Computer Vision and Pattern Recognition
Relative position embedding has become a standard mechanism for encoding positional information in Transformers. However, existing formulations are typically limited to a fixed geometric space, namely 1D sequences or regular 2D/3D grids, which restricts their applicability to many computer vision tasks that require geometric reasoning across camera views or between 2D and 3D spaces. To address this limitation, we propose URoPE, a universal extension of Rotary Position Embedding (RoPE) to cross-view or cross-dimensional geometric spaces. For each key/value image patch, URoPE samples 3D points along the corresponding camera ray at predefined depth anchors and projects them into the query image plane. Standard 2D RoPE can then be applied using the projected pixel coordinates. URoPE is a parameter-free and intrinsics-aware relative position embedding that is invariant to the choice of global coordinate systems, while remaining fully compatible with existing RoPE-optimized attention kernels. We evaluate URoPE as a plug-in positional encoding for transformer architectures across a diverse set of tasks, including novel view synthesis, 3D object detection, object tracking, and depth estimation, covering 2D-2D, 2D-3D, and temporal scenarios. Experiments show that URoPE consistently improves the performance of transformer-based models across all tasks, demonstrating its effectiveness and generality for geometric reasoning. Our project website is: https://urope-pe.github.io/.
title URoPE: Universal Relative Position Embedding across Geometric Spaces
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2604.18747