EventPrune: Cascaded Event-Assisted Token Pruning for Efficient First-Person Dynamic Spatial Reasoning

Fuente: arXiv
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Main Authors: Ma, Pengtao, Zhou, Ziliang, Ruan, Ciyu, Wang, Haoyang, Li, Kaiyuan, Gong, Zihang, Ding, Wenhua, Gao, Chen, Xu, Jingao, Chen, Xinlei
Format: Preprint
Published: 2026
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author Ma, Pengtao
Zhou, Ziliang
Ruan, Ciyu
Wang, Haoyang
Li, Kaiyuan
Gong, Zihang
Ding, Wenhua
Gao, Chen
Xu, Jingao
Chen, Xinlei
author_facet Ma, Pengtao
Zhou, Ziliang
Ruan, Ciyu
Wang, Haoyang
Li, Kaiyuan
Gong, Zihang
Ding, Wenhua
Gao, Chen
Xu, Jingao
Chen, Xinlei
contents First-person dynamic spatial reasoning requires models to track continuous motion and precise geometric structure, but the quadratic attention cost of Transformer-based Video-LLMs makes dense visual tokens computationally expensive. Existing token pruning paradigms predominantly rely on discrete static snapshots, failing to preserve the motion and geometric cues essential for reasoning. We propose Event Cascade Pruning (ECP), to our knowledge the first training-free framework that leverages the high-frequency motion cues from event cameras as a continuous event-guided motion prior to guide token selection. ECP combines three stages: Event-Triggered Causal Sampling to anchor motion-informative keyframes, Event-guided Motion Saliency Filtering to suppress event-inactive visual tokens, and Event-Attention Ranking Fusion to calibrate spatial attention with motion-salient dynamics. With 80% visual token reduction, ECP outperforms the full-token baseline (37.62% vs. 36.31%) while achieving 1.89x inference speedup and 52% GFLOPs reduction. We further introduce ESR-Real, the first real-world RGB-event benchmark for first-person spatial reasoning, where ECP improves accuracy by 2.68 percentage points over full-token baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2605_19506
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle EventPrune: Cascaded Event-Assisted Token Pruning for Efficient First-Person Dynamic Spatial Reasoning
Ma, Pengtao
Zhou, Ziliang
Ruan, Ciyu
Wang, Haoyang
Li, Kaiyuan
Gong, Zihang
Ding, Wenhua
Gao, Chen
Xu, Jingao
Chen, Xinlei
Computer Vision and Pattern Recognition
First-person dynamic spatial reasoning requires models to track continuous motion and precise geometric structure, but the quadratic attention cost of Transformer-based Video-LLMs makes dense visual tokens computationally expensive. Existing token pruning paradigms predominantly rely on discrete static snapshots, failing to preserve the motion and geometric cues essential for reasoning. We propose Event Cascade Pruning (ECP), to our knowledge the first training-free framework that leverages the high-frequency motion cues from event cameras as a continuous event-guided motion prior to guide token selection. ECP combines three stages: Event-Triggered Causal Sampling to anchor motion-informative keyframes, Event-guided Motion Saliency Filtering to suppress event-inactive visual tokens, and Event-Attention Ranking Fusion to calibrate spatial attention with motion-salient dynamics. With 80% visual token reduction, ECP outperforms the full-token baseline (37.62% vs. 36.31%) while achieving 1.89x inference speedup and 52% GFLOPs reduction. We further introduce ESR-Real, the first real-world RGB-event benchmark for first-person spatial reasoning, where ECP improves accuracy by 2.68 percentage points over full-token baselines.
title EventPrune: Cascaded Event-Assisted Token Pruning for Efficient First-Person Dynamic Spatial Reasoning
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2605.19506