ActFER: Agentic Facial Expression Recognition via Active Tool-Augmented Visual Reasoning

Fuente: arXiv
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Auteurs principaux: Liu, Shifeng, Zhang, Zhengye, Zhao, Sirui, Mao, Xinglong, Kan, Zhehan, Wei, Zhixiang, Wu, Shiwei, Fu, Chaoyou, Xu, Tong, Chen, Enhong
Format: Preprint
Publié: 2026
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author Liu, Shifeng
Zhang, Zhengye
Zhao, Sirui
Mao, Xinglong
Kan, Zhehan
Wei, Zhixiang
Wu, Shiwei
Fu, Chaoyou
Xu, Tong
Chen, Enhong
author_facet Liu, Shifeng
Zhang, Zhengye
Zhao, Sirui
Mao, Xinglong
Kan, Zhehan
Wei, Zhixiang
Wu, Shiwei
Fu, Chaoyou
Xu, Tong
Chen, Enhong
contents Recent advances in Multimodal Large Language Models (MLLMs) have created new opportunities for facial expression recognition (FER), moving it beyond pure label prediction toward reasoning-based affect understanding. However, existing MLLM-based FER methods still follow a passive paradigm: they rely on externally prepared facial inputs and perform single-pass reasoning over fixed visual evidence, without the capability for active facial perception. To address this limitation, we propose ActFER, an agentic framework that reformulates FER as active visual evidence acquisition followed by multimodal reasoning. Specifically, ActFER dynamically invokes tools for face detection and alignment, selectively zooms into informative local regions, and reasons over facial Action Units (AUs) and emotions through a visual Chain-of-Thought. To realize such behavior, we further develop Utility-Calibrated GRPO (UC-GRPO), a reinforcement learning algorithm tailored to agentic FER. UC-GRPO uses AU-grounded multi-level verifiable rewards to densify supervision, query-conditional contrastive utility estimation to enable sample-aware dynamic credit assignment for local inspection, and emotion-aware EMA calibration to reduce noisy utility estimates while capturing emotion-wise inspection tendencies. This algorithm enables ActFER to learn both when local inspection is beneficial and how to reason over the acquired evidence. Comprehensive experiments show that ActFER trained with UC-GRPO consistently outperforms passive MLLM-based FER baselines and substantially improves AU prediction accuracy.
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id arxiv_https___arxiv_org_abs_2604_08990
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publishDate 2026
record_format arxiv
spellingShingle ActFER: Agentic Facial Expression Recognition via Active Tool-Augmented Visual Reasoning
Liu, Shifeng
Zhang, Zhengye
Zhao, Sirui
Mao, Xinglong
Kan, Zhehan
Wei, Zhixiang
Wu, Shiwei
Fu, Chaoyou
Xu, Tong
Chen, Enhong
Computer Vision and Pattern Recognition
Recent advances in Multimodal Large Language Models (MLLMs) have created new opportunities for facial expression recognition (FER), moving it beyond pure label prediction toward reasoning-based affect understanding. However, existing MLLM-based FER methods still follow a passive paradigm: they rely on externally prepared facial inputs and perform single-pass reasoning over fixed visual evidence, without the capability for active facial perception. To address this limitation, we propose ActFER, an agentic framework that reformulates FER as active visual evidence acquisition followed by multimodal reasoning. Specifically, ActFER dynamically invokes tools for face detection and alignment, selectively zooms into informative local regions, and reasons over facial Action Units (AUs) and emotions through a visual Chain-of-Thought. To realize such behavior, we further develop Utility-Calibrated GRPO (UC-GRPO), a reinforcement learning algorithm tailored to agentic FER. UC-GRPO uses AU-grounded multi-level verifiable rewards to densify supervision, query-conditional contrastive utility estimation to enable sample-aware dynamic credit assignment for local inspection, and emotion-aware EMA calibration to reduce noisy utility estimates while capturing emotion-wise inspection tendencies. This algorithm enables ActFER to learn both when local inspection is beneficial and how to reason over the acquired evidence. Comprehensive experiments show that ActFER trained with UC-GRPO consistently outperforms passive MLLM-based FER baselines and substantially improves AU prediction accuracy.
title ActFER: Agentic Facial Expression Recognition via Active Tool-Augmented Visual Reasoning
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2604.08990