Perceive-to-Reason: Decoupling Perception and Reasoning for Fine-Grained Visual Reasoning
Abstract Overview
This paper presents Perceive-to-Reason (P2R), a framework for fine-grained visual reasoning that explicitly separates perception from reasoning. In P2R, the model first localizes question-relevant evidence as a Perceiver and then answers the question as a Reasoner using the annotated image and cropped regions. To train this decoupled pipeline under answer-only supervision, the authors introduce PRA-GRPO, a role-aware reinforcement learning strategy that alternates between perception-focused and reasoning-focused updates while keeping the other role fixed. The method is built on Qwen3-VL-Instruct backbones and evaluated on high-resolution visual reasoning benchmarks as well as a broader multimodal benchmark.
Novelty
The main novelty is the explicit two-stage formulation of fine-grained visual reasoning as separate evidence localization and answer generation within a unified model. The paper also introduces PRA-GRPO, an alternating role-aware RL strategy that uses only final-answer supervision to train both stages without ground-truth bounding boxes.
Results
Across Qwen3-VL-Instruct 2B, 4B, and 8B backbones, P2R consistently improves performance on V-Star, HR-Bench-4K, and HR-Bench-8K. For example, P2R-4B reaches 93.2% on V-Star, 81.9% on HR-Bench-4K, and 80.5% on HR-Bench-8K, and the paper reports average gains over the corresponding backbones of 8.1%, 11.0%, and 9.7% for the 2B, 4B, and 8B variants, respectively. The gains also extend to MME-RealWorld-Lite and a ReasonSeg grounding evaluation, indicating broader transfer beyond the primary high-resolution setting.
Key Points
- P2R reformulates fine-grained visual reasoning as a two-stage process in which a Perceiver localizes relevant evidence before a Reasoner answers the question from annotated and cropped visual inputs.
- PRA-GRPO alternates perception and reasoning updates under shared parameters, converting final-answer correctness into a more attributable training signal without requiring bounding box annotations.
- Empirically, the method improves multiple Qwen3-VL-Instruct scales on high-resolution benchmarks and also shows gains on broader multimodal reasoning and grounding tasks.
References
- arXiv: https://arxiv.org/abs/2607.01191v1
- Fugu-MT: https://fugumt.com/fugumt/paper_check/2607.01191v1
- Hugging Face Papers: https://huggingface.co/papers/2607.01191
- GitHub: https://github.com/ZJU-REAL/Perceive-to-Reason
- Hugging Face: https://huggingface.co/hongxingli/P2R-4B