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Main Authors: Cheng, Tao, Chen, Shi-Zhe, Zhang, Hao, Qin, Yixin, Luo, Jinwen, Wei, Zheng
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.20328
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author Cheng, Tao
Chen, Shi-Zhe
Zhang, Hao
Qin, Yixin
Luo, Jinwen
Wei, Zheng
author_facet Cheng, Tao
Chen, Shi-Zhe
Zhang, Hao
Qin, Yixin
Luo, Jinwen
Wei, Zheng
contents Chain-of-Thought (CoT) reasoning significantly elevates the complex problem-solving capabilities of multimodal large language models (MLLMs). However, adapting CoT to vision typically discretizes signals to fit LLM inputs, causing early semantic collapse and discarding fine-grained details. While external tools can mitigate this, they introduce a rigid bottleneck, confining reasoning to predefined operations. Although recent latent reasoning paradigms internalize visual states to overcome these limitations, optimizing the resulting hybrid discrete-continuous action space remains challenging. In this work, we propose HyLaR (Hybrid Latent Reasoning), a framework that seamlessly interleaves discrete text generation with continuous visual latent representations. Specifically, following an initial cold-start supervised fine-tuning (SFT), we introduce DePO (Decoupled Policy Optimization) to enable effective reinforcement learning within this hybrid space. DePO decomposes the policy gradient objective, applying independent trust-region constraints to the textual and latent components, alongside an exact closed-form von Mises-Fisher (vMF) KL regularizer. Extensive experiments demonstrate that HyLaR outperforms standard MLLMs and state-of-the-art latent reasoning approaches across fine-grained perception and general multimodal understanding benchmarks. Code is available at https://github.com/EthenCheng/HyLaR.
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publishDate 2026
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spellingShingle Hybrid Latent Reasoning with Decoupled Policy Optimization
Cheng, Tao
Chen, Shi-Zhe
Zhang, Hao
Qin, Yixin
Luo, Jinwen
Wei, Zheng
Computer Vision and Pattern Recognition
Chain-of-Thought (CoT) reasoning significantly elevates the complex problem-solving capabilities of multimodal large language models (MLLMs). However, adapting CoT to vision typically discretizes signals to fit LLM inputs, causing early semantic collapse and discarding fine-grained details. While external tools can mitigate this, they introduce a rigid bottleneck, confining reasoning to predefined operations. Although recent latent reasoning paradigms internalize visual states to overcome these limitations, optimizing the resulting hybrid discrete-continuous action space remains challenging. In this work, we propose HyLaR (Hybrid Latent Reasoning), a framework that seamlessly interleaves discrete text generation with continuous visual latent representations. Specifically, following an initial cold-start supervised fine-tuning (SFT), we introduce DePO (Decoupled Policy Optimization) to enable effective reinforcement learning within this hybrid space. DePO decomposes the policy gradient objective, applying independent trust-region constraints to the textual and latent components, alongside an exact closed-form von Mises-Fisher (vMF) KL regularizer. Extensive experiments demonstrate that HyLaR outperforms standard MLLMs and state-of-the-art latent reasoning approaches across fine-grained perception and general multimodal understanding benchmarks. Code is available at https://github.com/EthenCheng/HyLaR.
title Hybrid Latent Reasoning with Decoupled Policy Optimization
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2604.20328