Didi Zhu

Didi Zhu

Imperial College London London, United Kingdom

Reliable multimodal reasoning for changing worlds.

About Me

I build multimodal systems for visual alignment, model composition, and reliable reasoning in changing worlds.

I am currently a Postdoctoral Research Associate at Imperial College London, supervised by Prof. Jiankang Deng and Prof. Stefanos Zafeiriou. Previously, I completed my Ph.D. at Zhejiang University, advised by Prof. Chao Wu and co-supervised by Prof. Kun Kuang and Prof. Fei Wu. I was also fortunate to collaborate with Yibing Song from the Alibaba DAMO Academy.

I am always open to collaboration opportunities and conversations with fellow researchers. Recently in London, I have been collecting sunsets, parks, coffee conversations, and new research questions. 😊

Research Map

01

Align

Using structure and theory to make vision-language models generalize beyond familiar distributions.

VLMs Prompt Tuning Neural Collapse
02

Compose

Understanding how multimodal models forget, merge, and reuse specialized capabilities.

Model Tailor REMEDY LoRA Merging
03

Reason

Eliciting reliable multimodal reasoning through lightweight reinforcement learning and curated supervision.

MLLMs RL Reasoning

Recent Highlights

  • 2026.04 🚀 Released LLaVA-OneVision-2, our next-generation 8B multimodal foundation model unifying image, long-form video, and spatial understanding, where I served as a core contributor.
  • 2025.12 🚀 Released LLaVA-OneVision-1.5-RL, a fully open framework for democratized multimodal reinforcement learning, where I served as a core contributor.
  • 2025.09 🎉 One first-author paper has been accepted to NeurIPS 2025 Multimodal Algorithmic Reasoning Workshop.
  • 2025.09 🎉 One co-author paper has been accepted to NeurIPS 2025.
  • 2025.07 🎉 One co-author paper has been accepted to ICCV 2025.
  • 2025.07 🎉 One co-author paper has been accepted to KDD 2025.
Earlier updates
  • 2025.05 🎉 Four co-author papers have been accepted to ICML 2025.
  • 2025.04 🥳 I will attend the ICLR conference in Singapore, welcome to discuss in person.
  • 2025.02 🎉 One co-author paper has been accepted to ICLR 2025 FL Workshop.
  • 2025.01 🎉 Three papers (One first-author paper and two co-author papers) have been accepted to ICLR 2025.
  • 2024.07 🥳 I went to Vienna, Austria to attend the ICML conference.
  • 2024.05 🎉 One first-author paper has been accepted to KDD 2024.
  • 2024.05 🎉 One first-author paper has been accepted to ICML 2024.
  • 2023.10 🥳 I went to Paris, France to attend the ICCV conference.
  • 2023.07 🎉 One first-author paper has been accepted to ICCV 2023.
  • 2023.07 🎉 One first-author paper has been accepted to ACM Multimedia 2023.
  • 2023.05 🎉 One paper has been accepted to KDD 2023.
  • 2022.11 🎉 One paper has been accepted to IEEE Transactions on Big Data.
  • 2021.05 🎉 One paper has been accepted to IJCAI 2021 FL Workshop.

📝 Publications

Selected and recent works
Tech Report 2026
sym

Reason

LLaVA-OneVision-2: Towards Next-Generation Perceptual Intelligence
Xiang An, Yin Xie, Feilong Tang, Yunyao Yan, Huajie Tan, Didi Zhu, Changrui Chen, Xiuwei Zhao, Bin Qin, Kaicheng Yang, et al.
Project Leaders: Bo Li, Ziyong Feng, Ziwei Liu, Zongyuan Ge, Jiankang Deng

  • An 8B multimodal foundation model unifying image, long-form video, and 3D-aware spatial understanding under a single architecture via codec-aligned vision encoders.
  • Fully open end-to-end release: data, encoders, training pipeline, checkpoints, and training logs.
Tech Report 2025
sym

Reason

LLaVA-OneVision-1.5-RL: Unlocking Multimodal Reasoning via Lightweight Reinforcement Learning
Didi Zhu (First Author, RL Section), Zhiyu Qu, Zerui Chen, Polydefkis Gkagkos, Xiang An, Bo Li
RL Section of Technical Report. Project Leaders: Changrui Chen, Jiankang Deng

  • Leveraging lightweight RL framework (GRPO) on top of supervised instruct model to elicit latent reasoning capabilities.
  • Using only 67K curated examples with discrepancy-based selection, significantly boosting performance on complex STEM, Coding, and Reasoning tasks.
ICLR 2025
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Compose

REMEDY: Recipe Merging Dynamics in Large Vision-Language Models .
Didi Zhu, Yibing Song, Tao Shen, Ziyu Zhao, Jinluan Yang, Min Zhang, Chao Wu

  • First exploration of the LoRA fusion problem in Multimodal Large Language Models
  • Proposing a dynamic fusion scheme enhances zero-shot generalization capability of MLLMs.
ICML 2024
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Compose

Model Tailor: Mitigating Catastrophic Forgetting in Multi-modal Large Language Models.
Didi Zhu, Zhongyisun Sun, Zexi Li, Tao Shen, Ke Yan, Shouhong Ding, Chao Wu, Kun Kuang

  • Pioneered the first comprehensive exploration and revelation of catastrophic forgetting in MLLMs such as InstructBLIP and LLaVa.
  • Addressed the issue through an innovative training-free model grafting technique.
KDD 2024
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Align

Neural Collapse Anchored Prompt Tuning for Generalizable Vision-Language Models.
Didi Zhu, Zexi Li, Min Zhang, Junkun Yuan, Jiashuo Liu, Kun Kuang, Chao Wu

  • The first exploration of large vision-language models through the lens of neural collapse in deep learning theory.
  • Tackle class imbalance in generalization tasks for large vision-language models by leveraging neural collapse theory.
ICCV 2023
sym

Align

Universal domain adaptation via compressive attention matching.
Didi Zhu, Yinchuan Li, Junkun Yuan, Zexi Li, Kun Kuang, Chao Wu

  • Addressed the issue of inconsistent source-target label spaces in Universal Domain Adaptation directly using self-attention in ViT.
ACM Multimedia 2023
sym

Align

Generalized Universal Domain Adaptation with Generative Flow Networks.
Didi Zhu, Yinchuan Li, Yunfeng Shao, Jianye Hao, Fei Wu, Kun Kuang, Jun Xiao, Chao Wu

  • Introduced a comprehensive problem called Generalized Universal Domain Adaptation, achieving a unification of all Domain Adaptation sub-problems involving label heterogeneity.
  • Implemented an exploration-aware active learning strategy based on Generative Flow Networks to effectively address GUDA.

Publications by Research Theme

AlignRobust VLMs, domain shift, and generalization

ComposeModel merging, forgetting, and modular reuse

ReasonMultimodal reasoning and perceptual intelligence

Educations

2020.09 - 2025.06

Ph.D. Student

Computer Science and Technology, Zhejiang University Hangzhou

2016.09 - 2020.06

Undergraduate

Computer Science and Technology, Beijing University of Chemical Technology Beijing

Research Experiences

2025.09 - Present

Postdoctoral Research Associate

Imperial College London London, United Kingdom

Internships

2024.03 - 2025.03

Alibaba DAMO Academy

Hangzhou, China

2023.10 - 2024.02

Tencent Youtu Lab

Shanghai, China

Services

Reviewing

CVPR 2026 ICLR 2026 KDD 2026 NeurIPS 2025 ICCV 2025 ICLR 2025 KDD 2025 KDD 2024 TIP Machine Learning Journal MM 2024 MM 2023

Honors and Awards

2024.12

National Scholarship

Top 5%

2020.10

Beijing Outstanding Graduates

Top 1%

2019.10

National Scholarship

Top 1%

2018.10

National Scholarship

Top 1%

2017.10

National Scholarship

Top 1%

Miscellaneous

I recently arrived in London and have fallen in love with the city's sunsets, parks, and ever-changing light. I believe life is a grand experience to be savored, and I am always happy to share a coffee, a walk, or a conversation about what this next chapter might hold.