Research

My research focuses on 3D computer vision and world models, with the long-term goal of building spatial intelligence grounded in the real world. I study how to reconstruct and understand 3D scenes under challenging conditions, including sparse observations and ambiguities from repeated or symmetric structures. Building on this, I am interested in world models that reason over space, time, and physical plausibility, enabling models to infer missing 3D structure and predict future scene evolution beyond what is directly visible. More broadly, I aim to bridge 3D spatial understanding with the semantic reasoning capabilities of vision-language models, toward AI systems that can understand and reason about complex real-world scenes.
Selected Publications
Additional Publications
Long-Tail Internet Photo Reconstruction
CVPR 2026
Yuan Li, Yuanbo Xiangli, Hadar Averbuch-Elor, Noah Snavely, Ruojin Cai
Emergent Extreme-View Geometry in 3D Foundation Models
CVPR 2026
Yiwen Zhang, Joseph Tung, Ruojin Cai, David Fouhey, Hadar Averbuch-Elor
ArchSym: Detecting 3D-Grounded Architectural Symmetries in the Wild
CVPR 2026
Hanyu Chen, Ruojin Cai, Steve Marschner, Noah Snavely
Can Generative Video Models Help Pose Estimation?
CVPR 2025 (Highlight)
Ruojin Cai, Jason Y. Zhang, Philipp Henzler, Zhengqi Li, Noah Snavely, Ricardo Martin-Brualla
Doppelgangers++: Improved Visual Disambiguation with Geometric 3D Features
CVPR 2025 (Highlight)
Yuanbo Xiangli, Ruojin Cai, Hanyu Chen, Jeffrey Byrne, Noah Snavely
Extreme Rotation Estimation in the Wild
CVPR 2025
Hana Bezalel, Dotan Ankri, Ruojin Cai, Hadar Averbuch-Elor
MegaScenes: Scene-Level View Synthesis at Scale
ECCV 2024
Joseph Tung*, Gene Chou*, Ruojin Cai, Guandao Yang, Kai Zhang, Gordon Wetzstein, Bharath Hariharan, Noah Snavely
Doppelgangers: Learning to Disambiguate Images of Similar Structures
ICCV 2023 (Oral)
Ruojin Cai, Joseph Tung, Qianqian Wang, Hadar Averbuch-Elor, Bharath Hariharan, Noah Snavely
Tracking Everything Everywhere All at Once
ICCV 2023 (Best Student Paper Award)
Qianqian Wang, Yen-Yu Chang, Ruojin Cai, Zhengqi Li, Bharath Hariharan, Aleksander Holynski, Noah Snavely
Neural Scene Chronology
CVPR 2023
Haotong Lin, Qianqian Wang, Ruojin Cai, Sida Peng, Hadar Averbuch-Elor, Xiaowei Zhou, Noah Snavely
Extreme Rotation Estimation using Dense Correlation Volumes
CVPR 2021
Ruojin Cai, Bharath Hariharan, Noah Snavely, Hadar Averbuch-Elor
CondenseNet V2: Sparse Feature Reactivation for Deep Networks
CVPR 2021
Le Yang*, Haojun Jiang*, Ruojin Cai, Yulin Wang, Shiji Song, Gao Huang, Qi Tian
Learning Gradient Fields for Shape Generation
ECCV 2020 (Spotlight)
Ruojin Cai*, Guandao Yang*, Hadar Averbuch-Elor, Zekun Hao, Serge Belongie, Noah Snavely, Bharath Hariharan
Order-Sensitive Deep Hashing for Multimorbidity Medical Image Retrieval
MICCAI 2018
Zhixiang Chen*, Ruojin Cai*, Jiwen Lu, Jianjiang Feng, Jie Zhou