Estimating 2D Camera Motion with Hybrid Motion Basis

Haipeng Li, Tianhao Zhou, Zhanglei Yang, Yi Wu, Yan Chen, Zijing Mao, Shen Cheng, Bing Zeng, Shuaicheng Liu; Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), 2025, pp. 7624-7633

Estimating 2D camera motion is a fundamental computer vision task that models the projection of 3D camera movements onto the 2D image plane. Current methods rely on either homography-based approaches, limited to planar scenes, or meshflow techniques that use grid-based local homographies but struggle with complex non-linear transformations. We introduce CamFlow, a novel framework that represents camera motion using hybrid motion bases: physical bases derived from camera geometry and stochastic bases for complex scenarios. Our approach includes a hybrid probabilistic loss function based on the Laplace distribution that enhances training robustness. For evaluation, we create a new benchmark by masking dynamic objects in existing optical flow datasets to isolate pure camera motion. Experiments show CamFlow outperforms state-of-the-art methods across diverse scenarios, demonstrating superior robustness and generalization in zero-shot settings. Code and datasets are available at our project page: https://lhaippp.github.io/CamFlow/.