Light-X：具備攝影機與光照控制的生成式四維影片渲染技術
Light-X: Generative 4D Video Rendering with Camera and Illumination Control
December 4, 2025
作者: Tianqi Liu, Zhaoxi Chen, Zihao Huang, Shaocong Xu, Saining Zhang, Chongjie Ye, Bohan Li, Zhiguo Cao, Wei Li, Hao Zhao, Ziwei Liu
cs.AI
摘要
近期光照控制技術的進展已將基於圖像的方法延伸至影片領域，但仍在光照逼真度與時間一致性之間面臨取捨。超越單純的重打光技術，實現真實場景生成建模的關鍵步驟在於聯合控制相機軌跡與光照，因為視覺動態本質上是由幾何結構與光照共同塑造的。為此，我們提出Light-X——一個能從單目影片中實現視點與光照雙重可控渲染的影片生成框架。1）我們提出解耦設計方案：通過沿用戶定義相機軌跡投影的動態點雲捕捉幾何與運動信息，同時由經重打光處理的幀序列持續投影至同一幾何空間來提供光照信號。這種顯式細粒度信號實現有效解耦，並引導生成高質量光照效果。2）針對缺乏配對多視角與多光照影片數據的問題，我們開發Light-Syn基於退化與逆向映射的合成流程，可從真實場景單目素材自動生成訓練樣本。該策略構建的數據集涵蓋靜態、動態及AI生成場景，確保模型訓練的魯棒性。大量實驗表明，Light-X在聯合相機-光照控制任務上超越基準方法，並在文本條件與背景條件設定下均優於現有影片重打光技術。
English
Recent advances in illumination control extend image-based methods to video, yet still facing a trade-off between lighting fidelity and temporal consistency. Moving beyond relighting, a key step toward generative modeling of real-world scenes is the joint control of camera trajectory and illumination, since visual dynamics are inherently shaped by both geometry and lighting. To this end, we present Light-X, a video generation framework that enables controllable rendering from monocular videos with both viewpoint and illumination control. 1) We propose a disentangled design that decouples geometry and lighting signals: geometry and motion are captured via dynamic point clouds projected along user-defined camera trajectories, while illumination cues are provided by a relit frame consistently projected into the same geometry. These explicit, fine-grained cues enable effective disentanglement and guide high-quality illumination. 2) To address the lack of paired multi-view and multi-illumination videos, we introduce Light-Syn, a degradation-based pipeline with inverse-mapping that synthesizes training pairs from in-the-wild monocular footage. This strategy yields a dataset covering static, dynamic, and AI-generated scenes, ensuring robust training. Extensive experiments show that Light-X outperforms baseline methods in joint camera-illumination control and surpasses prior video relighting methods under both text- and background-conditioned settings.