Sketching is a direct and inexpensive means of visual expression. Though image-based sketching has been well studied, video-based sketch animation generation is still very challenging due to the temporal coherence requirement. In this paper, we propose a novel end-to-end automatic generation approach for vector sketch animation. To solve the flickering issue, we introduce a Differentiable Motion Trajectory (DMT) representation that describes the frame-wise movement of stroke control points using differentiable polynomial-based trajectories. DMT enables global semantic gradient propagation across multiple frames, significantly improving the semantic consistency and temporal coherence, and producing high-framerate output. DMT employs a Bernstein basis to balance the sensitivity of polynomial parameters, thus achieving more stable optimization. Instead of implicit fields, we introduce sparse track points for explicit spatial modeling, which improves efficiency and supports long-duration video processing. Evaluations on DAVIS and LVOS datasets demonstrate the superiority of our approach over SOTA methods. Cross-domain validation on 3D models and text-to-video data confirms the robustness and compatibility of our approach.

翻译：草图是一种直接且低成本的视觉表达方式。尽管基于图像的草图技术已得到充分研究，但由于时序一致性的要求，基于视频的草图动画生成仍然极具挑战性。本文提出了一种新颖的端到端自动生成方法，用于矢量草图动画。为解决闪烁问题，我们引入了一种可微运动轨迹（DMT）表示方法，该方法利用基于多项式的可微轨迹描述笔画控制点的逐帧运动。DMT能够实现跨多帧的全局语义梯度传播，显著提升了语义一致性与时序连贯性，并生成高帧率输出。DMT采用伯恩斯坦基来平衡多项式参数的敏感性，从而实现更稳定的优化。不同于隐式场，我们引入了稀疏跟踪点进行显式空间建模，这提高了效率并支持长时视频处理。在DAVIS和LVOS数据集上的评估表明，我们的方法优于最先进方法。在3D模型和文本生成视频数据上的跨域验证证实了本方法的鲁棒性与兼容性。