arXiv:2509.14591cs.CV2025-09

通过双向特征对齐实现高效动态点云压缩,提升运动建模与解码细节。

Bidirectional Feature-aligned Motion Transformation for Efficient Dynamic Point Cloud Compression

  • 在特征空间隐式建模运动,双向对齐前后帧特征生成统一预测上下文。
  • 在解码端引入交叉注意力模块,恢复运动对齐中丢失的精细空间细节。
  • 支持帧级并行编码,显著降低延迟,适合实时动态点云传输应用。

高效动态点云压缩(DPCC)依赖于精确的运动估计与补偿。然而,点云固有的不规则结构和显著的局部变化使该任务极具挑战性。现有方法通常依赖显式运动估计,其编码的运动矢量难以捕捉复杂动态,且未能充分挖掘时间相关性。为此,我们提出双向特征对齐运动变换(Bi-FMT)框架,通过在特征空间隐式建模运动,对齐过去与未来帧的特征,生成时序一致的潜在表示,作为条件编码流程中的预测上下文,形成统一的“运动+条件”表示。在此基础上,我们在解码端引入交叉变压器精炼模块(CTR),利用向量注意力建模跨帧依赖,自适应优化局部对齐特征,增强局部一致性并恢复运动对齐中丢失的细粒度空间细节。此外,我们设计了一种随机访问(RA)参考策略,将双向对齐特征作为条件上下文,实现帧级并行压缩,消除序列编码依赖。大量实验表明,Bi-FMT在压缩效率与运行时方面均优于D-DPCC和AdaDPCC,分别实现20%(D1)和9.4%(D1)的BD-Rate降低。

原文摘要 · Abstract (English)

Efficient dynamic point cloud compression (DPCC) critically depends on accurate motion estimation and compensation. However, the inherently irregular structure and substantial local variations of point clouds make this task highly challenging. Existing approaches typically rely on explicit motion estimation, whose encoded motion vectors often fail to capture complex dynamics and inadequately exploit temporal correlations. To address these limitations, we propose a Bidirectional Feature-aligned Motion Transformation (Bi-FMT) framework that implicitly models motion in the feature space. Bi-FMT aligns features across both past and future frames to produce temporally consistent latent representations, which serve as predictive context in a conditional coding pipeline, forming a unified ``Motion + Conditional'' representation. Built upon this bidirectional feature alignment, we introduce a Cross-Transformer Refinement module (CTR) at the decoder side to adaptively refine locally aligned features. By modeling cross-frame dependencies with vector attention, CRT enhances local consistency and restores fine-grained spatial details that are often lost during motion alignment. Moreover, we design a Random Access (RA) reference strategy that treats the bidirectionally aligned features as conditional context, enabling frame-level parallel compression and eliminating the sequential encoding. Extensive experiments demonstrate that Bi-FMT surpasses D-DPCC and AdaDPCC in both compression efficiency and runtime, achieving BD-Rate reductions of 20% (D1) and 9.4% (D1), respectively.

点云压缩运动建模特征对齐并行编码

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