Unifying Watermarking via Dimension-Aware Mapping
Jiale Meng, Runyi Hu, Jie Zhang, Zheming Lu, Ivor Tsang, Tianwei Zhang
TL;DR
The paper addresses unifying deep watermarking by treating embedding and extraction as dimension-aware mappings between multi-dimensional payloads. It introduces DiM, defining payload spaces $\mathcal{P}^{(d)}$ for $d\in\{1,2,3\}$ and mappings $\mathcal{M}\{d_e,d_d\}$ that connect embedding and extraction across dimensions, including same-dimensional and cross-dimensional configurations. The authors instantiate DiM in video as DiM-V, demonstrating payloads $\mathbf{W}$, $\mathbf{M}^{(2)}$, and $\mathbf{M}^{(3)}$ and a unified pipeline that supports global and local embedding, spatiotemporal localization, and temporal order recovery without architectural changes. Results show that varying $d_e$ and $d_d$ yields capabilities such as spatiotemporal tamper localization, frame-order reconstruction under disruptions, and robust performance under diverse distortions, with a compression-aware fine-tuning strategy further enhancing robustness. Overall, DiM provides a principled, generalized framework for interpreting and designing watermarking systems with clarified trade-offs and richer functionality.
Abstract
Deep watermarking methods often share similar encoder-decoder architectures, yet differ substantially in their functional behaviors. We propose DiM, a new multi-dimensional watermarking framework that formulates watermarking as a dimension-aware mapping problem, thereby unifying existing watermarking methods at the functional level. Under DiM, watermark information is modeled as payloads of different dimensionalities, including one-dimensional binary messages, two-dimensional spatial masks, and three-dimensional spatiotemporal structures. We find that the dimensional configuration of embedding and extraction largely determines the resulting watermarking behavior. Same-dimensional mappings preserve payload structure and support fine-grained control, while cross-dimensional mappings enable spatial or spatiotemporal localization. We instantiate DiM in the video domain, where spatiotemporal representations enable a broader set of dimension mappings. Experiments demonstrate that varying only the embedding and extraction dimensions, without architectural changes, leads to different watermarking capabilities, including spatiotemporal tamper localization, local embedding control, and recovery of temporal order under frame disruptions.
