ST-Mark: A Spatiotemporal Feature-Based Watermarking Method for Marine Data

To address the challenges of copyright protection for marine environmental datasets in open sharing environments, this paper proposes ST-Mark, a robust watermarking framework that synergistically integrates established geometric invariants and Quantization Index Modulation (QIM) techniques to meet the strict physical constraints of marine environmental datasets. The proposed method first extracts feature points by analyzing the spatiotemporal distribution of the data. It then constructs a local reference frame from the convex hull vertices and computes the geometrically invariant angles and distance ratios of the feature points relative to this reference pair to achieve robust partitioning. Finally, the watermark is embedded into the attribute domain of the grouped data through the Quantization Index Modulation (QIM) strategy while constraining perturbations within observational uncertainty bounds. Extensive experiments demonstrate that ST-Mark exhibits strong robustness: under extreme conditions such as temporal deletion attacks with an intensity of 0.9, the average normalized correlation (NC) remains above the robustness threshold of 0.75, with peak values reaching 0.99 on high-resolution datasets, although performance may fluctuate or fall near this threshold under severe spatial restrictions and numerical quantization, while still supporting reliable copyright verification under typical operational conditions.