iESTA: Instance-Enhanced Spatial–Temporal Alignment for Video Copy Localization

Video copy Segment Localization (VSL) requires the identification of the temporal segments within a pair of videos that contain copied content. Current methods primarily focus on global temporal modeling, overlooking the complementarity of global semantic and local fine-grained features, which limits their effectiveness. Some related methods attempt to incorporate local spatial information but often disrupt spatial semantic structures, resulting in less accurate matching. To address these issues, we propose the Instance-Enhanced Spatial-Temporal Alignment Framework (iESTA), based on a proper representation granularity that integrates instance-level local features and semantic global features. Specifically, the Instance-relation Graph (IRG) is constructed to capture instance-level features and fine-grained interactions, preserving local information integrity and better representing the video feature space in a proper granularity. An instance-GNN structure is designed to refine these graph representations. For global features, we enhance the representation of semantic information, capturing temporal relationships within videos using a Transformer framework. Additionally, we design a Complementarity-perception Alignment Module (CAM) to effectively process and integrate complementary spatial-temporal information, producing accurate frame-to-frame alignment maps. Our approach also incorporates a differentiable Dynamic Time Warping (DTW) method to utilize latent temporal alignments as weak supervisory signals, improving the accuracy of the matching process. Experimental results indicate that our proposed iESTA outperforms state-of-the-art methods on both the small-scale dataset VCDB and the large-scale dataset VCSL.