GloPER: Unsupervised Animal Pattern Extraction from Local Reconstruction

Traditional image segmentation methods struggle with finegrained pattern extraction, especially in an unsupervised setting without labeled data. Shallow and deep learning approaches either lack structural coherence or focus on object-level segmentation rather than internal textures. Additionally, existing methods often fail to generalize across diverse animal species due to variations in pattern complexity and lighting variations. We introduce GloPER, an unsupervised segmentation framework that extracts finegrained animal patterns without labeled supervision. By enforcing local image reconstruction with only two colors per region, GloPER captures structured patterns while mitigating the effects of shadows and lighting inconsistencies. Given the lack of fine-detailed labeled data, we construct a dataset of 10 animal species, each with at least 100 well labeled images, enabling direct segmentation assessment. Experimental results show that GloPER outperforms both shallow and deep segmentation baselines, with a 42.44% higher DICE score on average across all 10 animal species. We also assess its effectiveness through animal re-identification (ReID), where GloPER's extracted binary patterns achieve superior accuracy, in some cases exceeding full-image ReID performance, underscoring the discriminative power of structured segmentation.