Generative data augmentation for metamorphic rock thin-section classification based on one-step diffusion model
摘要
Automated classification of metamorphic rocks is crucial for geological surveys yet faces dual challenges: the scarcity of labeled thin-section samples and high intraclass heterogeneity caused by complex mineral assemblages. Traditional methods, such as transfer learning, often fail to generalize effectively as they struggle to capture the fine-grained, high-frequency petrographic textures inherent in metamorphic rocks. To address these limitations, this study repositions the task from direct identification to a Generative Data Augmentation strategy. We introduce a novel one-step diffusion model in latent space guided by energy distribution (ODLE). Unlike traditional GANs, ODLE incorporates an energy-guided mechanism to ensure that synthesized images preserve geologically meaningful features, such as mineral boundaries and structural relationships. Using a Variational Autoencoder (VAE), rock thin-section images are compressed into a latent space and reconstructed via diffusion. This process creates a diverse, realistic dataset that fills gaps in the original distribution. Our model leverages a pre-trained diffusion noise prediction model to generate high-quality images efficiently, overcoming data scarcity challenges. Experimental results demonstrate that this approach significantly improves downstream lithological classification accuracy and generates high-fidelity synthetic samples with potential applications in petrographic education and automated texture analysis.