Transformer-Based Multi-Modal Fusion for Martian Impact Crater Classification

Impact craters, as key geomorphic features on Mars, provide important insights into surface processes and geological evolution. However, automatic classification of crater morphologies remains challenging due to substantial variations in size, degradation degree, and data quality across different types of Martian craters. This study proposes a multi-modal framework for Martian crater classification by integrating infrared imagery, an optical map, and digital elevation model (DEM) data. Specifically, daytime infrared imagery from THEMIS, a color map from the Tianwen-1 MoRIC instrument, and topographic data derived from combined MOLA–HRSC observations are used to capture complementary thermal, morphological, and elevation-related characteristics. A transformer-based feature extraction and cross-modal fusion strategy is adopted, where infrared imagery guides the interaction among multi-source features. Experiments on a carefully constructed dataset covering four crater categories, i.e., standard craters, layered ejecta craters, degraded craters, and secondary craters, demonstrate that the proposed approach achieves an overall precision of 0.848 and a recall of 0.851, outperforming single-modality baselines. Layered ejecta craters exhibit the highest classification performance, benefiting from their distinctive ejecta morphologies, whereas secondary craters remain more difficult to classify due to their small spatial scales. The results highlight the value of multi-modal data for Martian crater morphology classification.