Multimodal RAG and Cross-Modal Retrieval

Vision-native document RAG is one slice. Production multimodal RAG goes wider — retrieving across text, images, audio, and video for workflows like trip planning ("find me a quiet vegan brunch with natural light"), medical triage ("what injury matches this photo + these notes"), e-commerce ("outfits similar to this selfie, in my size"), and field service ("diagnose this engine sound plus photo of the part"). Three 2025 surveys — Abootorabi et al., Mei et al., Zhao et al. — codified the sub-problems: cross-modal retrieval, retrieval fusion, generation grounding, multimodal evaluation. This lesson reads the surveys and designs a production pipeline.