blip-2
**BLIP-2** is an **efficient vision-language model architecture** — that connects frozen image encoders to frozen Large Language Models (LLMs) using a lightweight Q-Former (Query Transformer) bridging module.
**What Is BLIP-2?**
- **Definition**: A generalized and efficient VLM pre-training strategy.
- **Innovation**: The **Q-Former**, a bottleneck module that extract visual features relevant to the text.
- **Efficiency**: Keeps the massive vision and language models frozen, training only the lightweight Q-Former.
- **Generative Power**: Can leverage powerful LLMs (like OPT, Flan-T5) for strong reasoning.
**Why BLIP-2 Matters**
- **Compute Efficient**: Very cheap to train compared to end-to-end models like Flamingo.
- **Modularity**: You can swap in different LLMs (e.g., swap OPT for Vicuna) easily.
- **Performance**: Outperformed Flamingo-80B with 54x fewer trainable parameters.
**Two-Stage Training**
1. **Vision-Language Representation Learning**: Q-Former learns to extract visual features aligned with text.
2. **Vision-to-Language Generative Learning**: Q-Former output is projected to LLM input space.
**BLIP-2** is **the democratizer of VLM research** — employing a modular design that allows researchers to build powerful multimodal models with consumer-grade hardware.