OpenBMB/VisRAG

Parsing-free RAG supported by VLMs

What it solves

VisRAG addresses the information loss that occurs when documents are parsed into text for traditional Retrieval-Augmented Generation (RAG). By treating documents as images rather than text, it preserves the original layout and visual data, maximizing the retention of information during the retrieval and generation process.

How it works

The system operates through a vision-language model (VLM) pipeline consisting of three main components:

  1. VisRAG-Ret (Retriever): A document embedding model that embeds documents directly as images to retrieve relevant visual pages based on a query.
  2. VisRAG-Gen (Generator): A VLM (such as GPT-4o or MiniCPM-V) that generates an answer based on the retrieved images.
  3. EVisRAG (VisRAG 2.0): An advanced end-to-end framework that improves multi-image reasoning. It uses a four-step process—observing images, recording evidence, reasoning, and answering—and is trained using Reward-Scoped Group Relative Policy Optimization (RS-GRPO) to optimize both visual perception and reasoning.

Who it’s for

Developers and researchers working with complex documents (like PDFs) where visual layout, charts, and images are critical to the answer and cannot be easily captured by text-only parsing.

Highlights

  • Visual-First RAG: Eliminates parsing-induced information loss by embedding documents as images.
  • Evidence-Guided Reasoning: EVisRAG uses a structured approach to collect per-image evidence before final reasoning.
  • RS-GRPO Training: Employs a specialized reinforcement learning algorithm to jointly optimize perception and reasoning.
  • Multi-Image Support: Specifically designed to handle questions that require reasoning across multiple retrieved visual documents.

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