hf/transformers/docs/source/en/model_doc/blip-2.mdx

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# BLIP-2

## Overview

The BLIP-2 model was proposed in [BLIP-2: Bootstrapping Language-Image Pre-training with Frozen Image Encoders and Large Language Models](https://arxiv.org/abs/2301.12597) by
Junnan Li, Dongxu Li, Silvio Savarese, Steven Hoi. BLIP-2 leverages frozen pre-trained image encoders and large language models (LLMs) by training a lightweight, 12-layer Transformer
encoder in between them, achieving state-of-the-art performance on various vision-language tasks. Most notably, BLIP-2 improves upon [Flamingo](https://arxiv.org/abs/2204.14198), an 80 billion parameter model, by 8.7%
on zero-shot VQAv2 with 54x fewer trainable parameters. 

The abstract from the paper is the following:

*The cost of vision-and-language pre-training has become increasingly prohibitive due to end-to-end training of large-scale models. This paper proposes BLIP-2, a generic and efficient pre-training strategy that bootstraps vision-language pre-training from off-the-shelf frozen pre-trained image encoders and frozen large language models. BLIP-2 bridges the modality gap with a lightweight Querying Transformer, which is pre-trained in two stages. The first stage bootstraps vision-language representation learning from a frozen image encoder. The second stage bootstraps vision-to-language generative learning from a frozen language model. BLIP-2 achieves state-of-the-art performance on various vision-language tasks, despite having significantly fewer trainable parameters than existing methods. For example, our model outperforms Flamingo80B by 8.7% on zero-shot VQAv2 with 54x fewer trainable parameters. We also demonstrate the model's emerging capabilities of zero-shot image-to-text generation that can follow natural language instructions.*

Tips:

- BLIP-2 can be used for conditional text generation given an image and an optional text prompt. At inference time, it's recommended to use the [`generate`] method.
- One can use [`Blip2Processor`] to prepare images for the model, and decode the predicted tokens ID's back to text.

<img src="https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/transformers/model_doc/blip2_architecture.jpg"
alt="drawing" width="600"/> 

<small> BLIP-2 architecture. Taken from the <a href="https://arxiv.org/abs/2301.12597">original paper.</a> </small>

This model was contributed by [nielsr](https://huggingface.co/nielsr).
The original code can be found [here](https://github.com/salesforce/LAVIS/tree/5ee63d688ba4cebff63acee04adaef2dee9af207).

## Resources

A list of official Hugging Face and community (indicated by 🌎) resources to help you get started with BLIP-2.

- Demo notebooks for BLIP-2 for image captioning, visual question answering (VQA) and chat-like conversations can be found [here](https://github.com/NielsRogge/Transformers-Tutorials/tree/master/BLIP-2).

If you're interested in submitting a resource to be included here, please feel free to open a Pull Request and we'll review it! The resource should ideally demonstrate something new instead of duplicating an existing resource.

## Blip2Config

[[autodoc]] Blip2Config
    - from_vision_qformer_text_configs

## Blip2VisionConfig

[[autodoc]] Blip2VisionConfig

## Blip2QFormerConfig

[[autodoc]] Blip2QFormerConfig

## Blip2Processor

[[autodoc]] Blip2Processor

## Blip2VisionModel

[[autodoc]] Blip2VisionModel
    - forward

## Blip2QFormerModel

[[autodoc]] Blip2QFormerModel
    - forward

## Blip2Model

[[autodoc]] Blip2Model
    - forward
    - get_text_features
    - get_image_features
    - get_qformer_features

## Blip2ForConditionalGeneration

[[autodoc]] Blip2ForConditionalGeneration
    - forward
    - generate