ICLR 2026: EvoQuality

Self-Evolving Vision-Language Models for Image Quality Assessment via Voting and Ranking

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Abstract

EvoQuality is a self-supervised framework that enables a Vision-Language Model (VLM) to autonomously refine its image quality perception capability via pairwise majority voting and GRPO-based iterative evolution, without requiring any ground-truth labels.

Figure 1: Overview of the EvoQuality Framework

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Model

The pre-trained EvoQuality model weights are publicly available on Hugging Face:

• 🤗 ByteDance/EvoQuality

You can download the model directly via git lfs or the huggingface_hub Python API:

git lfs install
git clone https://huggingface.co/ByteDance/EvoQuality

from huggingface_hub import snapshot_download
snapshot_download(repo_id="ByteDance/EvoQuality", local_dir="./EvoQuality")

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️ Installation

1. Clone the repository

git clone https://github.com/your-organization/evoquality.git
cd evoquality/verl

2. Create a virtual environment

conda create -n evoquality python=3.9 -y
conda activate evoquality

3. Install dependencies

We provide a setup script:

bash setup.sh

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Quick Start

1. Prepare Data

Place your dataset in the data/ directory. The expected structure is:

data/
└── YourDataset/
    ├── train.parquet
    ├── test.parquet
    └── data.csv

2. Training

To train EvoQuality:

cd examples/ttrl/Qwen-Pair/

# Set environment variables or modify the script directly
export DATA_LOCAL_DIR="./data"
export BACKBONE_PATH="./model/Qwen2.5-VL-7B-Instruct"
export WANDB_PROJECT="EvoQuality"

bash train.sh

3. Merge Checkpoint

After training, you need to merge the FSDP checkpoint into a Hugging Face format:

cd ../../..  # Go back to verl/ directory

python3 -m verl.model_merger merge \
    --backend fsdp \
    --local_dir /path/to/your/checkpoint/global_step_XXX/actor \
    --target_dir /path/to/merged/hf/model

Example:

python3 -m verl.model_merger merge \
    --backend fsdp \
    --local_dir ./ckpts/EvoQuality/0318/Experiment-grpo-000000/global_step_300/actor \
    --target_dir ./merged_hf_model/Qwen25-Finetuned-Pair-300

4. Inference

Batch Inference for Single Image Quality Assessment

cd scripts/

python batch_image_inference.py \
    --root_checkpoint /path/to/merged/hf/model \
    --root_data /path/to/image/directory \
    --data /path/to/data.csv \
    --save_result_root ./results

Batch Inference for Pairwise Comparison with Voting

python batch_image_pair_inference_voting.py \
    --root_checkpoint /path/to/merged/hf/model \
    --root_data /path/to/image/directory \
    --data /path/to/pair_data.csv \
    --save_result_root ./results \
    --n_prompt 64

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Project Structure

EvoQuality/
├── verl/
│   ├── examples/
│   │   └── ttrl/
│   │       └── Qwen-Pair/
│   │           └── train.sh          # Training script
│   ├── scripts/
│   │   ├── batch_image_inference.py  # Single image inference
│   │   └── batch_image_pair_inference_voting.py  # Pairwise inference
│   ├── verl/
│   │   ├── workers/
│   │   │   └── reward_manager/
│   │   │       └── ttrl_pair.py     # Pairwise reward manager
│   │   └── utils/
│   │       └── reward_score/
│   │           └── ttrl/             # TTRL metrics and utils
│   ├── setup.sh                      # Main setup script
│   └── setup.py                      # Package setup
└── README.md

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Citation

If you find EvoQuality useful for your research, please cite our paper:

@article{wen2025selfevolving,
  title={Self-Evolving Vision-Language Models for Image Quality Assessment via Voting and Ranking},
  author={Wen, Wen and Zhi, Tianwu and Fan, Kanglong and Li, Yang and Peng, Xinge and Zhang, Yabin and Liao, Yiting and Li, Junlin and Zhang, Li},
  journal={arXiv preprint arXiv:2509.25787},
  year={2025}
}

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License Agreement

The models in this repository are licensed under the Apache 2.0 License. We claim no rights over the your generated contents, granting you the freedom to use them while ensuring that your usage complies with the provisions of this license. You are fully accountable for your use of the models, which must not involve sharing any content that violates applicable laws, causes harm to individuals or groups, disseminates personal information intended for harm, spreads misinformation, or targets vulnerable populations. For a complete list of restrictions and details regarding your rights, please refer to the full text of the license.

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Acknowledgements

We would like to thank the contributors to the verl, Qwen2.5-VL, transformers, vLLM, PEFT and HuggingFace repositories, for their open research.