Add dataset card with metadata and dataset structure

README.md

@@ -0,0 +1,53 @@
+---
+task_categories:
+- image-to-text
+tags:
+- medical
+- radiology
+- chest-xray
+---
+
+# REVA-PO Datasets
+
+This repository contains the processed annotations and dataset structures used in the paper **REVA-PO: Stabilizing Reinforcement Learning for Chest X-ray Report Generation** (ECCV 2026).
+
+[Paper (arXiv)](https://arxiv.org/abs/2607.10147) | [Code (GitHub)](https://github.com/LiGuo12/REVA_PO/)
+
+## Dataset Structure
+
+### 1. IU-Xray
+Download the [IU-Xray](https://huggingface.co/datasets/liguo12/REVA_PO_Datasets/tree/main/iuxray_dataset) files and unzip `images.zip`. 
+
+After unzipping, the directory structure should look like this:
+```text
+iuxray_dataset/
+├── images/
+└── annotation_with_categories.json
+```
+
+### 2. MIMIC-CXR
+Download the chest X-ray images of the MIMIC-CXR dataset from the [official PhysioNet website](https://physionet.org/content/mimic-cxr-jpg/2.0.0/), and download the [annotations](https://huggingface.co/datasets/liguo12/REVA_PO_Datasets/tree/main/mimic_dataset) from this repository.
+
+Place the annotations and images (`files` directory from PhysioNet) into the same folder:
+```text
+mimic_dataset/
+├── files/
+├── mimic_with_categories.json
+└── mimic_with_categories_sampled_10k.json
+```
+
+## Citation
+
+If you find this work or the datasets helpful, please cite the paper:
+
+```bibtex
+@misc{guo2026revapo,
+      title={REVA-PO: Stabilizing Reinforcement Learning for Chest X-ray Report Generation}, 
+      author={Li Guo and Anas M. Tahir and Z. Jane Wang},
+      year={2026},
+      eprint={2607.10147},
+      archivePrefix={arXiv},
+      primaryClass={cs.CV},
+      url={https://arxiv.org/abs/2607.10147}, 
+}
+```