Datasets:
license: gpl-3.0
task_categories:
- image-segmentation
tags:
- semantic-segmentation
- synthetic-data
- domain-adaptation
- cityscapes
- acdc
size_categories:
- 100K<n<1M
Dataset Summary
This dataset contains generated images for semantic segmentation targeting the Cityscapes and ACDC domains. The images are produced from five source datasets using the method described in: A Framework for Low-Effort Training Data Generation for Urban Semantic Segmentation.
Technical Specifications
- Subset Selection: To preserve storage space, we release the top 3 generated images per original source image, selected based on our proposed MCOC score.
- Label Mapping: All masks follow the standard Cityscapes 19-class format.
- Resolution: 512 x 1024 (Height x Width).
- Format: Images and masks are provided in
.pngformat.
Dataset Statistics
The following table reflects the number of source images used to generate the target domain data.
| Source Domain | Image Count | Status |
|---|---|---|
| GTA | 24,966 | Available |
| UrbanSyn | 7,539 | Available |
| VEIS | 3,018 | Available |
| SHIFT | 3,000 | Available |
| Synscapes | 0 | Restricted |
Note on Synscapes: Due to licensing restrictions, we are unable to release the generated Synscapes data. The folders contain the original license file for reference but do not include image data.
Dataset Structure
The data is organized by <Target_Domain>/<Source_Domain>/. The three image folders ship as zip archives so the repository stays within Hugging Face's file-count limits — images/ is split into ~2 GB chunks. splits/ and LICENSE are plain files.
<Target_Domain>/
└── <Source_Domain>/
├── images_000.zip … images_NNN.zip # Top 3 generated images per source (MCOC ranked)
├── original_tid.zip # Original source segmentation maps
├── hrda_tid.zip # HRDA pseudo-labels
├── splits/ # .txt files for training loading
└── LICENSE # Original source dataset license
Extracting the archives restores the layout the loading scripts expect. Entry names already carry their folder prefix (e.g. images/03666/0005.png), so every archive unpacks into the right place:
<Target_Domain>/
└── <Source_Domain>/
├── images/
├── original_tid/
├── hrda_tid/
├── splits/
└── LICENSE
| Pair | images chunks |
Download |
|---|---|---|
cityscapes/gta |
22 | 49.9 GB |
cityscapes/urbansyn |
7 | 15.5 GB |
cityscapes/shift |
3 | 6.1 GB |
cityscapes/veis |
3 | 5.8 GB |
acdc/urbansyn |
11 | 23.6 GB |
acdc/veis |
4 | 9.0 GB |
| Total | 50 | 110 GB |
Download & Extraction
pip install -U "huggingface_hub[cli]"
# Everything (~110 GB)
hf download dkalsan/FLEDGE --repo-type dataset --local-dir FLEDGE
# Or a single pair, e.g. ACDC generated from VEIS (~9 GB)
hf download dkalsan/FLEDGE --repo-type dataset --local-dir FLEDGE --include "acdc/veis/*"
Then unpack every archive in place, deleting each one as it succeeds:
cd FLEDGE
for z in */*/*.zip; do
unzip -q -o "$z" -d "$(dirname "$z")" && rm "$z"
done
Usage Example
Example data loading scripts that utilize the provided .txt split files are available in our official GitHub repository: github.com/vislearn/FLEDGE
Citation
@misc{kalsan2025fledge,
title={A Framework for Low-Effort Training Data Generation for Urban Semantic Segmentation},
author={Damjan Kalšan and Denis Zavadski and Tim Küchler and Haebom Lee and Stefan Roth and Carsten Rother},
year={2025},
eprint={2510.11567},
archivePrefix={arXiv},
primaryClass={cs.CV}
}