leodriesch/open-hdri-1k

Open HDRI 1K

A consolidated, public-domain (CC0-1.0) collection of 1,440 equirectangular HDR environment maps at 1K resolution, gathered from three free HDRI libraries: Poly Haven, ambientCG and Open HDRI.

Every map is stored as a linear, high-dynamic-range .exr file alongside a tonemapped .jpg preview, with a per-asset metadata row (dimensions, source, author, license, SHA-256 checksum and tags).

Contents

Source	Assets	Author(s)	License
Poly Haven	972	various (credited per asset)	CC0-1.0
ambientCG	409	Lennart Demes (ambientCG)	CC0-1.0
Open HDRI	59	Open HDRI	CC0-1.0
Total	1,440		CC0-1.0

All maps are 2:1 equirectangular. The width/height columns record the actual stored resolution of each EXR (typically 1024×512 at the "1K" tier).

Layout

open-hdri-1k/
├── README.md
├── train.csv
├── validation.csv
├── test.csv
└── data/
    ├── polyhaven/
    │   └── <id>/
    │       ├── <id>_1k.exr
    │       └── <id>_preview.jpg
    ├── ambientcg/
    │   └── <id>/
    │       ├── <id>_1k.exr
    │       └── <id>_preview.jpg
    └── openhdri/
        └── <id>/
            ├── <id>_1k.exr
            └── <id>_preview.jpg

Splits

Split	Poly Haven	ambientCG	Open HDRI	Total
train	791	327	47	1,165
validation	90	41	6	137
test	91	41	6	138

• ambientCG and Open HDRI are split randomly 80 / 10 / 10 within each source (seed = 42).
• Poly Haven uses a fixed held-out evaluation list of 181 assets, split 50 / 50 (90 / 91) into validation / test; all remaining 791 Poly Haven assets go to train.

Columns

Each split CSV has one row per HDRI with the following columns:

Column	Description
id	Asset slug (unique within its source).
file_path	Path to the HDR .exr, relative to the dataset root.
preview_path	Path to the tonemapped .jpg preview, relative to the dataset root.
width, height	Pixel dimensions of the EXR.
format	Always exr.
source	Poly Haven, ambientCG or Open HDRI.
source_url	Canonical URL of the asset (or its download URL for Open HDRI).
license	Always CC0-1.0.
author	Credited author(s).
sha256	SHA-256 checksum of the EXR file.
tags	Comma-separated tags/categories (may be empty for Open HDRI).
category	Scene-type label (10 classes), assigned by gemini-3.1-flash-lite.
lighting	Lighting / time-of-day label (5 classes), assigned by gemini-3.1-flash-lite.

Classification (category & lighting)

Every HDRI was auto-labeled along two independent axes by the gemini-3.1-flash-lite vision model (low reasoning effort, strict structured output), from its equirectangular preview image. These are model-generated heuristic labels (not human-verified); expect occasional errors.

category (scene type): sky_only (sky dominates), natural_landscape (forest / field / mountain / desert / snow), water_coastal (beach / lake / river / harbor), urban_exterior (streets / buildings / plazas), industrial_outdoor (factory yards / construction / ruins), indoor_residential (homes), indoor_public (offices / classrooms / halls / shops), indoor_industrial (workshops / warehouses / garages), studio (photographic studio / cyclorama), other (synthetic / test / unclassifiable).

lighting (time-of-day / light): daylight, golden_hour (sunrise / sunset), overcast, night, artificial (interior electric light).

A peek at some sample HDRIs:

Previews

Previews are tonemapped sRGB JPEGs:

• ambientCG previews are the tonemapped JPEGs bundled with the original assets.
• Poly Haven and Open HDRI previews are generated from the EXRs using a Reinhard global tonemap with log-average auto-exposure, followed by sRGB encoding.

Previews are for inspection only — always use the .exr files for image-based lighting and any HDR-dependent task.

Usage

The CSVs store paths to the image files (not embedded image bytes), so the dataset is convenient to stream while keeping the heavy EXRs on disk.

from datasets import load_dataset

ds = load_dataset("<your-namespace>/open-hdri-1k")
row = ds["train"][0]
print(row["id"], row["width"], row["height"], row["source"])

# Load the actual HDR map (paths are relative to the dataset root)
import cv2, os
os.environ["OPENCV_IO_ENABLE_OPENEXR"] = "1"
hdr = cv2.imread(row["file_path"], cv2.IMREAD_ANYCOLOR | cv2.IMREAD_ANYDEPTH)  # BGR float32

License & Attribution

All assets are released under the Creative Commons CC0 1.0 Universal public-domain dedication. No attribution is legally required, but please credit the original libraries and authors where practical:

• Poly Haven — https://polyhaven.com (individual authors credited in the author column)
• ambientCG / Lennart Demes — https://ambientcg.com
• Open HDRI — https://openhdri.org

This collection simply re-packages those assets; no rights are claimed over them.