Datasets:
Tasks:
Image Classification
Modalities:
Image
Formats:
imagefolder
Languages:
English
Size:
< 1K
License:
File size: 2,519 Bytes
0832232 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 | from __future__ import annotations
import argparse
import gzip
import hashlib
import json
import struct
from pathlib import Path
import numpy as np
def main() -> int:
parser = argparse.ArgumentParser(description="Export UFO-MNIST NPZ arrays to MNIST-style IDX gzip files.")
parser.add_argument("--dataset", type=Path, default=Path("data/ufo_mnist_v1/ufo_mnist_28x28.npz"))
parser.add_argument("--output", type=Path, default=Path("data/ufo"))
parser.add_argument("--checksums", type=Path, default=Path("data/ufo_mnist_v1/checksums.json"))
args = parser.parse_args()
data = np.load(args.dataset)
args.output.mkdir(parents=True, exist_ok=True)
files = {
"train-images-idx3-ubyte.gz": _write_images(args.output / "train-images-idx3-ubyte.gz", data["train_images"]),
"train-labels-idx1-ubyte.gz": _write_labels(args.output / "train-labels-idx1-ubyte.gz", data["train_labels"]),
"t10k-images-idx3-ubyte.gz": _write_images(args.output / "t10k-images-idx3-ubyte.gz", data["test_images"]),
"t10k-labels-idx1-ubyte.gz": _write_labels(args.output / "t10k-labels-idx1-ubyte.gz", data["test_labels"]),
}
if args.checksums.exists():
checksums = json.loads(args.checksums.read_text(encoding="utf-8"))
else:
checksums = {}
for name, digest in files.items():
checksums[f"data/ufo/{name}"] = digest
args.checksums.write_text(json.dumps(checksums, indent=2, sort_keys=True) + "\n", encoding="utf-8")
for name, digest in files.items():
print(f"{name} {digest}")
return 0
def _write_images(path: Path, images: np.ndarray) -> str:
images = np.asarray(images, dtype=np.uint8)
if images.ndim != 3:
raise ValueError("images must be shaped (N, rows, cols)")
header = struct.pack(">IIII", 2051, images.shape[0], images.shape[1], images.shape[2])
return _write_gzip(path, header + images.tobytes())
def _write_labels(path: Path, labels: np.ndarray) -> str:
labels = np.asarray(labels, dtype=np.uint8)
if labels.ndim != 1:
raise ValueError("labels must be shaped (N,)")
header = struct.pack(">II", 2049, labels.shape[0])
return _write_gzip(path, header + labels.tobytes())
def _write_gzip(path: Path, payload: bytes) -> str:
with gzip.GzipFile(filename="", mode="wb", fileobj=path.open("wb"), mtime=0) as handle:
handle.write(payload)
return hashlib.sha256(path.read_bytes()).hexdigest()
if __name__ == "__main__":
raise SystemExit(main())
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