| """Fetch a small PHerc0139 example from the official server; no CT is redistributed. |
| |
| Data terms: https://dl.ash2txt.org/LICENSE.txt |
| This reconstructs the exposed backend-comparison input, not held-out ink labels. |
| """ |
| import argparse |
| import hashlib |
| import json |
| from pathlib import Path |
| from urllib.request import urlopen |
|
|
| import numpy as np |
| from scipy.ndimage import map_coordinates |
|
|
| BASE = ('https://vesuvius-challenge-open-data.s3.us-east-1.amazonaws.com/' |
| 'PHerc0139/segments/20260112000000-w043_2026011217/surface-volumes/' |
| '9.362um-1.2m-113keV-volume-20250728140407.zarr/0') |
| CHUNKS = { |
| (35, 20): 'e1594169b84799d3556d2907c94be7aa145f53f37741b3fabc674b1b187d29c1', |
| (35, 21): 'f3781ae4d3391ab433457874c2d57901ded5e9ef4a7a81bc4165bf4b6b1b1ca8', |
| (36, 20): '7e103b25b0851a6b340ab03e128c5d006a5ac1bebb7c6ea7084ca2a9772150a4', |
| (36, 21): 'b982a846f80eb78a472d760994446bad9824864e8e42c9d97e69e9ee005776cc', |
| } |
| DEPTH = [4.4291245739319605, 5.454546492325465, 6.479968410718972, |
| 7.505390329112477, 8.530812247505981, 9.55623416589949, |
| 10.581656084292995, 11.6070780026865, 12.632499921080004, |
| 13.65792183947351, 14.683343757867018, 15.708765676260523, |
| 16.734187594654028, 17.759609513047533, 18.785031431441038, |
| 19.810453349834543] |
| EXPECTED = '04224e26f565c4a5c1ff7f018e4904a381e7d0d6a217a6ade09ab6ec313e312a' |
|
|
|
|
| def fetch(output: Path) -> None: |
| if output.exists(): |
| raise FileExistsError(output) |
| with urlopen(BASE + '/.zarray', timeout=30) as response: |
| meta = json.load(response) |
| expected = {'shape': [28, 6120, 8120], 'chunks': [28, 128, 128], 'dtype': '|u1', |
| 'compressor': None, 'filters': None, 'order': 'C', 'dimension_separator': '/'} |
| if any(meta.get(k) != v for k, v in expected.items()): |
| raise ValueError('The public source metadata changed') |
| block = np.empty((28, 256, 256), dtype=np.uint8) |
| for (y, x), digest in CHUNKS.items(): |
| with urlopen(f'{BASE}/0/{y}/{x}', timeout=30) as response: |
| raw = response.read(28 * 128 * 128 + 1) |
| if hashlib.sha256(raw).hexdigest() != digest: |
| raise ValueError(f'Source chunk changed: {y}/{x}') |
| block[:, (y-35)*128:(y-34)*128, (x-20)*128:(x-19)*128] = np.frombuffer(raw, np.uint8).reshape(28, 128, 128) |
| |
| |
| xy = (np.arange(192, 288) + .5) * 512 / 499 - .5 |
| coordinates = np.array(np.broadcast_arrays(np.array(DEPTH)[:, None, None], |
| (xy - 160)[None, :, None], (xy - 120)[None, None, :])) |
| image = map_coordinates(block.astype(np.float32), coordinates, order=1, prefilter=False) |
| image = image.clip(0, 255).astype(np.uint8) |
| output.parent.mkdir(parents=True, exist_ok=True) |
| with output.open('xb') as stream: |
| np.save(stream, image, allow_pickle=False) |
| if hashlib.sha256(output.read_bytes()).hexdigest() != EXPECTED: |
| raise ValueError('The reconstructed example differs from the recorded input') |
| print(f'{output}: {EXPECTED}') |
|
|
|
|
| if __name__ == '__main__': |
| parser = argparse.ArgumentParser(description=__doc__) |
| parser.add_argument('--output', type=Path, default=Path('pherc0139_crop.npy')) |
| fetch(parser.parse_args().output) |
|
|
