| """Read raw pixel annotations; no coordinate quantization or target formatting.""" |
| import base64 |
| import io |
| import json |
| from pathlib import Path |
| from PIL import Image |
|
|
|
|
| class RawTSVDataset: |
| def __init__(self, root, positive_only=False): |
| self.root = Path(root) |
| self.manifest = json.loads((self.root/'manifest.json').read_text()) |
| name = 'train.positive.annotations.tsv.lineidx' if positive_only else 'train.annotations.tsv.lineidx' |
| self.offsets = [int(x) for x in (self.root/name).read_text().splitlines()] |
|
|
| def __len__(self): |
| return len(self.offsets) |
|
|
| def __getitem__(self, index): |
| |
| with (self.root/'train.annotations.tsv').open('rb') as f: |
| f.seek(self.offsets[index]) |
| offset, payload = f.readline().split(b'\t', 1) |
| annotation = json.loads(payload) |
| with (self.root/'train.images.tsv').open('rb') as f: |
| f.seek(int(offset)) |
| key, encoded = f.readline().rstrip(b'\n').split(b'\t', 1) |
| if int(key) != int(offset): |
| raise ValueError('Image offset mismatch') |
| data = base64.b64decode(encoded, validate=True) |
| return {'image_bytes': data, 'annotation': annotation} |
|
|
| @staticmethod |
| def decode(sample): |
| |
| with Image.open(io.BytesIO(sample['image_bytes'])) as source: |
| image = source.convert('RGB') |
| image.info.pop('exif', None) |
| ann = sample['annotation'] |
| if image.size != (ann['width'], ann['height']): |
| raise ValueError('Image size mismatch') |
| return {'image': image, 'annotation': ann} |
|
|
