| # Verification |
|
|
| This copy was checked against the official COCO 2017 release rather than assumed |
| correct. Every check below passed. |
|
|
| ## Image and mask integrity |
|
|
| | Check | Result | |
| |---|---| |
| | JPEG bytes SHA-256 identical to the official files | 287,360 / 287,360 | |
| | Mask PNG bytes SHA-256 identical to the official files | 246,574 / 246,574 | |
| | JPEGs fully decoded (not header-checked) | 287,360, 0 corrupt | |
| | Decoded pixel dimensions vs. dimensions declared in the JSON | 0 mismatches | |
| | Row count per split vs. files on disk | exact for all splits | |
|
|
| Image counts match the official release: 118,287 train / 5,000 val / 40,670 test / |
| 123,403 unlabeled. |
|
|
| ## Annotation conversion is lossless |
|
|
| Every annotation was reconstructed from Parquet back into its original COCO JSON |
| shape and compared field by field against the source file. |
|
|
| | Family | Annotations compared | Mismatches | |
| |---|---|---| |
| | `instances` | 896,782 | 0 | |
| | `captions` | 616,767 | 0 | |
| | `person_keypoints` | 273,469 | 0 | |
| | `stuff` | 780,259 | 0 | |
| | `panoptic` | 1,386,712 segments | 0 | |
|
|
| This covers `bbox`, `area`, `category_id`, `iscrowd`, `keypoints`, `num_keypoints`, |
| `caption`, and every `segmentation` in all three of its formats, plus per-image |
| metadata (`file_name`, `width`, `height`, `license`, `coco_url`, `flickr_url`, |
| `date_captured`) and the category tables for all five families. |
|
|
| ## Round-trip behaviour |
|
|
| - `image` and `mask` columns decode as PIL images through `datasets`. |
| - Reconstructed segmentations decode through `pycocotools` (2,000 sampled, 100%). |
| - Annotation `image_id`s and image `image_id`s cover each other exactly, in both |
| directions, for every split. |
| - Every `panoptic_file_name` resolves to a mask present in `panoptic_masks_*`. |
|
|
| ## Reproducing |
|
|
| The scripts that built and checked this repo are in `scripts/`: |
|
|
| ```bash |
| python scripts/build_annotations.py # JSONs -> annotation configs |
| python scripts/build_images.py # JPEGs -> image configs |
| python scripts/build_masks.py # PNGs -> mask configs |
| python scripts/verify_release.py # full verification (byte + round-trip) |
| python scripts/validate.py # counts, joins, feature decoding |
| ``` |
|
|
| `verify_release.py` accepts `images`, `masks`, `annotations`, `features` or `all`. |
| It compares against a local copy of the official release; paths are set at the top |
| of each script. |
|
|
