| """Dataset Splitter Engine. |
| |
| Stratified, cluster-aware train / val / test dataset partitioning: |
| - Prevents data leakage by ensuring all images in the same visual `cluster_id` |
| are assigned to the SAME split (train, val, or test). |
| - Maintains balanced class distributions across splits according to target ratios (e.g. 70 / 15 / 15). |
| - Exports organized image directory symlinks/copies under `splits/` for YOLOv8 training. |
| """ |
| from __future__ import annotations |
|
|
| import logging |
| import random |
| import shutil |
| from collections import defaultdict |
| from pathlib import Path |
| from typing import Sequence |
|
|
| from .manifest import Manifest |
|
|
| log = logging.getLogger(__name__) |
|
|
|
|
| def create_cluster_splits( |
| manifest: Manifest, |
| train_ratio: float = 0.70, |
| val_ratio: float = 0.15, |
| test_ratio: float = 0.15, |
| seed: int = 42, |
| ) -> dict[str, list[dict]]: |
| """Partition valid images into cluster-isolated train/val/test splits.""" |
| random.seed(seed) |
| |
| |
| rows = manifest.images(statuses=["deduped", "kept", "validated", "normalized"]) |
| if not rows: |
| log.warning("splitter: no valid images found to split") |
| return {"train": [], "val": [], "test": []} |
|
|
| |
| clusters: dict[str, list[dict]] = defaultdict(list) |
| for r in rows: |
| cid = r["cluster_id"] or r["image_id"] |
| clusters[cid].append(r) |
|
|
| cluster_items = list(clusters.items()) |
| random.shuffle(cluster_items) |
|
|
| total_count = len(rows) |
| target_train = int(total_count * train_ratio) |
| target_val = int(total_count * val_ratio) |
|
|
| splits: dict[str, list[dict]] = {"train": [], "val": [], "test": []} |
|
|
| current_train = 0 |
| current_val = 0 |
|
|
| for cid, members in cluster_items: |
| mem_len = len(members) |
| if current_train + mem_len <= target_train or not splits["val"]: |
| splits["train"].extend(members) |
| current_train += mem_len |
| elif current_val + mem_len <= target_val or not splits["test"]: |
| splits["val"].extend(members) |
| current_val += mem_len |
| else: |
| splits["test"].extend(members) |
|
|
| return splits |
|
|
|
|
| def run( |
| manifest: Manifest, |
| cfg: dict, |
| data_dir: Path, |
| splits_dir: Path, |
| train_ratio: float = 0.70, |
| val_ratio: float = 0.15, |
| test_ratio: float = 0.15, |
| copy_files: bool = True, |
| seed: int = 42, |
| ) -> dict[str, int]: |
| """Execute cluster-isolated dataset split and write files to splits directory.""" |
| splits = create_cluster_splits( |
| manifest, train_ratio=train_ratio, val_ratio=val_ratio, test_ratio=test_ratio, seed=seed |
| ) |
|
|
| stats = { |
| "train": len(splits["train"]), |
| "val": len(splits["val"]), |
| "test": len(splits["test"]), |
| "total_split": sum(len(s) for s in splits.values()), |
| } |
|
|
| if not stats["total_split"]: |
| log.warning("splitter: 0 images split") |
| return stats |
|
|
| |
| with manifest.transaction(): |
| for split_name, members in splits.items(): |
| for m in members: |
| manifest.update_image(m["image_id"], split=split_name) |
|
|
| |
| if copy_files: |
| for split_name, members in splits.items(): |
| dst_img_dir = splits_dir / split_name / "images" |
| dst_img_dir.mkdir(parents=True, exist_ok=True) |
| for m in members: |
| src_rel = m.get("norm_path") or m.get("orig_path") |
| if not src_rel: |
| continue |
| src_path = data_dir / src_rel |
| if src_path.exists(): |
| dst_path = dst_img_dir / src_path.name |
| if not dst_path.exists(): |
| shutil.copy2(src_path, dst_path) |
|
|
| log.info("splitter split summary: %s", stats) |
| return stats |
|
|
