| from __future__ import annotations |
|
|
| import json |
| import random |
| from collections import defaultdict |
| from dataclasses import dataclass |
| from pathlib import Path |
|
|
|
|
| @dataclass(frozen=True) |
| class PairRecord: |
| path_s1: str |
| path_s2: str |
| identity_id: str |
| finger_id: str |
| sensor_s1: str |
| sensor_s2: str |
| dataset: str |
|
|
|
|
| def build_cross_sensor_pairs( |
| samples: list[dict[str, str]], |
| dataset: str, |
| min_sensors: int = 2, |
| max_pairs_per_finger: int = 5, |
| seed: int = 42, |
| ) -> list[PairRecord]: |
| """Build cross-sensor pairs for the same identity/finger tuple.""" |
|
|
| rng = random.Random(seed) |
| grouped: dict[tuple[str, str], list[dict[str, str]]] = defaultdict(list) |
|
|
| for sample in samples: |
| if sample.get("dataset") != dataset: |
| continue |
| key = (sample["identity_id"], sample["finger_id"]) |
| grouped[key].append(sample) |
|
|
| all_pairs: list[PairRecord] = [] |
| for (identity_id, finger_id), items in grouped.items(): |
| by_sensor: dict[str, list[dict[str, str]]] = defaultdict(list) |
| for item in items: |
| by_sensor[item["sensor_id"]].append(item) |
|
|
| if len(by_sensor) < min_sensors: |
| continue |
|
|
| sensor_names = sorted(by_sensor.keys()) |
| candidate_pairs: list[PairRecord] = [] |
| for i, sensor_a in enumerate(sensor_names): |
| for sensor_b in sensor_names[i + 1 :]: |
| for sa in by_sensor[sensor_a]: |
| for sb in by_sensor[sensor_b]: |
| candidate_pairs.append( |
| PairRecord( |
| path_s1=sa["image_path"], |
| path_s2=sb["image_path"], |
| identity_id=identity_id, |
| finger_id=finger_id, |
| sensor_s1=sensor_a, |
| sensor_s2=sensor_b, |
| dataset=dataset, |
| ) |
| ) |
|
|
| if len(candidate_pairs) > max_pairs_per_finger: |
| candidate_pairs = rng.sample(candidate_pairs, max_pairs_per_finger) |
| all_pairs.extend(candidate_pairs) |
|
|
| return all_pairs |
|
|
|
|
| def export_pairs_json(pairs: list[PairRecord], output_path: str) -> None: |
| """Write pair records to disk as JSON list.""" |
|
|
| path = Path(output_path) |
| path.parent.mkdir(parents=True, exist_ok=True) |
| with path.open("w", encoding="utf-8") as f: |
| json.dump([p.__dict__ for p in pairs], f, indent=2) |
|
|
