| """Per-camera calibration: zone polygons (stop-line, no-parking, lane) loaded from |
| ``configs/<camera_id>.json``. Used by the Tier-C rules. No calibration => no zones => |
| those rules simply don't fire (the system degrades to Tier-A only). |
| """ |
|
|
| from __future__ import annotations |
|
|
| import json |
| import os |
|
|
| from core.schemas import Zone |
|
|
| CONFIG_DIR = "configs" |
|
|
|
|
| def load_zones(camera_id: str | None) -> list[Zone]: |
| if not camera_id: |
| return [] |
| path = os.path.join(CONFIG_DIR, f"{camera_id}.json") |
| if not os.path.exists(path): |
| return [] |
| with open(path, encoding="utf-8") as fh: |
| data = json.load(fh) |
| zones: list[Zone] = [] |
| for z in data.get("zones", []): |
| zones.append( |
| Zone( |
| id=z.get("id", z["kind"]), |
| kind=z["kind"], |
| polygon=[(float(p[0]), float(p[1])) for p in z["polygon"]], |
| direction=z.get("direction"), |
| ) |
| ) |
| return zones |
|
|
|
|
| def point_in_polygon( |
| point: tuple[float, float], polygon: list[tuple[float, float]] |
| ) -> bool: |
| """Ray-casting test. Pure Python so the rules need no geometry dependency.""" |
| x, y = point |
| inside = False |
| n = len(polygon) |
| if n < 3: |
| return False |
| j = n - 1 |
| for i in range(n): |
| xi, yi = polygon[i] |
| xj, yj = polygon[j] |
| if ((yi > y) != (yj > y)) and ( |
| x < (xj - xi) * (y - yi) / (yj - yi + 1e-12) + xi |
| ): |
| inside = not inside |
| j = i |
| return inside |
|
|
