From 406c0f5b6cbb89c6481b7c5f74a5f3ffdae9064b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EC=9C=A0=EC=B0=BD=EC=9A=B1?= <changukyu@gmail.com>
Date: Sat, 11 Jul 2026 21:05:42 +0900
Subject: [PATCH] feat(edge): ZoneIntrusionDetector (foot-anchor
 point-in-polygon, debounce)

---
 edge/detectors/zone.py | 60 ++++++++++++++++++++++++++++++++++++++++++
 tests/test_zone.py     | 33 +++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 edge/detectors/zone.py
 create mode 100644 tests/test_zone.py

diff --git a/edge/detectors/zone.py b/edge/detectors/zone.py
new file mode 100644
index 0000000..e15370b
--- /dev/null
+++ b/edge/detectors/zone.py
@@ -0,0 +1,60 @@
+from dataclasses import dataclass
+
+from edge.tracking import Track
+from edge.models import L_ANKLE, R_ANKLE
+
+
+def point_in_polygon(x: float, y: float, poly: list[tuple[float, float]]) -> bool:
+    inside = False
+    n = len(poly)
+    j = n - 1
+    for i in range(n):
+        xi, yi = poly[i]
+        xj, yj = poly[j]
+        if ((yi > y) != (yj > y)) and (x < (xj - xi) * (y - yi) / ((yj - yi) or 1e-9) + xi):
+            inside = not inside
+        j = i
+    return inside
+
+
+@dataclass(frozen=True)
+class Zone:
+    zone_id: str
+    level: str  # "warning" | "restricted"
+    polygon: list  # list[tuple[float,float]]
+
+
+@dataclass
+class ZoneConfig:
+    debounce_s: float = 0.75
+
+
+class ZoneIntrusionDetector:
+    def __init__(self, zones: list[Zone], cfg: ZoneConfig):
+        self.zones = zones
+        self.cfg = cfg
+        self._inside_since: dict[tuple[int, str], float] = {}
+        self._fired: set[tuple[int, str]] = set()
+
+    def _foot(self, track: Track) -> tuple[float, float]:
+        kps = track.latest.keypoints
+        a, b = kps[L_ANKLE], kps[R_ANKLE]
+        return ((a.x + b.x) / 2, (a.y + b.y) / 2)
+
+    def active_zone_ids(self, track_id: int) -> set:
+        return {z for (tid, z) in self._inside_since if tid == track_id}
+
+    def update(self, track: Track, now: float) -> list[dict]:
+        fx, fy = self._foot(track)
+        out = []
+        for zone in self.zones:
+            key = (track.track_id, zone.zone_id)
+            if point_in_polygon(fx, fy, zone.polygon):
+                start = self._inside_since.setdefault(key, now)
+                if now - start >= self.cfg.debounce_s and key not in self._fired:
+                    self._fired.add(key)
+                    out.append({"zone_id": zone.zone_id, "level": zone.level})
+            else:
+                self._inside_since.pop(key, None)
+                self._fired.discard(key)
+        return out
diff --git a/tests/test_zone.py b/tests/test_zone.py
new file mode 100644
index 0000000..887b24b
--- /dev/null
+++ b/tests/test_zone.py
@@ -0,0 +1,33 @@
+from collections import deque
+from edge.models import Keypoint, BBox
+from edge.tracking import Track, TrackFrame
+from edge.detectors.zone import point_in_polygon, Zone, ZoneIntrusionDetector, ZoneConfig
+
+SQUARE = [(0, 0), (100, 0), (100, 100), (0, 100)]
+
+def test_point_in_polygon_basic():
+    assert point_in_polygon(50, 50, SQUARE) is True
+    assert point_in_polygon(150, 50, SQUARE) is False
+
+def _track_with_ankles(ax, ay, t):
+    kps = [Keypoint(ax, ay, 0.9) for _ in range(17)]
+    kps[15] = Keypoint(ax, ay, 0.9)   # L_ANKLE
+    kps[16] = Keypoint(ax, ay, 0.9)   # R_ANKLE
+    return Track(1, deque([TrackFrame(t, BBox(ax - 10, ay - 60, ax + 10, ay), kps)], maxlen=90))
+
+def test_intrusion_fires_after_debounce():
+    z = Zone("z1", "restricted", SQUARE)
+    det = ZoneIntrusionDetector([z], ZoneConfig(debounce_s=0.5))
+    tr = _track_with_ankles(50, 50, 0.0)
+    assert det.update(tr, now=0.0) == []
+    tr = _track_with_ankles(50, 50, 0.6)
+    out = det.update(tr, now=0.6)
+    assert out == [{"zone_id": "z1", "level": "restricted"}]
+
+def test_leaving_zone_resets():
+    z = Zone("z1", "warning", SQUARE)
+    det = ZoneIntrusionDetector([z], ZoneConfig(debounce_s=0.5))
+    det.update(_track_with_ankles(50, 50, 0.0), now=0.0)
+    det.update(_track_with_ankles(200, 200, 0.6), now=0.6)  # 이탈
+    out = det.update(_track_with_ankles(50, 50, 1.0), now=1.0)  # 재진입, 디바운스 재시작
+    assert out == []