feat: base face detection

ref: N25B-397

src/robot_interface/endpoints/face_detector.py

@@ -0,0 +1,113 @@
+from __future__ import unicode_literals
+import logging
+import threading
+import zmq
+
+from robot_interface.endpoints.socket_base import SocketBase
+from robot_interface.state import state
+from robot_interface.core.config import settings
+
+
+class FaceDetectionSender(SocketBase):
+    """
+    Face detection sender endpoint.
+
+    Subscribes to ALFaceDetection and forwards face detection
+    events over ZeroMQ.
+    """
+
+    def __init__(self, zmq_context, port=settings.agent_settings.face_sender_port):
+        super(FaceDetectionSender, self).__init__("face")
+        self.create_socket(zmq_context, zmq.PUB, port)
+
+        self._face_service = None
+        self._memory_service = None
+        self._subscriber = None
+        self._thread = None
+
+    def start_face_detection(self):
+        """
+        Initializes ALFaceDetection and starts listening for face events.
+        """
+        if not state.qi_session:
+            logging.info("No Qi session available. Not starting face detection.")
+            return
+
+        import qi  # Lazy import (same pattern as rest of codebase)
+
+        self._face_service = state.qi_session.service("ALFaceDetection")
+        self._memory_service = state.qi_session.service("ALMemory")
+
+        # Enable face detection
+        self._face_service.setTrackingEnabled(True)
+        self._face_service.setRecognitionEnabled(False)
+
+        # Subscribe to FaceDetected memory event
+        self._subscriber = self._memory_service.subscriber("FaceDetected")
+        self._subscriber.signal.connect(self._on_face_detected)
+
+        # Start keep-alive thread
+        self._thread = threading.Thread(target=self._face_loop)
+        self._thread.daemon = True
+        self._thread.start()
+
+        logging.info("Face detection started.")
+
+    def _face_loop(self):
+        """
+        Keeps the face detection alive until shutdown.
+        """
+        while not state.exit_event.is_set():
+            state.exit_event.wait(0.1)
+
+        self._cleanup()
+
+    def _on_face_detected(self, value):
+        """
+        Callback for ALMemory FaceDetected event.
+
+        :param value: Face detection data structure from NAOqi
+        """
+        if not value or len(value) < 2:
+            return
+
+        timestamp = value[0]
+        faces = value[1]
+
+        face_data = {
+            "timestamp": timestamp,
+            "face_count": len(faces),
+            "faces": []
+        }
+
+        for face in faces:
+            face_info = face[0]      # Shape info
+            extra_info = face[1]     # Extra info (ID, score, etc.)
+
+            face_data["faces"].append({
+                "alpha": face_info[1],
+                "beta": face_info[2],
+                "width": face_info[3],
+                "height": face_info[4],
+                "confidence": extra_info[1] if len(extra_info) > 1 else None
+            })
+
+        try:
+            self.socket.send_json(face_data)
+        except Exception:
+            logging.warn("Failed to send face detection data.")
+
+    def _cleanup(self):
+        """
+        Cleanup subscriptions and disable face detection.
+        """
+        try:
+            if self._subscriber:
+                self._subscriber.signal.disconnect(self._on_face_detected)
+
+            if self._face_service:
+                self._face_service.setTrackingEnabled(False)
+
+            logging.info("Face detection stopped.")
+        except Exception:
+            logging.warn("Error during face detection cleanup.")