diff --git a/jetson/main.py b/jetson/main.py
new file mode 100644
index 0000000..9ebd58d
--- /dev/null
+++ b/jetson/main.py
@@ -0,0 +1,389 @@
+#!/usr/bin/env python3
+"""
+Pickle Vision - Referee System main entry point for Jetson.
+Dual CSI cameras, real-time YOLO detection, trajectory tracking, VAR triggers.
+"""
+
+import sys
+import os
+import cv2
+import time
+import base64
+import argparse
+import threading
+import numpy as np
+
+# Add project root to path
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from ultralytics import YOLO
+from src.streaming.camera_reader import CameraReader
+from src.streaming.ring_buffer import FrameRingBuffer
+from src.physics.trajectory import TrajectoryModel
+from src.physics.event_detector import EventDetector
+from src.calibration.camera_calibrator import (
+    CameraCalibrator, get_half_court_3d_points,
+    COURT_LENGTH, COURT_WIDTH, HALF_COURT_LENGTH
+)
+from src.web.app import app, state
+
+BALL_CLASS_ID = 32  # sports ball in COCO
+
+# Global references set in main()
+_cam_readers = {}
+_args = None
+
+
+def auto_calibrate():
+    """One-click calibration: detect court lines from current frames,
+    compute camera pose, save to config.
+
+    Each camera sees one half of the court from the net position.
+    We use the court lines visible in each frame to build correspondences.
+
+    For now: use a simple approach — detect the 4 most prominent lines
+    (baseline, two sidelines, kitchen line) and map to known 3D coords.
+    Falls back to estimated corners based on frame geometry if detection fails.
+    """
+    results = {}
+
+    for sensor_id, reader in _cam_readers.items():
+        frame = reader.grab()
+        if frame is None:
+            results[str(sensor_id)] = {'ok': False, 'error': 'No frame available'}
+            continue
+
+        h, w = frame.shape[:2]
+        side = 'left' if sensor_id == 0 else 'right'
+
+        # Try to detect court lines using edge detection + Hough
+        corners_pixel = _detect_court_corners(frame, side)
+
+        if corners_pixel is None:
+            # Fallback: estimate corners from typical camera-at-net perspective
+            corners_pixel = _estimate_corners_from_net(w, h, side)
+
+        # Get known 3D coordinates for this half
+        corners_3d = get_half_court_3d_points(side)
+
+        # Calibrate
+        cal = CameraCalibrator()
+        ok = cal.calibrate(
+            np.array(corners_pixel, dtype=np.float32),
+            corners_3d,
+            w, h
+        )
+
+        if ok:
+            # Save to config
+            cal_path = os.path.join(_args.calibration_dir,
+                                    f'cam{sensor_id}_calibration.json')
+            os.makedirs(os.path.dirname(cal_path), exist_ok=True)
+            cal.save(cal_path)
+
+            state['calibrators'][sensor_id] = cal
+
+            # Get camera position for 3D scene
+            cam_pos = (-cal.rotation_matrix.T @ cal.translation_vec).flatten()
+
+            results[str(sensor_id)] = {
+                'ok': True,
+                'camera_position': cam_pos.tolist(),
+                'corners_pixel': corners_pixel.tolist() if isinstance(corners_pixel, np.ndarray)
+                    else corners_pixel,
+            }
+            print(f"[CAM {sensor_id}] Calibrated! Camera at "
+                  f"({cam_pos[0]:.1f}, {cam_pos[1]:.1f}, {cam_pos[2]:.1f})")
+        else:
+            results[str(sensor_id)] = {'ok': False, 'error': 'Calibration failed'}
+
+    return results
+
+
+def _detect_court_corners(frame, side):
+    """Detect court corners from frame using edge detection.
+
+    Returns 4 corner points as numpy array, or None if detection fails.
+    """
+    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
+    blur = cv2.GaussianBlur(gray, (5, 5), 0)
+    edges = cv2.Canny(blur, 50, 150)
+
+    # Detect lines
+    lines = cv2.HoughLinesP(edges, 1, np.pi / 180, threshold=80,
+                            minLineLength=100, maxLineGap=20)
+
+    if lines is None or len(lines) < 4:
+        return None
+
+    # Classify lines into horizontal and vertical
+    horizontals = []
+    verticals = []
+
+    for line in lines:
+        x1, y1, x2, y2 = line[0]
+        angle = abs(np.arctan2(y2 - y1, x2 - x1) * 180 / np.pi)
+
+        if angle < 30 or angle > 150:
+            horizontals.append(line[0])
+        elif 60 < angle < 120:
+            verticals.append(line[0])
+
+    if len(horizontals) < 2 or len(verticals) < 2:
+        return None
+
+    # Cluster lines by position to find the dominant ones
+    h_positions = sorted(horizontals, key=lambda l: (l[1] + l[3]) / 2)
+    v_positions = sorted(verticals, key=lambda l: (l[0] + l[2]) / 2)
+
+    # Take the most separated horizontal pair (top and bottom court lines)
+    top_line = h_positions[0]
+    bottom_line = h_positions[-1]
+
+    # Take the most separated vertical pair (left and right sidelines)
+    left_line = v_positions[0]
+    right_line = v_positions[-1]
+
+    # Find intersections as corner points
+    def line_intersection(l1, l2):
+        x1, y1, x2, y2 = l1
+        x3, y3, x4, y4 = l2
+        denom = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4)
+        if abs(denom) < 1e-6:
+            return None
+        t = ((x1 - x3) * (y3 - y4) - (y1 - y3) * (x3 - x4)) / denom
+        ix = x1 + t * (x2 - x1)
+        iy = y1 + t * (y2 - y1)
+        return [ix, iy]
+
+    corners = [
+        line_intersection(top_line, left_line),     # TL
+        line_intersection(top_line, right_line),    # TR
+        line_intersection(bottom_line, right_line), # BR
+        line_intersection(bottom_line, left_line),  # BL
+    ]
+
+    if any(c is None for c in corners):
+        return None
+
+    return np.array(corners, dtype=np.float32)
+
+
+def _estimate_corners_from_net(w, h, side):
+    """Estimate court corner positions for a camera mounted at the net.
+
+    Camera looks down the half-court. Perspective: far baseline is smaller
+    (top of frame), near net line is wider (bottom of frame).
+    """
+    # Near edge (bottom of frame, close to camera = at the net)
+    near_left = [w * 0.05, h * 0.85]
+    near_right = [w * 0.95, h * 0.85]
+
+    # Far edge (top of frame, baseline = far from camera)
+    far_left = [w * 0.20, h * 0.15]
+    far_right = [w * 0.80, h * 0.15]
+
+    # For camera at net looking at court half:
+    # - bottom of frame = net line (near)
+    # - top of frame = baseline (far)
+    # Order must match get_half_court_3d_points output
+    if side == 'left':
+        # 3D order: baseline near-left, baseline near-right, net far-right, net far-left
+        return np.array([far_left, far_right, near_right, near_left], dtype=np.float32)
+    else:
+        return np.array([far_left, far_right, near_right, near_left], dtype=np.float32)
+
+
+def _capture_var_snapshot(frame, event):
+    """Create a snapshot for VAR event and store it in state."""
+    # Draw VAR overlay on frame
+    snapshot = frame.copy()
+    cv2.putText(snapshot, "VAR DETECT", (10, 40),
+                cv2.FONT_HERSHEY_SIMPLEX, 1.2, (0, 0, 255), 3)
+    cv2.putText(snapshot, f"Line: {event['line']}  Dist: {event['distance_m']*100:.0f}cm",
+                (10, 80), cv2.FONT_HERSHEY_SIMPLEX, 0.8, (0, 0, 255), 2)
+
+    _, jpeg = cv2.imencode('.jpg', snapshot, [cv2.IMWRITE_JPEG_QUALITY, 85])
+    b64 = base64.b64encode(jpeg.tobytes()).decode('ascii')
+
+    state['last_var'] = {
+        'event': event,
+        'snapshot_b64': b64,
+    }
+
+
+def detection_loop(cam_readers, model, conf_threshold, ring_buffer):
+    """Main detection loop: alternate cameras, run YOLO, update state."""
+    frame_counts = {sid: 0 for sid in cam_readers}
+    start_times = {sid: time.time() for sid in cam_readers}
+    trajectory = state['trajectory']
+    event_detector = state['event_detector']
+    calibrators = state['calibrators']
+
+    while True:
+        for sensor_id, reader in cam_readers.items():
+            cam = state['cameras'][sensor_id]
+
+            frame = reader.grab()
+            if frame is None:
+                continue
+
+            now = time.time()
+
+            # Store raw frame in ring buffer for VAR
+            ring_buffer.push(frame, now, sensor_id)
+
+            # YOLO detection
+            results = model(frame, verbose=False, classes=[BALL_CLASS_ID], conf=conf_threshold)
+
+            det_count = 0
+            best_detection = None
+            best_conf = 0
+
+            for r in results:
+                for box in r.boxes:
+                    x1, y1, x2, y2 = map(int, box.xyxy[0])
+                    conf = float(box.conf[0])
+                    cv2.rectangle(frame, (x1, y1), (x2, y2), (0, 255, 0), 3)
+                    label = f"Ball {conf:.0%}"
+                    (tw, th), _ = cv2.getTextSize(label, cv2.FONT_HERSHEY_SIMPLEX, 0.7, 2)
+                    cv2.rectangle(frame, (x1, y1 - th - 10), (x1 + tw, y1), (0, 255, 0), -1)
+                    cv2.putText(frame, label, (x1, y1 - 5),
+                                cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0, 0, 0), 2)
+                    det_count += 1
+
+                    if conf > best_conf:
+                        best_conf = conf
+                        cx = (x1 + x2) / 2
+                        cy = (y1 + y2) / 2
+                        diameter = max(x2 - x1, y2 - y1)
+                        best_detection = (cx, cy, diameter, conf)
+
+            # Update trajectory if we have calibration and a detection
+            if best_detection and sensor_id in calibrators:
+                cal = calibrators[sensor_id]
+                if cal.calibrated:
+                    px, py, diam, conf = best_detection
+                    pos_3d = cal.pixel_to_3d(px, py, diam)
+                    if pos_3d:
+                        trajectory.add_observation(
+                            pos_3d[0], pos_3d[1], pos_3d[2],
+                            now, frame_counts[sensor_id], sensor_id, conf
+                        )
+
+                        # Check for close calls
+                        event = event_detector.check(trajectory)
+                        if event:
+                            print(f"[VAR] Close call! Line: {event['line']}, "
+                                  f"Distance: {event['distance_m']*100:.0f}cm")
+                            state['events'].append(event)
+                            _capture_var_snapshot(frame, event)
+
+            # FPS tracking
+            frame_counts[sensor_id] += 1
+            elapsed = time.time() - start_times[sensor_id]
+            fps_actual = frame_counts[sensor_id] / elapsed if elapsed > 0 else 0
+
+            # HUD overlay
+            cv2.putText(frame, f"CAM {sensor_id} | FPS: {fps_actual:.1f}", (10, 30),
+                        cv2.FONT_HERSHEY_SIMPLEX, 0.8, (0, 255, 255), 2)
+            if det_count > 0:
+                cv2.putText(frame, f"Balls: {det_count}", (10, 60),
+                            cv2.FONT_HERSHEY_SIMPLEX, 0.8, (0, 255, 0), 2)
+
+            # Encode JPEG and update shared state
+            _, jpeg = cv2.imencode('.jpg', frame, [cv2.IMWRITE_JPEG_QUALITY, 80])
+            with cam['lock']:
+                cam['frame'] = jpeg.tobytes()
+            cam['fps'] = fps_actual
+            cam['detections'] = det_count
+
+            if frame_counts[sensor_id] % 150 == 0:
+                speed = trajectory.get_speed()
+                speed_str = f"{speed:.1f} m/s" if speed else "N/A"
+                print(f"[CAM {sensor_id}] Frame {frame_counts[sensor_id]}, "
+                      f"FPS: {fps_actual:.1f}, Det: {det_count}, Speed: {speed_str}")
+
+
+def main():
+    global _cam_readers, _args
+
+    parser = argparse.ArgumentParser(description='Pickle Vision Referee System')
+    parser.add_argument('--width', type=int, default=1280)
+    parser.add_argument('--height', type=int, default=720)
+    parser.add_argument('--fps', type=int, default=30)
+    parser.add_argument('--model', type=str, default='yolov8n.pt')
+    parser.add_argument('--conf', type=float, default=0.25)
+    parser.add_argument('--port', type=int, default=8080)
+    parser.add_argument('--buffer-seconds', type=int, default=10,
+                        help='Ring buffer size in seconds for VAR clips')
+    parser.add_argument('--calibration-dir', type=str,
+                        default=os.path.join(os.path.dirname(__file__), 'config'),
+                        help='Directory with calibration JSON files')
+    args = parser.parse_args()
+    _args = args
+
+    # Load YOLO model
+    print(f"Loading YOLO model: {args.model}")
+    model = YOLO(args.model)
+    try:
+        model.to("cuda")
+        print("Inference on CUDA")
+    except Exception:
+        print("CUDA unavailable, using CPU")
+
+    # Initialize shared state
+    state['trajectory'] = TrajectoryModel(fps=args.fps)
+    state['event_detector'] = EventDetector(trigger_distance_m=0.3)
+    state['calibration_dir'] = args.calibration_dir
+    state['calibrate_fn'] = auto_calibrate
+
+    ring_buffer = FrameRingBuffer(max_seconds=args.buffer_seconds, fps=args.fps)
+
+    # Load calibrations if available
+    os.makedirs(args.calibration_dir, exist_ok=True)
+    for sensor_id in [0, 1]:
+        cal = CameraCalibrator()
+        cal_path = os.path.join(args.calibration_dir, f'cam{sensor_id}_calibration.json')
+        if os.path.exists(cal_path):
+            if cal.load(cal_path):
+                print(f"[CAM {sensor_id}] Loaded calibration from {cal_path}")
+        state['calibrators'][sensor_id] = cal
+
+    # Start camera readers
+    cam_readers = {}
+    for sensor_id in [0, 1]:
+        state['cameras'][sensor_id] = {
+            'frame': None, 'lock': threading.Lock(), 'fps': 0, 'detections': 0
+        }
+        cam_readers[sensor_id] = CameraReader(sensor_id, args.width, args.height, args.fps)
+
+    _cam_readers = cam_readers
+
+    # Wait for at least one camera
+    print("Waiting for cameras...")
+    for _ in range(100):
+        if any(r.grab() is not None for r in cam_readers.values()):
+            break
+        time.sleep(0.1)
+
+    # Start detection loop
+    det_thread = threading.Thread(
+        target=detection_loop,
+        args=(cam_readers, model, args.conf, ring_buffer),
+        daemon=True
+    )
+    det_thread.start()
+
+    time.sleep(2)
+
+    print(f"\n{'=' * 50}")
+    print(f"  Pickle Vision Referee System")
+    print(f"  Open in browser: http://192.168.1.253:{args.port}")
+    print(f"{'=' * 50}\n")
+
+    app.run(host='0.0.0.0', port=args.port, threaded=True)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/src/calibration/__init__.py b/src/calibration/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/calibration/camera_calibrator.py b/src/calibration/camera_calibrator.py
new file mode 100644
index 0000000..613b35f
--- /dev/null
+++ b/src/calibration/camera_calibrator.py
@@ -0,0 +1,191 @@
+"""
+3D camera calibration using court geometry.
+Extracted from dagster_project/assets/camera_calibration.py and coordinate_transform_3d.py.
+
+For our setup: two cameras mounted at the net center, looking at opposite halves.
+Each camera gets its own calibration.
+"""
+
+import cv2
+import numpy as np
+import json
+from typing import Dict, Optional, Tuple
+
+# Pickleball court dimensions (meters)
+COURT_LENGTH = 13.4
+COURT_WIDTH = 6.1
+HALF_COURT_LENGTH = COURT_LENGTH / 2  # 6.7m
+NET_HEIGHT = 0.914  # meters at center
+BALL_DIAMETER = 0.074  # meters (74mm)
+
+
+class CameraCalibrator:
+    """3D camera calibration using solvePnP with known court geometry."""
+
+    def __init__(self):
+        self.camera_matrix = None
+        self.rotation_vec = None
+        self.translation_vec = None
+        self.rotation_matrix = None
+        self.homography = None  # ground plane homography
+        self.calibrated = False
+
+    def calibrate(self, court_corners_pixel: np.ndarray,
+                  court_corners_3d: np.ndarray,
+                  image_width: int, image_height: int) -> bool:
+        """Calibrate camera using court corner correspondences.
+
+        Args:
+            court_corners_pixel: Nx2 array of corner positions in pixels
+            court_corners_3d: Nx3 array of corresponding 3D world coordinates
+            image_width, image_height: frame dimensions
+        """
+        # Estimate camera matrix
+        focal_length = float(max(image_width, image_height))
+        cx, cy = image_width / 2.0, image_height / 2.0
+
+        self.camera_matrix = np.array([
+            [focal_length, 0, cx],
+            [0, focal_length, cy],
+            [0, 0, 1]
+        ], dtype=np.float32)
+
+        try:
+            success, self.rotation_vec, self.translation_vec = cv2.solvePnP(
+                court_corners_3d.astype(np.float32),
+                court_corners_pixel.astype(np.float32),
+                self.camera_matrix,
+                None,
+                flags=cv2.SOLVEPNP_ITERATIVE
+            )
+            if not success:
+                return False
+
+            self.rotation_matrix, _ = cv2.Rodrigues(self.rotation_vec)
+
+            # Build ground plane homography (Z=0)
+            ground_2d = court_corners_3d[:, :2].astype(np.float32)
+            self.homography = cv2.getPerspectiveTransform(
+                court_corners_pixel[:4].astype(np.float32),
+                ground_2d[:4]
+            )
+
+            self.calibrated = True
+            return True
+        except Exception as e:
+            print(f"Calibration failed: {e}")
+            return False
+
+    def pixel_to_ground(self, px: float, py: float) -> Optional[Tuple[float, float]]:
+        """Project pixel to ground plane (Z=0) using homography."""
+        if self.homography is None:
+            return None
+        pt = np.array([[[px, py]]], dtype=np.float32)
+        result = cv2.perspectiveTransform(pt, self.homography)
+        return float(result[0][0][0]), float(result[0][0][1])
+
+    def pixel_to_3d(self, px: float, py: float,
+                    ball_diameter_px: float = 20.0) -> Optional[Tuple[float, float, float]]:
+        """Estimate 3D position using ray casting and ball size.
+
+        If ball appears large (>30px diameter), assume on ground (Z=0).
+        Otherwise, estimate height from apparent size.
+        """
+        if not self.calibrated:
+            return None
+
+        # Large ball → on ground
+        if ball_diameter_px > 30:
+            ground = self.pixel_to_ground(px, py)
+            if ground:
+                return (ground[0], ground[1], 0.0)
+            return None
+
+        fx = self.camera_matrix[0, 0]
+        fy = self.camera_matrix[1, 1]
+        cx = self.camera_matrix[0, 2]
+        cy = self.camera_matrix[1, 2]
+        focal = (fx + fy) / 2
+
+        # Ray direction in camera coords
+        ray_cam = np.array([
+            (px - cx) / fx,
+            (py - cy) / fy,
+            1.0
+        ])
+        ray_cam /= np.linalg.norm(ray_cam)
+
+        # Transform to world coords
+        ray_world = self.rotation_matrix.T @ ray_cam
+
+        # Distance from apparent ball size
+        distance = (BALL_DIAMETER * focal) / max(ball_diameter_px, 1.0)
+
+        # Camera position in world
+        cam_pos = (-self.rotation_matrix.T @ self.translation_vec).flatten()
+
+        point_3d = cam_pos + ray_world * distance
+        x, y, z = point_3d
+
+        # Sanity check
+        if z < 0 or z > 10:
+            ground = self.pixel_to_ground(px, py)
+            if ground:
+                return (ground[0], ground[1], 0.0)
+            return None
+
+        return (float(x), float(y), float(z))
+
+    def save(self, filepath: str):
+        if not self.calibrated:
+            return
+        data = {
+            'camera_matrix': self.camera_matrix.tolist(),
+            'rotation_vector': self.rotation_vec.flatten().tolist(),
+            'translation_vector': self.translation_vec.flatten().tolist(),
+            'rotation_matrix': self.rotation_matrix.tolist(),
+            'homography': self.homography.tolist() if self.homography is not None else None,
+        }
+        with open(filepath, 'w') as f:
+            json.dump(data, f, indent=2)
+
+    def load(self, filepath: str) -> bool:
+        try:
+            with open(filepath, 'r') as f:
+                data = json.load(f)
+            self.camera_matrix = np.array(data['camera_matrix'], dtype=np.float32)
+            self.rotation_vec = np.array(data['rotation_vector'], dtype=np.float32).reshape(3, 1)
+            self.translation_vec = np.array(data['translation_vector'], dtype=np.float32).reshape(3, 1)
+            self.rotation_matrix = np.array(data['rotation_matrix'], dtype=np.float32)
+            if data.get('homography'):
+                self.homography = np.array(data['homography'], dtype=np.float32)
+            self.calibrated = True
+            return True
+        except Exception as e:
+            print(f"Failed to load calibration: {e}")
+            return False
+
+
+def get_half_court_3d_points(side: str) -> np.ndarray:
+    """Get 3D coordinates for one half of the court.
+
+    Args:
+        side: 'left' (CAM 0, X: 0 to 6.7m) or 'right' (CAM 1, X: 6.7 to 13.4m)
+
+    Returns:
+        4x3 array of court corners in world coords (X=along court, Y=across, Z=up)
+    """
+    if side == 'left':
+        return np.array([
+            [0, 0, 0],                        # near-left (baseline)
+            [0, COURT_WIDTH, 0],               # near-right
+            [HALF_COURT_LENGTH, COURT_WIDTH, 0],  # far-right (net)
+            [HALF_COURT_LENGTH, 0, 0],            # far-left (net)
+        ], dtype=np.float32)
+    else:
+        return np.array([
+            [COURT_LENGTH, 0, 0],              # near-left (baseline)
+            [COURT_LENGTH, COURT_WIDTH, 0],    # near-right
+            [HALF_COURT_LENGTH, COURT_WIDTH, 0],  # far-right (net)
+            [HALF_COURT_LENGTH, 0, 0],            # far-left (net)
+        ], dtype=np.float32)
diff --git a/src/detection/__init__.py b/src/detection/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/physics/__init__.py b/src/physics/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/physics/event_detector.py b/src/physics/event_detector.py
new file mode 100644
index 0000000..c322fc4
--- /dev/null
+++ b/src/physics/event_detector.py
@@ -0,0 +1,113 @@
+"""
+Close call / event detector for referee system.
+Watches the trajectory model and triggers VAR when ball lands near a line.
+"""
+
+import time
+from typing import Optional, Tuple, List, Dict
+from .trajectory import TrajectoryModel
+
+# Court line definitions in meters (X=along court, Y=across court)
+# Full court: 13.4 x 6.1
+COURT_LENGTH = 13.4
+COURT_WIDTH = 6.1
+HALF = COURT_LENGTH / 2  # 6.7 (net / center line)
+NVZ = 2.13  # non-volley zone (kitchen) depth from net
+
+COURT_LINES = {
+    'baseline_left': {'type': 'horizontal', 'x': 0, 'y_start': 0, 'y_end': COURT_WIDTH},
+    'baseline_right': {'type': 'horizontal', 'x': COURT_LENGTH, 'y_start': 0, 'y_end': COURT_WIDTH},
+    'sideline_near': {'type': 'vertical', 'y': 0, 'x_start': 0, 'x_end': COURT_LENGTH},
+    'sideline_far': {'type': 'vertical', 'y': COURT_WIDTH, 'x_start': 0, 'x_end': COURT_LENGTH},
+    'centerline': {'type': 'horizontal', 'x': HALF, 'y_start': 0, 'y_end': COURT_WIDTH},
+    'kitchen_left': {'type': 'horizontal', 'x': HALF - NVZ, 'y_start': 0, 'y_end': COURT_WIDTH},
+    'kitchen_right': {'type': 'horizontal', 'x': HALF + NVZ, 'y_start': 0, 'y_end': COURT_WIDTH},
+    'center_service_left': {'type': 'vertical', 'y': COURT_WIDTH / 2,
+                            'x_start': 0, 'x_end': HALF - NVZ},
+    'center_service_right': {'type': 'vertical', 'y': COURT_WIDTH / 2,
+                             'x_start': HALF + NVZ, 'x_end': COURT_LENGTH},
+}
+
+
+class EventDetector:
+    """Detects close calls by monitoring ball trajectory near court lines."""
+
+    def __init__(self, trigger_distance_m=0.3, cooldown_seconds=5.0):
+        self.trigger_distance = trigger_distance_m
+        self.cooldown = cooldown_seconds
+        self.last_trigger_time = 0.0
+        self.events: List[Dict] = []
+
+    def check(self, trajectory: TrajectoryModel) -> Optional[Dict]:
+        """Check if current trajectory warrants a VAR trigger.
+
+        Conditions:
+        1. Ball is descending (vz < 0) or near ground (z < 0.3m)
+        2. Predicted landing point is within trigger_distance of a line
+        3. Cooldown has passed since last trigger
+        """
+        now = time.time()
+        if now - self.last_trigger_time < self.cooldown:
+            return None
+
+        if not trajectory.points or trajectory.velocity is None:
+            return None
+
+        last = trajectory.points[-1]
+        vz = trajectory.velocity[2]
+
+        # Ball must be descending or near ground
+        if vz > 0 and last.z > 0.5:
+            return None
+
+        # Get predicted landing
+        landing = trajectory.predict_landing()
+        if landing is None:
+            return None
+
+        land_x, land_y, time_to_land = landing
+
+        # Check distance to each line
+        closest_line = None
+        closest_dist = float('inf')
+
+        for name, line in COURT_LINES.items():
+            dist = self._distance_to_line(land_x, land_y, line)
+            if dist < closest_dist:
+                closest_dist = dist
+                closest_line = name
+
+        if closest_dist <= self.trigger_distance:
+            self.last_trigger_time = now
+            event = {
+                'type': 'close_call',
+                'timestamp': now,
+                'line': closest_line,
+                'distance_m': closest_dist,
+                'landing_x': land_x,
+                'landing_y': land_y,
+                'time_to_land': time_to_land,
+                'ball_z': last.z,
+                'ball_speed': trajectory.get_speed(),
+            }
+            self.events.append(event)
+            return event
+
+        return None
+
+    def _distance_to_line(self, x: float, y: float, line: Dict) -> float:
+        if line['type'] == 'horizontal':
+            lx = line['x']
+            y_start, y_end = line['y_start'], line['y_end']
+            if y_start <= y <= y_end:
+                return abs(x - lx)
+            return float('inf')
+        else:  # vertical
+            ly = line['y']
+            x_start, x_end = line['x_start'], line['x_end']
+            if x_start <= x <= x_end:
+                return abs(y - ly)
+            return float('inf')
+
+    def is_in_bounds(self, x: float, y: float) -> bool:
+        return 0 <= x <= COURT_LENGTH and 0 <= y <= COURT_WIDTH
diff --git a/src/physics/trajectory.py b/src/physics/trajectory.py
new file mode 100644
index 0000000..41a6f13
--- /dev/null
+++ b/src/physics/trajectory.py
@@ -0,0 +1,190 @@
+"""
+Physical trajectory model for pickleball.
+Accumulates ball positions across frames, fits physics-based curves,
+smooths noise, and predicts ball path.
+
+Key physics:
+- Gravity: 9.81 m/s^2
+- Pickleball drag coefficient: ~0.4 (perforated ball)
+- Typical serve speed: 10-25 m/s
+- Bounce coefficient of restitution: ~0.4
+"""
+
+import numpy as np
+from collections import deque
+from typing import List, Optional, Tuple, Dict
+import time
+
+GRAVITY = 9.81  # m/s^2
+BALL_MASS = 0.026  # kg
+BALL_RADIUS = 0.037  # meters
+DRAG_COEFF = 0.4
+AIR_DENSITY = 1.225  # kg/m^3
+CROSS_SECTION = np.pi * BALL_RADIUS ** 2
+BOUNCE_COR = 0.4  # coefficient of restitution
+
+
+class TrajectoryPoint:
+    __slots__ = ('x', 'y', 'z', 'timestamp', 'frame', 'sensor_id',
+                 'confidence', 'interpolated')
+
+    def __init__(self, x, y, z, timestamp, frame, sensor_id,
+                 confidence=1.0, interpolated=False):
+        self.x = x
+        self.y = y
+        self.z = z
+        self.timestamp = timestamp
+        self.frame = frame
+        self.sensor_id = sensor_id
+        self.confidence = confidence
+        self.interpolated = interpolated
+
+    def to_dict(self):
+        return {
+            'x': self.x, 'y': self.y, 'z': self.z,
+            'timestamp': self.timestamp,
+            'frame': self.frame,
+            'sensor_id': self.sensor_id,
+            'confidence': self.confidence,
+            'interpolated': self.interpolated,
+        }
+
+
+class TrajectoryModel:
+    """Accumulates ball observations and builds a physics-consistent trajectory."""
+
+    def __init__(self, max_points=300, fps=30):
+        self.points: deque = deque(maxlen=max_points)
+        self.fps = fps
+        self.velocity = None  # estimated (vx, vy, vz) m/s
+        self._last_update = 0.0
+
+    def add_observation(self, x: float, y: float, z: float,
+                        timestamp: float, frame: int, sensor_id: int,
+                        confidence: float = 1.0):
+        """Add a new observed ball position."""
+        pt = TrajectoryPoint(x, y, z, timestamp, frame, sensor_id, confidence)
+        self.points.append(pt)
+        self._update_velocity()
+
+    def _update_velocity(self):
+        """Estimate current velocity from last few points."""
+        real_pts = [p for p in self.points if not p.interpolated and p.confidence > 0.3]
+        if len(real_pts) < 2:
+            self.velocity = None
+            return
+
+        p1, p2 = real_pts[-2], real_pts[-1]
+        dt = p2.timestamp - p1.timestamp
+        if dt <= 0:
+            return
+
+        self.velocity = np.array([
+            (p2.x - p1.x) / dt,
+            (p2.y - p1.y) / dt,
+            (p2.z - p1.z) / dt,
+        ])
+
+    def predict_position(self, dt_ahead: float) -> Optional[Tuple[float, float, float]]:
+        """Predict where the ball will be dt_ahead seconds from now.
+
+        Uses simple ballistic model: constant horizontal velocity + gravity.
+        """
+        if not self.points or self.velocity is None:
+            return None
+
+        last = self.points[-1]
+        vx, vy, vz = self.velocity
+
+        # Simple drag approximation (reduces horizontal speed)
+        speed = np.sqrt(vx**2 + vy**2 + vz**2)
+        if speed > 0:
+            drag_decel = (0.5 * DRAG_COEFF * AIR_DENSITY * CROSS_SECTION * speed**2) / BALL_MASS
+            drag_factor = max(0, 1 - (drag_decel / speed) * dt_ahead)
+        else:
+            drag_factor = 1.0
+
+        x = last.x + vx * dt_ahead * drag_factor
+        y = last.y + vy * dt_ahead * drag_factor
+        z = last.z + vz * dt_ahead - 0.5 * GRAVITY * dt_ahead**2
+
+        # Bounce off ground
+        if z < 0:
+            z = abs(z) * BOUNCE_COR
+
+        return (x, y, max(z, 0))
+
+    def predict_landing(self) -> Optional[Tuple[float, float, float]]:
+        """Predict where the ball will hit the ground (Z=0).
+
+        Returns (x, y, time_to_landing) or None.
+        """
+        if not self.points or self.velocity is None:
+            return None
+
+        last = self.points[-1]
+        vz = self.velocity[2]
+
+        # Already on ground
+        if last.z <= 0.05:
+            return (last.x, last.y, 0.0)
+
+        # Solve: z + vz*t - 0.5*g*t^2 = 0
+        # 0.5*g*t^2 - vz*t - z = 0
+        a = 0.5 * GRAVITY
+        b = -vz
+        c = -last.z
+
+        discriminant = b**2 - 4*a*c
+        if discriminant < 0:
+            return None
+
+        t = (-b + np.sqrt(discriminant)) / (2 * a)
+        if t < 0:
+            t = (-b - np.sqrt(discriminant)) / (2 * a)
+        if t < 0:
+            return None
+
+        predicted = self.predict_position(t)
+        if predicted:
+            return (predicted[0], predicted[1], t)
+        return None
+
+    def get_smoothed_trajectory(self, window=5) -> List[Dict]:
+        """Get trajectory with moving average smoothing on real observations."""
+        pts = list(self.points)
+        if len(pts) < window:
+            return [p.to_dict() for p in pts]
+
+        result = []
+        for i, p in enumerate(pts):
+            start = max(0, i - window // 2)
+            end = min(len(pts), i + window // 2 + 1)
+            neighbors = [pts[j] for j in range(start, end)
+                         if not pts[j].interpolated]
+
+            if neighbors:
+                d = p.to_dict()
+                d['x_smooth'] = np.mean([n.x for n in neighbors])
+                d['y_smooth'] = np.mean([n.y for n in neighbors])
+                d['z_smooth'] = np.mean([n.z for n in neighbors])
+                result.append(d)
+            else:
+                result.append(p.to_dict())
+
+        return result
+
+    def get_recent(self, n=60) -> List[Dict]:
+        """Get last N trajectory points as dicts."""
+        pts = list(self.points)[-n:]
+        return [p.to_dict() for p in pts]
+
+    def get_speed(self) -> Optional[float]:
+        """Current ball speed in m/s."""
+        if self.velocity is None:
+            return None
+        return float(np.linalg.norm(self.velocity))
+
+    def clear(self):
+        self.points.clear()
+        self.velocity = None
diff --git a/src/streaming/__init__.py b/src/streaming/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/streaming/camera_reader.py b/src/streaming/camera_reader.py
new file mode 100644
index 0000000..d66e14a
--- /dev/null
+++ b/src/streaming/camera_reader.py
@@ -0,0 +1,81 @@
+"""
+Non-blocking camera frame reader using GStreamer subprocess.
+Extracted from web_detection_stream.py for reuse across the system.
+"""
+
+import cv2
+import time
+import subprocess
+import threading
+import numpy as np
+
+
+class CameraReader:
+    """Non-blocking camera frame reader using a background thread."""
+
+    def __init__(self, sensor_id, width=1280, height=720, fps=30):
+        self.sensor_id = sensor_id
+        self.width = width
+        self.height = height
+        self.frame = None
+        self.lock = threading.Lock()
+        self.running = True
+
+        gst_pipeline = (
+            f"gst-launch-1.0 --quiet -e "
+            f"nvarguscamerasrc sensor-id={sensor_id} ! "
+            f"'video/x-raw(memory:NVMM),width={width},height={height},framerate={fps}/1' ! "
+            f"nvvidconv ! 'video/x-raw,format=BGRx,width={width},height={height}' ! "
+            f"fdsink"
+        )
+        print(f"[CAM {sensor_id}] Starting GStreamer: {width}x{height}@{fps}")
+        self.proc = subprocess.Popen(
+            gst_pipeline, shell=True,
+            stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+        )
+        self.frame_bytes = width * height * 4
+
+        time.sleep(2)
+        if self.proc.poll() is not None:
+            stderr = self.proc.stderr.read().decode()
+            print(f"[CAM {sensor_id}] GStreamer failed: {stderr[:200]}")
+            print(f"[CAM {sensor_id}] Falling back to V4L2")
+            self.use_gst = False
+            self.cap = cv2.VideoCapture(f"/dev/video{sensor_id}", cv2.CAP_V4L2)
+        else:
+            self.use_gst = True
+            self.cap = None
+
+        self.thread = threading.Thread(target=self._read_loop, daemon=True)
+        self.thread.start()
+
+    def _read_loop(self):
+        while self.running:
+            if self.use_gst:
+                raw = self.proc.stdout.read(self.frame_bytes)
+                if len(raw) != self.frame_bytes:
+                    print(f"[CAM {self.sensor_id}] Pipe broken")
+                    break
+                f = np.frombuffer(raw, dtype=np.uint8).reshape(
+                    self.height, self.width, 4)[:, :, :3].copy()
+            else:
+                ret, f = self.cap.read()
+                if not ret:
+                    time.sleep(0.01)
+                    continue
+                if f.shape[1] != self.width or f.shape[0] != self.height:
+                    f = cv2.resize(f, (self.width, self.height))
+
+            with self.lock:
+                self.frame = f
+
+    def grab(self):
+        with self.lock:
+            return self.frame.copy() if self.frame is not None else None
+
+    def stop(self):
+        self.running = False
+        if self.use_gst and self.proc.poll() is None:
+            self.proc.terminate()
+        elif self.cap:
+            self.cap.release()
diff --git a/src/streaming/ring_buffer.py b/src/streaming/ring_buffer.py
new file mode 100644
index 0000000..28e6653
--- /dev/null
+++ b/src/streaming/ring_buffer.py
@@ -0,0 +1,54 @@
+"""
+Ring buffer for storing raw video frames.
+Used to cut VAR clips when a close call is triggered.
+"""
+
+import threading
+import numpy as np
+from collections import deque
+from typing import Optional, List, Tuple
+
+
+class FrameRingBuffer:
+    """Thread-safe ring buffer that stores the last N seconds of raw frames."""
+
+    def __init__(self, max_seconds=10, fps=30):
+        self.max_frames = max_seconds * fps
+        self.fps = fps
+        self.buffer = deque(maxlen=self.max_frames)
+        self.lock = threading.Lock()
+        self.frame_count = 0
+
+    def push(self, frame: np.ndarray, timestamp: float, sensor_id: int):
+        with self.lock:
+            self.buffer.append((frame.copy(), timestamp, sensor_id, self.frame_count))
+            self.frame_count += 1
+
+    def get_clip(self, seconds_before: float, seconds_after: float = 0) -> List[Tuple]:
+        """Extract a clip from the buffer.
+
+        Returns list of (frame, timestamp, sensor_id, frame_number) tuples.
+        """
+        with self.lock:
+            if not self.buffer:
+                return []
+
+            latest_ts = self.buffer[-1][1]
+            start_ts = latest_ts - seconds_before
+            end_ts = latest_ts + seconds_after
+
+            return [
+                entry for entry in self.buffer
+                if start_ts <= entry[1] <= end_ts
+            ]
+
+    def get_last_n_frames(self, n: int, sensor_id: Optional[int] = None) -> List[Tuple]:
+        with self.lock:
+            frames = list(self.buffer)
+            if sensor_id is not None:
+                frames = [f for f in frames if f[2] == sensor_id]
+            return frames[-n:]
+
+    def __len__(self):
+        with self.lock:
+            return len(self.buffer)
diff --git a/src/web/__init__.py b/src/web/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/web/app.py b/src/web/app.py
new file mode 100644
index 0000000..9fb4166
--- /dev/null
+++ b/src/web/app.py
@@ -0,0 +1,143 @@
+"""
+Flask web application for Pickle Vision referee system.
+Three tabs: Detection, Court, Trajectory.
+"""
+
+import os
+import cv2
+import time
+import json
+import base64
+import threading
+import numpy as np
+from pathlib import Path
+from flask import Flask, Response, render_template, jsonify, request
+
+app = Flask(__name__, template_folder=os.path.join(os.path.dirname(__file__), 'templates'))
+
+# Global state — set by main.py before starting
+state = {
+    'cameras': {},           # sensor_id -> {frame: bytes, lock, fps, detections}
+    'trajectory': None,      # TrajectoryModel instance
+    'event_detector': None,
+    'calibrators': {},       # sensor_id -> CameraCalibrator
+    'calibration_dir': '',   # path to save calibration files
+    'events': [],            # recent VAR events
+    'last_var': None,        # last VAR event with snapshot
+    'calibrate_fn': None,    # callback for calibration trigger
+}
+
+
+@app.route('/')
+def index():
+    return render_template('index.html')
+
+
+@app.route('/frame/<int:sensor_id>')
+def frame(sensor_id):
+    cam = state['cameras'].get(sensor_id)
+    if not cam:
+        return "Camera not found", 404
+    with cam['lock']:
+        jpg = cam.get('frame')
+    if jpg is None:
+        return "No frame yet", 503
+    return Response(jpg, mimetype='image/jpeg',
+                    headers={'Cache-Control': 'no-cache, no-store'})
+
+
+@app.route('/api/stats')
+def api_stats():
+    result = {}
+    for k, v in state['cameras'].items():
+        result[str(k)] = {
+            'fps': v.get('fps', 0),
+            'detections': v.get('detections', 0),
+        }
+    return jsonify(result)
+
+
+@app.route('/api/trajectory')
+def api_trajectory():
+    traj = state.get('trajectory')
+    if traj is None:
+        return jsonify({'points': [], 'speed': None, 'landing': None})
+
+    points = traj.get_recent(120)
+    speed = traj.get_speed()
+    landing = traj.predict_landing()
+
+    return jsonify({
+        'points': points,
+        'speed': speed,
+        'landing': {'x': landing[0], 'y': landing[1], 't': landing[2]} if landing else None,
+    })
+
+
+@app.route('/api/events')
+def api_events():
+    return jsonify(state.get('events', [])[-20:])
+
+
+@app.route('/api/var/last')
+def api_var_last():
+    """Get last VAR event with snapshot image."""
+    last = state.get('last_var')
+    if not last:
+        return jsonify(None)
+
+    result = {
+        'event': last['event'],
+        'ago_seconds': time.time() - last['event']['timestamp'],
+        'snapshot_b64': last.get('snapshot_b64'),
+    }
+    return jsonify(result)
+
+
+@app.route('/api/calibration/status')
+def api_calibration_status():
+    cals = {}
+    for sid, cal in state.get('calibrators', {}).items():
+        cals[str(sid)] = cal.calibrated
+    return jsonify(cals)
+
+
+@app.route('/api/calibration/trigger', methods=['POST'])
+def api_calibration_trigger():
+    """Trigger one-click court calibration from current camera frames."""
+    fn = state.get('calibrate_fn')
+    if fn is None:
+        return jsonify({'ok': False, 'error': 'Calibration not available'}), 500
+
+    try:
+        result = fn()
+        return jsonify({'ok': True, 'result': result})
+    except Exception as e:
+        return jsonify({'ok': False, 'error': str(e)}), 500
+
+
+@app.route('/api/calibration/data')
+def api_calibration_data():
+    """Return calibration data for 3D scene reconstruction."""
+    cals = state.get('calibrators', {})
+    result = {}
+    for sid, cal in cals.items():
+        if not cal.calibrated:
+            continue
+        # Camera position in world coordinates
+        cam_pos = (-cal.rotation_matrix.T @ cal.translation_vec).flatten()
+        # Camera look direction (Z axis of camera in world coords)
+        look_dir = cal.rotation_matrix.T @ np.array([0, 0, 1.0])
+
+        result[str(sid)] = {
+            'position': cam_pos.tolist(),
+            'look_direction': look_dir.tolist(),
+            'focal_length': float(cal.camera_matrix[0, 0]),
+            'image_size': [int(cal.camera_matrix[0, 2] * 2),
+                           int(cal.camera_matrix[1, 2] * 2)],
+        }
+    return jsonify(result)
+
+
+def run(host='0.0.0.0', port=8080):
+    app.run(host=host, port=port, threaded=True)
diff --git a/src/web/templates/index.html b/src/web/templates/index.html
new file mode 100644
index 0000000..d3c322a
--- /dev/null
+++ b/src/web/templates/index.html
@@ -0,0 +1,769 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <title>Pickle Vision - Referee System</title>
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
+    <script src="https://cdn.jsdelivr.net/npm/three@0.128.0/examples/js/controls/OrbitControls.js"></script>
+    <style>
+        * { margin: 0; padding: 0; box-sizing: border-box; }
+        body {
+            background: #0a0a1a;
+            color: #e0e0e0;
+            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
+            overflow-x: hidden;
+        }
+
+        /* Header */
+        .header {
+            display: flex;
+            align-items: center;
+            justify-content: space-between;
+            padding: 12px 24px;
+            background: #111128;
+            border-bottom: 1px solid #2a2a4a;
+        }
+        .logo { font-size: 20px; font-weight: 700; color: #4ecca3; }
+        .tabs { display: flex; gap: 4px; }
+        .tab {
+            padding: 8px 20px;
+            border: 1px solid #333;
+            border-radius: 6px;
+            background: transparent;
+            color: #888;
+            cursor: pointer;
+            font-size: 14px;
+            transition: all 0.2s;
+        }
+        .tab:hover { color: #ccc; border-color: #555; }
+        .tab.active {
+            background: #4ecca3;
+            color: #000;
+            border-color: #4ecca3;
+            font-weight: 600;
+        }
+        .status-bar {
+            display: flex;
+            gap: 16px;
+            font-size: 13px;
+            color: #666;
+        }
+        .status-bar .val { color: #4ecca3; font-weight: 600; }
+
+        /* Tab content */
+        .tab-content { display: none; }
+        .tab-content.active { display: block; }
+
+        /* Camera feeds */
+        .cameras {
+            display: flex;
+            gap: 8px;
+            padding: 8px;
+            justify-content: center;
+        }
+        .cam-box {
+            flex: 1;
+            max-width: 50%;
+            position: relative;
+        }
+        .cam-box img {
+            width: 100%;
+            border-radius: 6px;
+            border: 1px solid #222;
+            display: block;
+        }
+        .cam-label {
+            position: absolute;
+            top: 8px;
+            left: 8px;
+            background: rgba(0,0,0,0.7);
+            color: #4ecca3;
+            padding: 2px 8px;
+            border-radius: 4px;
+            font-size: 12px;
+            font-weight: 600;
+        }
+
+        /* 3D viewport */
+        .viewport-3d {
+            width: 100%;
+            height: 400px;
+            border-top: 1px solid #222;
+            position: relative;
+        }
+        .viewport-3d canvas { width: 100% !important; height: 100% !important; }
+
+        /* Calibrate button */
+        .calibrate-bar {
+            display: flex;
+            align-items: center;
+            gap: 16px;
+            padding: 8px 16px;
+            background: #111128;
+            border-bottom: 1px solid #222;
+        }
+        .btn-calibrate {
+            padding: 8px 24px;
+            background: #4ecca3;
+            color: #000;
+            border: none;
+            border-radius: 6px;
+            font-size: 14px;
+            font-weight: 600;
+            cursor: pointer;
+            transition: all 0.2s;
+        }
+        .btn-calibrate:hover { background: #3dbb92; }
+        .btn-calibrate:disabled { background: #333; color: #666; cursor: not-allowed; }
+        .calibrate-status {
+            font-size: 13px;
+            color: #666;
+        }
+        .calibrate-status .ok { color: #4ecca3; }
+        .calibrate-status .fail { color: #ff4444; }
+
+        /* VAR panel */
+        .var-panel {
+            display: flex;
+            align-items: stretch;
+            gap: 12px;
+            padding: 8px 16px;
+            background: #111128;
+            border-top: 1px solid #222;
+            min-height: 60px;
+        }
+        .var-indicator {
+            display: flex;
+            align-items: center;
+            gap: 8px;
+            padding: 0 12px;
+        }
+        .var-dot {
+            width: 14px;
+            height: 14px;
+            border-radius: 50%;
+            background: #333;
+            transition: background 0.3s;
+        }
+        .var-dot.active {
+            background: #ff3333;
+            box-shadow: 0 0 12px rgba(255, 51, 51, 0.6);
+            animation: var-pulse 1.5s infinite;
+        }
+        @keyframes var-pulse {
+            0%, 100% { box-shadow: 0 0 8px rgba(255, 51, 51, 0.4); }
+            50% { box-shadow: 0 0 20px rgba(255, 51, 51, 0.8); }
+        }
+        .var-label { font-size: 14px; font-weight: 700; color: #888; }
+        .var-label.active { color: #ff3333; }
+
+        .var-info {
+            display: flex;
+            flex-direction: column;
+            justify-content: center;
+            font-size: 13px;
+            color: #888;
+            min-width: 200px;
+        }
+        .var-info .var-line { color: #e0e0e0; font-weight: 600; }
+        .var-info .var-timer { color: #ff6666; font-size: 16px; font-weight: 700; }
+        .var-info .var-dist { color: #aaa; }
+
+        .var-snapshot {
+            width: 160px;
+            height: 90px;
+            border-radius: 4px;
+            border: 1px solid #333;
+            object-fit: cover;
+            background: #1a1a2e;
+        }
+        .var-snapshot.empty {
+            display: flex;
+            align-items: center;
+            justify-content: center;
+            color: #444;
+            font-size: 11px;
+        }
+
+        /* Event banner */
+        .event-banner {
+            display: none;
+            position: fixed;
+            top: 60px;
+            left: 50%;
+            transform: translateX(-50%);
+            background: rgba(255, 60, 60, 0.95);
+            color: white;
+            padding: 12px 32px;
+            border-radius: 8px;
+            font-size: 18px;
+            font-weight: 700;
+            z-index: 100;
+            animation: pulse 1s infinite;
+        }
+        .event-banner.show { display: block; }
+        @keyframes pulse {
+            0%, 100% { opacity: 1; }
+            50% { opacity: 0.7; }
+        }
+
+        /* Info panel */
+        .info-panel {
+            display: flex;
+            gap: 24px;
+            padding: 8px 24px;
+            background: #111128;
+            border-top: 1px solid #2a2a4a;
+            font-size: 13px;
+            justify-content: center;
+            flex-wrap: wrap;
+        }
+        .info-item .label { color: #666; }
+        .info-item .value { color: #4ecca3; font-weight: 600; margin-left: 4px; }
+    </style>
+</head>
+<body>
+
+<div class="header">
+    <div class="logo">Pickle Vision</div>
+    <div class="tabs">
+        <button class="tab active" data-tab="detection">Detection</button>
+        <button class="tab" data-tab="court">Court</button>
+        <button class="tab" data-tab="trajectory">Trajectory</button>
+    </div>
+    <div class="status-bar">
+        <div>CAM0: <span class="val" id="fps0">--</span> fps</div>
+        <div>CAM1: <span class="val" id="fps1">--</span> fps</div>
+    </div>
+</div>
+
+<div class="event-banner" id="eventBanner">VAR: Close Call</div>
+
+<!-- Tab 1: Detection -->
+<div class="tab-content active" id="tab-detection">
+    <div class="cameras">
+        <div class="cam-box">
+            <div class="cam-label">CAM 0 - Left Court</div>
+            <img id="det-cam0" alt="Camera 0">
+        </div>
+        <div class="cam-box">
+            <div class="cam-label">CAM 1 - Right Court</div>
+            <img id="det-cam1" alt="Camera 1">
+        </div>
+    </div>
+</div>
+
+<!-- Tab 2: Court -->
+<div class="tab-content" id="tab-court">
+    <div class="calibrate-bar">
+        <button class="btn-calibrate" id="btnCalibrate" onclick="doCalibrate()">Calibrate Court</button>
+        <div class="calibrate-status" id="calStatus">
+            CAM 0: <span id="calStatus0">not calibrated</span> |
+            CAM 1: <span id="calStatus1">not calibrated</span>
+        </div>
+    </div>
+    <div class="cameras">
+        <div class="cam-box">
+            <div class="cam-label">CAM 0 - Court Lines</div>
+            <img id="court-cam0" alt="Camera 0">
+        </div>
+        <div class="cam-box">
+            <div class="cam-label">CAM 1 - Court Lines</div>
+            <img id="court-cam1" alt="Camera 1">
+        </div>
+    </div>
+    <div class="viewport-3d" id="court-3d"></div>
+</div>
+
+<!-- Tab 3: Trajectory -->
+<div class="tab-content" id="tab-trajectory">
+    <div class="cameras">
+        <div class="cam-box">
+            <div class="cam-label">CAM 0 - Tracking</div>
+            <img id="traj-cam0" alt="Camera 0">
+        </div>
+        <div class="cam-box">
+            <div class="cam-label">CAM 1 - Tracking</div>
+            <img id="traj-cam1" alt="Camera 1">
+        </div>
+    </div>
+    <div class="viewport-3d" id="trajectory-3d"></div>
+    <!-- VAR panel at the bottom of trajectory tab -->
+    <div class="var-panel">
+        <div class="var-indicator">
+            <div class="var-dot" id="varDot"></div>
+            <div class="var-label" id="varLabel">VAR</div>
+        </div>
+        <div class="var-info" id="varInfo">
+            <div class="var-line" id="varLine">No events</div>
+            <div class="var-timer" id="varTimer"></div>
+            <div class="var-dist" id="varDist"></div>
+        </div>
+        <img class="var-snapshot" id="varSnapshot" style="display:none">
+        <div class="var-snapshot empty" id="varSnapshotEmpty">No snapshot</div>
+    </div>
+</div>
+
+<div class="info-panel">
+    <div class="info-item"><span class="label">Speed:</span><span class="value" id="ball-speed">--</span></div>
+    <div class="info-item"><span class="label">Height:</span><span class="value" id="ball-height">--</span></div>
+    <div class="info-item"><span class="label">Landing:</span><span class="value" id="ball-landing">--</span></div>
+    <div class="info-item"><span class="label">Events:</span><span class="value" id="event-count">0</span></div>
+</div>
+
+<script>
+// ===================== Tab switching =====================
+var activeTab = 'detection';
+document.querySelectorAll('.tab').forEach(function(tab) {
+    tab.addEventListener('click', function() {
+        var target = this.dataset.tab;
+        activeTab = target;
+        document.querySelectorAll('.tab').forEach(function(t) { t.classList.remove('active'); });
+        document.querySelectorAll('.tab-content').forEach(function(c) { c.classList.remove('active'); });
+        this.classList.add('active');
+        document.getElementById('tab-' + target).classList.add('active');
+
+        if (target === 'court' && !courtSceneInitialized) initCourtScene();
+        if (target === 'trajectory' && !trajSceneInitialized) initTrajectoryScene();
+    });
+});
+
+// ===================== Calibration =====================
+function doCalibrate() {
+    var btn = document.getElementById('btnCalibrate');
+    btn.disabled = true;
+    btn.textContent = 'Calibrating...';
+
+    fetch('/api/calibration/trigger', { method: 'POST' })
+        .then(function(r) { return r.json(); })
+        .then(function(data) {
+            btn.disabled = false;
+            if (data.ok) {
+                btn.textContent = 'Re-calibrate';
+                updateCalibrationStatus();
+
+                // Fetch camera positions and add to 3D scene
+                fetch('/api/calibration/data')
+                    .then(function(r) { return r.json(); })
+                    .then(function(camData) { addCamerasToScene(camData); });
+            } else {
+                btn.textContent = 'Calibrate Court';
+                alert('Calibration failed: ' + (data.error || 'Unknown error'));
+            }
+        })
+        .catch(function(e) {
+            btn.disabled = false;
+            btn.textContent = 'Calibrate Court';
+            alert('Error: ' + e);
+        });
+}
+
+function updateCalibrationStatus() {
+    fetch('/api/calibration/status')
+        .then(function(r) { return r.json(); })
+        .then(function(data) {
+            var s0 = document.getElementById('calStatus0');
+            var s1 = document.getElementById('calStatus1');
+            s0.textContent = data['0'] ? 'OK' : 'not calibrated';
+            s0.className = data['0'] ? 'ok' : '';
+            s1.textContent = data['1'] ? 'OK' : 'not calibrated';
+            s1.className = data['1'] ? 'ok' : '';
+        });
+}
+// Check on load
+updateCalibrationStatus();
+
+function addCamerasToScene(camData) {
+    if (!courtSceneInitialized) return;
+
+    for (var sid in camData) {
+        var cam = camData[sid];
+        var pos = cam.position;
+
+        // Camera pyramid
+        var geo = new THREE.ConeGeometry(0.3, 0.5, 4);
+        var mat = new THREE.MeshBasicMaterial({
+            color: sid === '0' ? 0x44aaff : 0xff44aa,
+            wireframe: true
+        });
+        var mesh = new THREE.Mesh(geo, mat);
+        mesh.position.set(pos[0], pos[1], pos[2]);
+
+        // Point cone toward look direction
+        var dir = cam.look_direction;
+        mesh.lookAt(pos[0] + dir[0], pos[1] + dir[1], pos[2] + dir[2]);
+
+        courtScene.add(mesh);
+
+        // Label
+        // (Three.js r128 doesn't have CSS2DRenderer built-in, so skip label for now)
+    }
+}
+
+// ===================== Camera frame polling =====================
+var camPrefixes = { 'detection': 'det', 'court': 'court', 'trajectory': 'traj' };
+
+function refreshCam(tabName, camId) {
+    var prefix = camPrefixes[tabName];
+    var img = document.getElementById(prefix + '-cam' + camId);
+    if (!img) return;
+
+    var newImg = new Image();
+    newImg.onload = function() {
+        img.src = newImg.src;
+        setTimeout(function() { refreshCam(tabName, camId); }, 50);
+    };
+    newImg.onerror = function() {
+        setTimeout(function() { refreshCam(tabName, camId); }, 500);
+    };
+    newImg.src = '/frame/' + camId + '?' + Date.now();
+}
+
+['detection', 'court', 'trajectory'].forEach(function(tab) {
+    refreshCam(tab, 0);
+    refreshCam(tab, 1);
+});
+
+// ===================== Stats polling =====================
+setInterval(function() {
+    fetch('/api/stats').then(function(r) { return r.json(); }).then(function(d) {
+        document.getElementById('fps0').textContent = d['0'] ? d['0'].fps.toFixed(1) : '--';
+        document.getElementById('fps1').textContent = d['1'] ? d['1'].fps.toFixed(1) : '--';
+    });
+}, 2000);
+
+// ===================== Three.js: Court Scene (Tab 2) =====================
+var courtSceneInitialized = false;
+var courtScene, courtCamera, courtRenderer, courtBallMesh;
+
+function initCourtScene() {
+    courtSceneInitialized = true;
+    var container = document.getElementById('court-3d');
+    var w = container.clientWidth;
+    var h = container.clientHeight;
+
+    courtScene = new THREE.Scene();
+    courtScene.background = new THREE.Color(0x0a0a1a);
+
+    courtCamera = new THREE.PerspectiveCamera(50, w / h, 0.1, 100);
+    courtCamera.position.set(6.7, -8, 12);
+    courtCamera.lookAt(6.7, 3.05, 0);
+
+    courtRenderer = new THREE.WebGLRenderer({ antialias: true });
+    courtRenderer.setSize(w, h);
+    container.appendChild(courtRenderer.domElement);
+
+    var controls = new THREE.OrbitControls(courtCamera, courtRenderer.domElement);
+    controls.target.set(6.7, 3.05, 0);
+    controls.update();
+
+    // Court surface
+    var courtGeo = new THREE.PlaneGeometry(13.4, 6.1);
+    var courtMat = new THREE.MeshBasicMaterial({ color: 0x1a5c3a, side: THREE.DoubleSide });
+    var courtMesh = new THREE.Mesh(courtGeo, courtMat);
+    courtMesh.position.set(6.7, 3.05, 0);
+    courtScene.add(courtMesh);
+
+    drawCourtLines(courtScene);
+
+    // Net (wide plane)
+    var netMat = new THREE.MeshBasicMaterial({ color: 0xffffff, transparent: true, opacity: 0.4, side: THREE.DoubleSide });
+    var netWide = new THREE.PlaneGeometry(6.1, 0.914);
+    var netWideMesh = new THREE.Mesh(netWide, netMat);
+    netWideMesh.rotation.y = Math.PI / 2;
+    netWideMesh.position.set(6.7, 3.05, 0.457);
+    courtScene.add(netWideMesh);
+
+    // Ball
+    var ballGeo = new THREE.SphereGeometry(0.15, 16, 16);
+    var ballMat = new THREE.MeshBasicMaterial({ color: 0xffff00 });
+    courtBallMesh = new THREE.Mesh(ballGeo, ballMat);
+    courtBallMesh.visible = false;
+    courtScene.add(courtBallMesh);
+
+    courtScene.add(new THREE.AmbientLight(0xffffff, 0.8));
+
+    // Load existing calibration cameras
+    fetch('/api/calibration/data')
+        .then(function(r) { return r.json(); })
+        .then(function(camData) { addCamerasToScene(camData); })
+        .catch(function() {});
+
+    function animateCourt() {
+        requestAnimationFrame(animateCourt);
+        controls.update();
+        courtRenderer.render(courtScene, courtCamera);
+    }
+    animateCourt();
+
+    window.addEventListener('resize', function() {
+        var w2 = container.clientWidth;
+        var h2 = container.clientHeight;
+        courtCamera.aspect = w2 / h2;
+        courtCamera.updateProjectionMatrix();
+        courtRenderer.setSize(w2, h2);
+    });
+}
+
+// ===================== Three.js: Trajectory Scene (Tab 3) =====================
+var trajSceneInitialized = false;
+var trajScene, trajCamera, trajRenderer, trajBallMesh, trajLine;
+
+function initTrajectoryScene() {
+    trajSceneInitialized = true;
+    var container = document.getElementById('trajectory-3d');
+    var w = container.clientWidth;
+    var h = container.clientHeight;
+
+    trajScene = new THREE.Scene();
+    trajScene.background = new THREE.Color(0x0a0a1a);
+
+    trajCamera = new THREE.PerspectiveCamera(50, w / h, 0.1, 100);
+    trajCamera.position.set(6.7, -10, 8);
+    trajCamera.lookAt(6.7, 3.05, 1);
+
+    trajRenderer = new THREE.WebGLRenderer({ antialias: true });
+    trajRenderer.setSize(w, h);
+    container.appendChild(trajRenderer.domElement);
+
+    var controls = new THREE.OrbitControls(trajCamera, trajRenderer.domElement);
+    controls.target.set(6.7, 3.05, 1);
+    controls.update();
+
+    // Court surface
+    var courtGeo = new THREE.PlaneGeometry(13.4, 6.1);
+    var courtMat = new THREE.MeshBasicMaterial({ color: 0x1a5c3a, side: THREE.DoubleSide });
+    var courtMesh = new THREE.Mesh(courtGeo, courtMat);
+    courtMesh.position.set(6.7, 3.05, 0);
+    trajScene.add(courtMesh);
+
+    drawCourtLines(trajScene);
+
+    // Net
+    var netMat = new THREE.MeshBasicMaterial({ color: 0xffffff, transparent: true, opacity: 0.3, side: THREE.DoubleSide });
+    var netMesh = new THREE.Mesh(new THREE.PlaneGeometry(6.1, 0.914), netMat);
+    netMesh.rotation.y = Math.PI / 2;
+    netMesh.position.set(6.7, 3.05, 0.457);
+    trajScene.add(netMesh);
+
+    // Ball
+    trajBallMesh = new THREE.Mesh(
+        new THREE.SphereGeometry(0.15, 16, 16),
+        new THREE.MeshBasicMaterial({ color: 0xffff00 })
+    );
+    trajBallMesh.visible = false;
+    trajScene.add(trajBallMesh);
+
+    // Trajectory line
+    trajLine = new THREE.Line(
+        new THREE.BufferGeometry(),
+        new THREE.LineBasicMaterial({ color: 0xff6600, linewidth: 2 })
+    );
+    trajScene.add(trajLine);
+
+    // Landing marker
+    window.landingMarker = new THREE.Mesh(
+        new THREE.RingGeometry(0.1, 0.2, 32),
+        new THREE.MeshBasicMaterial({ color: 0xff0000, side: THREE.DoubleSide, transparent: true, opacity: 0.6 })
+    );
+    window.landingMarker.position.z = 0.01;
+    window.landingMarker.visible = false;
+    trajScene.add(window.landingMarker);
+
+    // Shadow
+    window.ballShadow = new THREE.Mesh(
+        new THREE.CircleGeometry(0.1, 16),
+        new THREE.MeshBasicMaterial({ color: 0x000000, transparent: true, opacity: 0.3 })
+    );
+    window.ballShadow.position.z = 0.005;
+    window.ballShadow.visible = false;
+    trajScene.add(window.ballShadow);
+
+    trajScene.add(new THREE.AmbientLight(0xffffff, 0.8));
+
+    function animateTraj() {
+        requestAnimationFrame(animateTraj);
+        controls.update();
+        trajRenderer.render(trajScene, trajCamera);
+    }
+    animateTraj();
+
+    window.addEventListener('resize', function() {
+        var w2 = container.clientWidth;
+        var h2 = container.clientHeight;
+        trajCamera.aspect = w2 / h2;
+        trajCamera.updateProjectionMatrix();
+        trajRenderer.setSize(w2, h2);
+    });
+}
+
+// ===================== Draw court lines =====================
+function drawCourtLines(scene) {
+    var mat = new THREE.LineBasicMaterial({ color: 0xffffff });
+
+    function addLine(x1, y1, x2, y2, material) {
+        var geo = new THREE.BufferGeometry().setFromPoints([
+            new THREE.Vector3(x1, y1, 0.01),
+            new THREE.Vector3(x2, y2, 0.01)
+        ]);
+        scene.add(new THREE.Line(geo, material || mat));
+    }
+
+    // Outer boundaries
+    addLine(0, 0, 13.4, 0);
+    addLine(13.4, 0, 13.4, 6.1);
+    addLine(13.4, 6.1, 0, 6.1);
+    addLine(0, 6.1, 0, 0);
+
+    // Net / center line
+    addLine(6.7, 0, 6.7, 6.1, new THREE.LineBasicMaterial({ color: 0xcccccc }));
+
+    // Kitchen lines (NVZ)
+    var kitchenMat = new THREE.LineBasicMaterial({ color: 0xff6666 });
+    addLine(6.7 - 2.13, 0, 6.7 - 2.13, 6.1, kitchenMat);
+    addLine(6.7 + 2.13, 0, 6.7 + 2.13, 6.1, kitchenMat);
+
+    // Center service lines
+    var svcMat = new THREE.LineBasicMaterial({ color: 0x888888 });
+    addLine(0, 3.05, 6.7 - 2.13, 3.05, svcMat);
+    addLine(6.7 + 2.13, 3.05, 13.4, 3.05, svcMat);
+}
+
+// ===================== Trajectory data polling =====================
+setInterval(function() {
+    if (activeTab !== 'trajectory' && activeTab !== 'court') return;
+
+    fetch('/api/trajectory').then(function(r) { return r.json(); }).then(function(data) {
+        var points = data.points || [];
+        var speed = data.speed;
+        var landing = data.landing;
+
+        document.getElementById('ball-speed').textContent =
+            speed !== null ? (speed * 3.6).toFixed(1) + ' km/h' : '--';
+
+        if (points.length > 0) {
+            var last = points[points.length - 1];
+            document.getElementById('ball-height').textContent =
+                last.z !== null ? last.z.toFixed(2) + ' m' : '--';
+        }
+
+        document.getElementById('ball-landing').textContent =
+            landing ? '(' + landing.x.toFixed(1) + ', ' + landing.y.toFixed(1) + ') ' + landing.t.toFixed(2) + 's' : '--';
+
+        if (points.length > 0) {
+            var last = points[points.length - 1];
+
+            if (courtBallMesh) {
+                courtBallMesh.visible = true;
+                courtBallMesh.position.set(last.x, last.y, last.z || 0.15);
+            }
+
+            if (trajBallMesh) {
+                trajBallMesh.visible = true;
+                trajBallMesh.position.set(last.x, last.y, last.z || 0.15);
+
+                if (window.ballShadow) {
+                    window.ballShadow.visible = true;
+                    window.ballShadow.position.set(last.x, last.y, 0.005);
+                }
+
+                var linePoints = points.map(function(p) {
+                    return new THREE.Vector3(p.x, p.y, p.z || 0);
+                });
+                if (linePoints.length > 1) {
+                    trajLine.geometry.dispose();
+                    trajLine.geometry = new THREE.BufferGeometry().setFromPoints(linePoints);
+                }
+            }
+
+            if (landing && window.landingMarker) {
+                window.landingMarker.visible = true;
+                window.landingMarker.position.set(landing.x, landing.y, 0.01);
+            } else if (window.landingMarker) {
+                window.landingMarker.visible = false;
+            }
+        }
+    }).catch(function() {});
+}, 100);
+
+// ===================== VAR panel polling =====================
+var varTimerInterval = null;
+var lastVarTimestamp = null;
+
+function updateVarTimer() {
+    if (!lastVarTimestamp) return;
+    var ago = (Date.now() / 1000) - lastVarTimestamp;
+    var el = document.getElementById('varTimer');
+    if (ago < 60) {
+        el.textContent = ago.toFixed(0) + 's ago';
+    } else if (ago < 3600) {
+        el.textContent = Math.floor(ago / 60) + 'm ' + Math.floor(ago % 60) + 's ago';
+    } else {
+        el.textContent = Math.floor(ago / 3600) + 'h ago';
+    }
+
+    // Red dot stays active for 30 seconds
+    var dot = document.getElementById('varDot');
+    var label = document.getElementById('varLabel');
+    if (ago < 30) {
+        dot.classList.add('active');
+        label.classList.add('active');
+        label.textContent = 'VAR ACTIVE';
+    } else {
+        dot.classList.remove('active');
+        label.classList.remove('active');
+        label.textContent = 'VAR';
+    }
+}
+
+setInterval(function() {
+    fetch('/api/var/last')
+        .then(function(r) { return r.json(); })
+        .then(function(data) {
+            if (!data) return;
+
+            var event = data.event;
+            lastVarTimestamp = event.timestamp;
+
+            document.getElementById('varLine').textContent =
+                'Line: ' + event.line;
+            document.getElementById('varDist').textContent =
+                'Distance: ' + (event.distance_m * 100).toFixed(0) + ' cm';
+
+            updateVarTimer();
+
+            // Show snapshot
+            if (data.snapshot_b64) {
+                var img = document.getElementById('varSnapshot');
+                img.src = 'data:image/jpeg;base64,' + data.snapshot_b64;
+                img.style.display = 'block';
+                document.getElementById('varSnapshotEmpty').style.display = 'none';
+            }
+        })
+        .catch(function() {});
+}, 1000);
+
+// Update timer every second
+setInterval(updateVarTimer, 1000);
+
+// ===================== Event banner =====================
+var lastEventCount = 0;
+setInterval(function() {
+    fetch('/api/events').then(function(r) { return r.json(); }).then(function(events) {
+        document.getElementById('event-count').textContent = events.length;
+
+        if (events.length > lastEventCount) {
+            var banner = document.getElementById('eventBanner');
+            var latest = events[events.length - 1];
+            banner.textContent = 'VAR: Close Call - ' + latest.line +
+                ' (' + (latest.distance_m * 100).toFixed(0) + 'cm)';
+            banner.classList.add('show');
+            setTimeout(function() { banner.classList.remove('show'); }, 5000);
+            lastEventCount = events.length;
+        }
+    }).catch(function() {});
+}, 1000);
+</script>
+</body>
+</html>