Lecture 9.6 - Mini Project # 11 - Ball Tracking.ipynb

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    "## Mini Project # 10 - Object Tracking"
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    "#Object Tracking\n",
    "import cv2\n",
    "import numpy as np\n",
    "\n",
    "# Initalize camera\n",
    "cap = cv2.VideoCapture(0)\n",
    "\n",
    "# define range of purple color in HSV\n",
    "lower_purple = np.array([130,50,90])\n",
    "upper_purple = np.array([170,255,255])\n",
    "\n",
    "# Create empty points array\n",
    "points = []\n",
    "\n",
    "# Get default camera window size\n",
    "ret, frame = cap.read()\n",
    "Height, Width = frame.shape[:2]\n",
    "frame_count = 0\n",
    "\n",
    "while True:\n",
    "\n",
    "    # Capture webcame frame\n",
    "    ret, frame = cap.read()\n",
    "    hsv_img = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)\n",
    "\n",
    "    # Threshold the HSV image to get only blue colors\n",
    "    mask = cv2.inRange(hsv_img, lower_purple, upper_purple)\n",
    "    #mask = cv2.morphologyEx(mask, cv2.MORPH_OPEN, kernel)\n",
    "    \n",
    "    # Find contours, OpenCV 3.X users use this line instead\n",
    "    #  _, contours, _ = cv2.findContours(mask.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)\n",
    "    contours, _ = cv2.findContours(mask.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)\n",
    "    \n",
    "    # Create empty centre array to store centroid center of mass\n",
    "    center =   int(Height/2), int(Width/2)\n",
    "\n",
    "    if len(contours) > 0:\n",
    "        \n",
    "        # Get the largest contour and its center \n",
    "        c = max(contours, key=cv2.contourArea)\n",
    "        (x, y), radius = cv2.minEnclosingCircle(c)\n",
    "        M = cv2.moments(c)\n",
    "        try:\n",
    "            center = (int(M[\"m10\"] / M[\"m00\"]), int(M[\"m01\"] / M[\"m00\"]))\n",
    "\n",
    "        except:\n",
    "            center =   int(Height/2), int(Width/2)\n",
    "\n",
    "        # Allow only countors that have a larger than 15 pixel radius\n",
    "        if radius > 25:\n",
    "            \n",
    "            # Draw cirlce and leave the last center creating a trail\n",
    "            cv2.circle(frame, (int(x), int(y)), int(radius),(0, 0, 255), 2)\n",
    "            cv2.circle(frame, center, 5, (0, 255, 0), -1)\n",
    "            \n",
    "    # Log center points \n",
    "    points.append(center)\n",
    "    \n",
    "    # loop over the set of tracked points\n",
    "    if radius > 25:\n",
    "        for i in range(1, len(points)):\n",
    "            try:\n",
    "                cv2.line(frame, points[i - 1], points[i], (0, 255, 0), 2)\n",
    "            except:\n",
    "                pass\n",
    "            \n",
    "        # Make frame count zero\n",
    "        frame_count = 0\n",
    "    else:\n",
    "        # Count frames \n",
    "        frame_count += 1\n",
    "        \n",
    "        # If we count 10 frames without object lets delete our trail\n",
    "        if frame_count == 10:\n",
    "            points = []\n",
    "            # when frame_count reaches 20 let's clear our trail \n",
    "            frame_count = 0\n",
    "            \n",
    "    # Display our object tracker\n",
    "    frame = cv2.flip(frame, 1)\n",
    "    cv2.imshow(\"Object Tracker\", frame)\n",
    "\n",
    "    if cv2.waitKey(1) == 13: #13 is the Enter Key\n",
    "        break\n",
    "\n",
    "# Release camera and close any open windows\n",
    "cap.release()\n",
    "cv2.destroyAllWindows()"
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