6-OpticalFlow.ipynb

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    "Python OpenCV: Optical Flow with Lucas-Kanade method"
   ]
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   "source": [
    "import numpy as np\n",
    "import cv2\n",
    "\n",
    "# Load the video\n",
    "cap = cv2.VideoCapture(\"./Assets/car3.mp4\")\n",
    "  \n",
    "\n",
    "# Get the first frame\n",
    "ret, frame1 = cap.read()\n",
    "\n",
    "# Convert to grayscale\n",
    "prev_gray = cv2.cvtColor(frame1, cv2.COLOR_BGR2GRAY)\n",
    "\n",
    "# Create a mask for drawing the optical flow vectors\n",
    "mask = np.zeros_like(frame1)\n",
    "\n",
    "# Set the Lucas-Kanade parameters\n",
    "lk_params = dict(winSize=(15, 15),maxLevel=4,criteria=(cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, 10, 0.03))\n",
    "\n",
    "# Define the points to track\n",
    "# You can either select them manually or use an algorithm like Shi-Tomasi corner detection\n",
    "# Here, we'll use Shi-Tomasi corner detection to automatically detect the points\n",
    "feature_params = dict(maxCorners=100,\n",
    "                      qualityLevel=0.3,\n",
    "                      minDistance=7,\n",
    "                      blockSize=7)\n",
    "\n",
    "# Get the points to track\n",
    "p0 = cv2.goodFeaturesToTrack(prev_gray, mask=None, **feature_params)\n",
    "\n",
    "# Loop over the frames\n",
    "while True:\n",
    "    # Get the next frame\n",
    "    ret, frame2 = cap.read()\n",
    "\n",
    "    # Convert to grayscale\n",
    "    next_gray = cv2.cvtColor(frame2, cv2.COLOR_BGR2GRAY)\n",
    "\n",
    "    # Calculate the optical flow using the Lucas-Kanade method\n",
    "    p1, st, err = cv2.calcOpticalFlowPyrLK(prev_gray, next_gray, p0, None, **lk_params)\n",
    "\n",
    "    # Select good points\n",
    "    good_new = p1[st == 1]\n",
    "    good_old = p0[st == 1]\n",
    "\n",
    "    # Draw the optical flow vectors\n",
    "    for i, (new, old) in enumerate(zip(good_new, good_old)):\n",
    "        a, b = new.ravel()\n",
    "        c, d = old.ravel()\n",
    "        mask = cv2.line(mask, (int(a), int(b)), (int(c), int(d)), (0, 255, 0), 2)\n",
    "        frame2 = cv2.circle(frame2, (int(a), int(b)), 5, (0, 0, 255), -1)\n",
    "\n",
    "    img = cv2.add(frame2, mask)\n",
    "\n",
    "    # Display the result\n",
    "    cv2.imshow('frame', img)\n",
    "\n",
    "    # Exit if 'q' is pressed\n",
    "    if cv2.waitKey(1) & 0xFF == ord('q'):\n",
    "        break\n",
    "\n",
    "    # Update the previous frame and points\n",
    "    prev_gray = next_gray.copy()\n",
    "    p0 = good_new.reshape(-1, 1, 2)\n",
    "\n",
    "# Release the video capture and destroy the windows\n",
    "cap.release()\n",
    "cv2.destroyAllWindows()\n"
   ]
  }
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