Sec08_Object_Tracking/02_Background_Subtraction/02_Background_Subtraction.ipynb

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   "cell_type": "markdown",
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   "source": [
    "## Background Subtraction"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 1. Gaussian Mixture-based Background/Foreground Segmentation Algorithm"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
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   "outputs": [],
   "source": [
    "# OpenCV 2.4.13 only\n",
    "import numpy as np\n",
    "import cv2\n",
    "\n",
    "cap = cv2.VideoCapture('walking.avi')\n",
    "\n",
    "# Initlaize background subtractor\n",
    "foreground_background = cv2.createBackgroundSubtractorMOG2()\n",
    "\n",
    "while True:\n",
    "    \n",
    "    ret, frame = cap.read()\n",
    "\n",
    "    # Apply background subtractor to get our foreground mask\n",
    "    foreground_mask = foreground_background.apply(frame)\n",
    "\n",
    "    cv2.imshow('Output', foreground_mask)\n",
    "    if cv2.waitKey(1) == 13: \n",
    "        break\n",
    "\n",
    "cap.release()\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### What about using this on our webcam input?"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
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   "outputs": [],
   "source": [
    "# OpenCV 2.4.13 only\n",
    "import numpy as np\n",
    "import cv2\n",
    "\n",
    "# Intialize Webcam\n",
    "cap = cv2.VideoCapture(0)\n",
    "\n",
    "# Initlaize background subtractor\n",
    "foreground_background = cv2.createBackgroundSubtractorMOG2()\n",
    "\n",
    "while True:\n",
    "    \n",
    "    ret, frame = cap.read()\n",
    "\n",
    "    # Apply background subtractor to get our foreground mask\n",
    "    foreground_mask = foreground_background.apply(frame)\n",
    "\n",
    "    cv2.imshow('Output', foreground_mask)\n",
    "    if cv2.waitKey(1) == 13: \n",
    "        break\n",
    "\n",
    "cap.release()\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Let's try the Improved adaptive Gausian mixture model for background subtraction"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "ename": "error",
     "evalue": "OpenCV(4.1.0) /Users/travis/build/skvark/opencv-python/opencv/modules/highgui/src/window.cpp:352: error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'imshow'\n",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31merror\u001b[0m                                     Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-1-810529111959>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m     14\u001b[0m     \u001b[0mforeground_mask\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mforeground_background\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mapply\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mframe\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m     15\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m---> 16\u001b[0;31m     \u001b[0mcv2\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mimshow\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m'Output'\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mforeground_mask\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m     17\u001b[0m     \u001b[0;32mif\u001b[0m \u001b[0mcv2\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mwaitKey\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;36m1\u001b[0m\u001b[0;34m)\u001b[0m \u001b[0;34m==\u001b[0m \u001b[0;36m13\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m     18\u001b[0m         \u001b[0;32mbreak\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
      "\u001b[0;31merror\u001b[0m: OpenCV(4.1.0) /Users/travis/build/skvark/opencv-python/opencv/modules/highgui/src/window.cpp:352: error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'imshow'\n"
     ]
    }
   ],
   "source": [
    "# OpenCV 2.4.13\n",
    "import numpy as np\n",
    "import cv2\n",
    "\n",
    "cap = cv2.VideoCapture('walking.avi')\n",
    "\n",
    "# Initlaize background subtractor\n",
    "foreground_background = cv2.createBackgroundSubtractorMOG2()\n",
    "\n",
    "while True:\n",
    "    ret, frame = cap.read()\n",
    "\n",
    "    # Apply background subtractor to get our foreground mask\n",
    "    foreground_mask = foreground_background.apply(frame)\n",
    "\n",
    "    cv2.imshow('Output', foreground_mask)\n",
    "    if cv2.waitKey(1) == 13: \n",
    "        break\n",
    "\n",
    "cap.release()\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Applying it to our webcam stream"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "# OpenCV 2.4.13\n",
    "import numpy as np\n",
    "import cv2\n",
    "\n",
    "# Intialize Webcam\n",
    "cap = cv2.VideoCapture(0)\n",
    "\n",
    "# Initlaize background subtractor\n",
    "foreground_background = cv2.createBackgroundSubtractorMOG2()\n",
    "\n",
    "while True:\n",
    "    ret, frame = cap.read()\n",
    "    \n",
    "    # Apply background subtractor to get our foreground mask\n",
    "    foreground_mask = foreground_background.apply(frame)\n",
    "\n",
    "    cv2.imshow('Output', foreground_mask)\n",
    "    if cv2.waitKey(1) == 13: \n",
    "        break\n",
    "\n",
    "cap.release()\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## What about foreground substraction?"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "ename": "KeyboardInterrupt",
     "evalue": "",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mKeyboardInterrupt\u001b[0m                         Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-3-3bcdb716aeb4>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m     11\u001b[0m \u001b[0;32mwhile\u001b[0m \u001b[0mTrue\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m     12\u001b[0m     \u001b[0;31m# Get webcam frmae\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m---> 13\u001b[0;31m     \u001b[0mret\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mframe\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mcap\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mread\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m     14\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m     15\u001b[0m     \u001b[0;31m# 0.01 is the weight of image, play around to see how it changes\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
      "\u001b[0;31mKeyboardInterrupt\u001b[0m: "
     ]
    }
   ],
   "source": [
    "import cv2\n",
    "import numpy as np\n",
    "\n",
    "# Initalize webacam and store first frame\n",
    "cap = cv2.VideoCapture(0)\n",
    "ret, frame = cap.read()\n",
    "\n",
    "# Create a flaot numpy array with frame values\n",
    "average = np.float32(frame)\n",
    "\n",
    "while True:\n",
    "    # Get webcam frmae\n",
    "    ret, frame = cap.read()\n",
    "    \n",
    "    # 0.01 is the weight of image, play around to see how it changes\n",
    "    cv2.accumulateWeighted(frame, average, 0.01)\n",
    "    \n",
    "    # Scales, calculates absolute values, and converts the result to 8-bit\n",
    "    background = cv2.convertScaleAbs(average)\n",
    "\n",
    "    cv2.imshow('Input', frame)\n",
    "    cv2.imshow('Disapearing Background', background)\n",
    "    \n",
    "    if cv2.waitKey(1) == 13: #13 is the Enter Key\n",
    "        break\n",
    "\n",
    "cv2.destroyAllWindows()\n",
    "cap.release()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Background Substraction KKN\n",
    "#### OpenCV 3.X only!"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "# OpenCV 3.1.0\n",
    "import numpy as np\n",
    "import cv2\n",
    "\n",
    "cap = cv2.VideoCapture(0)\n",
    "\n",
    "kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE,(3,3))\n",
    "fgbg = cv2.createBackgroundSubtractorKNN()\n",
    "\n",
    "while(1):\n",
    "    ret, frame = cap.read()\n",
    "\n",
    "    fgmask = fgbg.apply(frame)\n",
    "    fgmask = cv2.morphologyEx(fgmask, cv2.MORPH_OPEN, kernel)\n",
    "\n",
    "    cv2.imshow('frame',fgmask)\n",
    "    \n",
    "    if cv2.waitKey(1) == 13: \n",
    "        break\n",
    "\n",
    "cap.release()\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
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