{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "import cv2\n",
    "import os, json\n",
    "import numpy as np"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Capture a background image"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "settings_filename = 'settings.json'\n",
    "\n",
    "with open(settings_filename) as json_file:\n",
    "    cfg = json.load(json_file)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Define BGR colors\n",
    "BGR_COLOR = {\n",
    "    'red': (0,0,255),\n",
    "    'green': (127,255,0),\n",
    "    'blue': (255,127,0),\n",
    "    'yellow': (0,127,255),\n",
    "    'black': (0,0,0),\n",
    "    'white': (255,255,255)\n",
    "}\n",
    "\n",
    "cap = cv2.VideoCapture(0)  # if slow https://github.com/opencv/opencv/issues/17687\n",
    "cap.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc('M', 'J', 'P', 'G'))\n",
    "cap.set(cv2.CAP_PROP_FRAME_WIDTH, cfg['resolution_x'])\n",
    "cap.set(cv2.CAP_PROP_FRAME_HEIGHT, cfg['resolution_y'])\n",
    "cap.set(cv2.CAP_PROP_FPS, 20)\n",
    "cap.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc('M', 'J', 'P', 'G'))    \n",
    "\n",
    "while(True):\n",
    "    ret, frame = cap.read()\n",
    "\n",
    "    # Draw the arena area\n",
    "    cv2.circle(frame, (cfg['arena_x'], cfg['arena_y']), cfg['arena_radius'], BGR_COLOR['red'], 2)\n",
    "\n",
    "    # Mask the space outside the arena\n",
    "    mask = np.zeros(shape=frame.shape, dtype=\"uint8\")\n",
    "    cv2.circle(mask, (cfg['arena_x'], cfg['arena_y']), cfg['arena_radius'], BGR_COLOR['white'], -1)\n",
    "\n",
    "    frame = cv2.bitwise_and(src1=frame, src2=mask)\n",
    "    cv2.imshow('Press \"c\" to capture, \"q\" to quit', frame)\n",
    "\n",
    "    k = cv2.waitKey(33)\n",
    "    if k == ord('c'):\n",
    "        cv2.imwrite(os.path.join('assets', 'background.png'), frame)\n",
    "        break\n",
    "    if k == ord('q'):\n",
    "        break        \n",
    "\n",
    "# When the background image is captured, release the capture\n",
    "cap.release()\n",
    "cv2.destroyAllWindows()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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