png_compression_quality_test.ipynb

{
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   "cell_type": "code",
   "execution_count": 22,
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   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 22,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "import cv2\n",
    "c=cv2.imread('test.png')\n",
    "cv2.imwrite('q0.png', c, [cv2.IMWRITE_PNG_COMPRESSION, 0])\n",
    "cv2.imwrite('q9.png', c, [cv2.IMWRITE_PNG_COMPRESSION, 9])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "q9.png 825350 bytes\n",
      "q0.png 6231996 bytes\n"
     ]
    }
   ],
   "source": [
    "import os\n",
    "import glob\n",
    "for i in glob.glob('q*.png'):\n",
    "    print(i, os.path.getsize(i), 'bytes')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0.0 0.0\n"
     ]
    }
   ],
   "source": [
    "import numpy as np\n",
    "q0 = cv2.imread('q0.png')\n",
    "q9 = cv2.imread('q9.png')\n",
    "print(np.linalg.norm(q0-c), np.linalg.norm(q9-c))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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