super-resolution.ipynb

{
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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Code for **super-resolution** (figures $1$ and $5$ from main paper).. Change `factor` to $8$ to reproduce images from fig. $9$ from supmat.\n",
    "\n",
    "You can play with parameters and see how they affect the result. "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Import libs"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "from __future__ import print_function\n",
    "import matplotlib.pyplot as plt\n",
    "%matplotlib inline\n",
    "\n",
    "import argparse\n",
    "import os\n",
    "# os.environ['CUDA_VISIBLE_DEVICES'] = '1'\n",
    "\n",
    "import numpy as np\n",
    "from models import *\n",
    "\n",
    "import torch\n",
    "import torch.optim\n",
    "\n",
    "from skimage.measure import compare_psnr\n",
    "from models.downsampler import Downsampler\n",
    "\n",
    "from utils.sr_utils import *\n",
    "\n",
    "torch.backends.cudnn.enabled = True\n",
    "torch.backends.cudnn.benchmark =True\n",
    "dtype = torch.cuda.FloatTensor\n",
    "\n",
    "imsize = -1 \n",
    "factor = 4 # 4\n",
    "enforse_div32 = 'CROP' # we usually need the dimensions to be divisible by a power of two (32 in this case)\n",
    "PLOT = True\n",
    "\n",
    "# To produce images from the paper we took *_GT.png images from LapSRN viewer for corresponding factor,\n",
    "# e.g. x4/zebra_GT.png for factor=4, and x8/zebra_GT.png for factor=8 \n",
    "path_to_image = 'data/sr/zebra_GT.png'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Load image and baselines"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Starts here\n",
    "imgs = load_LR_HR_imgs_sr(path_to_image , imsize, factor, enforse_div32)\n",
    "\n",
    "imgs['bicubic_np'], imgs['sharp_np'], imgs['nearest_np'] = get_baselines(imgs['LR_pil'], imgs['HR_pil'])\n",
    "\n",
    "if PLOT:\n",
    "    plot_image_grid([imgs['HR_np'], imgs['bicubic_np'], imgs['sharp_np'], imgs['nearest_np']], 4,12);\n",
    "    print ('PSNR bicubic: %.4f   PSNR nearest: %.4f' %  (\n",
    "                                        compare_psnr(imgs['HR_np'], imgs['bicubic_np']), \n",
    "                                        compare_psnr(imgs['HR_np'], imgs['nearest_np'])))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Set up parameters and net"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "input_depth = 32\n",
    " \n",
    "INPUT =     'noise'\n",
    "pad   =     'reflection'\n",
    "OPT_OVER =  'net'\n",
    "KERNEL_TYPE='lanczos2'\n",
    "\n",
    "LR = 0.01\n",
    "tv_weight = 0.0\n",
    "\n",
    "OPTIMIZER = 'adam'\n",
    "\n",
    "if factor == 4: \n",
    "    num_iter = 2000\n",
    "    reg_noise_std = 0.03\n",
    "elif factor == 8:\n",
    "    num_iter = 4000\n",
    "    reg_noise_std = 0.05\n",
    "else:\n",
    "    assert False, 'We did not experimented with other factors'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "net_input = get_noise(input_depth, INPUT, (imgs['HR_pil'].size[1], imgs['HR_pil'].size[0])).type(dtype).detach()\n",
    "\n",
    "NET_TYPE = 'skip' # UNet, ResNet\n",
    "net = get_net(input_depth, 'skip', pad,\n",
    "              skip_n33d=128, \n",
    "              skip_n33u=128, \n",
    "              skip_n11=4, \n",
    "              num_scales=5,\n",
    "              upsample_mode='bilinear').type(dtype)\n",
    "\n",
    "# Losses\n",
    "mse = torch.nn.MSELoss().type(dtype)\n",
    "\n",
    "img_LR_var = np_to_var(imgs['LR_np']).type(dtype)\n",
    "\n",
    "downsampler = Downsampler(n_planes=3, factor=factor, kernel_type=KERNEL_TYPE, phase=0.5, preserve_size=True).type(dtype)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Define closure and optimize"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def closure():\n",
    "    global i\n",
    "    \n",
    "    if reg_noise_std > 0:\n",
    "        net_input.data = net_input_saved + (noise.normal_() * reg_noise_std)\n",
    "        \n",
    "    out_HR = net(net_input)\n",
    "    out_LR = downsampler(out_HR)\n",
    "\n",
    "    total_loss = mse(out_LR, img_LR_var) \n",
    "    \n",
    "    if tv_weight > 0:\n",
    "        total_loss += tv_weight * tv_loss(out_HR)\n",
    "        \n",
    "    total_loss.backward()\n",
    "\n",
    "    # Log\n",
    "    psnr_LR = compare_psnr(imgs['LR_np'], var_to_np(out_LR))\n",
    "    psnr_HR = compare_psnr(imgs['HR_np'], var_to_np(out_HR))\n",
    "    print ('Iteration %05d    PSNR_LR %.3f   PSNR_HR %.3f' % (i, psnr_LR, psnr_HR), '\\r', end='')\n",
    "                      \n",
    "    # History\n",
    "    psnr_history.append([psnr_LR, psnr_HR])\n",
    "    \n",
    "    if PLOT and i % 500 == 0:\n",
    "        out_HR_np = var_to_np(out_HR)\n",
    "        plot_image_grid([imgs['HR_np'], imgs['bicubic_np'], np.clip(out_HR_np, 0, 1)], factor=13, nrow=3)\n",
    "\n",
    "    i += 1\n",
    "    \n",
    "    return total_loss"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "psnr_history = [] \n",
    "net_input_saved = net_input.data.clone()\n",
    "noise = net_input.data.clone()\n",
    "\n",
    "i = 0\n",
    "p = get_params(OPT_OVER, net, net_input)\n",
    "optimize(OPTIMIZER, p, closure, LR, num_iter)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "out_HR_np = np.clip(var_to_np(net(net_input)), 0, 1)\n",
    "result_deep_prior = put_in_center(out_HR_np, imgs['orig_np'].shape[1:])\n",
    "\n",
    "# For the paper we acually took `_bicubic.png` files from LapSRN viewer and used `result_deep_prior` as our result\n",
    "plot_image_grid([imgs['HR_np'],\n",
    "                 imgs['bicubic_np'],\n",
    "                 out_HR_np], factor=4, nrow=1);"
   ]
  }
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