light_field.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import cv2\n",
    "import numpy as np\n",
    "from sklearn.feature_extraction import image\n",
    "import matplotlib.pyplot as plt\n",
    "from scipy.ndimage import shift\n",
    "from tqdm import tqdm\n",
    "\n",
    "#im,side = (cv2.imread(\"fluor.jpg\"),20)\n",
    "#im,side = (cv2.imread(\"crystal.jpg\"),17)\n",
    "im,side = (cv2.imread(\"lego_512.jpg\"),17)\n",
    "#im,side = (cv2.imread(\"chess.jpg\"),17)\n",
    "\n",
    "im[:,:,[2,1,0]] = im[:,:,[0,1,2]] #bgr to rgb\n",
    "im = im/255 # normalize image\n",
    "light_field = im"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "height,width,dim = light_field.shape\n",
    "u,v = (8,8)\n",
    "light_field_patch = light_field[u:-1:side,v:-1:side,:]\n",
    "\n",
    "plt.figure(figsize = (15,15))\n",
    "plt.imshow(light_field_patch)\n",
    "plt.show()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "rendered_height,rendered_width,dim = light_field_patch.shape\n",
    "\n",
    "(inds,jnds) = np.mgrid[0:height:side,0:width:side]\n",
    "\n",
    "radiance = np.zeros((rendered_height,rendered_width,side,side,3))\n",
    "\n",
    "for u in tqdm(range(0,side)):\n",
    "    for v in range(0,side):\n",
    "        radiance[:,:,u,v] = light_field[inds+u,jnds+v]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "from ipywidgets import interact, interactive, fixed, interact_manual\n",
    "import ipywidgets as widgets\n",
    "\n",
    "slider_v = widgets.IntSlider(\n",
    "    value=0,\n",
    "    min=0,\n",
    "    max=side-1,\n",
    "    step=1,\n",
    "    description='u:',\n",
    "    disabled=False,\n",
    "    continuous_update=False,\n",
    "    orientation='horizontal',\n",
    "    readout=True,\n",
    "    readout_format='d'\n",
    ")\n",
    "\n",
    "slider_u = widgets.IntSlider(\n",
    "    value=0,\n",
    "    min=0,\n",
    "    max=side-1,\n",
    "    step=1,\n",
    "    description='v:',\n",
    "    disabled=False,\n",
    "    continuous_update=False,\n",
    "    orientation='vertical',\n",
    "    readout=True,\n",
    "    readout_format='d'\n",
    ")\n",
    "\n",
    "slider_alpha = widgets.IntSlider(\n",
    "    value=0,\n",
    "    min=0,\n",
    "    max=int(side/2),\n",
    "    step=1,\n",
    "    description='f-stop:',\n",
    ")\n",
    "\n",
    "slider_focus = widgets.FloatSlider(\n",
    "    value=0,\n",
    "    min=-2.0,\n",
    "    max=2.0,\n",
    "    step=0.05,\n",
    "    description='C:'\n",
    ")\n",
    "\n",
    "def rendered_direction(u,v,returnVal = False):\n",
    "    plt.figure(figsize = (13,13))\n",
    "    plt.imshow(radiance[:,:,u,v])\n",
    "    if returnVal:\n",
    "        return radiance[:,:,u,v]\n",
    "    \n",
    "\"\"\"Pixel location in microlens image gives (u,v) coord\"\"\"\n",
    "def rendered_focus(C,returnVal = False):\n",
    "    rendered = np.zeros((rendered_height,rendered_width,3))\n",
    "    center_uv = int(side/2)\n",
    "    for u in tqdm(range(0, side)):\n",
    "        for v in range(0, side):\n",
    "            shift_x,shift_y = C*(center_uv-u),C*(center_uv-v)\n",
    "            rendered[:,:] += shift(radiance[:,:,u,v],(shift_x,shift_y,0))\n",
    "    final = rendered / (side*side)\n",
    "    plt.figure(figsize = (15,15))\n",
    "    plt.imshow(final)\n",
    "    if returnVal:\n",
    "        return final\n",
    "    \n",
    "def rendered_aperture(alpha,returnVal = False):\n",
    "    rendered = np.zeros((rendered_height,rendered_width,3))\n",
    "    for u in tqdm(range(alpha, side-alpha)):\n",
    "        for v in range(alpha, side-alpha):\n",
    "            rendered[:,:] += radiance[:,:,u,v]\n",
    "    final = rendered / ((side-2*alpha) * (side-2*alpha))\n",
    "    plt.figure(figsize = (15,15))\n",
    "    plt.imshow(final)\n",
    "    if returnVal:\n",
    "        return final"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "interact(rendered_direction, u=slider_u,v=slider_v)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "interact(rendered_aperture,alpha=slider_alpha)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Use this one with caution! This can take a lot of time depending on the size of the image rendered\n",
    "rendered_focus(C=0.1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Write the refocused images to a gif file (THIS TAKE LONG TIME)\n",
    "import imageio\n",
    "from PIL import Image\n",
    "\n",
    "cs = np.linspace(-3,3,30)\n",
    "\n",
    "with imageio.get_writer('refocused.gif', mode='I') as writer:\n",
    "    for c in cs:\n",
    "        refocused = rendered_focus(C=c,returnVal=True)\n",
    "        imageio.imwrite('temp.png', refocused)\n",
    "        image = imageio.imread('temp.png')\n",
    "        writer.append_data(image)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Aperture changes\n",
    "import imageio\n",
    "from PIL import Image\n",
    "\n",
    "fstop = np.arange(9)\n",
    "\n",
    "with imageio.get_writer('aperture.gif', mode='I',fps=10) as writer:\n",
    "    for stop in fstop:\n",
    "        refocused = rendered_aperture(alpha=stop,returnVal=True)\n",
    "        imageio.imwrite('temp.png', refocused)\n",
    "        image = imageio.imread('temp.png')\n",
    "        writer.append_data(image)"
   ]
  }
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