{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Bit-slicing\n",
    "stough 202-\n",
    "\n",
    "A quick bit-slicing demo to show that the low-order bits often show little relevant information, while the high-order bits show more. We'll also show this off as an example of [steganography](https://en.wikipedia.org/wiki/Steganography)."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "%matplotlib widget\n",
    "import matplotlib.pyplot as plt\n",
    "import numpy as np\n",
    "import matplotlib.colors as mcolors\n",
    "import skimage.color as color\n",
    "from ipywidgets import VBox, HBox, IntSlider\n",
    "from scipy.interpolate import interp1d\n",
    "\n",
    "# For importing from alternative directory sources\n",
    "import sys  \n",
    "sys.path.insert(0, '../dip_utils')\n",
    "\n",
    "from matrix_utils import (arr_info,\n",
    "                          make_linmap)\n",
    "\n",
    "from vis_utils import (vis_rgb_cube,\n",
    "                       vis_hsv_cube,\n",
    "                       vis_hists,\n",
    "                       vis_pair,\n",
    "                       lab_uniform)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "I = plt.imread('../dip_pics/roadforest.jpg')\n",
    "I = (255*color.rgb2gray(I)).astype('uint8')\n",
    "\n",
    "#Load the message image\n",
    "Im = plt.imread('../dip_pics/happy1BitPad.png')[...,0]\n",
    "Im = Im.astype('uint8')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "vis_pair(I, Im, show_ticks=False, cmap='gray')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(arr_info(I))\n",
    "print(arr_info(Im))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Use bit-wise and (&0b) to view each plane of the image.\n",
    "plt.figure(figsize=(6,3))\n",
    "plt.imshow(I&0x08, cmap='gray');"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Use bit-wise and (&0b) to view each plane of the image.\n",
    "plt.figure(figsize=(6,3))\n",
    "plt.imshow(I|Im, cmap='gray');"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "J = I|Im\n",
    "plt.figure(figsize=(6,3))\n",
    "plt.imshow(J&0x01, cmap='gray');"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "vis_pair(I, J, cmap='gray')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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