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Author: krishnaik06

Haarcascades/haarcascade_car.xml

@@ -0,0 +1,258 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Hi and welcome to your first code along lesson!\n",
+    "\n",
+    "#### Reading, writing and displaying images with OpenCV"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Let's start by importing the OpenCV libary "
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Press CTRL + ENTER to run this line\n",
+    "# You should see an * between the [ ] on the left\n",
+    "# OpenCV takes a couple seconds to import the first time\n",
+    "\n",
+    "import cv2"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Now let's import numpy\n",
+    "# We use as np, so that everything we call on numpy, we can type np instead\n",
+    "# It's short and looks neater\n",
+    "\n",
+    "import numpy as np "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Let's now load our first image"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# We don't need to do this again, but it's a good habit\n",
+    "import cv2 \n",
+    "\n",
+    "# Load an image using 'imread' specifying the path to image\n",
+    "input = cv2.imread('./image_examples/elephant.jpg')\n",
+    "\n",
+    "# Our file 'input.jpg' is now loaded and stored in python \n",
+    "# as a varaible we named 'image'\n",
+    "\n",
+    "# To display our image variable, we use 'imshow'\n",
+    "# The first parameter will be title shown on image window\n",
+    "# The second parameter is the image varialbe\n",
+    "cv2.imshow('Test Elephant Image', input)\n",
+    "\n",
+    "# 'waitKey' allows us to input information when a image window is open\n",
+    "# By leaving it blank it just waits for anykey to be pressed before \n",
+    "# continuing. By placing numbers (except 0), we can specify a delay for\n",
+    "# how long you keep the window open (time is in milliseconds here)\n",
+    "cv2.waitKey()\n",
+    "\n",
+    "# This closes all open windows \n",
+    "# Failure to place this will cause your program to hang\n",
+    "cv2.destroyAllWindows()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "\n",
+    "\n",
+    "import cv2 \n",
+    "\n",
+    "input = cv2.imread('./image_examples/elephant.jpg')\n",
+    "\n",
+    "cv2.imshow('Test Elephant Image', input)\n",
+    "cv2.waitKey()\n",
+    "cv2.destroyAllWindows()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Let's take a closer look at how images are stored"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Import numpy\n",
+    "import numpy as np"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "(519, 778, 3)\n"
+     ]
+    }
+   ],
+   "source": [
+    "print(input.shape)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#### Shape gives the dimensions of the image array\n",
+    "\n",
+    "The 2D dimensions are 830 pixels in high bv 1245 pixels wide.\n",
+    "The '3L' means that there are 3 other components (RGB) that make up this image."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Height of Image: 519 pixels\n",
+      "Width of Image:  778 pixels\n"
+     ]
+    }
+   ],
+   "source": [
+    "# Let's print each dimension of the image\n",
+    "\n",
+    "print('Height of Image:', int(input.shape[0]), 'pixels')\n",
+    "print('Width of Image: ', int(input.shape[1]), 'pixels')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### How do we save images we edit in OpenCV?"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "True"
+      ]
+     },
+     "execution_count": 11,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "# Simply use 'imwrite' specificing the file name and the image to be saved\n",
+    "cv2.imwrite('output.jpg', input)\n",
+    "cv2.imwrite('output.png', input)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.7.1"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 1
+}