102-rotate_image.ipynb

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    "colab": {
      "name": "rotate-image.ipynb",
      "provenance": [],
      "collapsed_sections": [],
      "toc_visible": true,
      "include_colab_link": true
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    "kernelspec": {
      "name": "python3",
      "display_name": "Python 3"
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  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "view-in-github",
        "colab_type": "text"
      },
      "source": [
        "<a href=\"https://colab.research.google.com/github/parekhakhil/pyImageSearch/blob/main/102-rotate_image.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "c7uPgNc0NyO7"
      },
      "source": [
        "# OpenCV Rotate Image\n",
        "\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "Mpthbjs-N2qJ"
      },
      "source": [
        "\n",
        "## This notebook is associated with the [OpenCV Rotate Image](https://www.pyimagesearch.com/2021/01/20/opencv-rotate-image/) blog post published on 01-20-2021.\n",
        "\n",
        "Only the code for the blog post is here. Most codeblocks have a 1:1 relationship with what you find in the blog post with two exceptions: (1) Python classes are not separate files as they are typically organized with PyImageSearch projects, and (2) Command Line Argument parsing is replaced with an `args` dictionary that you can manipulate as needed.\n",
        "\n",
        "We recommend that you execute (press ▶️) the code block-by-block, as-is, before adjusting parameters and `args` inputs. Once you've verified that the code is working, you are welcome to hack with it and learn from manipulating inputs, settings, and parameters. For more information on using Jupyter and Colab, please refer to these resources:\n",
        "\n",
        "*   [Jupyter Notebook User Interface](https://jupyter-notebook.readthedocs.io/en/stable/notebook.html#notebook-user-interface)\n",
        "*   [Overview of Google Colaboratory Features](https://colab.research.google.com/notebooks/basic_features_overview.ipynb)\n",
        "\n",
        "\n",
        "Happy hacking!\n",
        "\n",
        "*Akhil*\n",
        "\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "0pL5rHGgOAMk"
      },
      "source": [
        "### Download the code zip file"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "uEZbwcwepI9V",
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "outputId": "286e36ff-4c5e-4490-9afd-4c78d556ff8d"
      },
      "source": [
        "!wget https://pyimagesearch-code-downloads.s3-us-west-2.amazonaws.com/opencv-rotate/opencv-rotate.zip\n",
        "!unzip -qq opencv-rotate.zip\n",
        "%cd opencv-rotate"
      ],
      "execution_count": 1,
      "outputs": [
        {
          "output_type": "stream",
          "text": [
            "--2021-05-14 06:58:51--  https://pyimagesearch-code-downloads.s3-us-west-2.amazonaws.com/opencv-rotate/opencv-rotate.zip\n",
            "Resolving pyimagesearch-code-downloads.s3-us-west-2.amazonaws.com (pyimagesearch-code-downloads.s3-us-west-2.amazonaws.com)... 52.218.228.233\n",
            "Connecting to pyimagesearch-code-downloads.s3-us-west-2.amazonaws.com (pyimagesearch-code-downloads.s3-us-west-2.amazonaws.com)|52.218.228.233|:443... connected.\n",
            "HTTP request sent, awaiting response... 200 OK\n",
            "Length: 37160 (36K) [application/zip]\n",
            "Saving to: ‘opencv-rotate.zip’\n",
            "\n",
            "opencv-rotate.zip   100%[===================>]  36.29K  --.-KB/s    in 0.04s   \n",
            "\n",
            "2021-05-14 06:58:51 (985 KB/s) - ‘opencv-rotate.zip’ saved [37160/37160]\n",
            "\n",
            "/content/opencv-rotate\n"
          ],
          "name": "stdout"
        }
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "8yYRCnThOQXl"
      },
      "source": [
        "## Blog Post Code"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "BcmY4DDJOSIt"
      },
      "source": [
        "### Import Packages"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "BlcPho8lOOuF"
      },
      "source": [
        "# import the necessary packages\n",
        "import matplotlib.pyplot as plt\n",
        "import argparse\n",
        "import imutils\n",
        "import cv2"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "uY1ceK63OuFY"
      },
      "source": [
        "### Function to display images in Jupyter Notebooks and Google Colab"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "gkPDb7emOuwQ"
      },
      "source": [
        "def plt_imshow(title, image):\n",
        "    # convert the image frame BGR to RGB color space and display it\n",
        "\timage = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)\n",
        "\tplt.imshow(image)\n",
        "\tplt.title(title)\n",
        "\tplt.grid(False)\n",
        "\tplt.show()"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "X7_c5NjTOZEe"
      },
      "source": [
        "### Implementing image rotation with OpenCV"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "Txalo2DGObge"
      },
      "source": [
        "# # construct the argument parser and parse the arguments\n",
        "# ap = argparse.ArgumentParser()\n",
        "# ap.add_argument(\"-i\", \"--image\", type=str, default=\"opencv_logo.png\",\n",
        "# \thelp=\"path to the input image\")\n",
        "# args = vars(ap.parse_args())\n",
        "\n",
        "# since we are using Jupyter Notebooks we can replace our argument\n",
        "# parsing code with *hard coded* arguments and values\n",
        "args = {\n",
        "    \"image\": \"opencv_logo.png\"\n",
        "}"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "8ZgqVr3VOqlU"
      },
      "source": [
        "# load the image and show it\n",
        "image = cv2.imread(args[\"image\"])\n",
        "plt_imshow(\"Original\", image)\n",
        "\n",
        "# grab the dimensions of the image and calculate the center of the\n",
        "# image\n",
        "(h, w) = image.shape[:2]\n",
        "(cX, cY) = (w // 2, h // 2)\n",
        "\n",
        "# rotate our image by 45 degrees around the center of the image\n",
        "M = cv2.getRotationMatrix2D((cX, cY), 45, 1.0)\n",
        "rotated = cv2.warpAffine(image, M, (w, h))\n",
        "plt_imshow(\"Rotated by 45 Degrees\", rotated)\n",
        "\n",
        "# rotate our image by -90 degrees around the image\n",
        "M = cv2.getRotationMatrix2D((cX, cY), -90, 1.0)\n",
        "rotated = cv2.warpAffine(image, M, (w, h))\n",
        "plt_imshow(\"Rotated by -90 Degrees\", rotated)"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "mP7WQv9zOveK"
      },
      "source": [
        "# rotate our image around an arbitrary point rather than the center\n",
        "M = cv2.getRotationMatrix2D((10, 10), 45, 1.0)\n",
        "rotated = cv2.warpAffine(image, M, (w, h))\n",
        "plt_imshow(\"Rotated by Arbitrary Point\", rotated)"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "e03VvyFhO0o5"
      },
      "source": [
        "# use our imutils function to rotate an image 180 degrees\n",
        "rotated = imutils.rotate(image, 180)\n",
        "plt_imshow(\"Rotated by 180 Degrees\", rotated)"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "15kHAH0PO3wv"
      },
      "source": [
        "# rotate our image by 33 degrees counterclockwise, ensuring the\n",
        "# entire rotated image still views in the viewing area\n",
        "rotated = imutils.rotate_bound(image, -33)\n",
        "plt_imshow(\"Rotated Without Cropping\", rotated)"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "iIK0y_52aETm"
      },
      "source": [
        "For a detailed walkthrough of the concepts and code, be sure to refer to the full tutorial, [OpenCV Rotate Image](https://www.pyimagesearch.com/2021/01/20/opencv-rotate-image/) published on 01-20-2021."
      ]
    }
  ]
}