{
  "id": 13033,
  "title": "Inverted Image Orientation",
  "url": "/competitions/diabetic-retinopathy-detection/discussion/13033",
  "author_name": "",
  "post_date": "2015-03-24T19:43:14.967Z",
  "votes": null,
  "comment_count": 4,
  "views": 2934,
  "content": "<p>Can anyone clarify the difference between an inverted image and non-inverted image? Are they mirror images of each other horizontally, eg the top of the image becomes the bottom?</p>",
  "messages": [
    {
      "id": "68062",
      "postDate": "03/24/2015 19:43:14",
      "content": "<p>Can anyone clarify the difference between an inverted image and non-inverted image? Are they mirror images of each other horizontally, eg the top of the image becomes the bottom?</p>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "68068",
      "postDate": "03/24/2015 19:58:09",
      "content": "<p>If I understood it well, an inverted image is flipped horizontally. For example on non-inverted images you will find the optic disk on the left side on images named &quot;xx_left&quot;. On inverted images, where there is no small mark present on the upper-right direction, this is the opposite. Have a look at&nbsp;13_left, which is a normal image with the optic disk on the left, while 16_left is an inverted one having the optic disk on the right side and also no small mark is present.</p>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "69101",
      "postDate": "03/30/2015 22:56:49",
      "content": "<p>Inverted images are <strong>not flipped horizontally</strong>, you must<strong> rotate the image by 180 degrees</strong> to change from one orientation to the other.</p>\n<p>From the data tab description:</p>\n<p><em>Some images are shown as one would see the retina anatomically (macula on the left, optic nerve on the right for the right eye). Others are shown as one would see through a microscope condensing lens (i.e. inverted, as one sees in a typical live eye exam). There are generally two ways to tell if an image is inverted:</em></p>\n<ul>\n<li><em>It is inverted if the macula (the small dark central area) is slightly higher than the midline through the optic nerve. If the macula is lower than the midline of the optic nerve, it's not inverted.</em></li>\n<li><em>If there is a notch on the side of the image (square, triangle, or circle) then it's not inverted. If there is no notch, it's inverted.</em></li>\n</ul>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "69124",
      "postDate": "03/31/2015 05:36:43",
      "content": "<p>Thanks for the correction Alastair. The horizontal flip was the only thing I had in mind as it changes the location of the macula and the optic disk. :)</p>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "80063",
      "postDate": "05/26/2015 18:49:17",
      "content": "<p>Inverted means both a horizontal and vertical flip, this is what happens with convex lenses (real inverted image):</p>\n<p><img src=\"http://www.olympusmicro.com/primer/images/magnification/convexlens3.jpg\" alt=\"convex lens\" width=\"342\" height=\"147\"></p>\n\n<p>For more info:&nbsp;<a href=\"http://en.wikipedia.org/wiki/Ophthalmoscopy\">http://en.wikipedia.org/wiki/Ophthalmoscopy</a></p>",
      "rawMarkdown": "",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 68068,
      "author_name": "zoltanfegyver",
      "author_url": "",
      "post_date": "03/24/2015 19:58:09",
      "content": "<p>If I understood it well, an inverted image is flipped horizontally. For example on non-inverted images you will find the optic disk on the left side on images named &quot;xx_left&quot;. On inverted images, where there is no small mark present on the upper-right direction, this is the opposite. Have a look at&nbsp;13_left, which is a normal image with the optic disk on the left, while 16_left is an inverted one having the optic disk on the right side and also no small mark is present.</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 69101,
      "author_name": "alastairk",
      "author_url": "",
      "post_date": "03/30/2015 22:56:49",
      "content": "<p>Inverted images are <strong>not flipped horizontally</strong>, you must<strong> rotate the image by 180 degrees</strong> to change from one orientation to the other.</p>\n<p>From the data tab description:</p>\n<p><em>Some images are shown as one would see the retina anatomically (macula on the left, optic nerve on the right for the right eye). Others are shown as one would see through a microscope condensing lens (i.e. inverted, as one sees in a typical live eye exam). There are generally two ways to tell if an image is inverted:</em></p>\n<ul>\n<li><em>It is inverted if the macula (the small dark central area) is slightly higher than the midline through the optic nerve. If the macula is lower than the midline of the optic nerve, it's not inverted.</em></li>\n<li><em>If there is a notch on the side of the image (square, triangle, or circle) then it's not inverted. If there is no notch, it's inverted.</em></li>\n</ul>",
      "votes": null,
      "replies": []
    },
    {
      "id": 69124,
      "author_name": "zoltanfegyver",
      "author_url": "",
      "post_date": "03/31/2015 05:36:43",
      "content": "<p>Thanks for the correction Alastair. The horizontal flip was the only thing I had in mind as it changes the location of the macula and the optic disk. :)</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 80063,
      "author_name": "ilyakava",
      "author_url": "",
      "post_date": "05/26/2015 18:49:17",
      "content": "<p>Inverted means both a horizontal and vertical flip, this is what happens with convex lenses (real inverted image):</p>\n<p><img src=\"http://www.olympusmicro.com/primer/images/magnification/convexlens3.jpg\" alt=\"convex lens\" width=\"342\" height=\"147\"></p>\n\n<p>For more info:&nbsp;<a href=\"http://en.wikipedia.org/wiki/Ophthalmoscopy\">http://en.wikipedia.org/wiki/Ophthalmoscopy</a></p>",
      "votes": null,
      "replies": []
    }
  ],
  "raw_markdown_by_id": {
    "68062": "",
    "68068": "",
    "69101": "",
    "69124": "",
    "80063": ""
  },
  "source": "meta"
}