{
  "id": 37108,
  "title": "Are Image Coordinates Zero-Indexed or One-Indexed?",
  "url": "/competitions/carvana-image-masking-challenge/discussion/37108",
  "author_name": "",
  "post_date": "2017-07-27T05:54:31.359746100Z",
  "votes": 3,
  "comment_count": 2,
  "views": 0,
  "content": "<p>Reading the evaluation rules, it's not 100% clear.  I feel like its implying that 'pixel 1' is the first pixel rather than pixel 0, but I just wanted to be sure since it never actually explicitly states that pixel 1 is the first pixel.</p>\n\n<p>Thanks</p>",
  "messages": [
    {
      "id": "207666",
      "postDate": "07/27/2017 05:54:31",
      "content": "<p>Reading the evaluation rules, it's not 100% clear.  I feel like its implying that 'pixel 1' is the first pixel rather than pixel 0, but I just wanted to be sure since it never actually explicitly states that pixel 1 is the first pixel.</p>\n\n<p>Thanks</p>",
      "rawMarkdown": "Reading the evaluation rules, it's not 100% clear.  I feel like its implying that 'pixel 1' is the first pixel rather than pixel 0, but I just wanted to be sure since it never actually explicitly states that pixel 1 is the first pixel.\n\nThanks",
      "votes": null
    },
    {
      "id": "207774",
      "postDate": "07/27/2017 12:10:22",
      "content": "<p>It doesn't explicitly state either, but I believe they are zero-indexed (edit: nope they're one-indexed). @wcukierski will need to confirm.</p>\n\n<p>&gt; E.g. '1 3' implies starting at pixel 1 and running a total of 3 pixels (1,2,3).</p>\n\n<p>(edit: one-indexed, '1 3' would be [1, 1, 1, 0, ..] and [0, 1, 1, 1, 0, ..] would be '2 3') I would look at this as talking about how to encode a set of output pixels [0, 1, 1, 1, 0, ...] but the example could just as easily have used '0 3' to represent [1, 1, 1, 0, ...]</p>\n\n<p>As an exercise to try out generating a submission, you could use the <code>train_masks/*.gif</code> files as the input instead of the test JPGs, output a submission based on matching white pixels in the masks, and then compare that to <code>train_masks.csv</code> (changing <code>{ID}_{ANGLE}_mask.gif</code> to <code>{ID}_{ANGLE}.jpg</code> of course)</p>",
      "rawMarkdown": "It doesn't explicitly state either, but I believe they are zero-indexed (edit: nope they're one-indexed). @wcukierski will need to confirm.\n\n&gt; E.g. '1 3' implies starting at pixel 1 and running a total of 3 pixels (1,2,3).\n\n(edit: one-indexed, '1 3' would be [1, 1, 1, 0, ..] and [0, 1, 1, 1, 0, ..] would be '2 3') I would look at this as talking about how to encode a set of output pixels [0, 1, 1, 1, 0, ...] but the example could just as easily have used '0 3' to represent [1, 1, 1, 0, ...]\n\nAs an exercise to try out generating a submission, you could use the `train_masks/*.gif` files as the input instead of the test JPGs, output a submission based on matching white pixels in the masks, and then compare that to `train_masks.csv` (changing `{ID}_{ANGLE}_mask.gif` to `{ID}_{ANGLE}.jpg` of course)",
      "votes": null
    },
    {
      "id": "207840",
      "postDate": "07/27/2017 16:27:01",
      "content": "<p>They are one-indexed</p>",
      "rawMarkdown": "They are one-indexed",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 207774,
      "author_name": "brianshaler",
      "author_url": "",
      "post_date": "07/27/2017 12:10:22",
      "content": "<p>It doesn't explicitly state either, but I believe they are zero-indexed (edit: nope they're one-indexed). @wcukierski will need to confirm.</p>\n\n<p>&gt; E.g. '1 3' implies starting at pixel 1 and running a total of 3 pixels (1,2,3).</p>\n\n<p>(edit: one-indexed, '1 3' would be [1, 1, 1, 0, ..] and [0, 1, 1, 1, 0, ..] would be '2 3') I would look at this as talking about how to encode a set of output pixels [0, 1, 1, 1, 0, ...] but the example could just as easily have used '0 3' to represent [1, 1, 1, 0, ...]</p>\n\n<p>As an exercise to try out generating a submission, you could use the <code>train_masks/*.gif</code> files as the input instead of the test JPGs, output a submission based on matching white pixels in the masks, and then compare that to <code>train_masks.csv</code> (changing <code>{ID}_{ANGLE}_mask.gif</code> to <code>{ID}_{ANGLE}.jpg</code> of course)</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 207840,
      "author_name": "wcukierski",
      "author_url": "",
      "post_date": "07/27/2017 16:27:01",
      "content": "<p>They are one-indexed</p>",
      "votes": null,
      "replies": []
    }
  ],
  "raw_markdown_by_id": {
    "207666": "Reading the evaluation rules, it's not 100% clear.  I feel like its implying that 'pixel 1' is the first pixel rather than pixel 0, but I just wanted to be sure since it never actually explicitly states that pixel 1 is the first pixel.\n\nThanks",
    "207774": "It doesn't explicitly state either, but I believe they are zero-indexed (edit: nope they're one-indexed). @wcukierski will need to confirm.\n\n&gt; E.g. '1 3' implies starting at pixel 1 and running a total of 3 pixels (1,2,3).\n\n(edit: one-indexed, '1 3' would be [1, 1, 1, 0, ..] and [0, 1, 1, 1, 0, ..] would be '2 3') I would look at this as talking about how to encode a set of output pixels [0, 1, 1, 1, 0, ...] but the example could just as easily have used '0 3' to represent [1, 1, 1, 0, ...]\n\nAs an exercise to try out generating a submission, you could use the `train_masks/*.gif` files as the input instead of the test JPGs, output a submission based on matching white pixels in the masks, and then compare that to `train_masks.csv` (changing `{ID}_{ANGLE}_mask.gif` to `{ID}_{ANGLE}.jpg` of course)",
    "207840": "They are one-indexed"
  },
  "source": "meta"
}