{
  "id": 46687,
  "title": "About dealing with the big gap between validation set and test set",
  "url": "/competitions/sp-society-camera-model-identification/discussion/46687",
  "author_name": "",
  "post_date": "2018-01-01T17:14:02.417580300Z",
  "votes": 3,
  "comment_count": 5,
  "views": 0,
  "content": "<p>Many competitors encounter the problem that the model performs perfectly on the training and validation set, however, there's a huge gap between the validation set acc and the submission score. Could everyone say something about this?</p>",
  "messages": [
    {
      "id": "263930",
      "postDate": "01/01/2018 17:14:02",
      "content": "<p>Many competitors encounter the problem that the model performs perfectly on the training and validation set, however, there's a huge gap between the validation set acc and the submission score. Could everyone say something about this?</p>",
      "rawMarkdown": "Many competitors encounter the problem that the model performs perfectly on the training and validation set, however, there's a huge gap between the validation set acc and the submission score. Could everyone say something about this?",
      "votes": null
    },
    {
      "id": "263935",
      "postDate": "01/01/2018 17:34:34",
      "content": "<p>It's because the test set has a set number of images that have been transformed (scaled, compressed and gamma filters).</p>",
      "rawMarkdown": "It's because the test set has a set number of images that have been transformed (scaled, compressed and gamma filters).",
      "votes": null
    },
    {
      "id": "263936",
      "postDate": "01/01/2018 17:44:51",
      "content": "<p>I'm having the same problem. I've tried adding scale, compress and gamma aug - however it didn't help a lot.</p>",
      "rawMarkdown": "I'm having the same problem. I've tried adding scale, compress and gamma aug - however it didn't help a lot.",
      "votes": null
    },
    {
      "id": "263937",
      "postDate": "01/01/2018 17:45:21",
      "content": "<p>Yes, I know that. I have transformed the original training data, labeled them and use them to train the model. The gap described above is based on this situation.</p>",
      "rawMarkdown": "Yes, I know that. I have transformed the original training data, labeled them and use them to train the model. The gap described above is based on this situation.",
      "votes": null
    },
    {
      "id": "263947",
      "postDate": "01/01/2018 18:56:28",
      "content": "<p>Two possible reasons: (1) the image manipulations (compress, resize, gamma) which are still not completely clear (e.g. they could be <em>alternative</em> or <em>cumulative</em>) and (2) the fact that test images come from a second device (same model, but devices may be in different conditions, e.g. one has a scratch and the other doesn't).</p>",
      "rawMarkdown": "Two possible reasons: (1) the image manipulations (compress, resize, gamma) which are still not completely clear (e.g. they could be *alternative* or *cumulative*) and (2) the fact that test images come from a second device (same model, but devices may be in different conditions, e.g. one has a scratch and the other doesn't).",
      "votes": null
    },
    {
      "id": "271501",
      "postDate": "01/20/2018 15:49:05",
      "content": "<p>Some models have a lot of images of a specific type of object/lighting (eg. iPhone-4s) so models can learn those patterns in addition to pixel patterns, be careful...</p>",
      "rawMarkdown": "Some models have a lot of images of a specific type of object/lighting (eg. iPhone-4s) so models can learn those patterns in addition to pixel patterns, be careful...",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 263935,
      "author_name": "craigglastonbury",
      "author_url": "",
      "post_date": "01/01/2018 17:34:34",
      "content": "<p>It's because the test set has a set number of images that have been transformed (scaled, compressed and gamma filters).</p>",
      "votes": null,
      "replies": [
        {
          "id": 263937,
          "author_name": "yanxiangyi",
          "author_url": "",
          "post_date": "01/01/2018 17:45:21",
          "content": "<p>Yes, I know that. I have transformed the original training data, labeled them and use them to train the model. The gap described above is based on this situation.</p>",
          "votes": null,
          "replies": []
        }
      ]
    },
    {
      "id": 263936,
      "author_name": "heyt0ny",
      "author_url": "",
      "post_date": "01/01/2018 17:44:51",
      "content": "<p>I'm having the same problem. I've tried adding scale, compress and gamma aug - however it didn't help a lot.</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 263947,
      "author_name": "diogoff",
      "author_url": "",
      "post_date": "01/01/2018 18:56:28",
      "content": "<p>Two possible reasons: (1) the image manipulations (compress, resize, gamma) which are still not completely clear (e.g. they could be <em>alternative</em> or <em>cumulative</em>) and (2) the fact that test images come from a second device (same model, but devices may be in different conditions, e.g. one has a scratch and the other doesn't).</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 271501,
      "author_name": "rhgrossm",
      "author_url": "",
      "post_date": "01/20/2018 15:49:05",
      "content": "<p>Some models have a lot of images of a specific type of object/lighting (eg. iPhone-4s) so models can learn those patterns in addition to pixel patterns, be careful...</p>",
      "votes": null,
      "replies": []
    }
  ],
  "raw_markdown_by_id": {
    "263930": "Many competitors encounter the problem that the model performs perfectly on the training and validation set, however, there's a huge gap between the validation set acc and the submission score. Could everyone say something about this?",
    "263935": "It's because the test set has a set number of images that have been transformed (scaled, compressed and gamma filters).",
    "263936": "I'm having the same problem. I've tried adding scale, compress and gamma aug - however it didn't help a lot.",
    "263937": "Yes, I know that. I have transformed the original training data, labeled them and use them to train the model. The gap described above is based on this situation.",
    "263947": "Two possible reasons: (1) the image manipulations (compress, resize, gamma) which are still not completely clear (e.g. they could be *alternative* or *cumulative*) and (2) the fact that test images come from a second device (same model, but devices may be in different conditions, e.g. one has a scratch and the other doesn't).",
    "271501": "Some models have a lot of images of a specific type of object/lighting (eg. iPhone-4s) so models can learn those patterns in addition to pixel patterns, be careful..."
  },
  "source": "meta"
}