{
  "id": 402740,
  "title": "could we make use of directory 'sfm' to obtain intrinsics",
  "url": "/competitions/image-matching-challenge-2023/discussion/402740",
  "author_name": "",
  "post_date": "2023-04-19T14:35:20.498233600Z",
  "votes": null,
  "comment_count": 6,
  "views": 0,
  "content": "<p>When I tried example code, I found that it generate a approximate camera intrinsic instead of reading an accurate value from somewhere.<br>\nHowever, I found that there is a directory 'sfm' besides directory 'images'. So could we make use of this directory to obtain intrinsics? If not, how and if we could get camera intrinsics?</p>",
  "messages": [
    {
      "id": "2227153",
      "postDate": "04/19/2023 14:35:20",
      "content": "<p>When I tried example code, I found that it generate a approximate camera intrinsic instead of reading an accurate value from somewhere.<br>\nHowever, I found that there is a directory 'sfm' besides directory 'images'. So could we make use of this directory to obtain intrinsics? If not, how and if we could get camera intrinsics?</p>",
      "rawMarkdown": "When I tried example code, I found that it generate a approximate camera intrinsic instead of reading an accurate value from somewhere.\nHowever, I found that there is a directory 'sfm' besides directory 'images'. So could we make use of this directory to obtain intrinsics? If not, how and if we could get camera intrinsics?",
      "votes": null
    },
    {
      "id": "2227176",
      "postDate": "04/19/2023 14:54:50",
      "content": "<p>The directory <code>sfm</code> is available only for the training set. For the test data you have only images. </p>",
      "rawMarkdown": "The directory `sfm` is available only for the training set. For the test data you have only images.",
      "votes": null
    },
    {
      "id": "2227185",
      "postDate": "04/19/2023 15:00:09",
      "content": "<blockquote>\n  <p>The directory <code>sfm</code> is available only for the training set. For the test data you have only images.</p>\n</blockquote>\n<p>So does that means we are not able to get intrinsics?</p>",
      "rawMarkdown": "> The directory `sfm` is available only for the training set. For the test data you have only images.\n\nSo does that means we are not able to get intrinsics?",
      "votes": null
    },
    {
      "id": "2227283",
      "postDate": "04/19/2023 16:16:15",
      "content": "<p>You can compute intrinsics by your own (e.g. by COLMAP SfM bundle adjustment), so you are able to get intrinsics.</p>",
      "rawMarkdown": "You can compute intrinsics by your own (e.g. by COLMAP SfM bundle adjustment), so you are able to get intrinsics.",
      "votes": null
    },
    {
      "id": "2227295",
      "postDate": "04/19/2023 16:21:59",
      "content": "<p>but we can not estimate distort coefficient by colmap BA, so maybe we should regard all the images as perfect image without distortion?</p>",
      "rawMarkdown": "but we can not estimate distort coefficient by colmap BA, so maybe we should regard all the images as perfect image without distortion?",
      "votes": null
    },
    {
      "id": "2227299",
      "postDate": "04/19/2023 16:31:28",
      "content": "<p>Why not? You can set the camera model you like in the SfM…</p>",
      "rawMarkdown": "Why not? You can set the camera model you like in the SfM...",
      "votes": null
    },
    {
      "id": "2227345",
      "postDate": "04/19/2023 17:17:32",
      "content": "<blockquote>\n  <p>Why not? You can set the camera model you like in the SfM…</p>\n</blockquote>\n<p>oh, maybe I have some wrong knowledge about colmap. Thank you for your answering!</p>",
      "rawMarkdown": "> Why not? You can set the camera model you like in the SfM...\n\noh, maybe I have some wrong knowledge about colmap. Thank you for your answering!",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 2227176,
      "author_name": "oldufo",
      "author_url": "",
      "post_date": "04/19/2023 14:54:50",
      "content": "<p>The directory <code>sfm</code> is available only for the training set. For the test data you have only images. </p>",
      "votes": null,
      "replies": [
        {
          "id": 2227185,
          "author_name": "khuang724",
          "author_url": "",
          "post_date": "04/19/2023 15:00:09",
          "content": "<blockquote>\n  <p>The directory <code>sfm</code> is available only for the training set. For the test data you have only images.</p>\n</blockquote>\n<p>So does that means we are not able to get intrinsics?</p>",
          "votes": null,
          "replies": [
            {
              "id": 2227283,
              "author_name": "fabiobellavia",
              "author_url": "",
              "post_date": "04/19/2023 16:16:15",
              "content": "<p>You can compute intrinsics by your own (e.g. by COLMAP SfM bundle adjustment), so you are able to get intrinsics.</p>",
              "votes": null,
              "replies": [
                {
                  "id": 2227295,
                  "author_name": "khuang724",
                  "author_url": "",
                  "post_date": "04/19/2023 16:21:59",
                  "content": "<p>but we can not estimate distort coefficient by colmap BA, so maybe we should regard all the images as perfect image without distortion?</p>",
                  "votes": null,
                  "replies": [
                    {
                      "id": 2227299,
                      "author_name": "fabiobellavia",
                      "author_url": "",
                      "post_date": "04/19/2023 16:31:28",
                      "content": "<p>Why not? You can set the camera model you like in the SfM…</p>",
                      "votes": null,
                      "replies": [
                        {
                          "id": 2227345,
                          "author_name": "khuang724",
                          "author_url": "",
                          "post_date": "04/19/2023 17:17:32",
                          "content": "<blockquote>\n  <p>Why not? You can set the camera model you like in the SfM…</p>\n</blockquote>\n<p>oh, maybe I have some wrong knowledge about colmap. Thank you for your answering!</p>",
                          "votes": null,
                          "replies": []
                        }
                      ]
                    }
                  ]
                }
              ]
            }
          ]
        }
      ]
    }
  ],
  "raw_markdown_by_id": {
    "2227153": "When I tried example code, I found that it generate a approximate camera intrinsic instead of reading an accurate value from somewhere.\nHowever, I found that there is a directory 'sfm' besides directory 'images'. So could we make use of this directory to obtain intrinsics? If not, how and if we could get camera intrinsics?",
    "2227176": "The directory `sfm` is available only for the training set. For the test data you have only images.",
    "2227185": "> The directory `sfm` is available only for the training set. For the test data you have only images.\n\nSo does that means we are not able to get intrinsics?",
    "2227283": "You can compute intrinsics by your own (e.g. by COLMAP SfM bundle adjustment), so you are able to get intrinsics.",
    "2227295": "but we can not estimate distort coefficient by colmap BA, so maybe we should regard all the images as perfect image without distortion?",
    "2227299": "Why not? You can set the camera model you like in the SfM...",
    "2227345": "> Why not? You can set the camera model you like in the SfM...\n\noh, maybe I have some wrong knowledge about colmap. Thank you for your answering!"
  },
  "source": "meta"
}