{
  "id": 48028,
  "title": "Question about bicubic resizing manipulation",
  "url": "/competitions/sp-society-camera-model-identification/discussion/48028",
  "author_name": "Andrés Miguel Torrubia Sáez",
  "post_date": "2018-01-22T15:02:18.524000",
  "votes": 4,
  "comment_count": 0,
  "views": 0,
  "content": "<p>Hi,</p>\n\n<p>I understand one of the manipulations is to resize the image and apply a bicubic interpolation. I understand you take the center crop of the original image and apply the bicubic interpolation so that resulting image size is 512x512.</p>\n\n<p>One of the bicubic interpolation is 0.5x, this means that to get a 512x512 you'd need to have at a minimum 1024x1024 sized image. </p>\n\n<p>There's at least one image which is smaller than 1024x1024 so this manipulation would not be applicable:</p>\n\n<p><code>$ identify train/Motorola-Nexus-6/\\(MotoNex6\\)8.jpg\ntrain/Motorola-Nexus-6/(MotoNex6)8.jpg JPEG 1040x780 1040x780+0+0 8-bit sRGB 230KB 0.000u 0:00.000</code></p>\n\n<p>that image is only 1040x780 so if you scale it 0.5x you end up with 520x390 (less than 512x512).</p>\n\n<p>@inversion can you throw some light on how the bicubic scaling have been applied to the test images? </p>",
  "messages": [
    {
      "id": 272219,
      "postDate": "2018-01-22T15:02:18.523Z",
      "content": "<p>Hi,</p>\n\n<p>I understand one of the manipulations is to resize the image and apply a bicubic interpolation. I understand you take the center crop of the original image and apply the bicubic interpolation so that resulting image size is 512x512.</p>\n\n<p>One of the bicubic interpolation is 0.5x, this means that to get a 512x512 you'd need to have at a minimum 1024x1024 sized image. </p>\n\n<p>There's at least one image which is smaller than 1024x1024 so this manipulation would not be applicable:</p>\n\n<p><code>$ identify train/Motorola-Nexus-6/\\(MotoNex6\\)8.jpg\ntrain/Motorola-Nexus-6/(MotoNex6)8.jpg JPEG 1040x780 1040x780+0+0 8-bit sRGB 230KB 0.000u 0:00.000</code></p>\n\n<p>that image is only 1040x780 so if you scale it 0.5x you end up with 520x390 (less than 512x512).</p>\n\n<p>@inversion can you throw some light on how the bicubic scaling have been applied to the test images? </p>",
      "rawMarkdown": "Hi,\n\nI understand one of the manipulations is to resize the image and apply a bicubic interpolation. I understand you take the center crop of the original image and apply the bicubic interpolation so that resulting image size is 512x512.\n\nOne of the bicubic interpolation is 0.5x, this means that to get a 512x512 you'd need to have at a minimum 1024x1024 sized image. \n\nThere's at least one image which is smaller than 1024x1024 so this manipulation would not be applicable:\n\n`$ identify train/Motorola-Nexus-6/\\(MotoNex6\\)8.jpg\ntrain/Motorola-Nexus-6/(MotoNex6)8.jpg JPEG 1040x780 1040x780+0+0 8-bit sRGB 230KB 0.000u 0:00.000`\n\nthat image is only 1040x780 so if you scale it 0.5x you end up with 520x390 (less than 512x512).\n\n@inversion can you throw some light on how the bicubic scaling have been applied to the test images? \n",
      "votes": 4
    }
  ],
  "comments": [],
  "raw_markdown_by_id": {
    "272219": "Hi,\n\nI understand one of the manipulations is to resize the image and apply a bicubic interpolation. I understand you take the center crop of the original image and apply the bicubic interpolation so that resulting image size is 512x512.\n\nOne of the bicubic interpolation is 0.5x, this means that to get a 512x512 you'd need to have at a minimum 1024x1024 sized image. \n\nThere's at least one image which is smaller than 1024x1024 so this manipulation would not be applicable:\n\n`$ identify train/Motorola-Nexus-6/\\(MotoNex6\\)8.jpg\ntrain/Motorola-Nexus-6/(MotoNex6)8.jpg JPEG 1040x780 1040x780+0+0 8-bit sRGB 230KB 0.000u 0:00.000`\n\nthat image is only 1040x780 so if you scale it 0.5x you end up with 520x390 (less than 512x512).\n\n@inversion can you throw some light on how the bicubic scaling have been applied to the test images? \n"
  }
}