{
  "id": 12415,
  "title": "Possible error in the Tutorial?",
  "url": "/competitions/datasciencebowl/discussion/12415",
  "author_name": "Abecedarian",
  "post_date": "2015-02-05T06:43:35.913000",
  "votes": 0,
  "comment_count": 0,
  "views": 809,
  "content": "<p>Hello,</p>\n<p>First, I'd like to thank Aaron Sander for posting such a helpful tutorial.</p>\n<p>In [6] of http://www.kaggle.com/c/datasciencebowl/details/tutorial, I'm wondering whether the expression&nbsp;</p>\n<p>imagethres[labelmap == regionprop.label])*1.0/regionprop.area</p>\n<p>is always 1.</p>\n<p>The comment above it reads</p>\n<p># check to see if the region is at least 50% nonzero.</p>\n<p>This makes good intuitive sense. &nbsp;We want to make make sure that the connected component in the dilated image&nbsp;is not too much larger than the corresponding component in the thresholded non-dilated image. &nbsp;This prevents us from using a bad component for our aspect ratio.</p>\n<p>The problem, though, is that regionprop.area is the area of the <strong>un</strong>dilated connected component. &nbsp;This is because we have <strong>already&nbsp;</strong>un-dilated the regionprop.area by multiplying the label_list matrix by imagethr:</p>\n<p>label_list = imagethr*label_list</p>\n<p>I hope that this makes sense. &nbsp;Thanks for any help that anyone can provide.</p>",
  "messages": [
    {
      "id": 63631,
      "postDate": "2015-02-05T06:43:35.913Z",
      "content": "<p>Hello,</p>\n<p>First, I'd like to thank Aaron Sander for posting such a helpful tutorial.</p>\n<p>In [6] of http://www.kaggle.com/c/datasciencebowl/details/tutorial, I'm wondering whether the expression&nbsp;</p>\n<p>imagethres[labelmap == regionprop.label])*1.0/regionprop.area</p>\n<p>is always 1.</p>\n<p>The comment above it reads</p>\n<p># check to see if the region is at least 50% nonzero.</p>\n<p>This makes good intuitive sense. &nbsp;We want to make make sure that the connected component in the dilated image&nbsp;is not too much larger than the corresponding component in the thresholded non-dilated image. &nbsp;This prevents us from using a bad component for our aspect ratio.</p>\n<p>The problem, though, is that regionprop.area is the area of the <strong>un</strong>dilated connected component. &nbsp;This is because we have <strong>already&nbsp;</strong>un-dilated the regionprop.area by multiplying the label_list matrix by imagethr:</p>\n<p>label_list = imagethr*label_list</p>\n<p>I hope that this makes sense. &nbsp;Thanks for any help that anyone can provide.</p>"
    }
  ],
  "comments": [],
  "raw_markdown_by_id": {
    "63631": ""
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}