<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>Hi All,</span></div><div><br></div><div> Any guesses as to how I can address this 'fat edge' issue. Or does anybody have an idea how Matlab manages to get the thin lines ?</div><div><br></div><div>Thank you,</div><div>Emma<br><span></span></div><div><span> <br></span></div><div><br></div> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div dir="ltr"> <font face="Arial" size="2"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Sergio Vera <sergio.vera@alma3d.com><br> <b><span style="font-weight: bold;">To:</span></b> Emma Ryan <eryanvtk@yahoo.com> <br><b><span style="font-weight: bold;">Cc:</span></b> "insight-users@itk.org"
<insight-users@itk.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Wednesday, March 14, 2012 1:22 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [Insight-users] Sobel operator gives fat edges<br> </font> </div> <br>
<div id="yiv1204205330">Have you tried CannyEdge Detection Filter? Canny always returns the thinnest edges.<div><br></div><div>Hope to help Regards<br><br><div class="yiv1204205330gmail_quote">On Wed, Mar 14, 2012 at 2:59 AM, Emma Ryan <span dir="ltr"><<a rel="nofollow" ymailto="mailto:eryanvtk@yahoo.com" target="_blank" href="mailto:eryanvtk@yahoo.com">eryanvtk@yahoo.com</a>></span> wrote:<br>
<blockquote class="yiv1204205330gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div><div style="font-size:12pt;font-family:times new roman, new york, times, serif;"><br> <div style="font-family:times new roman, new york, times, serif;font-size:12pt;">
Hi ,<br><br> I am using the sobelOperator provided in itk. The following is my code snippet. I would like to understand<br><br>1. the default setting of the sobel and <br>2. how I can tune it. There dont seem to be too many member functions to manipulate the sobel.<br>
3. If I need to use Erosion filter to thin the edges, how do I design a 'line' structuring element. My code ( also added below) does not seem to allow line (which I am guessing derives from Box, line = 1-D Box)<br>
<br>Any help/suggestions is truly appreciated.<br><br>Thank you,<br>Emma<br><br><br>typedef itk::ConstNeighborhoodIterator<ImageType> NeighborhoodIteratorType;<br> typedef itk::ImageRegionIterator<
ImageType> IteratorType;<br><br> itk::SobelOperator<PixelType, 2> sobel;<br> sobel.SetDirection(1); <br> itk::Size<2> radius_s;<br> radius_s.Fill(1);<br> sobel.CreateToRadius(radius_s);<br>
<br> <br> NeighborhoodIteratorType::RadiusType radius = sobel.GetRadius();<br> NeighborhoodIteratorType it( radius, my_image, my_image->GetRequestedRegion() );<br> itk::NeighborhoodInnerProduct<ImageType> inner_product;<br>
<br> ImageType::Pointer output = ImageType::New();<br> output->SetRegions(my_image->GetRequestedRegion());<br> output->Allocate();<br> <br> IteratorType out(output, my_image->GetRequestedRegion());<br>
<br> for (it.GoToBegin(), out.GoToBegin(); !it.IsAtEnd(); ++it, ++out)<br> {<br> out.Set( inner_product( it, sobel ) );<br> }<br><br> output->Update();<br> <br><br>//Erosion Structuring Element: The following fails to compile if I use '1' instead of '2'<br>
typedef itk::FlatStructuringElement<2> StructuringElementType;<br> StructuringElementType::RadiusType element_radius;<br> element_radius.Fill(5);<br> <br> StructuringElementType strel = StructuringElementType::Box(element_radius);<br>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>Sergio Vera<br><br> Alma IT Systems<br> C/ Vilana, 4B, 4º 1ª<br> 08022 Barcelona<br> T. (+34) 932 380 592<br> <a rel="nofollow" target="_blank" href="http://www.alma3d.com">www.alma3d.com</a><br>
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