[Insight-users] Question about edge extraction

Tue May 4 08:22:30 EDT 2004

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Dear ITK users,
I want to extract the edge picture from one image. And I use 
itk::GradientMagnitudeImageFilter
It works fine. However the output is float type. I want to get binary
output image. If I use 
itk::BinaryThresholdImageFilter
to filter the output to binary, and simply set
SetUpperThreshold(),SetLowerThreshold() to some defined value, the
binary edge is not good, 
either with too much noise or the edge is not complete. 
Could some one tell me how can I get good binary edge extraction result?

Thanks a lot!

Chunyan Jiang

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<p class=3DMsoNormal><font size=3D1 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-ansi-language:EN-GB=
'>Dear
ITK users,<o:p></o:p></span></font></p>

I
want to extract the edge picture from one image. And I use =
<o:p></o:p>

<p class=3DMsoNormal><span class=3DSpellE><font size=3D1 =
face=3DArial><span lang=3DEN-GB
style=3D'font-size:9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-=
ansi-language:
EN-GB'>itk::GradientMagnitudeImageFilter</span></font></span><font =
size=3D1
face=3DArial><span lang=3DEN-GB =
style=3D'font-size:9.0pt;mso-bidi-font-size:10.0pt;
font-family:Arial;mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>

It
works fine. However the output is float type. I want to get binary =
output
image. If I use <o:p></o:p>

<p class=3DMsoNormal><span class=3DSpellE><font size=3D1 =
face=3DArial><span lang=3DEN-GB
style=3D'font-size:9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-=
ansi-language:
EN-GB'>itk::BinaryThresholdImageFilter</span></font></span><font =
size=3D1
face=3DArial><span lang=3DEN-GB =
style=3D'font-size:9.0pt;mso-bidi-font-size:10.0pt;
font-family:Arial;mso-ansi-language:EN-GB'><o:p></o:p></span></font></p>

<p class=3DMsoNormal><span class=3DGramE><font size=3D1 =
face=3DArial><span lang=3DEN-GB
style=3D'font-size:9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-=
ansi-language:
EN-GB'>to</span></font></span><font size=3D1 face=3DArial><span =
lang=3DEN-GB
style=3D'font-size:9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-=
ansi-language:
EN-GB'> filter the output to binary, and simply set <span =
class=3DSpellE>SetUpperThreshold</span>(),<span
class=3DSpellE>SetLowerThreshold</span>() to some defined value, the =
binary edge
is not good, <o:p></o:p></span></font></p>

either with too much noise or the edge is not complete. =
<o:p></o:p>

<p class=3DMsoNormal><font size=3D1 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-ansi-language:EN-GB=
'>Could
some one tell me how can I get good binary edge extraction =
result?<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D1 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-ansi-language:EN-GB=
'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoNormal><font size=3D1 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-ansi-language:EN-GB=
'>Thanks
a lot!<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D1 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-ansi-language:EN-GB=
'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoNormal><font size=3D1 face=3DArial><span lang=3DEN-GB =
style=3D'font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-ansi-language:EN-GB=
'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoNormal><span class=3DSpellE><font size=3D1 =
face=3DArial><span lang=3DEN-GB
style=3D'font-size:9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-=
ansi-language:
EN-GB'>Chunyan</span></font></span><font size=3D1 face=3DArial><span =
lang=3DEN-GB
style=3D'font-size:9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial;mso-=
ansi-language:
EN-GB'> <span class=3DSpellE>Jiang</span><o:p></o:p></span></font></p>

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