[Insight-users] Otsu Threshold

Fri, 27 Feb 2004 03:17:32 -0800

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Hi Luis,
I am using Otsu threshold for segmenting tissue from from the background. It
appears to work very well in most cases, however some
Cases it fails for unknown reasons.
In these cases, I have looked at the histogram, and I can clearly see two
well distinguished peaks for background and tissue, however, it appears to
give me a threshold that is past the 2nd peak (tissue peak) instead of
between the two peaks. Could you explain why this might be happening. I
tried to play with the number of bins for this case but everytime it
bypassed the actual threshold and gave back something past the tissue peak.
Thanks
Radhika

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<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Hi Luis,<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>I am using </span></font><st1:City><st1:place><span
  class=3DSpellE><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
  =
font-family:Arial'>Otsu</span></font></span></st1:place></st1:City><font=

size=3D2 face=3DArial> threshold
for segmenting tissue from from the =
background. It
appears to work very well in most cases, however =
some<o:p></o:p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Cases it fails for unknown =
reasons.<o:p></o:p></span></font></p>

In these cases, I have looked at the histogram, and =
I can
clearly see two well distinguished peaks for background and tissue, =
however, it
appears to give me a threshold that is past the 2nd peak =
(tissue
peak) instead of between the two peaks. Could you explain why this =
might be happening. I tried to play with the number of bins =
for this
case but everytime it bypassed the actual =
threshold
and gave back something past the tissue =
peak.<o:p></o:p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Thanks<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Radhika<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'><o:p>&nbsp;</o:p></span></font></p>

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<P><FONT SIZE=3D2 FACE=3D"Arial">                                       =
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Confidentiality Notice.

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privileged information. Any unauthorized review, use, disclosure or =
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please contact the sender by reply email and destroy all copies of the =
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