[Insight-users] Question about itkThresholdImageFilter
Parag Chandra
pchandra at radonc . unc . edu
Wed, 30 Jul 2003 14:57:03 -0400
This is a multi-part message in MIME format.
------=_NextPart_000_0013_01C356AA.D774A200
Content-Type: text/plain;
charset="US-ASCII"
Content-Transfer-Encoding: quoted-printable
Hi,
=20
I think I see a discrepancy between the documentation of this filter and =
its
actual behavior. The header file states for ::ThresholdAbove(), pixels =
>=3D
the threshold are set to the OutsideValue, and for ::ThresholdBelow, =
pixels
<=3D the threshold are set to OutsideValue. But when I examine the code, =
it
seems to me that this block:
=20
if (m_Lower <=3D value && value <=3D m_Upper)
{
// pixel passes to output unchanged and is replaced by =
m_OutsideValue
in
// the inverse output image
outIt.Set( inIt.Get() );
}
else
{
outIt.Set( m_OutsideValue );
}
=20
implies that the inequalities should be strictly < or >, not <=3D or =
>=3D. Am I
not interpreting it correctly?
=20
Thanks,
-Parag Chandra
=20
------=_NextPart_000_0013_01C356AA.D774A200
Content-Type: text/html;
charset="US-ASCII"
Content-Transfer-Encoding: quoted-printable
<html>
<head>
<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
charset=3Dus-ascii">
<meta name=3DGenerator content=3D"Microsoft Word 10 (filtered)">
<style>
<!--
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:purple;
text-decoration:underline;}
span.EmailStyle17
{font-family:Arial;
color:windowtext;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;}
div.Section1
{page:Section1;}
-->
</style>
</head>
<body lang=3DEN-US link=3Dblue vlink=3Dpurple>
<div class=3DSection1>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Hi,</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>I think I see a discrepancy between the documentation =
of
this filter and its actual behavior. The header file states for =
::ThresholdAbove(),
pixels >=3D the threshold are set to the OutsideValue, and for
::ThresholdBelow, pixels <=3D the threshold are set to OutsideValue. =
But when
I examine the code, it seems to me that this block:</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> if (m_Lower <=3D value =
&& value
<=3D m_Upper)</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> {</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> // pixel passes to =
output
unchanged and is replaced by m_OutsideValue in</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> // the inverse output =
image</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> outIt.Set( inIt.Get() =
);</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> }</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> else</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> {</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> outIt.Set( =
m_OutsideValue );</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> }</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>implies that the inequalities should be strictly < =
or
>, not <=3D or >=3D. Am I not interpreting it =
correctly?</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Thanks,</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>-</span></font><font size=3D2 face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial'>Parag =
Chandra</span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'> </span></font></p>
</div>
</body>
</html>
------=_NextPart_000_0013_01C356AA.D774A200--