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<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>Hi, all,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>By some filters of <span
class=SpellE>itk</span>, I get one closed contour as one image. This image is
one binary image that<o:p></o:p></span></font></p>
<p class=MsoNormal><span class=GramE><font size=1 face=Arial><span lang=EN-GB
style='font-size:9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>the</span></font></span><font
size=1 face=Arial><span lang=EN-GB style='font-size:9.0pt;mso-bidi-font-size:
10.0pt;font-family:Arial'> pixel value is 100 when is pixel is in the contour,
otherwise it is 0.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>Now I want to convert this
contour to <span class=SpellE>ChainCode</span>. My <span class=SpellE>pseudocode</span>
is as follow:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><span
style='mso-spacerun:yes'> </span>Search the image from the first pixel to
find the first point in the contour;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><span
style='mso-spacerun:yes'> </span>Add this point to <span class=SpellE>ChainCode</span>
list, and set its value to 0;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><span
style='mso-spacerun:yes'> </span>Search the immediate <span class=SpellE>neighbors</span>
of <span class=SpellE>of</span> this point to check if it is on contour;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><span style='mso-tab-count:
1'> </span>If this point’s
value==100;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><span style='mso-tab-count:
1'> </span>{<span
style='mso-tab-count:1'> </span>Add
it to <span class=SpellE>ChainCode</span>, and set its value to 0;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><span style='mso-tab-count:
2'> </span>Loop
searching<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><span style='mso-tab-count:
1'> </span>}<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><span style='mso-tab-count:
1'> </span><span class=GramE>else</span><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><span style='mso-tab-count:
2'> </span>Stop
searching;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><span style='mso-tab-count:
2'> </span>Finish
the <span class=SpellE>ChainCode</span>;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=DE style='font-size:9.0pt;
mso-bidi-font-size:10.0pt;font-family:Arial;mso-ansi-language:DE'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>// <span class=GramE>The</span>
order of checking <span class=SpellE>neighbors</span>. Assume the current <span
class=GramE>points is</span> at “0”.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>//<span
style='mso-spacerun:yes'> </span>------------------------<span
style='mso-tab-count:1'> </span><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>//<span
style='mso-spacerun:yes'> </span><span class=GramE>| <span
style='mso-spacerun:yes'> </span>5</span> <span
style='mso-spacerun:yes'> </span>| <span
style='mso-spacerun:yes'> </span>3 <span
style='mso-spacerun:yes'> </span>| <span
style='mso-spacerun:yes'> </span>8 <span
style='mso-spacerun:yes'> </span>|<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>//<span
style='mso-spacerun:yes'> </span>|-------------------------|<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>//<span
style='mso-spacerun:yes'> </span><span class=GramE>| <span
style='mso-spacerun:yes'> </span>1</span> <span
style='mso-spacerun:yes'> </span>| <span
style='mso-spacerun:yes'> </span>0 <span
style='mso-spacerun:yes'> </span>| <span
style='mso-spacerun:yes'> </span>2 <span
style='mso-spacerun:yes'> </span>|<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>//<span
style='mso-spacerun:yes'> </span>|-------------------------|<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>//<span
style='mso-spacerun:yes'> </span><span class=GramE>| <span
style='mso-spacerun:yes'> </span>7</span> <span
style='mso-spacerun:yes'> </span>| <span
style='mso-spacerun:yes'> </span>4 <span
style='mso-spacerun:yes'> </span>| <span
style='mso-spacerun:yes'> </span>6 <span
style='mso-spacerun:yes'> </span>|<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>//<span
style='mso-spacerun:yes'> </span>-----------------------<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=DE style='font-size:9.0pt;
mso-bidi-font-size:10.0pt;font-family:Arial;mso-ansi-language:DE'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>This searching method works,
but not always. Sometime, it stops at somewhere, but the contour is<o:p></o:p></span></font></p>
<p class=MsoNormal><span class=GramE><font size=1 face=Arial><span lang=EN-GB
style='font-size:9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>not</span></font></span><font
size=1 face=Arial><span lang=EN-GB style='font-size:9.0pt;mso-bidi-font-size:
10.0pt;font-family:Arial'> completed. And the stopped point is not different as
other found points. I even enlarge the <o:p></o:p></span></font></p>
<p class=MsoNormal><span class=GramE><font size=1 face=Arial><span lang=EN-GB
style='font-size:9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>neighbourhood</span></font></span><font
size=1 face=Arial><span lang=EN-GB style='font-size:9.0pt;mso-bidi-font-size:
10.0pt;font-family:Arial'> to a bigger circle. But it is still not stable. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>Maybe my question is beyond
the range of this <span class=SpellE>itk</span> <span class=SpellE>maillist</span>.
I’m really upset with this problem.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>Who can give me some
suggestions?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>Thanks a lot!<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'>Jiang<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=1 face=Arial><span lang=EN-GB style='font-size:
9.0pt;mso-bidi-font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
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