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<TITLE>Median filters</TITLE>
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<font size="+2" color="green">Median filters</font></P>
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<TD width="15%" valign="top"><B>Syntax</B>:</TD>
<TD width="85%" valign="top"><CODE>
FILTER x f npt<br />
FILTER\MEDIAN x f npt</CODE>
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<P>
The default is <CODE>\MEDIAN</CODE>, that is, to use a running median filter. The data array,
<CODE>x</CODE>, is filtered through a window <CODE>npt</CODE> points in width.
<CODE>npt</CODE> must be <CODE>>2</CODE>.</P>
<P>
The median filter is particularly good at removing 'spikes' from data. The
median filter moves a window over the data and outputs the median value of
the data points within each window placement. The window butts up against
the ends. When <CODE>npt</CODE> is even, the
filter is applied twice, first skewed left then skewed right, and the
results are averaged.</P>
<P>
<a href="filtercommand.htm"><img src="../shadow_left.gif">
<font size="+1" color="olive">FILTER command</font></a><br />
<a href="mean.htm"><img src="../shadow_right.gif">
<font size="+1" color="olive">Mean filters</font></a></P>
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