Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/M_FLE|ALGORITHM">ALGORITHM</a><hr>
<H4>LEE FILTER</H4>
Speckle noise in SAR images is generally assumed a multiplicative
error model. In the Lee filter, the multiplicative model is first
approximated by a linear model. Then the minimum mean square error
criterion is applied to the linear model.<p>
The resulting grey level value R for the smoothed pixel is:
<P>
<PRE>
       R = Ic * W + Im * (1 - W)
</PRE>
where:
<P>
<PRE>
       W   =   1 - Cu^2/Ci^2
       Cu  =   SQRT(1/NLOOK)
       Ci  =   S / Im
       Ic  =   center pixel pixel of filter window
       Im  =   mean value of intensity within window
       S   =   standard deviation of intensity within window
</PRE>
The Cu above is the estimated noise variation coefficient. 
Ci is the image variation coefficient. W is a weighting function.
<P>
<hr>
Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/M_FLE|ALGORITHM">ALGORITHM</a><br>
<a href="http://www.pcigeomatics.com/dev_corner/pcihlp_gateway.html">About PCI Help Gateway</a>