Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/IHS">IHS</a><hr>
<H3>DETAILS</H3>
IHS converts red, green, and blue image channels to intensity, hue,
and saturation image channels. This is useful for enhancing and
controlling the output colours for the given set of input
red/green/blue imagery.<p>
IHS is used by the FUSE and FUSEPCT procedures to perform data
fusion of colour imagery with a black-and-white image.<p>
CYLINDER was the original method used by the IHS and RGB programs in
older PCI software releases (Version 6.0.1 and before). The Hexcone
model is used by many commercial image processing software packages.
One model can produce more visually pleasing results than the other,
depending on the circumstances. The Hexcone model runs about 15%
faster than the Cylinder model.<p>
Input channels may be used as output channels, in which case the
original input image is overwritten by the output image. Duplicate
channel numbers can be specified for input channels, but NOT for
output channels.<p>
Only the following configurations of input and output channel types
are allowed:
<P>
<PRE>
 Output channels (DBOC)      Input channels (DBIC)

 Scaled results:  8-bit      8-bit
 Exact  results:  16/32-bit  any type
</PRE>
When all input and output channels are 8-bit, the output data are
linearly scaled between 0 and 255. When the three output channels
are any combination of 16-bit signed, 16-bit unsigned or 32-bit
real, then any type of input channels are allowed and the output
values are not scaled. If output channels are 16-bit, then unscaled
values are truncated to integer values.<p>
The RGB program can be used to convert intensity, hue, and
saturation channels output by IHS back to red, green, and blue
channels.
<P>
<hr>
Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/IHS">IHS</a><br>
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