map.dat \
  | awk '{print(($1+$2+$3)/3/255)}' |"
read image grayscale
close
</font></PRE>
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<p>

<!-- @node   Read Image Mask, Read Image, Read Image Grayscale, Read -->
<a name="ReadImageMask" ></a>
<h4>9.3.33.6: `<font color="#82140F"><code>read image mask</code></font>'</h4>

<!-- latex: \index{read image mask} -->

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<PRE>
<font color="#82140F">
`read image mask rasterfile|{.rows. .cols.}'
</font></PRE>
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