timeofday];
        my $td = tv_interval $t0, $t1;
        print &quot;TIME: bit_plane(): $td\n&quot;;</code></pre>

<h2 id="data-one_color-rgb_data-color">$data = one_color($rgb_data,$color)</h2>

<p>The function <code>one_color()</code> creates a RGB image with one color channel set to its value, but the two other colors are set to zero. This is done to better visualize the splitted channels of a RGB image.</p>

<pre><code> sub one_color {
        my ($img,$color) = @_;   # $color = red|green|blue

      