 to add new 
borders by interactively clicking on the image segments.</p>
<p>If the user creates one path (<code>incline = FALSE</code>), the argument 
<code>del</code> is used to remove ring borders. If the user creates two paths 
(<code>incline = TRUE</code>), arguments <code>del.u</code> and <code>del.l</code> are used 
to remove ring borders.</p>
<p>If <code>add = TRUE</code>, graphics windows opened by <code><a href='ring_detect.html'>ring_detect</a></code>
will be activated sequentially. When a graphi