surface using an optimal
signal value. Other rendering can be plotted with e.g.:<br>
<pre style="margin-left: 40px;">&gt;&gt; <span style="color: rgb(51, 102, 255);">plot</span>(c,<span style="color: rgb(204, 51, 204);">'surf median'</span>);    <span style="font-style: italic;">% plots the c=median(signal) isosurface, same as plot(d) [default]</span><br>&gt;&gt; <span style="color: rgb(51, 102, 255);">plot</span>(c,<span style="color: rgb(204, 51, 204);">'surf mean'</span>);      <span style="font-style: i