on
than the regions one level below or above. Note that due to the
discrete nature of the image, the region below / above may be
coincident with the actual region, in which case the region is still
deemed maximal.</p>

<p>However, even if an extremal region is maximally stable, it might be
rejected if:</p>

<ul>
<li>it is too big (see the parameter <code/>MaxArea</code>);</li>
<li>it is too small (see the parameter <code/>MinArea</code>);</li>
<li>it is too unstable (see the parameter <code/>MaxVariation</c