s</h3><ul><li class="level1"><a href="#id-579">Types of frames</a></li>
<li class="level1"><a href="#id-595">Features frames as geometric frames</a></li>
<li class="level1"><a href="#id-604">Oriented frames</a></li>
<li class="level1"><a href="#id-642">Converting between frame types</a></li>
</ul>
</div><!-- Table of contents -->


<p>This page introduces the notion of local feature frame used
extensively in VLFeat.  A <em>feature frame</em> or simply
a <em>frame</em>, is a geometric object such as a point,