pi/sift.html">SIFT</a> as well as multi-scale conern
(Harris-Laplace), and blob (Hessian-Laplace and Hessian-Hessian)
detectors. For example applications, see also
the <a shape="rect" href="sift.html">SIFT tutorial</a>.</p>

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<h1 id="tut.covdet.extract">Extracting frames and descriptors</h1>
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<p>The first example shows how to
use <code/><a href=../matlab/vl_covdet.html