ses the local extrema trace of the multiscale Laplacian
operator to detect features in scale and space (as in SIFT).</li>

<li>The <em>Hessian operator</em> uses the local extrema of the
mutli-scale determinant of Hessian operator.</li>

<li>The <em>Hessian Laplace</em> detector uses the extrema of the
multiscale determinant of Hessian operator for localisation in space,
and the extrema of the multiscale Laplacian operator for localisation
in scale.</li>

<li><em>Harris Laplace</em> uses the multiscale Harr