>(</span><span class="n">I</span><span class="p">)</span> <span class="p">;</span> <span class="n">hold</span> <span class="n">on</span> <span class="p">;</span> <span class="n">axis</span> <span class="n">equal</span> <span class="n">off</span><span class="p">;</span> <span class="n">colormap</span> <span class="n">gray</span> <span class="p">;</span>
<span class="p">[</span><span class="n">c</span><span class="p">,</span><span class="n">h</span><span class="p">]=</span><span class="n">contour</span><span 