pan class="c1"># this operation.</span>
    <span class="n">cc</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">convolve</span><span class="p">(</span><span class="n">np</span><span class="o">.</span><span class="n">flip</span><span class="p">(</span><span class="n">x</span><span class="p">),</span> <span class="n">y</span><span class="p">)</span>

    <span class="c1"># restrict the cross correlation result to just the relevant values</span>
    <span class="