le statistical centering and removes outliers</p></li>
<li><p><strong>Sharpening</strong> - This applies 2D convolution using a harpening filter: <code class="docutils literal notranslate"><span class="pre">original</span> <span class="pre">+</span> <span class="pre">(original</span> <span class="pre">?</span> <span class="pre">blurred)</span> <span class="pre">×</span> <span class="pre">amount</span></code></p></li>
<li><p><strong>Quality rejection</strong> - Using simple heuristics, if the image is found