"p">)</span> <span class="p">;</span>

<span class="n">r_</span> <span class="p">=</span> <span class="n">load</span><span class="p">(</span><span class="n">p_sed</span><span class="p">,</span><span class="s">&#39;-ASCII&#39;</span><span class="p">)</span><span class="o">&#39;</span><span class="p">;</span>
<span class="c">% note: bright-on-dark region seeds are negative</span>
<span class="n">r_</span> <span class="p">=</span> <span class="n">r_</span> <span class="o">+</span> <span class="nb">sign</span><