ing the difference</span>
0006 <span class="comment">%  between the new first frame and the old one. For this adaptation, the sample</span>
0007 <span class="comment">%  frequency must be non-null.</span>
0008 <span class="comment">%  The acquisition is represented by the handle H, obtained by the use of a</span>
0009 <span class="comment">%  btk* function.</span>
0010 <span class="comment">%</span>
0011 <span class="comment">%  BTKCROPACQUISITION(H, STARTAT, NUMFRAMES) keeps NUMFRAMES frames starting</span