title: Optimisation of zxing.net QR decode
body: <p>I am having great success with zxing on .NET and trying to get the best speed for decoding QR Barcodes (I have a lot to do -- 1.8M). The code I am using (well bits of it):</p>
  
  <pre><code>// Create Barcode decoder
  BarcodeReader q = new BarcodeReader();
  q.PossibleFormats = new List&lt;BarcodeFormat&gt;();
  q.PossibleFormats.Add(BarcodeFormat.QR_CODE);
  q.AutoRotate = true; // Not necessary for QR?
  q.TryHarder = false;
  
  // Decode result
  Result[] r = q.DecodeMultiple(imageFile);
  </code></pre>
  
  <p>My code is a little smarter in that it is in a loop and tries harder if it doesn't find it the first time.</p>
  
  <p>Is there a way to add a zone, ROI or smaller area to speed up the detection?</p>
  
  <p>Any other recommendations to improve performance?</p>