Why KeyPoint "detector" and "extractor" are different operation? <p>Bascially you have first to do a:</p> <pre><code>SurfFeatureDetector surf(400); surf.detect(image1, keypoints1); </code></pre> <p>And then a:</p> <pre><code>surfDesc.compute(image1, keypoints1, descriptors1); </code></pre> <p>Why detect and comput are 2 different operation?<br> Doing the computing after the detect doesn't make redundance loops?</p> <p>I found myself that <code>.compute</code> is the most expensive in my application. </p> <pre><code>.detect </code></pre> <p>is done in <strong>0.2secs</strong></p> <pre><code>.compute </code></pre> <p>Takes <strong>~1sec</strong>. Is there any way to speed up <code>.compute</code> ?</p>