title: How to crop a CvMat in OpenCV?
body: <p>I have an image converted in a <code>CvMat</code> Matrix say <code>CVMat source</code>. Once I get a region of interest from <code>source</code> I want the rest of the algorithm to be applied to that region of interest only. For that I think I will have to somehow crop the <code>source</code> matrix which I am unable to do so. Is there a method or a function that could crop a <code>CvMat</code> Matrix and return another cropped <code>CvMat</code> matrix? thanks.</p>