title: using compose panorama without estimateTransform
body: <p>I try to use compose panorama without estimateTransform...
  It works very well with the estimateTransform</p>
  
  <pre><code>stitcher.estimateTransform(imgs);
  stitcher.composePanorama(pano);
  </code></pre>
  
  <p>But I found another way to compute the imagerotation etc, thats why I want to use composepanorama like this:</p>
  
  <pre><code>vector&lt;Mat&gt; imgs;
  
   imgs.push_back(image1);
   imgs.push_back(image2);
   imgs.push_back(image3);
   imgs.push_back(image4);
   imgs.push_back(image5);
   imgs.push_back(image6);   
  
  stitcher.composePanorama(Inputimages,pano);
  </code></pre>
  
  <p>But everytime I trie this I get this error:</p>
  
  <pre><code>Error: Assertion failed (imgs.size() == imgs_.size()) in unknown function, file ......\src\opencv\modules\stitching\src\stitcher.cpp , line 128
  </code></pre>